1.
Massachusetts
–
It is bordered by the Atlantic Ocean to the east, the states of Connecticut and Rhode Island to the south, New Hampshire and Vermont to the north, and New York to the west. The state is named for the Massachusett tribe, which inhabited the area. The capital of Massachusetts and the most populous city in New England is Boston, over 80% of Massachusetts population lives in the Greater Boston metropolitan area, a region influential upon American history, academia, and industry. Originally dependent on agriculture, fishing and trade, Massachusetts was transformed into a manufacturing center during the Industrial Revolution, during the 20th century, Massachusetts economy shifted from manufacturing to services. Modern Massachusetts is a leader in biotechnology, engineering, higher education, finance. Plymouth was the site of the first colony in New England, founded in 1620 by the Pilgrims, in 1692, the town of Salem and surrounding areas experienced one of Americas most infamous cases of mass hysteria, the Salem witch trials. In 1777, General Henry Knox founded the Springfield Armory, which during the Industrial Revolution catalyzed numerous important technological advances, in 1786, Shays Rebellion, a populist revolt led by disaffected American Revolutionary War veterans, influenced the United States Constitutional Convention. In the 18th century, the Protestant First Great Awakening, which swept the Atlantic World, in the late 18th century, Boston became known as the Cradle of Liberty for the agitation there that led to the American Revolution. The entire Commonwealth of Massachusetts has played a commercial and cultural role in the history of the United States. Before the American Civil War, Massachusetts was a center for the abolitionist, temperance, in the late 19th century, the sports of basketball and volleyball were invented in the western Massachusetts cities of Springfield and Holyoke, respectively. Many prominent American political dynasties have hailed from the state, including the Adams, both Harvard University and the Massachusetts Institute of Technology, also in Cambridge, have been ranked among the most highly regarded academic institutions in the world. Massachusetts public school students place among the top nations in the world in academic performance, the official name of the state is the Commonwealth of Massachusetts. While this designation is part of the official name, it has no practical implications. Massachusetts has the position and powers within the United States as other states. Massachusetts was originally inhabited by tribes of the Algonquian language family such as the Wampanoag, Narragansett, Nipmuc, Pocomtuc, Mahican, and Massachusett. While cultivation of crops like squash and corn supplemented their diets, villages consisted of lodges called wigwams as well as longhouses, and tribes were led by male or female elders known as sachems. Between 1617 and 1619, smallpox killed approximately 90% of the Massachusetts Bay Native Americans, the first English settlers in Massachusetts, the Pilgrims, arrived via the Mayflower at Plymouth in 1620, and developed friendly relations with the native Wampanoag people. This was the second successful permanent English colony in the part of North America that later became the United States, the event known as the First Thanksgiving was celebrated by the Pilgrims after their first harvest in the New World which lasted for three days
Massachusetts
–
A portion of the north-central
Pioneer Valley in
Sunderland
Massachusetts
–
Flag
Massachusetts
–
Many coastal areas in Massachusetts provide breeding areas for species such as the
piping plover
Massachusetts
–
The
Mayflower in Plymouth Harbor by
William Halsall (1882). The
Pilgrims were a group of
Puritans who founded
Plymouth in 1620.
2.
Pollutant
–
A pollutant is a substance or energy introduced into the environment that has undesired effects, or adversely affects the usefulness of a resource. A pollutant may cause long- or short-term damage by changing the rate of plant or animal species, or by interfering with human amenities, comfort, health. Some pollutants are biodegradable and therefore will not persist in the environment in the long term, however the degradation products of some pollutants are themselves polluting such as the products DDE and DDD produced from degradation of DDT. Pollutants, towards which the environment has little or no absorptive capacity are called stock pollutants, stock pollutants accumulate in the environment over time. The damage they cause increases as more pollutant is emitted, stock pollutants can create a burden for future generations, by passing on damage that persists well after the ‘benefits received from incurring that damage, have been forgotten. Fund pollutants are those for which the environment has some absorptive capacity, fund pollutants do not cause damage to the environment unless the emission rate exceeds the receiving environments absorptive capacity. Fund pollutants are not destroyed, but rather converted into less harmful substances and it also encompasses ecological light pollution which describes the effect of artificial light on individual organisms and on the structure of ecosystems as a whole. Pollutants can also be defined by their zones of influence, both horizontally and vertically, the horizontal zone refers to the area that is damaged by a pollutant. Local pollutants cause damage near the emission source, regional pollutants cause damage further from the emission source. The vertical zone is referred to whether the damage is ground-level or atmospheric, surface pollutants cause damage by concentrations of the pollutant accumulating near the Earths surface Global pollutants cause damage by concentrations in the atmosphere. Pollutants can cross borders and therefore international regulations are needed for their control. The Stockholm Convention on Persistent Organic Pollutants, which entered force in 2004, is an international legally binding agreement for the control of persistent organic pollutants. Pollutant Release and Transfer Registers are systems to collect and disseminate information on releases and transfers of toxic chemicals from industrial. The National Emissions Standards for Hazardous Air Pollutants are additional emission standards that are set by EPA for toxic air pollutants, under the Clean Water Act, EPA promulgated national standards for municipal sewage treatment plants, also called publicly owned treatment works, in the Secondary Treatment Regulation. National standards for industrial dischargers are called Effluent guidelines and New Source Performance Standards, in addition, the Act requires states to publish water quality standards for individual water bodies to provide additional protection where the national standards are insufficient. The Resource Conservation and Recovery Act regulates the management, transport and disposal of solid waste, hazardous waste. A tank or piping network that has at least 10 percent of its volume underground is known as a storage tank. They often store substances such as petroleum, that are harmful to the environment should it become contaminated
Pollutant
–
Surface runoff, also called
nonpoint source pollution, from a farm field in Iowa, United States during a rain storm. Topsoil as well as farm fertilizers and other potential pollutants run off unprotected farm fields when heavy rains occur.
3.
Wastewater
–
Wastewater, also written as waste water, is any water that has been adversely affected in quality by anthropogenic influence. Wastewater can originate from a combination of domestic, industrial, commercial or agricultural activities, surface runoff or stormwater, municipal wastewater is usually conveyed in a combined sewer or sanitary sewer, and treated at a wastewater treatment plant. Treated wastewater is discharged into receiving water via an effluent pipe, wastewaters generated in areas without access to centralized sewer systems rely on on-site wastewater systems. These typically comprise a septic tank, drain field, and optionally an on-site treatment unit, the management of wastewater belongs to the overarching term sanitation, just like the management of human excreta, solid waste and stormwater. Sewerage is the infrastructure, including pipes, pumps, screens. Soluble organic material such as urea, fruit sugars, soluble proteins, drugs, pharmaceuticals, inorganic particles such as sand, grit, metal particles, ceramics, etc. Soluble inorganic material such as ammonia, road-salt, sea-salt, cyanide, hydrogen sulfide, thiocyanates, thiosulfates, animals such as protozoa, insects, arthropods, small fish, etc. Macro-solids such as napkins, nappies/diapers, condoms, needles, childrens toys, dead animals or plants. Gases such as sulfide, carbon dioxide, methane, etc. Emulsions such as paints, adhesives, mayonnaise, hair colorants, emulsified oils, toxins such as pesticides, poisons, herbicides, etc. The result is that the content of the water will be decreased. Those biochemical reactions create what is measured in the laboratory as the oxygen demand. Such chemicals are also liable to be broken down using strong oxidizing agents, both the BOD and COD tests are a measure of the relative oxygen-depletion effect of a waste contaminant. Both have been adopted as a measure of pollution effect. The BOD test measures the demand of biodegradable pollutants whereas the COD test measures the oxygen demand of oxidizable pollutants. The so-called 5-day BOD measures the amount of oxygen consumed by oxidation of waste contaminants in a 5-day period. The total amount of consumed when the biochemical reaction is allowed to proceed to completion is called the Ultimate BOD. Because the Ultimate BOD is so time consuming, the 5-day BOD has been almost universally adopted as a measure of pollution effect
Wastewater
–
Grand Coulee Dam
Wastewater
–
Wastewater treatment plant in
Cuxhaven, Germany
Wastewater
–
Industrial wastewater effluent with neutralized pH from tailing runoff. Taken in Peru.
Wastewater
–
Major types
4.
Sewage
–
Sewage is a water-carried waste, in solution or suspension, that is intended to be removed from a community. Also known as domestic or municipal wastewater, it is characterized by volume or rate of flow, physical condition, chemical and toxic constituents and it consists mostly of greywater, blackwater, soaps and detergents, and toilet paper. Whether it also contains surface runoff depends on the design of sewer system, all sewage ends up back in the environment, by any of several routes. A basic distinction in its route is whether it undergoes sewage treatment to mitigate its effect on the environment before arriving there, Sewage usually travels from a buildings plumbing either into a sewer, which will carry it elsewhere, or into an onsite sewage facility. Whether it is combined with surface runoff in the sewer depends on the sewer design, before the 20th century, sewers usually discharged into a body of water such as a stream, river, lake, bay, or ocean. There was no treatment, so the breakdown of the waste was left to the ecosystem. Today, the goal is that sewers route their contents to a treatment plant rather than directly to a body of water. In many countries, this is the norm, in developing countries. Thus other goals of modern sewage routing include handling surface runoff separately from sewage, handling greywater separately from toilet waste, proper collection and safe, nuisance-free disposal of the liquid wastes of a community are legally recognized as a necessity in an urbanized, industrialized society. In many developing countries the bulk of domestic and industrial wastewater is discharged without any treatment or after primary treatment only, the term sewage is nowadays regarded as an older term and is being more and more replaced by wastewater. In general American English usage, the sewage and sewerage mean the same thing. Both words are descended from Old French assewer, derived from the Latin exaquare, in American technical and professional English usage, sewerage refers to the infrastructure that conveys sewage. Wastes that result from an industrial processes such as the production or manufacture of goods are classed as industrial wastewater, surface runoff, also known as storm flow or overland flow, is that portion of precipitation that runs rapidly over the ground surface to a defined channel. Sewage is a mixture of chemicals, with many distinctive chemical characteristics. These include high concentrations of ammonium, nitrate, phosphorus, high conductivity, high alkalinity, the organic matter of sewage is measured by determining its biological oxygen demand or the chemical oxygen demand. Sewage also contains the nutrients nitrogen and phosphorus, Sewage can be monitored for both disease-causing and benign organisms with a variety of techniques. Traditional techniques involve filtering, staining, and examining samples under a microscope, sequencing DNA from an environmental sample is known as metagenomics. Sewage has also analyzed to determine relative rates of use of prescription
Sewage
–
Raw sewage arriving at a
sewage treatment plant in Syria
Sewage
–
Greywater samples before and after treatment in a
constructed wetland in Peru
Sewage
–
A medieval waste pipe in
Stockholm Old Town formerly deposited sewage on the street to be flushed away by rain.
Sewage
–
Major types
5.
Effluent
–
Effluent is an outflowing of water or gas from a natural body of water, or from a manmade structure. Effluent, in engineering, is the stream exiting a chemical reactor, effluent is defined by the United States Environmental Protection Agency as wastewater - treated or untreated - that flows out of a treatment plant, sewer, or industrial outfall. Generally refers to wastes discharged into surface waters, the Compact Oxford English Dictionary defines effluent as liquid waste or sewage discharged into a river or the sea. Effluent in the sense is in general considered to be water pollution. An effluent sump pump, for instance, pumps waste from toilets installed below a main sewage line, similar to wastewater produced in different establishments, industries, and facilities. This cleaner effluent is used to feed the bacteria in biofilters. In the context of a power station, the output of the cooling system may be referred to as the effluent cooling water. Effluent only refers to liquid discharge, in sugar beet processing, effluent is often settled in water tanks that allow the mud-contaminated water to settle. The mud sinks to the bottom, leaving the top section of water clear, free to be pumped back into the river or be reused in the process again. The Mississippi Rivers effluent of fresh water is so massive that a plume of water is detectable by the naked eye from space, even as it rounds Florida
Effluent
–
Wastewater discharge
6.
Sewage sludge
–
Sewage sludge refers to the residual, semi-solid material that is produced as a by-product during sewage treatment of industrial or municipal wastewater. The term septage is also referring to sludge from wastewater treatment but is connected to simple on-site sanitation systems. When fresh sewage or wastewater enters a primary settling tank, approximately 50% of the solid matter will settle out in an hour. This collection of solids is known as raw sludge or primary solids and is said to be fresh before anaerobic processes become active, the sludge will become putrescent in a short time once anaerobic bacteria take over, and must be removed from the sedimentation tank before this happens. This is accomplished in one of two ways, after digesting for an extended period, the result is called digested sludge and may be disposed of by drying and then landfilling. Biosolids is an often used in conjunction with reuse of sewage sludge after sewage sludge treatment. Biosolids can be defined as organic wastewater solids that can be reused after stabilization processes such as anaerobic digestion, opponents of sewage sludge reuse reject this term as a public relations term. Class A sludge is typically dried and pasteurized, and is known as exceptional quality. Class B includes all sludge not classified as Class A, Class B sludge is typically undigested and is volatile. Both classes of sludge may still contain radioactive or pharmaceutical wastes, the amount of sewage sludge produced is proportional to the amount and concentration of wastewater treated, and it also depends on the type of wastewater treatment process used. It can be expressed as kg dry solids per cubic metre of wastewater treated, the total sludge production from a wastewater treatment process is the sum of sludge from primary settling tanks plus excess sludge from the biological treatment step. For example, primary sedimentation produces about 110–170 kg/ML of so-called primary sludge, the sludge production is expressed as kg of dry solids produced per ML of wastewater treated, one mega litre is 103 m3. United States municipal wastewater treatment plants in 1997 produced about 7.7 million dry tons of sewage sludge, as of 2002, about 60% of all sewage sludge was applied to land as a soil amendment and fertilizer for growing crops. Bacteria in Class A sludge products can actually regrow under certain environmental conditions, Pathogens could easily remain undetected in untreated sewage sludge. Pathogens are not a significant health issue if sewage sludge is properly treated, micro-pollutants can become concentrated in sewage sludge. Each of these disposal options comes with a myriad of potential — and in some cases proven — human health, high levels of sterols and other hormones have been detected, with averages in the range of up to 1,000,000 µg/kg sludge. One of the concerns in the treated sludge is the concentrated metals content. Leaching methods can be used to reduce the content and meet the regulatory limit
Sewage sludge
–
Sludge
Sewage sludge
–
Desiccation cracks in dried sludge, the hard final remains from a
sewage plant.
7.
Sewage sludge treatment
–
Sewage sludge treatment describes the processes used to manage and dispose of sewage sludge produced during sewage treatment. Sludge is mostly water with lesser amounts of material removed from liquid sewage. Primary sludge includes settleable solids removed during treatment in primary clarifiers. Secondary sludge separated in secondary clarifiers includes treated sewage sludge from secondary treatment bioreactors, sludge treatment is focused on reducing sludge weight and volume to reduce disposal costs, and on reducing potential health risks of disposal options. Water removal is the means of weight and volume reduction, while pathogen destruction is frequently accomplished through heating during thermophilic digestion, composting. The choice of a treatment method depends on the volume of sludge generated. Coarse primary solids and secondary sewage sludge may include toxic chemicals removed from liquid sewage by sorption onto solid particles in clarifier sludge, reducing sludge volume may increase the concentration of some of these toxic chemicals in the sludge. In fact, biosolids are defined as organic wastewater solids that can be reused after stabilization processes such as anaerobic digestion, the term biosolids was introduced by the Water Environment Federation in the U. S. in 1998. Thickening is often the first step in a treatment process. Sludge from primary or secondary clarifiers may be stirred to form larger, primary sludge may be thickened to about 8 or 10 percent solids, while secondary sludge may be thickened to about 4 percent solids. Thickeners often resemble a clarifier with the addition of a stirring mechanism, thickened sludge with less than ten percent solids may receive additional sludge treatment while liquid thickener overflow is returned to the sewage treatment process. Water content of sludge may be reduced by centrifugation, filtration, and/or evaporation to reduce costs of disposal. Centrifugation may be a step to reduce sludge volume for subsequent filtration or evaporation. Filtration may occur through underdrains in a sand drying bed or as a mechanical process in a belt filter press. Filtrate and centrate are typically returned to the treatment process. After dewatering sludge may be handled as a solid containing 50 to 75 percent water, dewatered sludges with higher moisture content are usually handled as liquids. This liquid requires further treatment as it is high in nitrogen and phosphorus, the treatment can take place in the sewage treatment plant itself or as a separate process. One method for treating sludge dewatering streams is by using a process that is used for phosphorus recovery
Sewage sludge treatment
–
Dried, anaerobically digested sludge.
Sewage sludge treatment
–
A sewage sludge thickener.
Sewage sludge treatment
–
Sludge incineration process schematic (note the emphasis on air quality control).
Sewage sludge treatment
–
Sewage sludge after drying in a sludge drying bed.
8.
Wastewater treatment
–
The latter is called water reclamation and implies avoidance of disposal by use of treated wastewater effluent for various purposes. Treatment means removing impurities from water being treated, and some methods of treatment are applicable to water and wastewater. The physical infrastructure used for treatment is called a wastewater treatment plant. By-products from wastewater treatment plants, such as screenings, grit, if the wastewater is predominantly from municipal sources it is called sewage and its treatment is called sewage treatment. Although disposal or reuse occurs after treatment, it must be considered first, since disposal or reuse are the objectives of wastewater treatment, disposal or reuse options are the basis for treatment decisions. Acceptable impurity concentrations may vary with the type of use or location of disposal, ocean disposal is subject to international treaty requirements. International treaties may also regulate disposal into rivers crossing international borders, water bodies entirely within the jurisdiction of a single nation may be subject to regulations of multiple local governments. Acceptable impurity concentrations may vary widely among different jurisdictions for disposal of wastewater to evaporation ponds, infiltration basins, phase separation transfers impurities into a non-aqueous phase. Phase separation may occur at points in a treatment sequence to remove solids generated during oxidation or polishing. Grease and oil may be recovered for fuel or saponification, solids often require dewatering of sludge in a wastewater treatment plant. Disposal options for dried solids vary with the type and concentration of impurities removed from water, production of waste brine, however, may discourage wastewater treatment removing dissolved inorganic solids from water by methods like ion exchange, reverse osmosis, and distillation. Solids and non-polar liquids may be removed from wastewater by gravity when density differences are sufficient to overcome dispersion by turbulence, gravity separation of solids is the primary treatment of sewage, where the unit process is called primary settling tanks or primary sedimentation tanks. It is also used for the treatment of other wastewaters. Solids that are heavier than water will accumulate at the bottom of quiescent settling basins, more complex clarifiers also have skimmers to simultaneously remove floating grease like soap scum and solids like feathers or wood chips. Containers like the API oil-water separator are specifically designed to separate non-polar liquids, other types of water filters remove impurities by chemical or biological processes described below. Oxidation reduces the oxygen demand of wastewater, and may reduce the toxicity of some impurities. Secondary treatment converts some impurities to carbon dioxide, water, chemical oxidation is widely used for disinfection. Secondary treatment by biochemical oxidation of dissolved and colloidal organic compounds is used in sewage treatment and is applicable to some agricultural and industrial waste waters
Wastewater treatment
–
Clarifiers are widely used for wastewater treatment.
Wastewater treatment
–
Primary settling tank of wastewater treatment plant in Dresden-Kaditz, Germany
Wastewater treatment
–
Aeration tank of an
activated sludge process at the wastewater treatment plant in Dresden-Kaditz, Germany
Wastewater treatment
–
Overview of the wastewater treatment plant of Antwerpen-Zuid, located in the south of the agglomeration of Antwerp (Belgium)
9.
Sanitary sewer
–
A sanitary sewer or foul sewer is an underground carriage system specifically for transporting sewage from houses and commercial buildings through pipes to treatment or disposal. Sanitary sewers are part of a system called sewerage or sewage system. Sewage may be treated to water pollution before discharge to surface waters. Sanitary sewers serving industrial areas also carry industrial wastewater, separate sanitary sewer systems are designed to transport sewage alone. In municipalities served by sewers, separate storm drains may be constructed to convey surface runoff directly to surface waters. Sanitary sewers are distinguished from combined sewers, which combine sewage with stormwater runoff in the same pipe, sanitary sewer systems are considered beneficial because they avoid combined sewer overflows. To overcome these disadvantages, some cities built separate sanitary sewers to collect only municipal wastewater, the decision between a combined sewer system or two separate systems is mainly based on need for sewage treatment and cost of providing treatment during heavy rain events. Many cities with combined sewer systems built prior to sewage treatment have not replaced those sewer systems, in the developed world, sewers are pipes from buildings to one or more levels of larger underground trunk mains, which transport the sewage to sewage treatment facilities. Vertical pipes, usually made of precast concrete, called manholes, depending upon site application and use, these vertical pipes can be cylindrical, eccentric or concentric. The manholes are used for access to the pipes for inspection and maintenance. They also facilitate vertical and horizontal angles in otherwise straight pipelines, pipes conveying sewage from an individual building to a common gravity sewer line are called laterals. Branch sewers typically run under streets receiving laterals from buildings along that street, larger cities may have sewers called interceptors receiving flow from multiple trunk sewers. Design and sizing of sanitary sewers considers the population to be served over the life of the sewer, per capita wastewater production. Commercial and industrial flows are considered, but diversion of surface runoff to storm drains eliminates wet weather flow peaks of inefficient combined sewers. Pumps may be necessary where gravity sewers serve areas at lower elevations than the treatment plant. A lift station is a gravity sewer sump with a pump to lift accumulated sewage to a higher elevation, the pump may discharge to another gravity sewer at that location or may discharge through a pressurized force main to some distant location. Most of the solids are removed by the tanks, so the treatment plant can be much smaller than a typical plant. In addition, because of the vast reduction in solid waste, because the wastestream is pressurized, they can be laid just below the ground surface along the lands contour
Sanitary sewer
–
PVC Sanitary Sewer Installation. Sanitary sewers are sized to carry the amount of sewage generated by the collection area. Sanitary sewers are much smaller than combined sewers designed to also carry
surface runoff.
Sanitary sewer
–
Schematic of a conventional sanitary sewer to convey
blackwater and
greywater from households to a centralized
sewage treatment facility
Sanitary sewer
–
A
manhole cover for a sanitary sewer access point.
Sanitary sewer
–
View looking down into an open manhole showing two converging sanitary sewer lines. The larger line enters from the right and changes direction within the manhole to exit from the top of the photo. A smaller line enters from the bottom of the photo under the access steps. The concrete floor of the manhole has channels to minimize accumulation of solids.
10.
Industrial wastewater treatment
–
Industrial wastewater treatment covers the mechanisms and processes used to treat wastewater that is produced as a by-product of industrial or commercial activities. After treatment, the industrial wastewater may be reused or released to a sanitary sewer or to a surface water in the environment. Most industries produce some wastewater although recent trends in the world have been to minimise such production or recycle such wastewater within the production process. However, many industries remain dependent on processes that produce wastewaters, a range of industries manufacture or use complex organic chemicals. These include pesticides, pharmaceuticals, paints and dyes, petrochemicals, detergents, plastics, paper pollution, treatment facilities that do not need control of their effluent typically opt for a type of aerobic treatment, i. e. aerated lagoons. Fossil-fuel power stations, particularly coal-fired plants, are a source of industrial wastewater. Many of these plants discharge wastewater with significant levels of such as lead, mercury, cadmium and chromium, as well as arsenic, selenium. Wastewater streams include flue-gas desulfurization, fly ash, bottom ash, plants with air pollution controls such as wet scrubbers typically transfer the captured pollutants to the wastewater stream. Ash ponds, a type of surface impoundment, are a widely used treatment technology at coal-fired plants and these ponds use gravity to settle out large particulates from power plant wastewater. This technology does not treat dissolved pollutants, power stations use additional technologies to control pollutants, depending on the particular wastestream in the plant. These include dry ash handling, closed-loop ash recycling, chemical precipitation, biological treatment, processing of food from raw materials requires large volumes of high grade water. Vegetable washing generates waters with high loads of particulate matter and some dissolved organic matter, animal slaughter and processing produces very strong organic waste from body fluids, such as blood, and gut contents. This wastewater is contaminated by significant levels of antibiotics and growth hormones from the animals. Processing food for sale produces wastes generated from cooking which are rich in plant organic material and may also contain salt, flavourings, colouring material. Very significant quantities of oil or fats may also be present, the production of iron from its ores involves powerful reduction reactions in blast furnaces. Cooling waters are inevitably contaminated with products especially ammonia and cyanide, production of coke from coal in coking plants also requires water cooling and the use of water in by-products separation. The conversion of iron or steel sheet, wire or rods requires hot. Contaminants include hydraulic oils, tallow and particulate solids, the two acids commonly used are hydrochloric acid and sulfuric acid
Industrial wastewater treatment
–
Mine wastewater effluent in Peru, with neutralized pH from tailing runoff.
Industrial wastewater treatment
–
Appropriate technology
Industrial wastewater treatment
–
Major types
11.
Combined sewer
–
A combined sewer is a sewage collection system of pipes and tunnels designed to also collect surface runoff. Combined sewers can cause water pollution problems during combined sewer overflow events when wet weather flows exceed the sewage treatment plant capacity. This type of design is no longer used in building new communities. Recent archaeological discoveries have shown some of the earliest sewer systems were developed 2500 BC in the ancient city of Harappa. The primitive sewers were carved in the ground alongside buildings and this discovery reveals the conceptual understanding of waste disposal by the early civilizations. The earliest sewers were designed to carry street runoff away from inhabited areas, open sewers, consisting of gutters and urban streambeds, were common worldwide before the 20th century. Most sewage collection systems of the 19th and early to mid 20th century used single-pipe systems that collect both sewage and urban runoff from streets and roofs and this type of collection system is referred to as a combined sewer system. The rationale for combining the two was that it would be cheaper to build just a single system, most cities at that time did not have sewage treatment plants, so there was no perceived public health advantage in constructing a separate surface water sewerage or storm sewer system. When constructed, combined sewer systems were typically sized to carry three to 160 times the average dry weather sewage flows and it is generally infeasible to treat the volume of mixed sewage and surface runoff flowing in a combined sewer during peak runoff events caused by snowmelt or convective precipitation. As cities built sewage treatment plants, those plants were built to treat only the volume of sewage flowing during dry weather. These relief structures, called storm-water regulators are constructed in combined sewer systems to divert flows in excess of the design flow of the sewage treatment plant. CSO statistics may be confusing because the term may describe either the number of events or the number of relief structure locations at such events may occur. Overflow frequency and duration varies both from system to system, and from outfall to outfall, within a combined sewer system. Some CSO outfalls discharge infrequently, while others activate every time it rains, CSOs should not be confused with sanitary sewer overflows. Absence of a diversion outfall often causes sanitary sewer overflows to flood residential structures and/or flow over traveled road surfaces before reaching natural drainage channels, each storm is different in the quantity and type of pollutants it contributes. For example, storms occur in late summer, when it has not rained for a while, have the most pollutants. Pollutants like oil, grease, fecal coliform from pet and wildlife waste, in cold weather areas, pollutants from cars, people and animals also accumulate on hard surfaces and grass during the winter and then are flushed into the sewer systems during heavy spring rains. About 860 communities in the US have combined sewer systems, serving about 40 million people, CSO discharges during heavy storms can cause serious water pollution problems in these communities
Combined sewer
–
Combined Sewer System. During dry weather (and small storms), all flows are handled by the
publicly owned treatment works (POTW). During large storms, the relief structure allows some of the combined
stormwater and
sewage to be discharged untreated to an adjacent water body.
Combined sewer
–
Photo of the interior of a combined sewer in
Brighton, England.
Combined sewer
–
Most of the US combined sewer systems are in the
Northeast and
Great Lakes regions, and the
Pacific Northwest.
Combined sewer
–
The
civil engineer Joseph Bazalgette, constructed a sewerage system for London in the mid-19th century.
12.
Urban runoff
–
Urban runoff is surface runoff of rainwater created by urbanization. This runoff is a source of flooding and water pollution in urban communities worldwide. Impervious surfaces are constructed during land development, during rain storms and other precipitation events, these surfaces, along with rooftops, carry polluted stormwater to storm drains, instead of allowing the water to percolate through soil. This causes lowering of the table and flooding since the amount of water that remains on the surface is greater. Most municipal storm sewer systems discharge stormwater, untreated, to streams, rivers and this excess water can also make its way into peoples properties through basement backups and seepage through building wall and floors. Urban runoff is a cause of urban flooding, the inundation of land or property in a built-up environment caused by rainfall overwhelming the capacity of drainage systems. Where properties are built with basements, urban flooding is the cause of basement flooding. Flood flows in urban environments have been investigated relatively recently despite many centuries of flood events, some researchers mentioned the storage effect in urban areas. Several studies looked into the patterns and redistribution in streets during storm events. Some recent research considered the criteria for safe evacuation of individuals in flooded areas and these considerations ignore further the risks associated with large debris entrained by the flow motion. Roof runoff contributes high levels of organic compounds and zinc. Fertilizer use on lawns, parks and golf courses is a measurable source of nitrates. Eroding soils or poorly maintained construction sites can lead to increased sedimentation in runoff. Sedimentation often settles to the bottom of bodies and can directly affect water quality. Excessive levels of sediment in water bodies can increase the risk of infection and these high levels of nutrients can reduce oxygen and boost algae growth while limiting native vegetation growth. Limited native vegetation and excessive algae has the potential to disrupt the aquatic ecosystem due to limited light penetration, lower oxygen levels. Excessive levels of sediment and suspended solids have the potential to damage existing infrastructure as well, sedimentation can increase runoff by plugging underground injection systems, thereby increasing the amount of runoff on the surface. Increased sedimentation levels can also reduce storage behind reservoirs and this reduction of reservoir capacities can lead to increased expenses for public land agencies while also impacting the quality of water recreational areas
Urban runoff
–
Urban runoff flowing into a storm drain
Urban runoff
–
Relationship between
impervious surfaces and
surface runoff
Urban runoff
–
A creek filled with urban runoff after a storm
Urban runoff
–
Weasel Brook in
Passaic, New Jersey has been
channelized with concrete walls to control localized flooding.
13.
Piping
–
Within industry, piping is a system of pipes used to convey fluids from one location to another. The engineering discipline of piping design studies the efficient transport of fluid, industrial process piping can be manufactured from wood, fiberglass, glass, steel, aluminum, plastic, copper, and concrete. Piping systems are documented in piping and instrumentation diagrams, if necessary, pipes can be cleaned by the tube cleaning process. Plumbing pipes also remove waste in the form of sewage, fire sprinkler systems also use piping, and may transport nonpotable or potable water, or other fire-suppression fluids. Piping also has other industrial applications, which are crucial for moving raw. This evaluation is performed with the assistance of a specialized pipe stress analysis computer programs such as CAEPIPE. Steel structures will have areas of stress that may be caused by sharp corners in the design. The material with which a pipe is manufactured often forms as the basis for choosing any pipe. g, nonmetallic, e. g. tempered glass, Teflon lined, PVC, etc. Early wooden pipes were constructed out of logs that had a hole bored lengthwise through the center. Later wooden pipes were constructed with staves and hoops similar to wooden barrel construction, stave pipes have the advantage that they are easily transported as a compact pile of parts on a wagon and then assembled as a hollow structure at the job site. Wooden pipes were especially popular in regions where transport of heavy iron or concrete pipes would have been difficult. The thickness of wood afforded some insulating properties to the pipes which helped prevent freezing as compared to metal pipes, wood used for water pipes also does not rot very easily. Electrolysis, that bugbear of many iron pipe systems, doesnt affect wood pipes at all, in the Western United States where redwood was used for pipe construction, it was found that redwood had peculiar properties that protected it from weathering, acids, insects, and fungus growths. Redwood pipes stayed smooth and clean indefinitely while iron pipe by comparison would rapidly begin to scale and corrode, there are certain standard codes that need to be followed while designing or manufacturing any piping system. Engineer manual, entire document • • U. S. Army Corps of Engineers, EM 1110-l-4008, May 1999 Building services piping links at DMOZ
Piping
–
Large-scale piping system in an
HVAC mechanical room
14.
Gravity
–
Gravity, or gravitation, is a natural phenomenon by which all things with mass are brought toward one another, including planets, stars and galaxies. Since energy and mass are equivalent, all forms of energy, including light, on Earth, gravity gives weight to physical objects and causes the ocean tides. Gravity has a range, although its effects become increasingly weaker on farther objects. The most extreme example of this curvature of spacetime is a hole, from which nothing can escape once past its event horizon. More gravity results in time dilation, where time lapses more slowly at a lower gravitational potential. Gravity is the weakest of the four fundamental interactions of nature, the gravitational attraction is approximately 1038 times weaker than the strong force,1036 times weaker than the electromagnetic force and 1029 times weaker than the weak force. As a consequence, gravity has an influence on the behavior of subatomic particles. On the other hand, gravity is the dominant interaction at the macroscopic scale, for this reason, in part, pursuit of a theory of everything, the merging of the general theory of relativity and quantum mechanics into quantum gravity, has become an area of research. While the modern European thinkers are credited with development of gravitational theory, some of the earliest descriptions came from early mathematician-astronomers, such as Aryabhata, who had identified the force of gravity to explain why objects do not fall out when the Earth rotates. Later, the works of Brahmagupta referred to the presence of force, described it as an attractive force. Modern work on gravitational theory began with the work of Galileo Galilei in the late 16th and this was a major departure from Aristotles belief that heavier objects have a higher gravitational acceleration. Galileo postulated air resistance as the reason that objects with less mass may fall slower in an atmosphere, galileos work set the stage for the formulation of Newtons theory of gravity. In 1687, English mathematician Sir Isaac Newton published Principia, which hypothesizes the inverse-square law of universal gravitation. Newtons theory enjoyed its greatest success when it was used to predict the existence of Neptune based on motions of Uranus that could not be accounted for by the actions of the other planets. Calculations by both John Couch Adams and Urbain Le Verrier predicted the position of the planet. A discrepancy in Mercurys orbit pointed out flaws in Newtons theory, the issue was resolved in 1915 by Albert Einsteins new theory of general relativity, which accounted for the small discrepancy in Mercurys orbit. The simplest way to test the equivalence principle is to drop two objects of different masses or compositions in a vacuum and see whether they hit the ground at the same time. Such experiments demonstrate that all objects fall at the rate when other forces are negligible
Gravity
–
Sir Isaac Newton, an English physicist who lived from 1642 to 1727
Gravity
Gravity
–
Two-dimensional analogy of spacetime distortion generated by the mass of an object. Matter changes the geometry of spacetime, this (curved) geometry being interpreted as gravity. White lines do not represent the curvature of space but instead represent the
coordinate system imposed on the curved spacetime, which would be
rectilinear in a flat spacetime.
Gravity
–
Ball falling freely under gravity. See text for description.
15.
Pump
–
A pump is a device that moves fluids, or sometimes slurries, by mechanical action. Pumps can be classified into three groups according to the method they use to move the fluid, direct lift, displacement. Pumps operate by some mechanism, and consume energy to mechanical work by moving the fluid. Pumps operate via many energy sources, including operation, electricity, engines, or wind power, come in many sizes. Single stage pump - When in an only one impeller is revolving then it is called single stage pump. Double/ Multi stage pump - When in a two or more than two impellers are revolving then it is called double/ multi stage pump. In biology, many different types of chemical and bio-mechanical pumps have evolved, mechanical pumps may be submerged in the fluid they are pumping or be placed external to the fluid. Pumps can be classified by their method of displacement into positive displacement pumps, impulse pumps, velocity pumps, gravity pumps, steam pumps, there are two basic types of pumps, positive displacement and centrifugal. Although axial-flow pumps are classified as a separate type, they have essentially the same operating principles as centrifugal pumps. A positive displacement pump makes a move by trapping a fixed amount. Some positive displacement pumps use a cavity on the suction side. Liquid flows into the pump as the cavity on the suction side expands, the volume is constant through each cycle of operation. Positive displacement pumps, unlike centrifugal or roto-dynamic pumps, theoretically can produce the flow at a given speed no matter what the discharge pressure. Thus, positive displacement pumps are constant flow machines, however, a slight increase in internal leakage as the pressure increases prevents a truly constant flow rate. A positive displacement pump must not operate against a closed valve on the side of the pump. A relief or safety valve on the side of the positive displacement pump is therefore necessary. The relief valve can be internal or external, the pump manufacturer normally has the option to supply internal relief or safety valves. The internal valve is only used as a safety precaution
Pump
–
A small, electrically powered pump
Pump
–
A large, electrically driven pump (electropump) for
waterworks near the
Hengsteysee, Germany
Pump
–
Horizontally mounted lobe pump (right) shown with its electric motor (left) and drive-shaft bearing (middle)
Pump
–
Old hand water pump (c. 1924) at the Colored School in Alapaha, Georgia, US
16.
Bar screen
–
A bar screen is a mechanical filter used to remove large objects, such as rags and plastics, from wastewater. It is part of the primary filtration flow and typically is the first, or preliminary, level of filtration and they typically consist of a series of vertical steel bars spaced between 1 and 3 inches apart. Bar screens come in many designs, some employ automatic cleaning mechanisms using electric motors and chains, some must be cleaned manually by means of a heavy rake. Items removed from the influent are called screenings and are collected in dumpsters, as a bar screen collects objects, the water level will rise, and so they must be cleared regularly to prevent overflow
Bar screen
–
Bar screens in the WWTP Aachen-Soers, Germany
17.
Dumpster
–
A dumpster is a type of mobile garbage bin designed to be brought and taken away by a special truck. The word is a trademark of Dumpster, an American brand name for a specific design. Generic usage of dumpster is also common in Australia, although Dumpster is not a brand there. The containers were called Dumpsters, a portmanteau of the name with the word dump. The Dempster Dumpmaster, which became the first successful front-loading garbage truck that used this system, the word dumpster has had at least three trademarks associated with it by Dempster Brothers, but today it is often used as a genericized trademark. In British and Australian English, the wheelie bin and skip are more commonly used. In some other countries the more descriptive term frontloader container is often used, the main purpose of a dumpster is to store rubbish until it is emptied by a garbage truck and disposed of. Dumpsters can be used for all kinds of waste, or for recycling purposes, most dumpsters are emptied weekly by a hired rubbish removal service. Many businesses, apartment buildings, schools, offices, and industrial sites have one or more dumpsters, generally ranging from 2 to 6 cubic yards, Dumpsters are emptied by front-loading garbage trucks. These trucks have large prongs on the front which are aligned and inserted into arms on the dumpster, hydraulics then lift the prongs and the dumpster, eventually flipping the dumpster upside-down and emptying its contents into the trucks hopper. Other dumpsters are smaller and are emptied by rear-loading trucks, mobile construction dumpsters are 6 cubic yard dumpster trailers called Roadrunners, and are commonly used in Dallas, Texas on smaller remodeling jobs or for garage or lawn cleanouts. Roll-off dumpsters are large dumpsters from 10 to 45 cubic yards and these are used at demolition sites, cleanouts, renovations, construction sites, factories, and large businesses. Ninety-five gallon dumpsters are used by businesses and homes where a normal bin would be too small. Roll-off/containers/dumpsters/opentop containers are just a few of the given to these large capacity receptacles. Dumpster diving involves persons voluntarily climbing into a dumpster to find valuables, such as discarded metal scrap, or simply useful items, including food and it can also be a method of investigation. Going through garbage containers that are not strictly speaking dumpsters is nevertheless referred to as dumpster diving
Dumpster
–
Three dumpsters in various sizes
Dumpster
–
Roll-off container
Dumpster
–
Dumpster awaiting pick-up
Dumpster
–
In the remote Eskimo village of Anaktuvuk Pass, dumpsters are painted with slogans that affirm community values.
18.
Fat
–
Fat is one of the three main macronutrients, along with carbohydrate and protein. Fats, also known as triglycerides, are esters of three fatty acid chains and the alcohol glycerol, the terms oil, fat, and lipid are often confused. Oil normally refers to a fat with short or unsaturated fatty acid chains that is liquid at room temperature, lipid is the general term, as a lipid is not necessarily a triglyceride. Fats, like lipids, are generally hydrophobic, and are soluble in organic solvents. Fat is an important foodstuff for many forms of life, and they are a necessary part of the diet of most heterotrophs. Some fatty acids that are set free by the digestion of fats are called essential because they cannot be synthesized in the body from simpler constituents, there are two essential fatty acids in human nutrition, alpha-linolenic acid and linoleic acid. Other lipids needed by the body can be synthesized from these, fats and other lipids are broken down in the body by enzymes called lipases produced in the pancreas. Fats and oils are categorized according to the number and bonding of the atoms in the aliphatic chain. Fats that are saturated fats have no double bonds between the carbons in the chain, unsaturated fats have one or more double bonded carbons in the chain. The nomenclature is based on the end of the chain. This end is called the end or the n-end. Thus alpha-linolenic acid is called an omega-3 fatty acid because the 3rd carbon from that end is the first double bonded carbon in the counting from that end. Some oils and fats have double bonds and are therefore called polyunsaturated fats. Unsaturated fats can be divided into cis fats, which are the most common in nature, and trans fats. Unsaturated fats can be altered by reaction with hydrogen effected by a catalyst and this action, called hydrogenation, tends to break all the double bonds and makes a fully saturated fat. However, trans fats are generated during hydrogenation as contaminants created by a side reaction on the catalyst during partial hydrogenation. Saturated fats can stack themselves in a closely packed arrangement, so they can easily and are typically solid at room temperature. For example, animal fats tallow and lard are high in saturated fatty acid content and are solids, olive and linseed oils on the other hand are unsaturated and liquid
Fat
–
The
obese mouse on the left has large stores of adipose tissue. For comparison, a mouse with a normal amount of adipose tissue is shown on the right.
Fat
–
A fat, or
triglyceride, molecule. Note the three fatty acid chains attached to the central glycerol portion of the molecule.
19.
Grease (lubricant)
–
Grease generally consists of a soap emulsified with mineral or vegetable oil. This change in viscosity is called shear thinning, for example, petroleum jellies such as Vaseline are not generally classified as greases. Greases are applied to mechanisms that can only be lubricated infrequently and they also act as sealants to prevent ingress of water and incompressible materials. Grease-lubricated bearings have greater frictional characteristics due to their high viscosity, a true grease consists of an oil and/or other fluid lubricant that is mixed with a thickener, typically a soap, to form a solid or semisolid. Greases are a type of shear-thinning or pseudo-plastic fluid, which means that the viscosity of the fluid is reduced under shear, after sufficient force to shear the grease has been applied, the viscosity drops and approaches that of the base lubricant, such as the mineral oil. This sudden drop in shear force means that grease is considered a fluid. It is often applied using a gun, which applies the grease to the part being lubricated under pressure. Soaps are the most common emulsifying agent used, and the selection of the type of soap is determined by the application, soaps include calcium stearate, sodium stearate, lithium stearate, as well as mixtures of these components. Fatty acids derivatives other than stearates are also used, especially lithium 12-hydroxystearate, the nature of the soaps influences the temperature resistance, water resistance, and chemical stability of the resulting grease. Powdered solids may also be used as thickeners, especially as clays, fatty oil-based greases have also been prepared with other thickeners, such as tar, graphite, or mica, which also increase the durability of the grease. Lithium-based greases are the most commonly used, sodium and lithium-based greases have higher melting point than calcium-based greases but are not resistant to the action of water, lithium-based grease has a dropping point at 190 to 220 °C. However the maximum temperature for lithium-based grease is 120 °C. The amount of grease in a sample can be determined in a laboratory by extraction with a solvent followed by e. g. gravimetric determination, gear greases consist of rosin oil, condensed with lime and stirred with mineral oil, with some percentage of water. Special-purpose greases contain glycerol and sorbitan esters and they are used, for example, in low-temperature conditions. Some greases are labeled EP, which indicates extreme pressure, under high pressure or shock loading, normal grease can be compressed to the extent that the greased parts come into physical contact, causing friction and wear. EP grease contains solid lubricants, usually graphite and/or molybdenum disulfide, the solid lubricants bond to the surface of the metal, and prevent metal-to-metal contact and the resulting friction and wear when the lubricant film gets too thin. These compounds are working as a release agent, all solid additives can not be used in bearings because due to tight tolerances only plain grease or oil are allowed. Solid additives will cause reinforced wear of bearings, grease from the early Egyptian or Roman eras is thought to have been prepared by combining lime with olive oil
Grease (lubricant)
–
Grease is used to lubricate glass stopcocks and joints. Some laboratories fill them into
syringes for easy application. Two typical examples: Left -
Krytox, a fluoroether-based grease; Right - a silicone-based high vacuum grease by
Dow Corning.
Grease (lubricant)
–
An inverse micelle formed when a soap is dispersed in an oil. This structure is broken reversibly upon shearing the grease.
20.
Septic tank
–
Other components may include pumps, alarms, sand filters, and clarified liquid effluent disposal methods such as a septic drain field, ponds, natural stone fiber filter plants or peat moss beds. Septic systems are a type of onsite sewage facility, in North America, approximately 25 percent of the population relies on septic tanks, including some suburbs and small towns as well as rural areas. Indianapolis is one example of a city where many of the citys neighborhoods still rely on separate septic systems. In Europe, septic systems are limited to rural areas. Since septic systems require large drainfields, they are not suitable for densely built cities, the term septic refers to the anaerobic bacterial environment that develops in the tank which decomposes or mineralizes the waste discharged into the tank. Septic tanks can be coupled with other onsite wastewater treatment units such as biofilters or aerobic systems involving artificially forced aeration, periodic preventive maintenance is required to remove solids that remain and gradually fill the tank, reducing its efficiency. Maintenance requires regular pumping to remove these, according to the US Environmental Protection Agency, in the United States it is the home owners responsibility to maintain their septic systems. Anyone who disregards this requirement will eventually be faced with costly repairs when solids escape the tank and clog the clarified liquid effluent disposal system. A septic tank consists of one or more concrete or plastic tanks of between 4000 and 7500 liters, one end is connected to a wastewater pipe and the other to a septic drain field. Generally these pipe connections are made with a T pipe, allowing liquid to enter, wastewater enters the first chamber of the tank, allowing solids to settle and scum to float. The settled solids are anaerobically digested, reducing the volume of solids, the liquid component flows through the dividing wall into the second chamber, where further settlement takes place. A percolation test is required prior to installation to ensure the porosity of the soil is adequate to serve as a drain field, a piping network, often laid in a stone-filled trench, distributes the wastewater throughout the field with multiple drainage holes in the network. The size of the field is proportional to the volume of wastewater. The entire septic system can operate by gravity alone or, where topographic considerations require, certain septic tank designs include siphons or other devices to increase the volume and velocity of outflow to the drainage field. These help to fill the pipe more evenly and extend the drainage field life by preventing premature clogging or bioclogging. An Imhoff tank is a septic system where the sludge is digested in a separate tank. This avoids mixing digested sludge with incoming sewage, also, some septic tank designs have a second stage where the effluent from the anaerobic first stage is aerated before it drains into the seepage field. A properly designed and normally operating septic system is odor-free and, besides periodic inspection and emptying of the septic tank, a well designed and maintained concrete, fiberglass, or plastic tank should last about 50 years
Septic tank
–
Septic tank in Lesotho (underground), concrete cover slab is visible
Septic tank
–
Schematic of a septic tank
Septic tank
–
A vacuum truck used to empty septic tanks in Germany
Septic tank
–
A septic tank before installation, with manhole cover on top
21.
Biofilters
–
Biofiltration is a pollution control technique using a bioreactor containing living material to capture and biologically degrade pollutants. Common uses include processing waste water, capturing harmful chemicals or silt from surface runoff, the air flows through a packed bed and the pollutant transfers into a thin biofilm on the surface of the packing material. Microorganisms, including bacteria and fungi are immobilized in the biofilm, trickling filters and bioscrubbers rely on a biofilm and the bacterial action in their recirculating waters. The technology finds greatest application in treating malodorous compounds and water-soluble volatile organic compounds, compounds treated are typically mixed VOCs and various sulfur compounds, including hydrogen sulfide. Engineered biofilters, designed and built since the early 1990s, have provided significant footprint reductions over the conventional flat-bed, one of the main challenges to optimum biofilter operation is maintaining proper moisture throughout the system. The air is normally humidified before it enters the bed with a system, humidification chamber, bioscrubber. A number of companies offer these types or proprietary packing materials and multi-year guarantees, for large volumes of air, a biofilter may be the only cost-effective solution. There is no pollution and degradation products form additional biomass, carbon dioxide. Media irrigation water, although many systems recycle part of it to operating costs, has a moderately high biochemical oxygen demand. However, this water, necessary for proper maintenance of any bio-oxidation system, is generally accepted by municipal publicly owned treatment works without any pretreatment. Biofilters are being utilized in Columbia Falls, Montana at Plum Creek Timber Companys fiberboard plant, the biofilters decrease the pollution emitted by the manufacturing process and the exhaust emitted is 98% clean. The biofilters use trillions of microscopic bacteria that cleanse the air being released from the plant, biofiltration was first introduced in England in 1893 as a trickling filter for wastewater treatment and has since been successfully used for the treatment of different types of water. Biological treatment has been used in Europe to filter water for drinking purposes since the early 1900s and is now receiving more interest worldwide. Biofiltration is also common in wastewater treatment, aquaculture and greywater recycling, a biofilter is a bed of media on which microorganisms attach and grow to form a biological layer called biofilm. Biofiltration is thus referred to as a fixed–film process. Generally, the biofilm is formed by a community of different microorganisms, macro-organisms, the aspect of the biofilm is usually slimy and muddy. Water to be treated can be applied intermittently or continuously over the media, via upflow or downflow, typically, a biofilter has two or three phases, depending on the feeding strategy, a solid phase, a liquid phase, a gaseous phase. Organic matter and other water components diffuse into the biofilm where the treatment occurs, biofiltration processes are usually aerobic, which means that microorganisms require oxygen for their metabolism
Biofilters
–
Biosolids composting plant biofilter mound - note sprinkler visible front right to maintain proper moisture level for optimum functioning
Biofilters
–
Air cycle system at biosolids composting plant. Large duct in foreground is exhaust air into biofilter shown in next photo
Biofilters
–
Biofilter installation at a commercial composting facility.
22.
Sewage collection and disposal
–
Water supply and sanitation has been a primary logistical challenge since the dawn of civilization. Where water resources or infrastructure or sanitation systems are insufficient for the population, people fall prey to disease, dehydration, Major human settlements could initially develop only where fresh surface water was plentiful, such as near rivers or natural springs. Throughout history people have devised systems to make getting water into their communities and households, and disposing wastewater more convenient. The historical focus of treatment was on the conveyance of raw sewage to a natural body of water, e. g. a river or ocean. Early human habitations were built next to water sources. Rivers would often double as a form of natural sewage disposal. Most of these early sewers received significant amounts of animal dung in street runoff. During the Neolithic, humans dug the first permanent water wells, wells dug around 6500 BC have been found in the Jezreel Valley. The size of settlements was largely dependent on nearby available water. The Indus Valley Civilization in Asia shows early evidence of water supply. The system the Indus developed and managed included a number of advanced features, a typical example is the Indus city of Lothal. The urban areas of the Indus Valley civilization included public and private baths, sewage was disposed through underground drains built with precisely laid bricks, and a sophisticated water management system with numerous reservoirs was established. In the drainage systems, drains from houses were connected to wider public drains, devices such as shadoofs and sakias were used to lift water to ground level. Ruins from the Indus Valley Civilization like Mohenjo-daro in Pakistan and Dholavira in Gujarat in India had settlements with some of the ancient worlds most sophisticated sewage systems and they included drainage channels, rain water harvesting, and street ducts. Stepwells have mainly used in Indian subcontinent. The earliest covered sewers uncovered by archaeologists are in the planned cities of the Indus Valley Civilization. Wastewater reuse is an ancient practice, which has applied since the dawn of human history. Reuse of untreated municipal wastewater has been practiced for centuries with the objective of diverting human waste outside of urban settlements
Sewage collection and disposal
–
Deer Island Waste Water Treatment Plant serving
Boston, Massachusetts, and vicinity.
Sewage collection and disposal
–
A large well and bathing platforms at
Harappa, remains of the city's final phase of occupation from 2200 to 1900 BC.
Sewage collection and disposal
–
The
civil engineer Joseph Bazalgette, constructed a modern sewerage system for London in the mid-19th century.
Sewage collection and disposal
–
Major types
23.
Household waste
–
Municipal solid waste, commonly known as trash or garbage in the United States and as refuse or rubbish in Britain, is a waste type consisting of everyday items that are discarded by the public. Garbage can also specifically to food waste, as in a garbage disposal. The composition of municipal solid waste varies greatly from municipality to municipality, in municipalities which have a well developed waste recycling system, the waste stream consists mainly of intractable wastes such as plastic film, and non-recyclable packaging materials. At the start of the 20th century, the majority of waste in the UK consisted of coal ash from open fires. Most definitions of municipal solid waste do not include industrial wastes, agricultural wastes, medical waste, Waste collection is performed by the municipality within a given area. The term residual waste relates to waste left from household sources containing materials that have not been separated out or sent for reprocessing, the municipal solid waste industry has four components, recycling, composting, disposal, and waste-to-energy via incineration. This location may be a processing facility, a transfer station or a landfill disposal site. Waste handling and separation involves activities associated with waste management until the waste is placed in containers for collection. Handling also encompasses the movement of loaded containers to the point of collection, separating different types of waste components is an important step in the handling and storage of solid waste at the source. The types of means and facilities that are now used for the recovery of materials that have been separated at the source include curbside collection, drop-off. This element involves two main steps, first, the waste is transferred from a smaller collection vehicle to larger transport equipment. The waste is transported, usually over long distances, to a processing or disposal site. In the recent years environmental organizations, such as Freegle or Freecycle Network, have been gaining popularity for their online reuse networks and these networks provide a worldwide online registry of unwanted items that would otherwise be thrown away, for individuals and nonprofits to reuse or recycle. Therefore, this free Internet-based service reduces landfill pollution and promotes the gift economy, landfills are created by land dumping. Land dumping methods vary, most commonly it involves the mass dumping of waste into a designated area, after the waste is dumped, it is then compacted by large machines. When the dumping cell is full, it is sealed with a plastic sheet. This is the method of dumping in the United States because of the low cost. Landfills pose the threat of pollution, and can intoxicate ground water, the signs of pollution are effectively masked by disposal companies and it is often hard to see any evidence
Household waste
–
Grand Coulee Dam
Household waste
–
Mixed municipal waste,
Hiriya,
Tel Aviv
Household waste
–
Major types
24.
Toilet
–
A toilet is a sanitation fixture used for the storing or disposal of human urine and feces. In developed countries, different forms of flush toilets are common. These are connected to a system in most urban areas. In many developing countries, especially in areas, dry toilets such as pit latrines. Dry toilets are usually placed in outhouses, i. e. not inside the dwelling, in many countries, private homes are designed with the flush toilet and the bath or shower in the same room, the bathroom, to simplify plumbing and reduce cost. Other cultures find this insanitary, and have one room for body-washing, public toilets are installed where their use is expected on a permanent basis, while portable toilets may be brought in for large but temporary gatherings. Chemical toilets are used in various contexts, such as passenger trains. Serious waterborne diseases such as cholera and diarrhea occur when open defecation or poor sanitation permits human waste to pollute water supplies, historically, sanitation has been a concern from the earliest stages of human settlements. The Indus Valley Civilization is particularly notable for its extensive sanitation works, for the most part, early cities emptied their waste into rivers or seas manually or via open ditches. Sanitation in ancient Rome was notably advanced, as were some of the reredorters of medieval monasteries, a precursor to the modern flush toilet system was designed by John Harington in 1596 but did not become common until the late 19th century. Even London, at time the worlds largest city, did not require indoor toilets in its building codes until after the First World War. A typical flush toilet is a ceramic bowl connected on the up side to a cistern that enables rapid filling with water, when a toilet is flushed, the sewage should flow into a septic tank or into a system connected to a Sewage treatment plant. However, in countries, this treatment does not happen. The water in the bowl is connected to a pipe shaped like an upside-down U. One side of the U channel is arranged as a tube longer than the water in the bowl is high. The siphon tube connects to the drain, the bottom of the drain pipe limits the height of the water in the bowl before it flows down the drain. The water in the acts as a barrier to sewer gas entering the building. Sewer gas escapes through a vent pipe attached to the sewer line, the amount of water used by conventional flush toilets usually makes up a significant portion of personal daily water usage
Toilet
–
Toilets come in various shapes and forms around the world: Top:
flush toilet in a home in Australia, with dispenser for
toilet paper and a
toilet brush in its holder; Bottom: Low-cost
dry toilet (
Arborloo at a school in Zimbabwe)
Toilet
Toilet
–
Flush toilet bowl (sitting style)
Toilet
–
A poorly maintained pit latrine in Yaounde,
Cameroon
25.
Bathing
–
Bathing is the washing of the body with a fluid, usually water or an aqueous solution, or the immersion of the body in water. It may be practiced for personal hygiene, religious ritual or therapeutic purposes, by analogy, especially as a recreational activity, the term is also applied to sun bathing and sea bathing. Bathing can take place in any situation where there is water and it can take place in a bathtub or shower, or it can be in a river, lake, water hole, pool or the sea, or any other water receptacle. The term for the act can vary, the city of Bath is famous for its public baths fed by hydrothermal springs. Throughout history, societies devised systems to water to be brought to population centres. Ancient Indians used elaborate practices for personal hygiene with three daily baths and washing and these are recorded in the works called grihya sutras which are in practice even today in some communities. Ancient Greece utilized small bathtubs, wash basins, and foot baths for personal cleanliness, the earliest findings of baths date from the mid-2nd millennium BC in the palace complex at Knossos, Crete, and the luxurious alabaster bathtubs excavated in Akrotiri, Santorini. The Greeks established public baths and showers within gymnasiums for relaxation, in fact, the word gymnasium comes from the Greek word gymnos, meaning naked. Ancient Rome developed a network of aqueducts to supply water to all towns and population centres and had indoor plumbing, with pipes that terminated in homes and at public wells. The Roman public baths were called thermae, with the fall of the Roman Empire the aqueduct network fell into disrepair and most of it ceased to be used. Before the 7th century, the Japanese probably mostly bathed in the springs in the open. In the 6th to 8th centuries the Japanese took the religion of Buddhism from China, for every Buddhist temple traditionally included a bathhouse for the monks. These baths were opened in time to the rest of the population, only the wealthy had private baths. The first public bathhouse was mentioned in 1266, in Edo, the first sentō was established in 1591. The early steam baths or steam baths were called iwaburo or kamaburo and it was natural or artificial caves or stone vaults. In iwaburo along the coast, the rocks were heated by burning wood, the entrance to these bath houses was very small, so that the steam escaped. There were no windows, so it was dark inside. The darkness could be used for sexual contact
Bathing
–
Hot springs at
Aachen, Germany, 1682
Bathing
–
Three young women bathing. Side B from an
Ancient Greek Attic
red-figure stamnos
Bathing
–
Codex Magliabecchiano from the Loubat collection, 1904
Bathing
–
A sweat bath: illumination from
Peter of Eboli, De Balneis Puteolanis ("The Baths of
Pozzuoli "), written in the early 13th century
26.
Shower
–
A shower is a place in which a person bathes under a spray of typically warm or hot water. Indoors, there is a drain in the floor, most showers have temperature, spray pressure and adjustable showerhead nozzle. The simplest showers have a swivelling nozzle aiming down on the user and this allows the showerer to spray the water at different parts of their body. A shower can be installed in a shower stall or bathtub with a plastic shower curtain or door. Showering is common in Western culture due to the efficiency of using it compared with a bathtub and its use in hygiene is therefore common practice. A shower uses less water on average than a bath,80 litres for a shower compared with 150 litres for a bath, the original showers were neither indoor structures nor man-made, but were common natural formations, waterfalls. The falling water rinsed the bathers completely clean and was more efficient than bathing in a traditional basin, ancient people began to reproduce these natural phenomena by pouring jugs of water, often very cold, over themselves after washing. There has been evidence of upper class Egyptian and Mesopotamians having indoor shower rooms where servants would bathe them in the privacy of their own homes. However, these were rudimentary by modern standards, having rudimentary drainage systems and water was carried, not pumped, the ancient Greeks were the first people to have showers. Their aqueducts and sewage systems made of lead pipes allowed water to be pumped both into and out of large communal shower rooms used by elites and common citizens alike. These rooms have been discovered at the site of the city Pergamum, the depictions are very similar to modern locker room showers, and even included bars to hang up clothing. The ancient Romans also followed this convention, their famous bathhouses can be all around the Mediterranean. The Romans not only had these showers, but also believed in bathing multiple times a week, the water and sewage systems developed by the Greeks and Romans broke down and fell out of use after the fall of the Roman Empire. The first mechanical shower, operated by a pump, was patented in England in 1767 by William Feetham. His shower contraption used a pump to force the water into a vessel above the users head, the system would also recycle the same dirty water through every cycle. This early start was greatly improved in the anonymously invented English Regency shower design of circa 1810, the original design was over 10 feet tall, and was made of several metal pipes painted to look like bamboo. A basin suspended above the pipes fed water into a nozzle that distributed the water over the users shoulders, the water on the ground was drained and pumped back through the pipes into the basin, where the cycle would repeat itself. The original prototype was improved upon in the following decades
Shower
–
A typical stall shower with height-adjustable nozzle.
Shower
–
A combination shower and bathtub.
Shower
–
Many public swimming areas offer poolside showers
Shower
–
Rib shower
27.
Kitchen
–
A kitchen is a room or part of a room used for cooking and food preparation in a dwelling or in a commercial establishment. Many households have an oven, a dishwasher and other electric appliances. The main function of a kitchen is serving as a location for storing, cooking and preparing food, commercial kitchens are found in restaurants, cafeterias, hotels, hospitals, educational and workplace facilities, army barracks, and similar establishments. These kitchens are generally larger and equipped with bigger and more heavy-duty equipment than a residential kitchen, for example, a large restaurant may have a huge walk-in refrigerator and a large commercial dishwasher machine. Commercial kitchens are generally subject to public health laws and they are inspected periodically by public-health officials, and forced to close if they do not meet hygienic requirements mandated by law. The evolution of the kitchen is linked to the invention of the range or stove. Food was cooked over an open fire, technical advances in heating food in the 18th and 19th centuries changed the architecture of the kitchen. Before the advent of modern pipes, water was brought from a source such as wells. The houses in Ancient Greece were commonly of the atrium-type, the rooms were arranged around a courtyard for women. In many such homes, a covered but otherwise open patio served as the kitchen, homes of the wealthy had the kitchen as a separate room, usually next to a bathroom, both rooms being accessible from the court. In such houses, there was often a small storage room in the back of the kitchen used for storing food. In the Roman Empire, common folk in cities often had no kitchen of their own, some had small mobile bronze stoves, on which a fire could be lit for cooking. Wealthy Romans had relatively well-equipped kitchens, the fireplace was typically on the floor, placed at a wall—sometimes raised a little bit—such that one had to kneel to cook. Early medieval European longhouses had a fire under the highest point of the building. The kitchen area was between the entrance and the fireplace, in wealthy homes there was typically more than one kitchen. In some homes there were upwards of three kitchens, the kitchens were divided based on the types of food prepared in them. In place of a chimney, these buildings had a hole in the roof through which some of the smoke could escape. Besides cooking, the fire served as a source of heat
Kitchen
–
Modern
Western home kitchens
Kitchen
Kitchen
–
American type midcentury kitchen
Kitchen
–
Kitchen with stove and oven of a Roman inn (Mansio) at the Roman villa of Bad Neuenahr-Ahrweiler, Germany.
28.
Sink
–
A sink—also known by other names including sinker, washbowl, hand basin and wash basin—is a bowl-shaped plumbing fixture used for washing hands, dishwashing, and other purposes. Sinks have taps that supply hot and cold water and may include a feature to be used for faster rinsing. They also include a drain to remove used water, this drain may itself include a strainer and/or shut-off device, Sinks may also have an integrated soap dispenser. When a sink becomes stopped-up or clogged, a person will often resort to use a chemical drain cleaner or a plunger, the washstand was a bathroom sink made in the United States in the late 18th century. The washstands were small tables on which were placed a pitcher, sometimes the table had a hole where the large bowl rested, which led to the making of dry sinks. From about 1820 to 1900 the dry sink evolved by the addition of a cabinet with a trough built on the top. This is where the bowls or buckets for water were kept, splashboards were sometimes added to the back wall, as well as shelves and drawers, the more elaborate designs usually placed in the kitchen. Sinks are made of different materials. These include, Stainless steel is used in kitchens and commercial applications because it represents a good trade-off between cost, usability, durability, and ease of cleaning. Most stainless steel sinks are made by drawing a sheet of steel over a die. Some very deep sinks are fabricated by welding, Stainless steel sinks will not be damaged by hot or cold objects and resist damage from impacts. Enamel over cast iron is a material for kitchen and bathroom sinks. Heavy and durable, these sinks can also be manufactured in a wide range of shapes. Aggressive cleaning will dull the surface, leading to more dirt accumulation, enamel over steel is a similar-appearing but far less rugged and less cost-effective alternative. Solid ceramic sinks have many of the characteristics as enamel over cast iron. Plastic sinks come in basic forms, Inexpensive sinks are simply made using injection-molded thermoplastics. These are often deep, free-standing sinks used in laundry rooms, subject to damage by hot or sharp objects, the principal virtue of these sinks is their low cost. High-end acrylic drop-in and undermount sinks are becoming popular, although they tend to be easily damaged by hard objects - like scouring a cast iron frying pan in the sink
Sink
–
An old
Butler 's (Belfast) sink in a
kitchen
Sink
–
A sink/basin in a
bathroom
Sink
–
Bathroom
stainless steel vessel sink standing on a
wood surface. Brazilian creative design.
Sink
–
Sinks are available in many colors
29.
Greywater
–
Greywater or sullage is all wastewater generated in households or office buildings from streams without fecal contamination, i. e. all streams except for the wastewater from toilets. Sources of greywater include, e. g. sinks, showers, baths, the use of non-toxic and low-sodium soap and personal care products is recommended to protect vegetation when reusing greywater for irrigation purposes. Greywater, by definition, does not include the discharge of toilets or highly fecally contaminated wastewater, when greywater is mixed with toilet wastewater, it is called sewage or blackwater and should be treated in sewage treatment plants or onsite sewage facility, which often is a septic system. When it is separate, it may open up interesting decentralized treatment. The separate treatment of greywater falls under the concept of source separation which is one principle commonly applied in ecological sanitation approaches, the main advantage of keeping greywater separate from toilet wastewater is that the pathogen load is much reduced and the greywater is therefore easier to treat and reuse. Treated greywater has many uses, for example toilet flushing or irrigation, in households with conventional flush toilets, greywater makes up about 65% of the total wastewater produced by that household. In may be a source of water for reuse, because there is a close relationship between the production of greywater and the potential demand for toilet flushing water. Greywater usually contains traces of excreta and is therefore not free of pathogens. The excreta comes from washing a persons anal area in the bath and shower, the quality of greywater can deteriorate rapidly during storage because it is often warm, contains some nutrients and organic matter as well as pathogens. Stored greywater also leads to odour nuisances for the same reason, most greywater is easier to treat and recycle than blackwater, because of lower levels of contaminants. If collected using a separate plumbing system from blackwater, domestic greywater can be recycled directly within the home, garden or company, if stored, it must be used within a very short time or it will begin to putrefy due to the organic solids in the water. Recycled greywater of this kind is never safe to drink, but a number of treatment steps can be used to water for washing or flushing toilets. Mechanical systems In constructed wetlands, the plants use contaminants of greywater, such as food particles, as nutrients in their growth. However, salt and soap residues can be toxic to microbial and plant life alike, but can be absorbed and degraded through constructed wetlands and aquatic plants such as sedges, rushes, and grasses. Demand on conventional water supplies and pressure on sewage treatment systems is reduced by the use of greywater, re-using greywater also reduces the volume of sewage effluent entering watercourses which can be ecologically beneficial. In times of drought, especially in areas, greywater use in gardens or toilet systems helps to achieve some of the goals of ecologically sustainable development. S. Greywater use for irrigation appears to be a safe practice, a 2015 epidemiological study found no additional burden of disease among graywater users irrigating arid regions. The safety of reuse of greywater as potable water has also been studied, a few organic micropollutants including benzene were found in greywater in significant concentrations but most pollutants were in very low concentrations
Greywater
–
Left: a bottle of greywater from an office building before treatment. Right: greywater following
membrane bioreactor treatment
Greywater
–
Example of a source of greywater in the household: dirty water from cleaning the floor
Greywater
–
Urban decentralized greywater treatment with
constructed wetland in Oslo, Norway
Greywater
–
Greywater treatment plant with
membrane bioreactor in the basement of an office building in Frankfurt, Germany
30.
Blackwater (waste)
–
Blackwater is used to describe wastewater containing feces, urine and flushwater from flush toilets along with anal cleansing water or toilet paper. Blackwater is to be distinguished from greywater which is the wastewater generated from washing food, clothes and dishware, as well as from bathing, according to a one source, Blackwater is the mixture of urine, faeces and flushwater along with anal cleansing water and/or dry cleansing materials. Blackwater contains the pathogens of faeces and the nutrients of urine that are diluted in the flushwater, Blackwater is a term dating to at least the 1970s. Water coming from domestic equipment other than toilets is called greywater, separation of blackwater and greywater nowadays happens with all ecological buildings. Especially in autonomous buildings, the separation is always present and it is also commonly used on recreational vehicles which feature a greywater holding tank and a blackwater holding tank. Blackwater contains pathogens that must decompose before they can be released safely into the environment and it is difficult to process blackwater if it contains a large quantity of excess water, or if it must be processed quickly, because of the high concentrations of organic material. However, if blackwater does not contain water, or if it receives primary treatment to de-water. The heat produced by naturally occurring thermophilic microorganisms, will heat the compost to over 60 °C, Blackwater generation can be avoided by making use of composting toilets and vermifilter toilets. In certain autonomous buildings, such as earthships, this is almost always present, besides saving water, composting toilets allow the user to reuse the nutrients found therein
Blackwater (waste)
–
E. coli bacteria under magnification
31.
Stormwater
–
Stormwater is water that originates during precipitation events and snow/ice melt. Stormwater can soak into the soil, be held on the surface and evaporate, or runoff and end up in streams, rivers. In natural landscapes such as forests, the soil absorbs much of the stormwater, Stormwater is also a resource and important as the worlds human population demand exceeds the availability of readily available water. Techniques of storm water harvesting with point source water management and purification can potentially make urban environments self-sustaining in terms of water, because impervious surfaces do not allow rain to infiltrate into the ground, more runoff is generated than in the undeveloped condition. This additional runoff can erode watercourses as well as cause flooding after the collection system is overwhelmed by the additional flow. Because the water is flushed out of the watershed during the event, little infiltrates the soil, replenishes groundwater. A first flush is the runoff of a rainstorm. During this phase, polluted water entering storm drains in areas with high proportions of impervious surfaces is more concentrated compared to the remainder of the storm. Consequently, these concentrations of urban runoff result in high levels of pollutants discharged from storm sewers to surface waters. Pollutants entering surface waters during precipitation events is termed polluted runoff, daily human activities result in deposition of pollutants on roads, lawns, roofs, farm fields, etc. When it rains or there is irrigation, water runs off and ultimately makes its way to a river, lake, in addition to the pollutants carried in stormwater runoff, urban runoff is being recognized as a cause of pollution in its own right. In natural catchments surface runoff entering waterways is a rare event, occurring only a few times each year. Before development occurred most rainfall soaked into the ground and contributed to groundwater recharge or was recycled into the atmosphere by vegetation through evapotranspiration. In addition to delivering higher pollutants from the catchment, increased stormwater flow can lead to stream erosion, encourage weed invasion. Native species often rely on such flow regimes for spawning, juvenile development, in some areas, especially along the U. S. coast, polluted runoff from roads and highways may be the largest source of water pollution. Stormwater is a cause of urban flooding. Urban flooding is the inundation of land or property in a built-up environment caused by overwhelming the capacity of drainage systems. Although triggered by events such as flash flooding or snow melt, urban flooding is a condition, characterized by its repetitive, costly
Stormwater
–
Urban runoff entering a
storm drain
Stormwater
–
Relationship between
impervious surfaces and
surface runoff
Stormwater
–
Urban runoff being discharged to
coastal waters
Stormwater
–
Stormwater filtration system for urban runoff
32.
Sewerage
–
Sewerage is the infrastructure that conveys sewage or surface runoff. It encompasses components such as receiving drains, manholes, pumping stations, storm overflows, Sewerage ends at the entry to a sewage treatment plant or at the point of discharge into the environment. It is the system of pipes, chambers, manholes, etc. that conveys the sewage or storm water, according to this definition, sewerage and sewage are two different terms. However, at least in American English colloquial usage, both terms are used interchangeably. The main part of a system is made up of large pipes that convey the sewage from the point of production to the point of treatment. In certain areas it has resulted in a significant lowering of the water table, in the example of Belgium, a lowering of the water table by 100 meters has been the result. The freshwater that is accumulated by the system is then piped to the sea. In areas where this is a concern, vacuum sewers may be used due to the shallow excavation that is possible for them. Severe constraints are applied to sewerage, which may result in premature deterioration and these include root intrusion, joint displacement, cracks and holes formation leading to a significant volume of leakage with an overall risk for the environment and public health. For example, it is estimated that 500 million m3 of contaminated water per year can leak into soil, the rehabilitation and replacement of damaged sewers is very costly. Annual rehabilitation costs for Los Angeles County are about €400 million, and in Germany, hydrogen sulfide is indirectly responsible for biogenic sulfide corrosion and consequently, sewerage need rehabilitation works. Various repairs options are available to Owners over a range of costs. Depending of the condition and contamination, the cleaning can range from simple high pressure jet water cleaning up to real hydro-demolition. One method to ensure sound concrete is exposed is to verify that the surface pH is superior to 10, as for any concrete repair, the state-of-the-art rules must be followed. It utilizes classical facade rotor pump, easily available in the market, the main drawback is the limited pumping distance that cannot exceed 75 meters. Spinning head wet spray, this method is similar to the first and this method is fast and especially suited for cylindrical chambers like manholes. When a structure is so severely corroded that man entry is a risk, high pressure dry spray, this method, also called “shotcrete” or “gunite” is allowing a faster rate of rehabilitation, and also to make a thicker application in a single pass. The main interest of dry shotcrete is the capacity to pump the mortar over a long distance, longest dry shotcrete distance the authors are aware is a job site in Australia in 2014 where 100% calcium aluminate mortar was air transported over 800 meters before being sprayed
Sewerage
–
Major types
33.
Infiltration/Inflow
–
Infiltration/Inflow causes dilution in sanitary sewers. Dilution of sewage decreases the efficiency of treatment, and may cause sewage volumes to exceed design capacity, although inflow is technically different from infiltration, it may be difficult to determine which is causing dilution problems in inaccessible sewers. The United States Environmental Protection Agency defines the term infiltration/inflow as combined contributions from both, early combined sewers used surface runoff to dilute waste from toilets and carry it away from urban areas into natural waterways. Sewage treatment can remove some pollutants from toilet waste, but treatment of diluted flow from combined sewers produces larger volumes of treated sewage with similar pollutant concentrations, modern sanitary sewers are designed to transport domestic and industrial wastewater directly to treatment facilities without dilution. Groundwater entering sanitary sewers through defective pipe joints and broken pipes is called infiltration, in general, volume of leakage will increase over time. Damaged and broken sewer cleanouts are a cause of infiltration into municipal sewer systems. Infiltration will occur where local groundwater elevation is higher than the sewer pipe, gravel bedding materials in sewer pipe trenches act as a French drain. Groundwater flows parallel to the sewer until it reaches the area of damaged pipe, in areas of low groundwater, sewage may exfiltrate into groundwater from a leaking sewer. Water entering sanitary sewers from inappropriate connections is called inflow, typical sources include sump pumps, roof drains, cellar drains, and yard drains where urban features prevent surface runoff, and storm drains are not conveniently accessible or identifiable. Inflow tends to peak during precipitation events, and causes greater flow variation than infiltration, peak flows caused by inflow may generate a foul flush of accumulated biofilm and sanitary solids scoured from the dry weather wetted perimeter of oversized sewers during peak flow turbulence. Sources of inflow can sometimes be identified by smoke testing, smoke is blown into the sewer during dry weather while observers watch for smoke emerging from yards, cellars, or roof gutters. Dilution of sewage directly increases costs of pumping and chlorination, ozonation, physical treatment structures including screens and pumps must be enlarged to handle the peak flow. Primary clarifiers must also be enlarged to treat average flows, although primary treatment of peak flows may be accomplished in detention basins, biological secondary treatment is effective only while the concentration of soluble and colloidal pollutants remains high enough to sustain a population of microorganisms digesting those pollutants. Unremoved organics are potentially converted to disinfection by-products by chemical disinfection prior to discharge, high rates of infiltration/inflow may make the sanitary sewer incapable of carrying sewage from the design service area. Sewage may back up into the lowest homes during wet weather, smoke test results may not correlate well with flow volumes, although they can identify potential problem locations. Small areas with large flow differences can be identified if the system provides adequate measuring locations. It may be necessary to replace a section of sewer line if flow differences cannot be corrected by removing identified connections
Infiltration/Inflow
–
Excessive infiltration/inflow may cause sanitary sewer overflows during wet weather.
34.
Urbanization
–
Urbanization refers to the population shift from rural to urban areas, the gradual increase in the proportion of people living in urban areas, and the ways in which each society adapts to the change. It is predominantly the process by which towns and cities are formed, the United Nations projected that half of the worlds population would live in urban areas at the end of 2008. It is predicted that by 2050 about 64% of the developing world and that is equivalent to approximately 3 billion urbanites by 2050, much of which will occur in Africa and Asia. Notably, the United Nations has also projected that nearly all global population growth from 2017 to 2030 will be absorbed by cities. Urbanization is relevant to a range of disciplines, including geography, sociology, economics, urban planning, the phenomenon has been closely linked to modernization, industrialization, and the sociological process of rationalization. Urbanization can be seen as a condition at a set time or as an increase in that condition over time. The first major change in settlement patterns was the accumulation of hunter-gatherers into villages many years ago. This unprecedented movement of people is forecast to continue and intensify during the few decades. Outside Asia, Mexico City, São Paulo, London, New York City, Lagos, in England the proportion of the population living in cities jumped from 17% in 1801 to 72% in 1891. Growing trade around the world also allowed cereals to be imported from North America and refrigerated meat from Australasia, spatially, cities also expanded due to the development of public transport systems, which facilitated commutes of longer distances to the city centre for the working class. Urbanization rapidly spread across the Western world and, since the 1950s, at the turn of the 20th century, just 15% of the world population lived in cities. According to the UN the year 2007 witnessed the turning point when more than 50% of the population were living in cities. Living in a city can provide opportunities of proximity, diversity, as against this, there may be alienation issues, stress, increased cost of living, and negative social aspects that result from mass marginalization. In cities, money, services, wealth and opportunities are centralized, many rural inhabitants come to the city to seek their fortune and alter their social position. Businesses, which provide jobs and exchange capital, are concentrated in urban areas. Whether the source is trade or tourism, it is also through the ports or banking systems, commonly located in cities, many people move into cities for the economic opportunities, but this does not fully explain the very high recent urbanization rates in places like China and India. Rural flight is a factor to urbanization. Farm living has always been susceptible to environmental conditions, and in times of drought, flood or pestilence
Urbanization
–
Guangzhou, a city of 12.7 million people, is one of the 8 adjacent metropolises located in the largest single agglomeration on earth, ringing the
Pearl River Delta of China.
Urbanization
–
Mumbai is the
most populous city in India, and the fourth
most populous city in the world, with a total
metropolitan area population of approximately 23.9 million.
Urbanization
–
Centre of
São Paulo, one of the largest
metropolises in the world.
Urbanization
–
Population age comparison between rural
Pocahontas County, Iowa and urban
Johnson County, Iowa, illustrating the flight of young adults (red) to urban centres in
Iowa.
35.
Soil
–
Soil is a mixture of minerals, organic matter, gases, liquids, and countless organisms that together support life on Earth. Soil is called the Skin of the Earth and interfaces with the lithosphere, the hydrosphere, the atmosphere, the term pedolith, used commonly to refer to the soil, literally translates ground stone. Soil consists of a phase of minerals and organic matter, as well as a porous phase that holds gases. Accordingly, soils are often treated as a system of solids, liquids. Soil is a product of the influence of climate, relief, organisms, Soil continually undergoes development by way of numerous physical, chemical and biological processes, which include weathering with associated erosion. Given its complexity and strong internal connectedness soil has been considered as an ecosystem by soil ecologists. Most soils have a dry bulk density between 1.1 and 1.6 g/cm3, while the particle density is much higher. Little of the soil of planet Earth is older than the Pleistocene and none is older than the Cenozoic, Soil science has two basic branches of study, edaphology and pedology. Edaphology is concerned with the influence of soils on living things, pedology is focused on the formation, description, and classification of soils in their natural environment. In engineering terms, soil is referred to as regolith, or loose material that lies above the solid geology. Soil is commonly referred to as earth or dirt, technically, as soil resources serve as a basis for food security, the international community advocates its sustainable and responsible use through different types of soil governance. Soil is a component of the Earths ecosystem. The worlds ecosystems are impacted in far-reaching ways by the carried out in the soil, from ozone depletion and global warming, to rainforest destruction. Following the atmosphere, the soil is the next largest carbon reservoir on Earth, as the planet warms, soils will add carbon dioxide to the atmosphere due to its increased biological activity at higher temperatures. Thus, soil carbon losses likely have a positive feedback response to global warming. Since soil has a range of available niches and habitats. A gram of soil can contain billions of organisms, belonging to thousands of species, mostly microbial, Soil has a mean prokaryotic density of roughly 108 organisms per gram, whereas the ocean has no more than 107 procaryotic organisms per milliliter of seawater. Since plant roots need oxygen, ventilation is an important characteristic of soil and this ventilation can be accomplished via networks of interconnected soil pores, which also absorb and hold rainwater making it readily available for plant uptake
Soil
–
A represents soil; B represents
laterite, a
regolith; C represents
saprolite, a less-weathered regolith; the bottom-most layer represents
bedrock.
Soil
–
Loess field in Germany.
Soil
–
Surface-water-
gley developed in
glacial till, Northern Ireland.
Soil
–
Iron-rich soil near Paint Pots in
Kootenay National Park,
Canada
36.
Sediment
–
For sediment in beverages, see dregs. For example, sand and silt can be carried in suspension in water and on reaching the sea be deposited by sedimentation. Sediments are most often transported by water, but also wind, beach sands and river channel deposits are examples of fluvial transport and deposition, though sediment also often settles out of slow-moving or standing water in lakes and oceans. Desert sand dunes and loess are examples of transport and deposition. Glacial moraine deposits and till are ice-transported sediments, sediment can be classified based on its grain size and/or its composition. Sediment size is measured on a log base 2 scale, called the Phi scale, composition of sediment can be measured in terms of, parent rock lithology mineral composition chemical make-up. This leads to an ambiguity in which clay can be used as both a size-range and a composition, sediment is transported based on the strength of the flow that carries it and its own size, volume, density, and shape. Stronger flows will increase the lift and drag on the particle, causing it to rise, rivers and streams carry sediment in their flows. This sediment can be in a variety of locations within the flow and these relationships are shown in the following table for the Rouse number, which is a ratio of sediment fall velocity to upwards velocity. If the upwards velocity is less than the settling velocity, but still high enough for the sediment to move, it will move along the bed as bed load by rolling, sliding. If the upwards velocity is higher than the velocity, the sediment will be transported high in the flow as wash load. As there are generally a range of different particle sizes in the flow, sediment motion can create self-organized structures such as ripples, dunes, antidunes on the river or stream bed. These bedforms are often preserved in rocks and can be used to estimate the direction. Overland flow can erode soil particles and transport them downslope, the erosion associated with overland flow may occur through different methods depending on meteorological and flow conditions. If the initial impact of rain droplets dislodges soil, the phenomenon is called rainsplash erosion, if overland flow is directly responsible for sediment entrainment but does not form gullies, it is called sheet erosion. If the flow and the substrate permit channelization, gullies may form, glaciers carry a wide range of sediment sizes, and deposit it in moraines. The overall balance between sediment in transport and sediment being deposited on the bed is given by the Exner equation and this expression states that the rate of increase in bed elevation due to deposition is proportional to the amount of sediment that falls out of the flow. This can be localized, and simply due to obstacles, examples are scour holes behind boulders, where flow accelerates
Sediment
–
Cobbles on a beach
Sediment
–
River Rhône flowing into
Lake Geneva
Sediment
–
Sediment billowing out from Italy's shore into the
Adriatic Sea
Sediment
–
Sediment in the
Gulf of Mexico
37.
Heavy metals
–
Heavy metals are generally defined as metals with relatively high densities, atomic weights, or atomic numbers. The criteria used, and whether metalloids are included, vary depending on the author, more specific definitions have been published, but none of these have been widely accepted. The definitions surveyed in this article encompass up to 96 out of the 118 chemical elements, only mercury, lead, despite this lack of agreement, the term is widely used in science. A density of more than 5 g/cm3 is sometimes quoted as a commonly used criterion and is used in the body of this article. The earliest known metals—common metals such as iron, copper, and tin, and precious metals such as silver, gold, and platinum—are heavy metals. From 1809 onwards, light metals, such as magnesium, aluminium, and titanium, were discovered, as well as less well-known heavy metals including gallium, thallium, and hafnium. Some heavy metals are essential nutrients, or relatively harmless. Other heavy metals, such as cadmium, mercury, and lead, are highly poisonous, potential sources of heavy metal poisoning include mining and industrial wastes, agricultural runoff, occupational exposure, and paints and treated timber. Physical and chemical characterisations of heavy metals need to be treated with caution, as well as being relatively dense, heavy metals tend to be less reactive than lighter metals and have much less soluble sulfides and hydroxides. Heavy metals are scarce in the Earths crust but are present in many aspects of modern life. They are used in, for example, golf clubs, cars, antiseptics, self-cleaning ovens, plastics, solar panels, mobile phones, there is no widely agreed criterion-based definition of a heavy metal. Different meanings may be attached to the term, depending on the context, density criteria range from above 3.5 g/cm3 to above 7 g/cm3. Atomic weight definitions can range from greater than sodium, greater than 40, or more than 200, atomic numbers of heavy metals are generally given as greater than 20, sometimes this is capped at 92. Definitions based on atomic number have been criticised for including metals with low densities. For example, rubidium in group 1 of the table has an atomic number of 37 but a density of only 1.532 g/cm3. The same problem may occur with atomic weight based definitions, criteria based on chemical behaviour or periodic table position have been used or suggested. The United States Pharmacopeia includes a test for metals that involves precipitating metallic impurities as their coloured sulfides. The lanthanides satisfy Hawkes three-part description, the status of the actinides is not completely settled, in biochemistry, heavy metals are sometimes defined—on the basis of the Lewis acid behaviour of their ions in aqueous solution—as class B and borderline metals
Heavy metals
–
A 25-foot (7.6 m) wall of coal
fly ash contaminated with toxic heavy metals, resulting from the
release of 5.4 million cubic yards of coal fly ash slurry into the
Emory River,
Tennessee, and nearby land and water features, in December 2008. Testing showed significantly elevated levels of arsenic, copper,
barium, cadmium, chromium, lead, mercury, nickel, and thallium in samples of slurry and river water. Cleanup costs may exceed $1.2 billion.
Heavy metals
–
Orpiment, a toxic arsenic mineral used in the tanning industry to remove hair from hides.
Heavy metals
–
Saint Isaac's Cathedral, in
Saint Petersburg, Russia. The
gold -mercury
amalgam used to
gild its dome caused numerous casualties among the workers involved.
Heavy metals
–
Potassium chromate, a
carcinogen, is used in the dyeing of fabrics, and as a
tanning agent to produce
leather.
38.
Organic compound
–
An organic compound is virtually any chemical compound that contains carbon, although a consensus definition remains elusive and likely arbitrary. Organic compounds are rare terrestrially, but of importance because all known life is based on organic compounds. The most basic petrochemicals are considered the building blocks of organic chemistry, for historical reasons discussed below, a few types of carbon-containing compounds, such as carbides, carbonates, simple oxides of carbon, and cyanides are considered inorganic. The distinction between organic and inorganic compounds, while useful in organizing the vast subject of chemistry. Organic chemistry is the science concerned with all aspects of organic compounds, Organic synthesis is the methodology of their preparation. The word organic is historical, dating to the 1st century, for many centuries, Western alchemists believed in vitalism. This is the theory that certain compounds could be synthesized only from their classical elements—earth, water, air, vitalism taught that these organic compounds were fundamentally different from the inorganic compounds that could be obtained from the elements by chemical manipulation. Vitalism survived for a while even after the rise of modern atomic theory and it first came under question in 1824, when Friedrich Wöhler synthesized oxalic acid, a compound known to occur only in living organisms, from cyanogen. A more decisive experiment was Wöhlers 1828 synthesis of urea from the inorganic salts potassium cyanate, urea had long been considered an organic compound, as it was known to occur only in the urine of living organisms. Wöhlers experiments were followed by others, in which increasingly complex organic substances were produced from inorganic ones without the involvement of any living organism. Even though vitalism has been discredited, scientific nomenclature retains the distinction between organic and inorganic compounds, still, even the broadest definition requires excluding alloys that contain carbon, including steel. The C-H definition excludes compounds that are considered organic, neither urea nor oxalic acid is organic by this definition, yet they were two key compounds in the vitalism debate. The IUPAC Blue Book on organic nomenclature specifically mentions urea and oxalic acid, other compounds lacking C-H bonds but traditionally considered organic include benzenehexol, mesoxalic acid, and carbon tetrachloride. Mellitic acid, which contains no C-H bonds, is considered an organic substance in Martian soil. The C-H bond-only rule also leads to somewhat arbitrary divisions in sets of carbon-fluorine compounds, for example, CF4 would be considered by this rule to be inorganic, whereas CF3H would be organic. Organic compounds may be classified in a variety of ways, one major distinction is between natural and synthetic compounds. Another distinction, based on the size of organic compounds, distinguishes between small molecules and polymers, natural compounds refer to those that are produced by plants or animals. Many of these are extracted from natural sources because they would be more expensive to produce artificially
Organic compound
–
Methane is one of the simplest organic compounds
39.
Jurisdiction
–
Jurisdiction is the practical authority granted to a legal body to administer justice within a defined area of responsibility, e. g. Michigan tax law. In federations like the U. S. areas of jurisdiction apply to local, state, colloquially it is used to refer to the geographical area to which such authority applies, e. g. the court has jurisdiction over all of Colorado. The legal term refers only to the authority, not to a geographical area. International laws and treaties provide agreements which nations agree to be bound to, supranational organizations provide mechanisms whereby disputes between nations may be resolved through arbitration or mediation. When a country is recognized as de jure, it is an acknowledgment by the de jure nations that the country has sovereignty. However, it is often at the discretion of each nation whether to co-operate or participate, if a nation does agree to participate in activities of the supranational bodies and accept decisions, the nation is giving up its sovereign authority and thereby allocating power to these bodies. The fact that organizations, courts and tribunals have been created raises the difficult question of how to co-ordinate their activities with those of national courts. But, to invoke the jurisdiction in any case, all the parties have to accept the prospective judgment as binding. This reduces the risk of wasting the Courts time, each such group may form transnational institutions with declared legislative or judicial powers. For example, in Europe, the European Court of Justice has been given jurisdiction as the appellate court to the member states on issues of European law. This jurisdiction is entrenched and its authority could only be denied by a member if that member nation asserts its sovereignty. Hence, in the Netherlands, all treaties and the orders of international organizations are effective without any action being required to convert international into municipal law, in nations adopting this theory, the local courts automatically accept jurisdiction to adjudicate on lawsuits relying on international law principles. Otherwise the courts have a discretion to apply international law where it does not conflict with statute or the common law. According to the Supreme Court of the United States, the treaty power authorizes Congress to legislate under the Necessary and this concerns the relationships both between courts in different jurisdictions, and between courts within the same jurisdiction. The usual legal doctrine under which questions of jurisdiction are decided is termed forum non conveniens, to deal with the issue of forum shopping, nations are urged to adopt more positive rules on conflict of laws. In addition, the Lugano Convention binds the European Union and the European Free Trade Association, council Regulation 44/2001 now also applies as between the rest of the EU Member States and Denmark due to an agreement reached between the European Community and Denmark. In some legal areas, at least, the CACA enforcement of judgments is now more straightforward. At a national level, the rules still determine jurisdiction over persons who are not domiciled or habitually resident in the European Union or the Lugano area
Jurisdiction
–
United States Federal Civil Procedure doctrines
40.
Retention basin
–
A retention basin is used to manage stormwater runoff to prevent flooding and downstream erosion, and improve water quality in an adjacent river, stream, lake or bay. Sometimes called a wet pond or wet detention basin or stormwater management pond, it is a lake with vegetation around the perimeter. It is distinguished from a basin, sometimes called a dry pond, which temporarily stores water after a storm. It also differs from a basin which is designed to direct stormwater to groundwater through permeable soils. Wet ponds are used for water quality improvement, groundwater recharge, flood protection. Sometimes they act as a replacement for the absorption of a forest or other natural process that was lost when an area is developed. As such, these structures are designed to blend into neighborhoods, in urban areas, impervious surfaces reduce the time spent by rainfall before entering into the stormwater drainage system. If left unchecked, this will cause flooding downstream. The function of a pond is to contain this surge. This slow release mitigates the size and intensity of storm-induced flooding on downstream receiving waters, stormwater ponds also collect suspended sediments, which are often found in high concentrations in stormwater water due to upstream construction and sand applications to roadways. Storm water is channeled to a retention basin through a system of street and/or parking lot storm drains. The basins are designed to allow relatively large flows of water to enter, retention ponds are often landscaped with a variety of grasses, shrubs and/or wetland plants to provide bank stability and aesthetic benefits. Vegetation also provides water quality benefits by removing soluble nutrients through uptake, in some areas the ponds can attract nuisance types of wildlife like ducks or Canada geese, particularly where there is minimal landscaping and grasses are mowed. This reduces the ability of foxes, coyotes and other predators to approach their prey unseen, such predators tend to hide in the cattails and other tall, thick grass surrounding natural water features. Depth of retention ponds is of importance, for removal of pollutants
Retention basin
–
Trounce Pond, a retention basin landscaped with natural grassland plants, in
Saskatoon,
Saskatchewan,
Canada
Retention basin
–
The Corporate Park retention basin in
Stafford,
Texas
Retention basin
–
Retention basin in
Pinnau,
Germany
41.
Constructed wetland
–
A constructed wetland is an artificial wetland created for the purpose of treating anthropogenic discharge such as municipal or industrial wastewater, or stormwater runoff. It may also be created for land reclamation after mining, refineries, constructed wetlands are engineered systems that use natural functions of vegetation, soil, and organisms to treat different water streams. Depending on the type of wastewater that has to be treated the system has to be adjusted accordingly which means that pre- or post-treatments might be necessary. Constructed wetlands can be designed to emulate the features of natural wetlands, some constructed wetlands may also serve as a habitat for native and migratory wildlife, although that is usually not their main purpose. The two main types of constructed wetlands are subsurface flow and surface flow wetlands, the planted vegetation plays a role in contaminant removal but the filter bed, consisting usually of a combination of sand and gravel, has an equally important role to play. Many terms are used to denote constructed wetlands, such as reed beds, soil infiltration beds, constructed treatment wetlands, treatment wetlands, beside engineered wetlands, the terms of man-made or artificial wetlands are often found as well. A biofilter has some similarities with a wetland, but is usually without plants. However, the term of constructed wetlands can also be used to describe restored and recultivated land that was destroyed in the past through draining and converting into farmland, ponds for wastewater treatment or water purification are not considered as constructed wetlands. They are referred to as ponds or treatment ponds, respectively. A constructed wetland is a sequence of water bodies designed to filter and treat waterborne pollutants found in sewage. Constructed wetlands are used for treatment or for greywater treatment. They can be used after a tank for primary treatment. Some CW designs however do not use upfront primary treatment, vegetation in a wetland provides a substrate upon which microorganisms can grow as they break down organic materials. This community of microorganisms is known as the periphyton, the periphyton and natural chemical processes are responsible for approximately 90 percent of pollutant removal and waste breakdown. The plants remove about seven to ten percent of pollutants, different species of aquatic plants have different rates of heavy metal uptake, a consideration for plant selection in a constructed wetland used for water treatment. Constructed wetlands are of two types, subsurface flow and surface flow wetlands. Many regulatory agencies list treatment wetlands as one of their recommended best management practices for controlling urban runoff, in most cases, the bottom is lined with either a polymer geomembrane, concrete or clay in order to protect the water table and surrounding grounds. The substrate can be either gravel—generally limestone or pumice/volcanic rock, depending on local availability, subsurface flow wetlands can be further classified as horizontal flow and vertical flow constructed wetlands
Constructed wetland
–
Constructed wetland in an ecoological settlement in Flintenbreite near Luebeck, Germany
Constructed wetland
–
Effluent from a constructed wetland for
greywater treatment at an ecological housing estate in Hamburg-Allermoehe, Germany
Constructed wetland
–
Constructed wetland for domestic wastewater treatment in Bayawan City, the Philippines
Constructed wetland
–
Schematic of a vertical subsurface flow constructed wetland: Effluent flows through pipes on the subsurface of the ground through the root zone to the ground.
42.
Stormwater detention vault
–
A stormwater detention vault is an underground structure designed to manage excess stormwater runoff on a developed site, often in an urban setting. This type of best management practice may be selected when there is insufficient space on the site to infiltrate the runoff or build a facility such as a detention basin or retention basin. Detention vaults manage stormwater quantity flowing to nearby surface waters and they help prevent flooding and can reduce erosion in rivers and streams. They do not provide treatment to improve quality, though some are attached to a media filter bank to remove pollutants. Underground stormwater detention allows for high volume storage of runoff in a small footprint area, the storage vessels can be made from a variety of materials, including corrugated metal pipe, aluminum, steel, plastic, fiberglass, pre-cast or poured-in-place concrete. The vault is buried under a parking lot or other open land on the site. In the latter case this underground vault may be preferable to a detention pond if other uses are intended for the land. In other situations a vault is used because installing a pond might pose other problems, in some sites a vault may be installed in the basement of a building, such as a parking garage. The outlet is generally a restricted-flow drain from the detention vessel, Detention vessels delay waters delivery downstream, and possibly creates a later water level peak post-rainfall. It is important to consider timing of release and the types of reservoirs feeding a waterway. Best management practice for water pollution Detention basin Retention basin
Stormwater detention vault
–
A stormwater detention system during installation beneath a parking lot
43.
Media filter
–
One design brings the water in the top of a container through a header which distributes the water evenly. The filter media start with fine sand on the top and then graduatingly coarser sand in a number of layers followed by gravel on the bottom, the top sand physically removes particles from the water. The job of the subsequent layers is to support the finer layer above, municipal drinking water systems often use a rapid sand filter and/or a slow sand filter for purification. Media filters are used to water quality in streams, rivers. They can be effective at removing pollutants in such as suspended solids. Sand is the most common filter material, in other filters, sometimes called organic filters, wood chips or leaf mold may be used. Media filters are used for cleaning the effluent from septic tanks. The materials commonly used are sand, peat and natural stone fibre, biofilter Bioretention Rapid sand filter Slow sand filter
Media filter
–
Peat-Sand Filter in
United States. The filter treats
stormwater runoff from a residential area. Stormwater from streets is first routed to a small
detention basin (rear of photo, behind berm), which removes coarse
sediment. After filtration an under-drain piping system discharges the filtered water to an adjacent stream.
Media filter
–
Media filter system for
urban runoff
44.
Industrial effluent
–
Industrial wastewater treatment covers the mechanisms and processes used to treat wastewater that is produced as a by-product of industrial or commercial activities. After treatment, the industrial wastewater may be reused or released to a sanitary sewer or to a surface water in the environment. Most industries produce some wastewater although recent trends in the world have been to minimise such production or recycle such wastewater within the production process. However, many industries remain dependent on processes that produce wastewaters, a range of industries manufacture or use complex organic chemicals. These include pesticides, pharmaceuticals, paints and dyes, petrochemicals, detergents, plastics, paper pollution, treatment facilities that do not need control of their effluent typically opt for a type of aerobic treatment, i. e. aerated lagoons. Fossil-fuel power stations, particularly coal-fired plants, are a source of industrial wastewater. Many of these plants discharge wastewater with significant levels of such as lead, mercury, cadmium and chromium, as well as arsenic, selenium. Wastewater streams include flue-gas desulfurization, fly ash, bottom ash, plants with air pollution controls such as wet scrubbers typically transfer the captured pollutants to the wastewater stream. Ash ponds, a type of surface impoundment, are a widely used treatment technology at coal-fired plants and these ponds use gravity to settle out large particulates from power plant wastewater. This technology does not treat dissolved pollutants, power stations use additional technologies to control pollutants, depending on the particular wastestream in the plant. These include dry ash handling, closed-loop ash recycling, chemical precipitation, biological treatment, processing of food from raw materials requires large volumes of high grade water. Vegetable washing generates waters with high loads of particulate matter and some dissolved organic matter, animal slaughter and processing produces very strong organic waste from body fluids, such as blood, and gut contents. This wastewater is contaminated by significant levels of antibiotics and growth hormones from the animals. Processing food for sale produces wastes generated from cooking which are rich in plant organic material and may also contain salt, flavourings, colouring material. Very significant quantities of oil or fats may also be present, the production of iron from its ores involves powerful reduction reactions in blast furnaces. Cooling waters are inevitably contaminated with products especially ammonia and cyanide, production of coke from coal in coking plants also requires water cooling and the use of water in by-products separation. The conversion of iron or steel sheet, wire or rods requires hot. Contaminants include hydraulic oils, tallow and particulate solids, the two acids commonly used are hydrochloric acid and sulfuric acid
Industrial effluent
–
Mine wastewater effluent in Peru, with neutralized pH from tailing runoff.
Industrial effluent
–
Appropriate technology
Industrial effluent
–
Major types
45.
Activated sludge
–
The activated sludge process is a process for treating sewage and industrial wastewaters using air and a biological floc composed of bacteria and protozoa. The general arrangement of an activated sludge process for removing carbonaceous pollution includes the following items, settling tank to allow the biological flocs to settle, thus separating the biological sludge from the clear treated water. Treatment of nitrogenous matter or phosphate involves additional steps where the liquor is left in anoxic condition. Other important constituents include motile and sedentary Rotifers and this material is often described as sewage fungus but true fungal communities are relatively uncommon. The combination of wastewater and biological mass is known as mixed liquor. Part of the material, the sludge, is returned to the head of the aeration system to re-seed the new wastewater entering the tank. This fraction of the floc is called activated sludge. The space required for a treatment plant can be reduced by using a membrane bioreactor to remove some wastewater from the mixed liquor prior to treatment. This results in a concentrated waste product that can then be treated using the activated sludge process. Many sewage treatment plants use axial flow pumps to transfer nitrified mixed liquor from the zone to the anoxic zone for denitrification. These pumps are often referred to as mixed liquor recycle pumps. The raw sewage, the RAS, and the mixed liquor are mixed by submersible mixers in the anoxic zones in order to achieve denitrification. Activated sludge is also the given to the active biological material produced by activated sludge plants. Excess sludge is called activated sludge or waste activated sludge and is removed from the treatment process to keep the ratio of biomass to food supplied in the wastewater in balance. The amount of sludge produced from the activated sludge process is directly proportional to the amount of wastewater treated. The total sludge production consists of the sum of sludge from the primary sedimentation tanks as well as waste activated sludge from the bioreactors. The activated sludge process produces about 70–100 kg/ML of waste activated sludge, a value of 80 kg/ML is regarded as being typical. In addition, about 110–170 kg/ML of primary sludge is produced in the sedimentation tanks which most -
Activated sludge
–
Activated sludge tank at Beckton
sewage treatment plant, UK - the white bubbles are due to the diffused air aeration system
Activated sludge
–
Activated sludge addition (seeding) to a pilot scale membrane bioreactor in Germany
Activated sludge
–
Activated sludge under the microscope
Activated sludge
–
The
Davyhulme Sewage Works Laboratory, where the activated sludge process was developed in the early 20th century.
46.
Pollution
–
Pollution is the introduction of contaminants into the natural environment that cause adverse change. Pollution can take the form of chemical substances or energy, such as noise, pollutants, the components of pollution, can be either foreign substances/energies or naturally occurring contaminants. Pollution is often classed as point source or nonpoint source pollution, Air pollution has always accompanied civilizations. Pollution started from prehistoric times when man created the first fires, metal forging appears to be a key turning point in the creation of significant air pollution levels outside the home. The burning of coal and wood, and the presence of horses in concentrated areas made the cities the cesspools of pollution. The Industrial Revolution brought an infusion of untreated chemicals and wastes into local streams that served as the water supply, king Edward I of England banned the burning of sea-coal by proclamation in London in 1272, after its smoke became a problem. But the fuel was so common in England that this earliest of names for it was acquired because it could be carted away from some shores by the wheelbarrow and it was the industrial revolution that gave birth to environmental pollution as we know it today. London also recorded one of the extreme cases of water quality problems with the Great Stink on the Thames of 1858. Pollution issues escalated as population growth far exceeded view ability of neighborhoods to handle their waste problem, reformers began to demand sewer systems, and clean water. In 1870, the conditions in Berlin were among the worst in Europe. There were no toilets in the streets or squares. Visitors, especially women, often became desperate when nature called, in the public buildings the sanitary facilities were unbelievably primitive. As a metropolis, Berlin did not emerge from a state of barbarism into civilization until after 1870. Chicago and Cincinnati were the first two American cities to enact laws ensuring cleaner air in 1881, as historian Martin Melosi notes, The generation that first saw automobiles replacing the horses saw cars as miracles of cleanliness. By the 1940s, however, automobile-caused smog was an issue in Los Angeles. Other cities followed around the country early in the 20th century. Extreme smog events were experienced by the cities of Los Angeles and Donora, Pennsylvania in the late 1940s, Air pollution would continue to be a problem in England, especially later during the industrial revolution, and extending into the recent past with the Great Smog of 1952. Awareness of atmospheric pollution spread widely after World War II, with fears triggered by reports of fallout from atomic warfare. Then a non-nuclear event, The Great Smog of 1952 in London and this prompted some of the first major modern environmental legislation, The Clean Air Act of 1956
Pollution
–
The
litter problem on the coast of
Guyana, 2010
Pollution
–
Air pollution in the US, 1973
Pollution
–
Smog Pollution in
Taiwan
Pollution
–
The
Lachine Canal in
Montreal,
Quebec, Canada.
47.
Secondary treatment
–
After this kind of treatment, the wastewater may be called as secondary-treated wastewater. Secondary treatment is the portion of a treatment sequence removing dissolved. Secondary treatment is applied to the liquid portion of sewage after primary treatment has removed settleable solids. Secondary treatment is performed by indigenous, aquatic microorganisms in a managed aerobic habitat. Bacteria and protozoa consume biodegradable soluble organic contaminants while reproducing to form cells of biological solids, biological oxidation processes are sensitive to temperature and, between 0 °C and 40 °C, the rate of biological reactions increase with temperature. Most surface aerated vessels operate at between 4 °C and 32 °C, primary treatment of sewage by quiescent settling allows separation of floating material and heavy solids from liquid waste. The remaining liquid usually contains less than half of the solids content and approximately two-thirds of the BOD in the form of colloids. Where nearby water bodies can rapidly dilute this liquid waste, primary treated sewage may be discharged so natural biological decomposition oxidizes remaining waste, the city of San Diego used Pacific Ocean dilution of primary treated effluent into the 21st century. The United States Environmental Protection Agency defined secondary treatment based on the performance observed at late 20th-century bioreactors treating typical United States municipal sewage, secondary treated sewage is expected to produce effluent with a monthly average of less than 30 mg/l BOD and less than 30 mg/l suspended solids. Weekly averages may be up to 50 percent higher, a sewage treatment plant providing both primary and secondary treatment is expected to remove at least 85 percent of the BOD and suspended solids from domestic sewage. The regulations also recognize the difficulty of meeting the specified removal percentages from combined sewers, dilute industrial wastewater, glacial sand deposits allowed some northeastern United States cities to use intermittent sand filtration until more compact secondary treatment bioreactors became available. Biological nutrient removal is regarded by some sanitary engineers as secondary treatment, the differentiation may also differ from one country to another. The purpose of treatment is to provide a final treatment stage to further improve the effluent quality before it is discharged to the receiving environment. Tertiary treatment may include biological nutrient removal, disinfection and removal of micropollutants, process upsets are temporary decreases in treatment plant performance caused by significant population change within the secondary treatment ecosystem. Conditions likely to create upsets include for example toxic chemicals and unusually high or low concentrations of organic waste BOD providing food for the bioreactor ecosystem, Waste containing biocide concentrations exceeding the secondary treatment ecosystem tolerance level may kill a major fraction of one or more important ecosystem species. Waste containing unusually low BOD concentrations may fail to sustain the secondary treatment population required for normal waste concentrations, the reduced population surviving the starvation event may be unable to completely utilize available BOD when waste loads return to normal. Dilution may be caused by addition of large volumes of relatively uncontaminated water such as runoff into a combined sewer. Smaller sewage treatment plants may experience dilution from cooling water discharges, major plumbing leaks, firefighting, a similar problem occurs as BOD concentrations drop when low flow increases waste residence time within the secondary treatment bioreactor
Secondary treatment
–
This small secondary
clarifier at a rural sewage treatment plant is a typical phase separation mechanism to remove biological solids formed in a suspended growth or fixed-film bioreactor.
48.
Microfiltration
–
It is commonly used in conjunction with various other separation processes such as ultrafiltration and reverse osmosis to provide a product stream which is free of undesired contaminants. Microfiltration usually serves as a pre-treatment for other processes such as ultrafiltration. The typical particle size used for ranges from about 0.1 to 10 µm. In terms of molecular weight these membranes can separate macromolecules of molecular weights generally less than 100,000 g/mol. The filters used in the process are specially designed to prevent particles such as, sediment, algae. A pump is fitted onto the processing equipment to allow the liquid to pass through the membrane filter. There are also two pump configurations, either pressure driven or vacuum, a differential or regular pressure gauge is commonly attached to measure the pressure drop between the outlet and inlet streams. See Figure 1 for a general setup, the most abundant use of microfiltration membranes are in the water, beverage and bio-processing industries. The exit process stream after treatment using a micro-filter has a rate which generally ranges to about 90-98 %. Perhaps the most prominent use of microfiltration membranes pertains to the treatment of water supplies. The membranes are a key step in the disinfection of the uptake water stream. Such a stream might contain pathogens such as the protozoa Cryptosporidium, both species show a gradual resistance to traditional disinfectants. The use of MF membranes presents a physical means of separation as opposed to a chemical alternative, in this sense, both filtration and disinfection take place in a single step, negating the extra cost of chemical dosage and the corresponding equipment. Similarly, the MF membranes are used in wastewater effluents to remove turbidity. At this stage, coagulants may potentially be added to precipitate species such as phosphorus, another crucial application of MF membranes lies in the cold sterilisation of beverages and pharmaceuticals. Historically, heat was used to sterilize refreshments such as juice, wine and beer in particular, similarly, pharmaceuticals have been shown to lose their effectiveness upon heat addition. MF membranes are employed in industries as a method to remove bacteria and other undesired suspensions from liquids, a procedure termed as ‘cold sterilisation’. Furthermore, microfiltration membranes are finding increasing use in such as petroleum refining
Microfiltration
–
Figure 1: Overall setup for a microfiltration system
49.
Stream
–
A stream is a body of water with a current, confined within a bed and banks. Streams are important as conduits in the cycle, instruments in groundwater recharge. The biological habitat in the vicinity of a stream is called a riparian zone. Given the status of the ongoing Holocene extinction, streams play an important corridor role in connecting fragmented habitats, the study of streams and waterways in general is known as surface hydrology and is a core element of environmental geography. Brook A stream smaller than a creek, especially one that is fed by a spring or seep and it is usually small and easily forded. A brook is characterised by its shallowness and its bed being composed primarily of rocks, creek In North America, Australia and New Zealand, a small to medium-sized natural stream. Sometimes navigable by motor craft and may be intermittent, in parts of Maryland, New England, the UK and India, a tidal inlet, typically in a salt marsh or mangrove swamp, or between enclosed and drained former salt marshes or swamps. In these cases, the stream is the stream, the course of the seawater through the creek channel at low. River A large natural stream, which may be a waterway, runnel the linear channel between the parallel ridges or bars on a shoreline beach or river floodplain, or between a bar and the shore. Tributary A contributory stream, or a stream which does not reach the sea, sometimes also called a branch or fork. There are a number of names for a stream. Allt is used in Highland Scotland, beck is used in Yorkshire, Lancashire, Dumfriesshire, Cumbria, Norfolk, and Lincolnshire. Bourne or winterbourne is used in the chalk downland of southern England, brook is used in the Midlands, Lancashire and Cheshire. Burn is used in Scotland and North East England, gill or ghyll is seen in the north of England and other areas influenced by Old Norse. Rivulet is an term encountered in Victorian era publications, stream is used in Southern England. Syke is used in lowland Scotland and Cumbria for a seasonal stream, branch is used to name streams in Maryland and Virginia. Falls is also used to name streams in Maryland, for streams/rivers which have waterfalls on them, little Gunpowder Falls and The Jones Falls are actually rivers named in this manner, unique to Maryland. Kill in New York, Pennsylvania, Delaware, and New Jersey comes from a Dutch language word meaning riverbed or water channel, run in Ohio, Maryland, Michigan, New Jersey, Pennsylvania, Virginia, or West Virginia can be the name of a stream
Stream
–
Rocky stream in Italy
Stream
–
Stream in
Arkhangelsk Oblast, Russia
Stream
–
A rocky creek in
Spearfish Canyon,
South Dakota, US
Stream
–
Creek in
Heathcote National Park, Australia
50.
River
–
A river is a natural flowing watercourse, usually freshwater, flowing towards an ocean, sea, lake or another river. In some cases a river flows into the ground and becomes dry at the end of its course without reaching another body of water, small rivers can be referred to using names such as stream, creek, brook, rivulet, and rill. There are no official definitions for the term river as applied to geographic features. Many names for small rivers are specific to geographic location, examples are run in parts of the United States, burn in Scotland and northeast England. Sometimes a river is defined as being larger than a creek, but not always, Rivers are part of the hydrological cycle. Potamology is the study of rivers while limnology is the study of inland waters in general. Extraterrestrial rivers of liquid hydrocarbons have recently found on Titan. Channels may indicate past rivers on other planets, specifically outflow channels on Mars and rivers are theorised to exist on planets, a river begins at a source, follows a path called a course, and ends at a mouth or mouths. The water in a river is confined to a channel. In larger rivers there is also a wider floodplain shaped by flood-waters over-topping the channel. Floodplains may be wide in relation to the size of the river channel. This distinction between river channel and floodplain can be blurred, especially in areas where the floodplain of a river channel can become greatly developed by housing. Rivers can flow down mountains, through valleys or along plains, the term upriver refers to the direction towards the source of the river, i. e. against the direction of flow. Likewise, the term describes the direction towards the mouth of the river. The term left bank refers to the bank in the direction of flow. The river channel typically contains a stream of water, but some rivers flow as several interconnecting streams of water. Extensive braided rivers are now found in only a few regions worldwide and they also occur on peneplains and some of the larger river deltas. Anastamosing rivers are similar to braided rivers and are quite rare
River
–
Melting toe of Athabasca Glacier,
Jasper National Park,
Alberta, Canada
River
–
The River Cam from the Green Dragon Bridge, Cambridge (United Kingdom)
River
–
Nile River delta, as seen from Earth orbit. The Nile is an example of a wave-dominated delta that has the classic Greek letter delta (Δ) shape after which river deltas were named.
River
–
A radar image of a 400-kilometre (250 mi) river of methane and ethane near the north pole of Saturn's moon
Titan
51.
Bay
–
A bay is a recessed, coastal body of water that directly connects to a larger main body of water, such as an ocean, lake, or another bay. A large bay may be called a gulf, sea, sound, a cove is a type of smaller bay with a circular inlet and narrow entrance. A fjord is a particularly steep bay shaped by glacial activity, bays can be the estuary of a river, such as the Chesapeake Bay, an estuary of the Susquehanna River, which is the largest bay in North America. Bays may also be nested within each other, for example, some large bays, such as the Bay of Bengal and the Hudson Bay, have varied marine geology. The land surrounding a bay often reduces the strength of winds, bays were significant in the history of human settlement because they provided a safe place for fishing. Later they were important in the development of sea trade as the safe anchorage they provide encouraged their selection as ports, there are various ways from which bays can be created. The largest bays have developed as a result of plate tectonics, as the super-continent Pangaea broke up along curved and indented fault lines, the continents moved apart and the worlds largest bays formed. These include the Gulf of Guinea, Gulf of Mexico and the Bay of Bengal, another way bays form is via glacial and river erosion. A bay formed by a glacier is a fjord, rias are created by rivers and are characterised by more gradual slopes. Currents can make waves more constant, and soft rocks speed erosion, hard rock eroded less quickly, leaving headlands. The Gulf of California is an example of a bay created by plate tectonics as Baja California peninsula moves away from the Mexican mainland, Bay platform Great capes Headlands and bays
Bay
–
The bay at
San Sebastián,
Spain
Bay
–
The bay of
Baracoa,
Cuba
Bay
52.
Lagoon
–
A lagoon is a shallow body of water separated from a larger body of water by barrier islands or reefs. Lagoons are commonly divided into coastal lagoons and atoll lagoons and they have also been identified as occurring on mixed-sand and gravel coastlines. There is an overlap between bodies of water classified as coastal lagoons and bodies of water classified as estuaries, lagoons are common coastal features around many parts of the world. Lagoons can also be man-made and used for treatment, as is the case for e. g. aerated lagoons. Lagoons are shallow, often elongated bodies of water separated from a body of water by a shallow or exposed shoal, coral reef. Some authorities include fresh water bodies in the definition of lagoon, the distinction between lagoon and estuary also varies between authorities. Richard A. Davis Jr. restricts lagoon to bodies of water with little or no fresh water inflow, and little or no tidal flow, Davis does state that the terms lagoon and estuary are often loosely applied, even in scientific literature. Timothy M. Kusky characterizes lagoons as normally being elongated parallel to the coast, while estuaries are usually drowned river valleys, coastal lagoons are classified as inland bodies of water. Many lagoons do not include lagoon in their common names, in England, The Fleet at Chesil Beach has also been described as a lagoon. In Latin America, the term laguna in Spanish, which translates to. However, sometimes it is used to describe a full-sized lake, such as Laguna Catemaco in Mexico. The brackish water lagoon may be explicitly identified as a coastal lagoon. In Portuguese the same usage is found, lagoa may be a body of sea water. Lagoon is derived from the Italian laguna, which refers to the waters around Venice, Laguna is attested in English by at least 1612, and had been Anglicized to lagune by 1673. In 1697 William Dampier referred to a Lagune or Lake of Salt water on the coast of Mexico, captain James Cook described an island of Oval form with a Lagoon in the middle in 1769. Atoll lagoons form as coral reefs grow upwards while the islands that the reefs surround subside, unlike the lagoons that form shoreward of fringing reefs, atoll lagoons often contain some deep portions. Coastal lagoons form along gently sloping coasts where barrier islands or reefs can develop off-shore, coastal lagoons do not form along steep or rocky coasts, or if the range of tides is more than 4 metres. Due to the slope of the coast, coastal lagoons are shallow
Lagoon
–
Balos coastal lagoon of northwestern
Crete. The shallow lagoon is separated from the Mediterranean sea by narrow shoals connecting to a small, rocky mountain.
Lagoon
–
Garabogaz-Göl lagoon in
Turkmenistan
Lagoon
–
Coastal lagoon landscapes around the island of
Hiddensee near
Stralsund,
Germany. Many similar coastal lagoons can be found around the
Western Pomerania Lagoon Area National Park.
Lagoon
–
Aerial photograph of the Rakaia river-mouth and associated hapua
53.
Wetland
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A wetland is a land area that is saturated with water, either permanently or seasonally, such that it takes on the characteristics of a distinct ecosystem. The primary factor that distinguishes wetlands from other forms or water bodies is the characteristic vegetation of aquatic plants. Wetlands play a number of roles in the environment, principally water purification, flood control, carbon sink, Wetlands are also considered the most biologically diverse of all ecosystems, serving as home to a wide range of plant and animal life. Wetlands occur naturally on every continent except Antarctica, the largest including the Amazon River basin, the West Siberian Plain, the water found in wetlands can be freshwater, brackish, or saltwater. The main wetland types include swamps, marshes, bogs, and fens, and sub-types include mangrove, carr, pocosin, the UN Millennium Ecosystem Assessment determined that environmental degradation is more prominent within wetland systems than any other ecosystem on Earth. International conservation efforts are being used in conjunction with the development of rapid assessment tools to people about wetland issues. Constructed wetlands can be used to treat municipal and industrial wastewater as well as stormwater runoff and they may also play a role in water-sensitive urban design. A patch of land that develops pools of water after a storm would not be considered a wetland. Wetlands have unique characteristics, they are distinguished from other water bodies or landforms based on their water level. Specifically, wetlands are characterized as having a table that stands at or near the land surface for a long enough period each year to support aquatic plants. A more concise definition is a community composed of hydric soil, Wetlands have also been described as ecotones, providing a transition between dry land and water bodies. In environmental decision-making, there are subsets of definitions that are agreed upon to make regulatory and policy decisions. A wetland is an ecosystem that arises when inundation by water produces soils dominated by anaerobic processes, There are four main kinds of wetlands – marsh, swamp, bog and fen. Some experts also recognize wet meadows and aquatic ecosystems as additional wetland types, the largest wetlands in the world include the swamp forests of the Amazon and the peatlands of Siberia. Under the Ramsar international wetland conservation treaty, wetlands are defined as follows, Article 2.1, may incorporate riparian and coastal zones adjacent to the wetlands, and islands or bodies of marine water deeper than six metres at low tide lying within the wetlands. Although the general definition given above applies around the world, each county, Wetlands generally include swamps, marshes, bogs and similar areas. This definition has been used in the enforcement of the Clean Water Act, some US states, such as Massachusetts and New York, have separate definitions that may differ from the federal governments. It is not uncommon for a wetland to be dry for long portions of the growing season, the most important factor producing wetlands is flooding
Wetland
–
Laguna de Rocha, the largest wetland in the urban area in
Esteban Echeverría Partido,
Argentina
Wetland
–
Mangrove
swamps are coastal wetlands. This swamp is in the
Florida Everglades.
Wetland
–
Peat bogs are freshwater wetlands that develop in areas with
standing water and low
soil fertility.
Wetland
–
Marshes develop along the edges of rivers and lakes.
54.
Irrigation
–
Irrigation is the method in which a controlled amount of water is supplied to plants at regular intervals for agriculture. It is used to assist in the growing of crops, maintenance of landscapes. Additionally, irrigation also has a few uses in crop production. In contrast, agriculture that only on direct rainfall is referred to as rain-fed or dry land farming. Irrigation systems are used for dust suppression, disposal of sewage. Irrigation is often studied together with drainage, which is the natural or artificial removal of surface and sub-surface water from a given area, Irrigation has been a central feature of agriculture for over 5,000 years and is the product of many cultures. Historically, it was the basis for economies and societies across the globe, archaeological investigation has found evidence of irrigation where the natural rainfall was insufficient to support crops for rainfed agriculture. Ancient Egyptians practiced Basin irrigation using the flooding of the Nile to inundate land plots which had surrounded by dykes. The flood water was held until the sediment had settled before the surplus was returned to the watercourse. The Ancient Nubians developed a form of irrigation by using a device called a sakia. Irrigation began in Nubia some time between the third and second millennium BCE and it largely depended upon the flood waters that would flow through the Nile River and other rivers in what is now the Sudan. In sub-Saharan Africa irrigation reached the Niger River region cultures and civilizations by the first or second millennium BCE and was based on wet season flooding, terrace irrigation is evidenced in pre-Columbian America, early Syria, India, and China. These canals are the earliest record of irrigation in the New World, traces of a canal possibly dating from the 5th millennium BCE were found under the 4th millennium canal. Large scale agriculture was practiced and a network of canals was used for the purpose of irrigation. Ancient Persia as far back as the 6th millennium BCE, where barley was grown in areas where the rainfall was insufficient to support such a crop. The Qanats, developed in ancient Persia in about 800 BCE, are among the oldest known irrigation methods still in use today and they are now found in Asia, the Middle East and North Africa. The system comprises a network of wells and gently sloping tunnels driven into the sides of cliffs. The noria, a wheel with clay pots around the rim powered by the flow of the stream, was first brought into use at about this time
Irrigation
–
Irrigation canal near
Channagiri,
Davangere District,
India
Irrigation
–
Irrigation in a field in New Jersey, United States
Irrigation
–
An
irrigation sprinkler watering a lawn
Irrigation
–
Irrigation canal in
Osmaniye,
Turkey
55.
Groundwater recharge
–
Groundwater recharge or deep drainage or deep percolation is a hydrologic process where water moves downward from surface water to groundwater. Recharge is the method through which water enters an aquifer. This process usually occurs in the zone below plant roots and is often expressed as a flux to the water table surface. Recharge occurs both naturally and through anthropogenic processes, where rainwater and or reclaimed water is routed to the subsurface, groundwater is recharged naturally by rain and snow melt and to a smaller extent by surface water. Recharge may be impeded somewhat by human activities including paving, development and these activities can result in loss of topsoil resulting in reduced water infiltration, enhanced surface runoff and reduction in recharge. Use of groundwaters, especially for irrigation, may lower the water tables. Recharge can help move excess salts that accumulate in the zone to deeper soil layers. Tree roots increase water saturation into groundwater reducing water runoff, flooding temporarily increases river bed permeability by moving clay soils downstream, and this increases aquifer recharge. Artificial groundwater recharge is becoming important in India, where over-pumping of groundwater by farmers has led to underground resources becoming depleted. Another environmental issue is the disposal of waste through the water such as dairy farms, industrial. Wetlands help maintain the level of the table and exert control on the hydraulic head. This provides force for groundwater recharge and discharge to other waters as well, the extent of groundwater recharge by a wetland is dependent upon soil, vegetation, site, perimeter to volume ratio, and water table gradient. Groundwater recharge occurs through mineral soils found primarily around the edges of wetlands The soil under most wetlands is relatively impermeable, a high perimeter to volume ratio, such as in small wetlands, means that the surface area through which water can infiltrate into the groundwater is high. Groundwater recharge is typical in small wetlands such as prairie potholes, researchers have discovered groundwater recharge of up to 20% of wetland volume per season. If water falls uniformly over a field such that capacity of the soil is not exceeded. If instead water puddles in low-lying areas, the water volume concentrated over a smaller area may exceed field capacity resulting in water that percolates down to recharge groundwater. The larger the relative contributing runoff area is, the more focused infiltration is, the recurring process of water that falls relatively uniformly over an area, flowing to groundwater selectively under surface depressions is depression focused recharge. Water tables rise under such depressions, depression focused groundwater recharge can be very important in arid regions
Groundwater recharge
–
Air
Groundwater recharge
–
Water balance
56.
Process flow diagram
–
A process flow diagram is a diagram commonly used in chemical and process engineering to indicate the general flow of plant processes and equipment. The PFD displays the relationship between major equipment of a plant facility and does not show minor details such as piping details, another commonly used term for a PFD is a flowsheet. Rules and symbols are available from organizations such as DIN. Often PFDs are produced on large sheets of paper, PFDs of many commercial processes can be found in the literature, specifically in encyclopedias of chemical technology, although some might be outdated. To find recent ones, patent databases such as available from the United States Patent. Chemical Engineering Design Project, A Case Study Approach, analysis, Synthesis, and Design of Chemical Processes. Process Flow Sheet The PFD at The Engineering Tool Box Simplified process flowsheets, development of new integration methods and model flow diagrams
Process flow diagram
–
Some typical elements from process flow diagrams, as provided by the
open source program,
Dia. Click for image legend.
. PMID 22138989. doi:10.1128/AEM.07113-11.
