Manure management refers to capture, storage, treatment, and utilization of animal
manure
Manure is organic matter that is used as organic fertilizer in agriculture. Most manure consists of animal feces; other sources include compost and green manure. Manures contribute to the Soil fertility, fertility of soil by adding organic ma ...
s in an environmentally sustainable manner. It can be retained in various holding facilities. Animal manure (also referred to as animal waste) can occur in a liquid, slurry, or solid form. It is utilized by distribution on fields in amounts that enrich soils without causing water pollution or unacceptably high levels of nutrient enrichment. Manure management is a component of
nutrient management
Nutrient management is the science and practice directed to link soil, crop, weather, and hydrologic factors with cultural, irrigation, and soil and water conservation practices to achieve optimal nutrient use efficiency, crop yields, crop quali ...
.
In confined spaces the gasses from manure can lethally asphyxiate humans. There is also a drowning danger.
Risks posed by gases in livestock manure
Livestock manure produces several gases including four main toxic gases, hydrogen sulfide, methane, ammonia and carbon dioxide.
In animal housing it is very common in swine and beef breeding to have manure storage under the building's floor. In this setup low concentrations of these toxic gases are commonly noted throughout the year.
The highest concentrations of these gases are noted during manure agitation, stirring the manure to homogenize the manure for pumping out of the storage. During these times the concentrations easily approach levels that can pose health issues to the workers and animals in the facilities.
Hydrogen sulfide
Hydrogen Sulfide (), is a naturally occurring gas that is flammable, colorless and poisonous.
H2S has a characteristic rotten egg smell, though pungent at first it quickly deadens the sense of smell.
People are typically only able to smell at low concentrations.
is heavier than air causing the gas to travel close to the ground and collect in low-lying areas.
Common names for hydrogen sulfide include
hydrosulfuric acid (the product of it reacting with water), stink damp and sewer gas.
Sources of hydrogen sulfide exposure
Hydrogen sulfide naturally occurs in hot springs, crude petroleum and natural gas.
is also produced from the bacterial breakdown of animal and human wastes and organic materials in the absence of oxygen (
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 Waste management, manage waste or to produce fuels. Mu ...
).
is also a common metabolic end product of
sulfate reducing bacteria
Sulfate-reducing microorganisms (SRM) or sulfate-reducing prokaryotes (SRP) are a group composed of sulfate-reducing bacteria (SRB) and sulfate-reducing archaea (SRA), both of which can perform anaerobic respiration utilizing sulfate () as termina ...
which convert sulfates and hydrocarbons into carbon dioxide and hydrogen sulfide in the absence of free oxygen. There are multiple industrial sources of hydrogen sulfide. Such sources include: natural gas/petroleum drilling and refining, wastewater treatment, coke ovens, tanneries and paper mills.
Hydrogen sulfide is found in hydrocarbons both directly as an impurity and is produced by sulfate reducing microorganisms which can "eat" methane or other hydrocarbons, using sulfate as the electron receptor, similar to how aerobic metabolism uses oxygen. Other non-industrial sources of include emissions from livestock facilities and the land applications of animal manure.
[Hoff, Steven J.; Harmon, Jay D.; Bundy, Dwaine S.; and Zelle, Brian C., "Hydrogen Sulfide and Ammonia Receptor Concentrations in a Community of Multiple Swine Emission Sources: Preliminary Study" (2008). ''Agricultural and Biosystems Engineering Publications''. 86. http://lib.dr.iastate.edu/abe_eng_pubs/86][Muhlbauer, Ross V.; Swestka, Randy John; Burns, Robert T.; Xin, Hongwei; Hoff, Steven J.; and Li, Hong, "Development and Testing of a Hydrogen Sulfide Detection System for Use in Swine Housing" (2008). ''Agricultural and Biosystems Engineering Conference Proceedings and Presentations''. 145. http://lib.dr.iastate.edu/abe_eng_conf/145] During the agitation or mixing of swine manure in a deep pit storage system the concentration of hydrogen sulfide was observed in one study at levels exceeding 300 ppm inside the barn.
In a study examining the concentration of hydrogen sulfide in a residential cohort during manure application, it was reported the levels never exceeded the Agency for Toxic Substances and Disease Registry acute exposure MRL of 70 ppb and only 14 readings at 1-minute intervals reported levels above the intermediate exposure MRL of 20 ppb.
There are currently strong recommendations from both Pork Producer Associations and Land Grant Universities that suggest having to employees in a barn during agitation and pumping, maintain proper ventilation levels during agitation and pumping of manure, and to not enter a manure storage without proper equipment and training.
Effects
Acute
Hydrogen sulfide is most commonly inhaled, though through prolonged exposure skin and eye irritations resulting in painful dermatitis and burning eyes can occur.
Symptoms of acute exposure include nausea, headaches, disturbed equilibrium, tremors, convulsions and skin and eye irritations.
At high levels, inhalation of hydrogen sulfide will result in unconsciousness and death due to its effect on the body resulting in the lack of oxygen use in the cells.
the typical odor threshold for H2S is 0.01 to 1.5 ppm with the loss of smell occurring at levels around levels of 100 to 150 ppm.
Concentrations of 500 to 700 ppm can result in death within 30 to 60 minutes, 700 to 1000 ppm result in death within minutes, while death is nearly instantaneous at levels of 1000 to 2000 ppm.
Chronic
Chronic exposure to hydrogen sulfide can cause several long term health issues, though does not accumulate in the body.
Repeated or prolonged exposures have been reported to cause low blood pressure, headache, loss of appetite, chronic cough, inflammation of the eye membrane, weight loss and ataxia.
Regulations for exposures
The Occupational Safety and Health Administration (OSHA) and National Institute for Occupational Safety and Health (NIOSH) have set recommended exposure limits (REL NIOSH) and permissible exposure limits (PEL OSHA) for exposure in the workplace.
NIOSH's REL for a 10-minute maximum exposure is 10 ppm, OSHA's PEL for general industry, i.e. agriculture, construction, etc., is 20 ppm and OSHA's PEL levels are enforceable.
NIOSH also reports an IDLH or immediately dangerous to life and health, at 100 ppm, this is the level at which the effects of exposure would interfere with a person's ability to escape.
See also
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Manure
Manure is organic matter that is used as organic fertilizer in agriculture. Most manure consists of animal feces; other sources include compost and green manure. Manures contribute to the Soil fertility, fertility of soil by adding organic ma ...
*
Concentrated Animal Feeding Operation
In animal husbandry, a concentrated animal feeding operation (CAFO), as defined by the United States Department of Agriculture (USDA), is an intensive animal farming, intensive animal feeding operation (AFO) in which over 1,000 animal units are c ...
*
Animal feeding operation
The United States Environmental Protection Agency (EPA) defines an animal feeding operation (AFO) in the Code of Federal Regulations (CFR, Federal Register, V. 68 No. 1, page 7265) as a lot or facility (other than an aquatic animal production fac ...
*
Slurry pit
A slurry pit, also known as a farm slurry pit, slurry tank, slurry lagoon or slurry store, is a hole, dam, or circular concrete structure where farmers gather all their animal waste together with other unusable organic matter, such as hay and wa ...
*
Atmospheric methane
Atmospheric methane is the methane present in Earth's atmosphere. Atmospheric methane concentrations are of interest because it is one of the most potent greenhouse gases in Earth's atmosphere. Atmospheric methane is rising.
The 20-year globa ...
References
Report for Congress: Agriculture: A Glossary of Terms, Programs, and Laws, 2005 Edition
External links
Animal Manure Management on http://eXtension.orgAnimal Manure Management on http://eXtension.orgAnimal Manure Nutrient Management on http://eXtension.org
{{DEFAULTSORT:Manure management
Agricultural soil science
Feces
Organic fertilizers
Livestock