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An anaerobic lagoon or manure lagoon is a man-made outdoor earthen basin filled with animal waste that undergoes
anaerobic respiration Anaerobic respiration is respiration using electron acceptors other than molecular oxygen (O2). Although oxygen is not the final electron acceptor, the process still uses a respiratory electron transport chain. In aerobic organisms undergoing re ...
as part of a system designed to manage and treat refuse created by concentrated animal feeding operations (CAFOs). Anaerobic lagoons are created from a manure slurry, which is washed out from underneath the animal pens and then piped into the lagoon. Sometimes the slurry is placed in an intermediate holding tank under or next to the barns before it is deposited in a lagoon. Once in the lagoon, the manure settles into two layers: a solid or sludge layer and a liquid layer. The manure then undergoes the process of anaerobic respiration, whereby the volatile organic compounds are converted into
carbon dioxide Carbon dioxide ( chemical formula ) is a chemical compound made up of molecules that each have one carbon atom covalently double bonded to two oxygen atoms. It is found in the gas state at room temperature. In the air, carbon dioxide is tr ...
and
methane Methane ( , ) is a chemical compound with the chemical formula (one carbon atom bonded to four hydrogen atoms). It is a group-14 hydride, the simplest alkane, and the main constituent of natural gas. The relative abundance of methane on ...
. Anaerobic lagoons are usually used to pretreat high strength industrial wastewaters and municipal wastewaters. This allows for preliminary sedimentation of suspended solids as a pretreatment process. Anaerobic lagoons have been shown to harbor and emit substances which can cause adverse environmental and health effects. These substances are emitted through two main pathways: gas emissions and lagoon overflow. Gas emissions are continuous (though the amount may vary based on the season) and are a product of the manure slurry. The most prevalent gasses emitted by the lagoon are:
ammonia Ammonia is an inorganic compound of nitrogen and hydrogen with the formula . A stable binary hydride, and the simplest pnictogen hydride, ammonia is a colourless gas with a distinct pungent smell. Biologically, it is a common nitrogenous w ...
, hydrogen sulfide,
methane Methane ( , ) is a chemical compound with the chemical formula (one carbon atom bonded to four hydrogen atoms). It is a group-14 hydride, the simplest alkane, and the main constituent of natural gas. The relative abundance of methane on ...
, and
carbon dioxide Carbon dioxide ( chemical formula ) is a chemical compound made up of molecules that each have one carbon atom covalently double bonded to two oxygen atoms. It is found in the gas state at room temperature. In the air, carbon dioxide is tr ...
. Lagoon overflow is caused by faulty lagoons, such as breaches or improper construction, or adverse weather conditions, such as increased rainfall or strong winds. These overflows release harmful substances into the surrounding land and water such as: antibiotics, estrogens, bacteria, pesticides, heavy metals, and protozoa. In the U.S., the
Environmental Protection Agency A biophysical environment is a biotic and abiotic surrounding of an organism or population, and consequently includes the factors that have an influence in their survival, development, and evolution. A biophysical environment can vary in scal ...
(EPA) has responded to environmental and health concerns by strengthening regulation of CAFOs under the
Clean Water Act The Clean Water Act (CWA) is the primary federal law in the United States governing water pollution. Its objective is to restore and maintain the chemical, physical, and biological integrity of the nation's waters; recognizing the responsibilit ...
. Some states have imposed their own regulations as well. Because of repeated overflows and resultant health concerns,
North Carolina North Carolina () is a state in the Southeastern region of the United States. The state is the 28th largest and 9th-most populous of the United States. It is bordered by Virginia to the north, the Atlantic Ocean to the east, Georgia and ...
banned the construction of new anaerobic lagoons in 1999. There has also been a significant push for the research, development and implementation of environmentally sound technologies which would allow for safer containment and recycling of CAFO waste.


Background

Beginning in the 1950s with poultry production, and then later in the 1970s and 1980s with cattle and swine, meat producers in the United States have turned to CAFO as a way to more efficiently produce large quantities of meat. This switch has benefited the United States consumer by increasing the amount of meat that can be grown, thereby decreasing the price of meat. However, the increase in livestock has generated an increase in manure. In 2006, for example, livestock operations in the United States produced of manure. Unlike manure produced in a conventional farm, CAFO manure cannot all be used as direct fertilizer on agricultural land because of the poor quality of the manure. Moreover, CAFOs produce a high volume of manure. A feeding operation with 800,000 pigs could produce over of waste per year. The high quantity of manure produced by a CAFO must be dealt with in some way, as improper manure management can result in water, air and soil damage. As a result, manure collection and disposal has become an increasing problem. In order to manage their waste, CAFOs have developed
agricultural wastewater treatment 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 i ...
plans. To save on manual labor, many CAFOs handle manure waste as a liquid. In this system, the animals are kept in pens with grated floors so the waste and spray water can be drained from underfloor gutters and piped to storage tanks or anaerobic lagoons. Once at a lagoon, the purpose is to treat the waste and make it suitable for spreading on agricultural fields. There are three main types of lagoon: anaerobic, which is inhibited by oxygen; aerobic, which requires oxygen; and facultative, which is maintained with or without oxygen. Aerobic lagoons provide a higher degree of treatment with less odor production, though they require a significant amount of space and maintenance. Because of this demand, almost all livestock lagoons are anaerobic lagoons.


Design


Description

Anaerobic lagoons are earthen basins with a usual depth of , though greater depths are more beneficial to digestion as they minimize oxygen diffusion from the surface. To minimize leakage of animal waste into the ground water, newer lagoons are generally lined with clay Studies have shown that in fact the lagoons typically leak at a rate of approximately per day, with or without a clay liner, because it is the sludge deposited at the base of the lagoon that limits the leakage rate, not the clay liner or underlying native soil. Anaerobic lagoons are not heated, aerated or mixed. Anaerobic lagoons are most effective in warmer temperatures; anaerobic bacteria are ineffective below Lagoons must be separated from other structures by a certain distance to prevent contamination. States regulate this separation distance. The overall size of the lagoon is determined by addition of four components: minimum design volume, volume of manure storage between periods of disposal, dilution volume and the volume of sludge accumulation between periods of sludge removal.


Process

The lagoon is divided into two distinct layers: sludge and liquid. The sludge layer is a more solid layer formed by the stratification of sediments from the manure. After a while, this solid layer accumulates and eventually needs to be cleaned out. The liquid level is composed of grease, scum and other particulates. The liquid level CAFO wastewater enters at the bottom of the lagoon so that it can mix with the active microbial mass in the sludge layer. These anaerobic conditions are uniform throughout the lagoon, except in a small surface level. Sometimes aeration is applied to this level to dampen the odors emitted by the lagoons. If surface aeration is not applied, a crust will form that will trap heat and odors. Anaerobic lagoons should retain and treat wastewater from 20 to 150 days. Lagoons should be followed by aerobic or facultative lagoons to provide further required treatment. The liquid layer is periodically drained and used for fertilizer. In some instances, a cover can be provided to trap methane, which is used for energy. Anaerobic lagoons work through a process called
anaerobic digestion Anaerobic digestion is a sequence of processes by which microorganisms break down biodegradable material in the absence of oxygen. The process is used for industrial or domestic purposes to manage waste or to produce fuels. Much of the ferm ...
. Decomposition of the organic matter begins shortly after the animals void. Lagoons become anaerobic because of the high biological oxygen demand (BOD) of the feces, which contains a high level of soluble solids, resulting in higher BOD. Anaerobic microorganisms convert organic compounds into carbon dioxide and methane through acid formation and methane production.


Advantages of construction

* Manure can be easily manipulated with water using flushing systems, sewer lines, pumps and irrigation systems * Stabilization of the waste through digestion minimizes odor when manure is finally used as fertilizer * Manure is able to be stored long-term at a low cost * Manure is all in one area, instead of spread across a large area of land (This is called W.E.S., Waste Enlargement System).


Disadvantages of construction

*Requires relatively large area of land * Produces strong undesirable odors especially during spring and fall * Take a fairly long time for organic stabilization because of the slow rate of sludge digestion and slow growth rate of methane formers * Manure used as fertilizer is of lower quality because of low nutrient availability * Wastewater seepage may occur if the tanks break or are improperly constructed * Weather and other environmental elements can strongly affect the safety and efficacy of anaerobic lagoons


Environmental and health impacts


Gas emissions

Rates of asthma in children living near a CAFO are consistently elevated. The process of anaerobic digestion has been shown to release over 400 volatile compounds from lagoons. The most prevalent of these are: ammonia, hydrogen sulfide, methane, and carbon dioxide.


Ammonia

In the United States, 80 percent of ammonia emissions come from livestock production. A lagoon can vaporize up to 80 percent of its
nitrogen Nitrogen is the chemical element with the symbol N and atomic number 7. Nitrogen is a nonmetal and the lightest member of group 15 of the periodic table, often called the pnictogens. It is a common element in the universe, estimated at sevent ...
through the reaction: NH4+-N -> NH3 + H+. As pH or temperature increases, so does the amount of volatilized ammonia. Once ammonia has been volatilized, it can travel as far as 300 miles, and at closer ranges it is a respiratory irritant. Acidification and eutrophication of the ecosystem surrounding the lagoons could be caused by prolonged exposure to volatilized ammonia. This volatilized ammonia has been implicated in widespread ecological damage in Europe and is of growing concern for the United States.


Hydrogen sulfide

With averages greater than 30ppb, lagoons have high concentration of hydrogen sulfide, which is highly toxic. A study by the Minnesota Pollution Control Agency has found that concentrations of hydrogen sulfide near lagoons have exceeded the state standard, even as far away as 4.9 miles. Hydrogen sulfide is recognizable for its unpleasant rotten-egg odor. Because hydrogen sulfide is heavier than air, it tends to linger around lagoons even after ventilation. Levels of hydrogen sulfide are at their highest after agitation and during manure removal.


Methane

Methane is an odorless, tasteless, and colorless gas. Lagoons produce about 2,300,000 tonnes per year, with around 40 percent of this mass coming from hog farm lagoons. Methane is combustible at high temperatures, and explosions and fires are a real threat at or near lagoons. Additionally, methane is a greenhouse gas. The U.S. EPA estimated that 13 percent of all the
methane emissions Increasing methane emissions are a major contributor to the rising concentration of greenhouse gases in Earth's atmosphere, and are responsible for up to one-third of near-term global heating. During 2019, about 60% (360 million tons) of methane r ...
came from livestock manure in 1998, and this number has grown in recent years. Recently there has been interest in technology which would capture methane produced from lagoons and sell it as energy.


Water-soluble contaminants

Contaminants that are water-soluble can escape from anaerobic lagoons and enter the environment through leakage from badly constructed or poorly maintained manure lagoons as well as during excess rain or high winds, resulting in an overflow of lagoons. These leaks and overflows can contaminate surrounding surface and ground water with some hazardous materials which are contained in the lagoon. The most serious of these contaminants are pathogens, antibiotics, heavy metals and hormones. For example, runoff from farms in Maryland and North Carolina are a leading candidate for '' Pfiesteria piscicida.'' This contaminant has the ability to kill fish, and it can also cause skin irritation and short term memory loss in humans


Pathogens

More than 150 pathogens in manure lagoons that have been found to impact human health. Healthy individuals who come into contact with pathogens usually recover promptly. However, those who have a weakened immune system, such as cancer patients and young children, have an increased risk for a more severe illness or even death. About 20 percent of the U.S. population are categorized in this risk group. Some of the more notable pathogens are:


= ''E''. ''coli''

=
E. coli ''Escherichia coli'' (),Wells, J. C. (2000) Longman Pronunciation Dictionary. Harlow ngland Pearson Education Ltd. also known as ''E. coli'' (), is a Gram-negative, facultative anaerobic, rod-shaped, coliform bacterium of the genus '' Es ...
is found in the intestines and feces of both animal and humans. One particularly virulent strain, Escherichia coli O157:H7, is found specifically in the lumen of cattle raised in CAFOs. Because cattle are fed corn in CAFOs instead of grass, this changes the pH of the lumen so that it is more hospitable to ''E''. ''coli''. Grain-fed cattle have 80 percent more of this strain of ''E''. ''coli'' than grass-fed cattle. However, the amount of ''E''. ''coli'' found in the lumen of grain fed cattle can be significantly reduced by switching an animal to grass only a few days prior to slaughter. This reduction would decrease the pathogen's presence in both meat and waste of the cattle, and decrease the ''E''. ''coli'' population found in anaerobic lagoons.


= Cryptosporidium

=
Cryptosporidium ''Cryptosporidium'', sometimes informally called crypto, is a genus of apicomplexan parasitic alveolates that can cause a respiratory and gastrointestinal illness (cryptosporidiosis) that primarily involves watery diarrhea (intestinal crypto ...
is a parasite that causes diarrhea, vomiting, stomach cramps and fever. It is particularly problematic because it is resistant to most lagoon treatment regimens In a study performed in Canada, 37 percent of swine liquid-manure samples contained Cryptosporidium.


= Other common pathogens

= Other common pathogens (and their symptoms) include: *''Bacillus anthracis'', otherwise known as
Anthrax Anthrax is an infection caused by the bacterium '' Bacillus anthracis''. It can occur in four forms: skin, lungs, intestinal, and injection. Symptom onset occurs between one day and more than two months after the infection is contracted. The s ...
(skin sores, headache, fever, chills, nausea, vomiting) * Leptospira pomona (abdominal pain, muscle pain, vomiting, fever) *
Listeria monocytogenes ''Listeria monocytogenes'' is the species of pathogenic bacteria that causes the infection listeriosis. It is a facultative anaerobic bacterium, capable of surviving in the presence or absence of oxygen. It can grow and reproduce inside the hos ...
(fever, fatigue, nausea, vomiting, diarrhea) *
Salmonella ''Salmonella'' is a genus of rod-shaped (bacillus) Gram-negative bacteria of the family Enterobacteriaceae. The two species of ''Salmonella'' are ''Salmonella enterica'' and ''Salmonella bongori''. ''S. enterica'' is the type species and is f ...
(abdominal pain, diarrhea, nausea, chills, fever, headache) *
Clostridium tetani ''Clostridium tetani'' is a common soil bacterium and the causative agent of tetanus. Vegetative cells of ''Clostridium tetani'' are usually rod-shaped and up to 2.5 Ī¼m long, but they become enlarged and tennis racket- or drumstick-shaped wh ...
(violent muscle spasms, lockjaw, difficulty breathing) * Histoplasma capsulatum (fever, chills, muscle ache, cough rash, joint pain and stiffness) *''Microsporum'' and ''Trichophyton''
Ringworm Dermatophytosis, also known as ringworm, is a fungal infection of the skin. Typically it results in a red, itchy, scaly, circular rash. Hair loss may occur in the area affected. Symptoms begin four to fourteen days after exposure. Multiple ar ...
(itching, rash) *
Giardia lamblia ''Giardia duodenalis'', also known as ''Giardia intestinalis'' and ''Giardia lamblia'', is a flagellated parasitic microorganism of the genus '' Giardia'' that colonizes the small intestine, causing a diarrheal condition known as giardiasis. Th ...
(abdominal pain, abdominal gas, nausea, vomiting, fever) *
Cryptosporidium ''Cryptosporidium'', sometimes informally called crypto, is a genus of apicomplexan parasitic alveolates that can cause a respiratory and gastrointestinal illness (cryptosporidiosis) that primarily involves watery diarrhea (intestinal crypto ...
(diarrhea, dehydration, weakness, abdominal cramping) * Pfiesteria piscicida (neurological damage)


Antibiotics

Antibiotics are fed to livestock to prevent disease and to increase weight and development, so that there is a shortened time from birth to slaughter. However, because these antibiotics are administered at sub-therapeutic levels, bacterial colonies can build up resistance to the drugs through the
natural selection Natural selection is the differential survival and reproduction of individuals due to differences in phenotype. It is a key mechanism of evolution, the change in the heritable traits characteristic of a population over generations. Char ...
of bacteria resistant to these antibiotics. These antibiotic-resistant bacteria are then excreted and transferred to the lagoons, where they can infect humans and other animals. Each year, 24.6 million pounds of
antimicrobials An antimicrobial is an agent that kills microorganisms or stops their growth. Antimicrobial medicines can be grouped according to the microorganisms they act primarily against. For example, antibiotics are used against bacteria, and antifungals ar ...
are administered to livestock for non-therapeutic purposes. Seventy percent of all antibiotics and related drugs are given to animals as feed additives. Nearly half of the antibiotics used are nearly identical to ones given to humans. There is strong evidence that the use of antibiotics in animal feed is contributing to an increase in antibiotic-resistant microbes and causing antibiotics to be less effective for humans. Due to concerns over antibiotic-resistant bacteria, the
American Medical Association The American Medical Association (AMA) is a professional association and lobbying group of physicians and medical students. Founded in 1847, it is headquartered in Chicago, Illinois. Membership was approximately 240,000 in 2016. The AMA's st ...
passed a resolution stating its opposition to the use of sub-therapeutic levels of antimicrobials in livestock.


Hormones

Growth hormones such as rBST,
estrogen Estrogen or oestrogen is a category of sex hormone responsible for the development and regulation of the female reproductive system and secondary sex characteristics. There are three major endogenous estrogens that have estrogenic hormonal ac ...
, and
testosterone Testosterone is the primary sex hormone and anabolic steroid in males. In humans, testosterone plays a key role in the development of male reproductive tissues such as testes and prostate, as well as promoting secondary sexual characteristic ...
are administered to increase development rate and muscle mass for the livestock. Yet, only a fraction of these hormones are actually absorbed by the animal. The rest are excreted and wind up in lagoons. Studies have shown that these hormones, if they escape the lagoon and are emitted into the surrounding surface water, can alter fertility and reproductive habits of aquatic animals. One study found that several lagoons and monitoring wells from two facilities (a nursery and a farrowing sow operation) contained high levels of all three types of estrogen. For the nursery, lagoon effluent concentrations ranged from 390 to 620 ng/L for
estrone Estrone (E1), also spelled oestrone, is a steroid, a weak estrogen, and a minor female sex hormone. It is one of three major endogenous estrogens, the others being estradiol and estriol. Estrone, as well as the other estrogens, are synthesized ...
, 180 to 220 ng/L for
estriol Estriol (E3), also spelled oestriol, is a steroid, a weak estrogen, and a minor female sex hormone. It is one of three major endogenous estrogens, the others being estradiol and estrone. Levels of estriol in women who are not pregnant are almost ...
, and 40 to 50 ng/L for
estradiol Estradiol (E2), also spelled oestradiol, is an estrogen steroid hormone and the major female sex hormone. It is involved in the regulation of the estrous and menstrual female reproductive cycles. Estradiol is responsible for the development of ...
. For the farrowing sow operation, digester and primary lagoon effluent concentrations ranged from 9,600 to 24,900 ng/L for estrone, 5,000 to 10,400 ng/L for estriol, and 2,200 to 3,000 ng/L for estradiol. Ethinylestradiol was not detected in any of the lagoon or ground water samples. Natural estrogen concentrations in ground water samples were generally less than 0.4 ng/L, although, a few wells at the nursery operation showed quantifiable but low levels."


Heavy metals

Manure contains trace elements of many
heavy metals upright=1.2, Crystals of osmium, a heavy metal nearly twice as dense as lead">lead.html" ;"title="osmium, a heavy metal nearly twice as dense as lead">osmium, a heavy metal nearly twice as dense as lead Heavy metals are generally defined as ...
such as
arsenic Arsenic is a chemical element with the symbol As and atomic number 33. Arsenic occurs in many minerals, usually in combination with sulfur and metals, but also as a pure elemental crystal. Arsenic is a metalloid. It has various allotropes, but ...
,
copper Copper is a chemical element with the symbol Cu (from la, cuprum) and atomic number 29. It is a soft, malleable, and ductile metal with very high thermal and electrical conductivity. A freshly exposed surface of pure copper has a pinkish- ...
,
selenium Selenium is a chemical element with the symbol Se and atomic number 34. It is a nonmetal (more rarely considered a metalloid) with properties that are intermediate between the elements above and below in the periodic table, sulfur and tellurium, ...
,
zinc Zinc is a chemical element with the symbol Zn and atomic number 30. Zinc is a slightly brittle metal at room temperature and has a shiny-greyish appearance when oxidation is removed. It is the first element in group 12 (IIB) of the periodic t ...
,
cadmium Cadmium is a chemical element with the symbol Cd and atomic number 48. This soft, silvery-white metal is chemically similar to the two other stable metals in group 12, zinc and mercury. Like zinc, it demonstrates oxidation state +2 in most of ...
,
molybdenum Molybdenum is a chemical element with the symbol Mo and atomic number 42 which is located in period 5 and group 6. The name is from Neo-Latin ''molybdaenum'', which is based on Ancient Greek ', meaning lead, since its ores were confused with lea ...
,
nickel Nickel is a chemical element with symbol Ni and atomic number 28. It is a silvery-white lustrous metal with a slight golden tinge. Nickel is a hard and ductile transition metal. Pure nickel is chemically reactive but large pieces are slow to ...
,
lead Lead is a chemical element with the symbol Pb (from the Latin ) and atomic number 82. It is a heavy metal that is denser than most common materials. Lead is soft and malleable, and also has a relatively low melting point. When freshly cut, l ...
,
iron Iron () is a chemical element with symbol Fe (from la, ferrum) and atomic number 26. It is a metal that belongs to the first transition series and group 8 of the periodic table. It is, by mass, the most common element on Earth, right in fro ...
,
manganese Manganese is a chemical element with the symbol Mn and atomic number 25. It is a hard, brittle, silvery metal, often found in minerals in combination with iron. Manganese is a transition metal with a multifaceted array of industrial all ...
,
aluminum Aluminium (aluminum in American and Canadian English) is a chemical element with the symbol Al and atomic number 13. Aluminium has a density lower than those of other common metals, at approximately one third that of steel. It has ...
and
boron Boron is a chemical element with the symbol B and atomic number 5. In its crystalline form it is a brittle, dark, lustrous metalloid; in its amorphous form it is a brown powder. As the lightest element of the ''boron group'' it has th ...
. Sometimes these metals are given to animals as growth stimulants, some are introduced through pesticides used to rid livestock of insects, and some might pass through the animals as undigested food. Trace elements of these metals and salts from animal manure present risks to human health and ecosystems.


New River Spill

In 1999, Hurricane Floyd hit North Carolina, flooding hog waste lagoons, releasing 25 million gallons of manure into the New River and contaminating the water supply. Ronnie Kennedy, county director for environmental health, said that of 310 private wells he had tested for contamination since the storm, 9 percent, or three times the average across eastern North Carolina, had
fecal coliform A fecal coliform (British: faecal coliform) is a facultatively anaerobic, rod-shaped, gram-negative, non-sporulating bacterium. Coliform bacteria generally originate in the intestines of warm-blooded animals. Fecal coliforms are capable of growt ...
bacteria. Normally, tests showing any hint of feces in drinking water, an indication that it can be carrying disease-causing pathogens, are cause for immediate action.


Regulation

Anaerobic lagoons are built as part of a wastewater operation system. As such, compliance and permitting are handled as an extension of that operation. Therefore, manure lagoons are regulated on the state and national level through the CAFO which operates them. In recent years, because of the environmental and health effects associated with anaerobic lagoons, the EPA has increased regulation of CAFOs with a specific eye towards lagoons. North Carolina banned the construction of new anaerobic lagoons in 1999 and upheld that ban in 2007.


Further research

Some research has been done to develop and assess the economic feasibility of more environmentally superior technologies. Five main alternatives which have been implemented in North Carolina are: a solids separation/nitrificationā€“denitrification/soluble phosphorus removal system; a thermophilic anaerobic digester system; a centralized composting system; a gasification system; and a fluidized-bed combustion system. These systems were judged based on their ability to: reduce impacts of CAFO waste in the surface and groundwater, decrease ammonia emissions, decrease the escape of disease-transmitting pathogens, and lower the concentration of heavy metal contamination. The
U.S. Department of Agriculture The United States Department of Agriculture (USDA) is the federal executive department responsible for developing and executing federal laws related to farming, forestry, rural economic development, and food. It aims to meet the needs of com ...
(USDA) has also evaluated the prospect of creating a
cap and trade Emissions trading is a market-based approach to controlling pollution by providing economic incentives for reducing the emissions of pollutants. The concept is also known as cap and trade (CAT) or emissions trading scheme (ETS). Carbon emission t ...
program for CAFO's carbon dioxide and nitrous oxide emissions. This program has yet to be implemented, however the USDA speculates that such a program would encourage corporations to adopt EST practices. A comprehensive study of anaerobic swine lagoons nationwide has been launched by the U.S.
Agricultural Research Service The Agricultural Research Service (ARS) is the principal in-house research agency of the United States Department of Agriculture (USDA). ARS is one of four agencies in USDA's Research, Education and Economics mission area. ARS is charged with ext ...
. This study aims to explore the composition of lagoons and anaerobic lagoon influence on environmental factors and agronomic practices.


See also

*
Agricultural wastewater treatment 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 i ...
*
Anaerobic digestion Anaerobic digestion is a sequence of processes by which microorganisms break down biodegradable material in the absence of oxygen. The process is used for industrial or domestic purposes to manage waste or to produce fuels. Much of the ferm ...
* Aerated lagoon * Factory farming * List of waste water treatment technologies *
Sewage treatment Sewage treatment (or domestic wastewater treatment, municipal wastewater treatment) is a type of wastewater treatment which aims to remove contaminants from sewage to produce an effluent that is suitable for discharge to the surrounding en ...


References


External links

*{{Commons category-inline Waste management Sewerage