Sewage farm

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Morestead Sewage Farm, located in Hampshire, England. Morestead Sewage Farm - geograph.org.uk - 57146.jpg
Morestead Sewage Farm, located in Hampshire, England.

Sewage farms use sewage for irrigation and fertilizing agricultural land. The practice is common in warm, arid climates where irrigation is valuable while sources of fresh water are scarce. Suspended solids may be converted to humus by microbes and bacteria in order to supply nitrogen, phosphorus and other plant nutrients for crop growth. Many industrialized nations use conventional sewage treatment plants nowadays instead of sewage farms. These reduce vector and odor problems; but sewage farming remains a low-cost option for some developing countries. Sewage farming should not be confused with sewage disposal through infiltration basins or subsurface drains.

Contents

Advantages

Sewage farming allows use for irrigation of water which might otherwise be wasted. Some of the nutrients and organic solids in wastewater can be usefully incorporated into soil and agricultural products rather than fouling natural aquatic environments. Pumping to the point of application may be the only requirement if the village is not at a higher elevation than the sewage farm. [1]

Disadvantages

Polluted runoff may occur from sewage irrigation of fields when entering wastewater and precipitation exceed evaporation and percolation capacity. [2]

Sewage is usually generated at a relatively constant rate, but irrigation is required only during dry weather, and is useful only while temperatures are high enough to promote plant growth. Over-irrigation causes soils to become septic, sour, or sewage-sick. [2] Arid climates may allow temporary storage of sewage in holding ponds while the soils dry out during non-growing seasons, but such storage may cause odor and aquatic insect problems, including mosquitoes. [1]

It may be impractical to protect the crops being grown from sewage contact. Even optimum situations like irrigating fruit trees with flow in surface ditches may involve some risk of pathogen transfer from the sewage to the edible fruit by birds, insects, and similar vectors. Pathogen transfer is more likely with ground crops, and practically unavoidable with spray irrigation. [2]

Similar wastewater systems

Subsurface distribution piping is problematic since it is vulnerable to root blockage and to damage during soil cultivation. Also obstruction of distribution piping by sewage solids discourages sewage farming when wastewater is not pre-treated as it is typically the case in a septic drain field.

Sewage farming should not be confused with wastewater disposal through infiltration basins or subsurface drains.

Plows or harrows may be used to periodically break up vegetation mats which are slowing surface disposal. [3]

Subsurface disposal typically uses pipes placed deep enough to minimize root penetration and often manages overlying vegetation to avoid growth of plants with deep root systems. [4]

History

A 19th-century sewage farm near Barking, England Sewage farm near Barking, 19th century Wellcome L0001123.jpg
A 19th-century sewage farm near Barking, England

As a predecessor to modern sewage treatment systems, household sewage was collected from towns and cities and transported to nearby farm lands. During the Middle Ages this was accomplished with hand-carried buckets, but as local populations grew, during the Industrial Revolution sanitary sewer systems were built. These used a network of pipes and pumps to transport sewage beyond the city boundaries to large rented grasslands, into which the sewage trickled down. Berlin once operated 20 sewage farms occupying about 10,000 hectares. [5]

In Wales, it was the common means of sewage treatment when cess-pits became unusable as the population grew in towns during the industrial revolution. [6] The initial response to overloaded local disposal was often a trunk sewer conveying sewage to the nearest river but as populations increased further, sewage farms were established. [7]

Some of these farms remained in use until the end of the 20th century, at which point it became apparent that as it was usually contaminated with infectious pathogens and sometimes with industrial waste, sewage was not always suitable for use as a fertilizer. Therefore, sewage plants began to replace sewage farms. Modern sewage farms are usually combined with such plant, so that they irrigate the land with treated sewage (reclaimed water). Some types of untreated sewage can be used on a sewage farm, or filtered through a constructed wetland.

Examples

See also

Related Research Articles

Grey water Type of wastewater generated in households without toilet wastewater

Greywater refers to domestic 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 sinks, showers, baths, washing machines or dishwashers. As greywater contains fewer pathogens than domestic wastewater, it is generally safer to handle and easier to treat and reuse onsite for toilet flushing, landscape or crop irrigation, and other non-potable uses. Greywater may still have some pathogen content from laundering soiled clothing or cleaning the anal area in the shower or bath.

Wastewater Water that has been used and contaminated

Wastewater is water after it has been used in a variety of applications. A more detailed definition for wastewater is "Used water from any combination of domestic, industrial, commercial or agricultural activities, surface runoff/ stormwater, and any sewer inflow or sewer infiltration".

Septic tank method for basic wastewater treatment (on-site)

A septic tank is an underground chamber made of concrete, fiberglass, or plastic through which domestic wastewater (sewage) flows for basic treatment. Settling and anaerobic processes reduce solids and organics, but the treatment efficiency is only moderate. Septic tank systems are a type of simple onsite sewage facility (OSSF). They can be used in areas that are not connected to a sewerage system, such as rural areas. The treated liquid effluent is commonly disposed in a septic drain field, which provides further treatment. Nonetheless, groundwater pollution may occur and can be a problem.

Water pollution Contamination of water bodies

Water pollution is the contamination of water bodies, usually as a result of human activities, in such a manner that negatively affects its legitimate uses. Water bodies include for example lakes, rivers, oceans, aquifers, reservoirs and groundwater. Water pollution results when contaminants are introduced into these water bodies. For example, releasing inadequately treated wastewater into natural waters can lead to degradation of these aquatic ecosystems. All plants and organisms living in or being exposed to polluted water bodies can be impacted. The effects can damage individual species and impact the natural biological communities they are part of. Water pollution can also lead to water-borne diseases for people using polluted water for drinking, bathing, washing or irrigation.

Sanitary sewer Underground pipe or tunnel system for transporting sewage from houses or buildings to treatment facilities or disposal

A sanitary sewer or foul sewer is an underground pipe or tunnel system for transporting sewage from houses and commercial buildings to treatment facilities or disposal. Sanitary sewers are part of an overall system called a sewage system or sewerage.

Wastewater treatment Converting wastewater into an effluent for return to the water cycle

Wastewater treatment is a process used to remove contaminants from wastewater and convert it into an effluent that can be returned to the water cycle. Once returned to the water cycle, the effluent creates an acceptable impact on the environment or is reused for various purposes. The treatment process takes place in a wastewater treatment plant. There are several kinds of wastewater which are treated at the appropriate type of wastewater treatment plant. For domestic wastewater, the treatment plant is called a sewage treatment plant. For industrial wastewater, treatment either takes place in a separate industrial wastewater treatment plant, or in a sewage treatment plant. Further types of wastewater treatment plants include agricultural wastewater treatment plants and leachate treatment plants.

Constructed wetland An artificial wetland to treat municipal or industrial wastewater, greywater or stormwater runoff

A constructed wetland (CW) is an artificial wetland to treat municipal or industrial wastewater, greywater or stormwater runoff. It may also be designed for land reclamation after mining, or as a mitigation step for natural areas lost to land development. Constructed wetlands are engineered systems that use natural functions vegetation, soil, and organisms to treat wastewater. Depending on the type of wastewater the design of the constructed wetland has to be adjusted accordingly. Constructed wetlands have been used to treat both centralized and on-site wastewater. Primary treatment is recommended when there is a large amount of suspended solids or soluble organic matter.

Agricultural wastewater treatment Farm management for controlling pollution from confined animal operations and surface runoff

Agricultural wastewater treatment is a farm management agenda for controlling pollution from confined animal operations and from surface runoff that may be contaminated by chemicals in fertilizer, pesticides, animal slurry, crop residues or irrigation water. Agricultural wastewater treatment is required for continuous confined animal operations like milk and egg production. It may be performed in plants using mechanized treatment units similar to those used for industrial wastewater. Where land is available for ponds, settling basins and facultative lagoons may have lower operational costs for seasonal use conditions from breeding or harvest cycles. Animal slurries are usually treated by containment in anaerobic lagoons before disposal by spray or trickle application to grassland. Constructed wetlands are sometimes used to facilitate treatment of animal wastes.

Septic drain field Type of subsurface wastewater disposal facility

Septic drain fields, also called leach fields or leach drains, are subsurface wastewater disposal facilities used to remove contaminants and impurities from the liquid that emerges after anaerobic digestion in a septic tank. Organic materials in the liquid are catabolized by a microbial ecosystem.

Onsite sewage facilities (OSSF), also called septic systems, are wastewater systems designed to treat and dispose of effluent on the same property that produces the wastewater, in areas not served by public sewage infrastructure.

An aerobic treatment system (ATS), often called an aerobic septic system, is a small scale sewage treatment system similar to a septic tank system, but which uses an aerobic process for digestion rather than just the anaerobic process used in septic systems. These systems are commonly found in rural areas where public sewers are not available, and may be used for a single residence or for a small group of homes.

A mound system is an engineered drain field for treating wastewater in places with limited access to multi-stage wastewater treatment systems. Mound systems are an alternative to the traditional rural septic system drain field. They are used in areas where septic systems are prone to failure from extremely permeable or impermeable soils, soil with the shallow cover over porous bedrock, and terrain that features a high water table.

Sewage treatment Process of removing contaminants from municipal wastewater

Sewage treatment is a type of wastewater treatment which aims to remove contaminants from sewage. Sewage contains wastewater from households and businesses and possibly pre-treated industrial wastewater. Physical, chemical, and biological processes are used to remove contaminants and produce treated wastewater that is safe enough for release into the environment. A by-product of sewage treatment is a semi-solid waste or slurry, called sewage sludge. The sludge has to undergo further treatment before being suitable for disposal or application to land. The term "sewage treatment plant" is often used interchangeably with the term "wastewater treatment plant".

Sewage Wastewater that is produced by a community of people

Sewage is a type of wastewater that is produced by a community of people. It is typically transported through a sewer system (sewerage). Sewage consists of wastewater discharged from residences and from commercial, institutional and public facilities that exist in the locality. Sub-types of sewage are greywater and blackwater. Sewage also contains soaps and detergents, food waste ; and toilet paper. Sewage also contains micro-pollutants, municipal solid waste and pollutants from industrial wastewater.

Effluent sewer

Effluent sewer systems, also called septic tank effluent gravity (STEG) or solids-free sewer (SFS) systems, have septic tanks that collect sewage from residences and businesses, and the liquid fraction of sewage that comes out of the tank is conveyed to a downstream receiving body such as either a centralized sewage treatment plant or a distributed treatment system for further treatment or disposal away from the community generating the sewage. Most of the solids are removed by the interceptor tanks, so the treatment plant can be much smaller than a typical plant and any pumping for the supernatant can be simplier without grinders.

Urine-diverting dry toilet Dry toilet with separate collection of feces and urine without any flush water

A urine-diverting dry toilet (UDDT) is a type of dry toilet with urine diversion that can be used to provide safe, affordable sanitation in a variety of contexts worldwide. The separate collection of feces and urine without any flush water has many advantages, such as odor-free operation and pathogen reduction by drying. While dried feces and urine harvested from UDDTs can be and routinely are used in agriculture, many UDDTs installations do not apply any sort of recovery scheme. The UDDT is an example of a technology that can be used to achieve a sustainable sanitation system. This dry excreta management system is an alternative to pit latrines and flush toilets, especially where water is scarce, a connection to a sewer system and centralized wastewater treatment plant is not feasible or desired, fertilizer and soil conditioner are needed for agriculture, or groundwater pollution should be minimized.

Reuse of human excreta Safe, beneficial use of human excreta mainly in agriculture (after treatment)

Reuse of human excreta is the safe, beneficial use of treated human excreta after applying suitable treatment steps and risk management approaches that are customized for the intended reuse application. Beneficial uses of the treated excreta may focus on using the plant-available nutrients that are contained in the treated excreta. They may also make use of the organic matter and energy contained in the excreta. To a lesser extent, reuse of the excreta's water content might also take place, although this is better known as water reclamation from municipal wastewater. The intended reuse applications for the nutrient content may include: soil conditioner or fertilizer in agriculture or horticultural activities. Other reuse applications, which focus more on the organic matter content of the excreta, include use as a fuel source or as an energy source in the form of biogas.

Fecal sludge management Collection, transport, and treatment of fecal sludge from onsite sanitation systems

Fecal sludge management (FSM) is the collection, transport, and treatment of fecal sludge from pit latrines, septic tanks, or other onsite sanitation systems. Fecal sludge is a mixture of human excreta, water and solid wastes that are disposed of in pits, tanks or vaults of onsite sanitation systems. Fecal sludge that is removed from septic tanks is called septage.

Vermifilter Aerobic treatment system, consisting of a biological reactor containing media

A vermifilter is an aerobic treatment system, consisting of a biological reactor containing media that filters organic material from wastewater. The media also provides a habitat for aerobic bacteria and composting earthworms that purify the wastewater by removing pathogens and oxygen demand. The "trickling action" of the wastewater through the media dissolves oxygen into the wastewater, ensuring the treatment environment is aerobic for rapid decomposition of organic substances.

Decentralized wastewater system Processes to convey, treat and dispose or reuse wastewater from small communities and alike

Decentralized wastewater systems convey, treat and dispose or reuse wastewater from small and low-density communities, buildings and dwellings in remote areas, individual public or private properties. Wastewater flow is generated when appropriate water supply is available within the buildings or close to them.

References

  1. 1 2 Hutchins, Wells A. (March 1939). Sewage Irrigation as Practiced in the Western States. Washington DC: United States Department of Agriculture.
  2. 1 2 3 Fair, Gordon Maskew; Geyer, John Charles; Okun, Daniel Alexander (1968). Water and Wastewater Engineering: Water Purification and Wastewater Treatment and Disposal. 2. New York: John Wiley & Sons. p. 35-3.
  3. Reed, Sherwood C.; Middlebrooks, E. Joe; Crites, Ronald W. (1988). Natural Systems for Waste Management & Treatment. McGraw-Hill. pp.  220&246. ISBN   0-07-051521-2.
  4. Alth, Max & Charlotte (1984). Constructing & Maintaining Your Well & Septic System (First ed.). Tab Books. p.  213. ISBN   0-8306-0654-8.
  5. Berliner Rieselfelder [ failed verification ]
  6. "Welsh History Review - Vol. 14, nos. 1-4 1988-89 Merthyr Tydfil in the mid-Nineteenth Century: the struggle for public health". The National Library of Wales, Aberystwyth. Retrieved 23 October 2016.
  7. David Williams (1991). "The rehabilitation of the River Taff". National Rivers Authority. Retrieved 29 October 2016.