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.
[1]
: 6?8
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.
Nonpoint source pollution includes sediment runoff, nutrient runoff and pesticides. Point source pollution includes animal wastes, silage liquor, milking parlour (dairy farming) wastes, slaughtering waste, vegetable washing water and firewater. Many farms generate
nonpoint source pollution
from
surface runoff
which is not controlled through a treatment plant.
Farmers can install
erosion controls
to reduce runoff flows and retain soil on their fields.
[2]
[3]
: pp. 4-95?4-96
Common techniques include
contour plowing
, crop
mulching
,
crop rotation
, planting
perennial crops
and installing
riparian buffers
.
[4]
[3]
: pp. 4-95?4-96
Farmers can also develop and implement
nutrient management
plans to reduce excess application of nutrients
[4]
[3]
: pp. 4-37?4-38
and reduce the potential for
nutrient pollution
. To minimize pesticide impacts, farmers may use
Integrated Pest Management
(IPM) techniques (which can include
biological pest control
) to maintain control over pests, reduce reliance on chemical pesticides, and protect water quality.
[5]
Nonpoint source pollution
[
edit
]
Riparian buffer
lining a creek in
Iowa
Nonpoint source pollution
from farms is caused by
surface runoff
from fields during rain storms. Agricultural runoff is a major source of
pollution
, in some cases the only source, in many
watersheds
.
[6]
Sediment runoff
[
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]
Highly erodible soils on a farm in
Iowa
Soil
washed off fields is the largest source of
agricultural pollution
in the United States. Excess sediment causes high levels of
turbidity
in water bodies, which can inhibit growth of
aquatic plants
, clog
fish
gills
and smother animal
larvae
.
[6]
Farmers may utilize
erosion controls
to reduce runoff flows and retain soil on their fields. Common techniques include:
Nutrient runoff
[
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]
Manure spreader
Nitrogen
and
phosphorus
are key pollutants found in
runoff
, and they are applied to farmland in several ways, such as in the form of commercial
fertilizer
, animal
manure
, or municipal or industrial wastewater (effluent) or sludge. These chemicals may also enter runoff from
crop residues
,
irrigation
water,
wildlife
, and
atmospheric deposition
.
[3]
: p. 2?9
Farmers can develop and implement
nutrient management
plans to mitigate impacts on water quality by:
- mapping and documenting fields, crop types,
soil types
, water bodies
- developing realistic
crop yield
projections
- conducting
soil tests
and nutrient analyses of manures and/or sludges applied
- identifying other significant nutrient sources (e.g., irrigation water)
- evaluating significant field features such as highly erodible soils, subsurface drains, and shallow aquifers
- applying fertilizers, manures, and/or sludges based on realistic yield goals and using
precision agriculture
techniques.
[3]
: pp. 4-37?4-38
[9]
Pesticides
[
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]
Aerial application
(crop dusting) of
pesticides
over a
soybean
field in the U.S.
Pesticides
are widely used by farmers to control plant
pests
and enhance
production
, but chemical pesticides can also cause
water quality
problems. Pesticides may appear in
surface water
due to:
- direct application (e.g. aerial spraying or
broadcasting
over water bodies)
- runoff during rain storms
- aerial drift (from adjacent fields).
[3]
: p.2?22
Some pesticides have also been detected in
groundwater
.
[3]
: p.2?24
Farmers may use
Integrated Pest Management
(IPM) techniques (which can include
biological pest control
) to maintain control over pests, reduce reliance on chemical pesticides, and protect water quality.
[10]
[11]
There are few safe ways of disposing of pesticide surpluses other than through containment in well managed landfills or by
incineration
. In some parts of the world, spraying on land is a permitted method of disposal.
[12]
[13]
[
citation needed
]
Point source pollution and treatment steps
[
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]
Farms with large
livestock
and
poultry
operations, such as
factory farms
, can be a major source of
point source
wastewater. In the United States, these facilities are called
concentrated animal feeding operations
or
confined animal feeding operations
and are being subject to increasing government
regulation
.
[14]
Antibiotic-resistant bacteria
have been found to infiltrate the water cycle from farms. 73% of all antibiotics used globally are used in animal raising. As a result, wastewater treatment facilities can transfer antibiotic-resistant bacteria to humans.
[15]
[16]
Animal wastes
[
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]
Confined animal feeding operation in the United States
The constituents of animal wastewater typically contain
[17]
[18]
Animal wastes from cattle can be produced as solid or semisolid manure or as a liquid
slurry
. The production of slurry is especially common in housed dairy cattle.
- Treatment
Whilst solid manure heaps outdoors can give rise to polluting wastewaters from runoff, this type of waste is usually relatively easy to treat by containment and/or covering of the heap.
Animal slurries require special handling and are usually treated by containment in lagoons before disposal by spray or trickle application to grassland.
Constructed wetlands
are sometimes used to facilitate treatment of animal wastes, as are
anaerobic lagoons
. Excessive application or application to sodden land or insufficient land area can result in direct runoff to watercourses, with the potential for causing severe
pollution
. Application of slurries to land overlying
aquifers
can result in direct contamination or, more commonly, elevation of nitrogen levels as
nitrite
or nitrate.
The disposal of any wastewater containing animal waste upstream of a drinking water intake can pose serious health problems to those drinking the water because of the highly resistant spores present in many animals that are capable of causing disabling disease in humans. This risk exists even for very low-level seepage via shallow surface drains or from rainfall run-off.
Some animal slurries are treated by mixing with straws and
composted
at high temperature to produce a bacteriologically sterile and friable manure for soil improvement.
Piggery waste
[
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]
Hog
confinement barn or
piggery
Piggery waste is comparable to other animal wastes and is processed as for general animal waste, except that many piggery wastes contain elevated levels of
copper
that can be toxic in the natural environment. The liquid fraction of the waste is frequently separated off and re-used in the piggery to avoid the prohibitively expensive costs of disposing of copper-rich liquid.
Ascarid
worms and their eggs are also common in piggery waste and can infect humans if
wastewater treatment
is ineffective.
Silage liquor
[
edit
]
Fresh or wilted
grass
or other green crops can be made into a semi-
fermented
product called
silage
which can be stored and used as winter forage for cattle and sheep. The production of silage often involves the use of an acid conditioner such as
sulfuric acid
or
formic acid
. The process of silage making frequently produces a yellow-brown strongly smelling liquid which is very rich in simple
sugars
,
alcohol
, short-chain organic acids and silage conditioner. This liquor is one of the most polluting organic substances known. The volume of silage liquor produced is generally in proportion to the moisture content of the ensiled material.
- Treatment
Silage liquor is best treated through prevention by wilting crops well before silage making. Any silage liquor that is produced can be used as part of the food for pigs. The most effective treatment is by containment in a slurry lagoon and by subsequent spreading on land following substantial dilution with slurry. Containment of silage liquor on its own can cause structural problems in concrete pits because of the acidic nature of silage liquor.
Milking parlour (dairy farming) wastes
[
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]
Although milk is an important food product, its presence in wastewaters is highly polluting because of its organic strength, which can lead to very rapid
de-oxygenation
of receiving waters.
Milking parlour
wastes also contain large volumes of wash-down water, some animal waste together with cleaning and
disinfection
chemicals.
- Treatment
Milking parlour wastes are often treated in
admixture
with human sewage in a local
sewage treatment
plant. This ensures that disinfectants and cleaning agents are sufficiently diluted and amenable to treatment. Running milking wastewaters into a farm slurry lagoon is a possible option although this tends to consume lagoon capacity very quickly. Land spreading is also a treatment option.
[
citation needed
]
Slaughtering waste
[
edit
]
Wastewater from slaughtering activities is similar to milking parlour waste (see above) although considerably stronger in its organic composition and therefore potentially much more polluting.
- Treatment
As for milking parlour waste (see above).
Vegetable washing water
[
edit
]
Washing of
vegetables
produces large volumes of water contaminated by soil and vegetable pieces. Low levels of pesticides used to treat the vegetables may also be present together with moderate levels of disinfectants such as
chlorine
.
- Treatment
Most vegetable washing waters are extensively recycled with the solids removed by settlement and filtration. The recovered soil can be returned to the land.
Firewater
[
edit
]
Although few farms plan for fires, fires are nevertheless more common on farms than on many other industrial premises. Stores of pesticides, herbicides, fuel oil for farm machinery and fertilizers can all help promote fire and can all be present in environmentally lethal quantities in
firewater
from
fire fighting
at farms.
- Treatment
All farm environmental management plans should allow for containment of substantial quantities of firewater and for its subsequent recovery and disposal by specialist disposal companies.
[19]
The concentration and mixture of contaminants in firewater make them unsuited to any treatment method available on the farm. Even land spreading has produced severe taste and odour problems for downstream water supply companies in the past.
See also
[
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]
References
[
edit
]
- ^
Reed, Sherwood C. (1988).
Natural systems for waste management and treatment
. E. Joe Middlebrooks, Ronald W. Crites. New York: McGraw-Hill.
ISBN
0-07-051521-2
.
OCLC
16087827
.
- ^
"Erosion"
. Washington, DC: US Natural Resources Conservation Service. Archived from
the original
on 2021-04-14
. Retrieved
2020-11-19
.
- ^
a
b
c
d
e
f
g
h
National Management Measures to Control Nonpoint Source Pollution from Agriculture
(Report). EPA. July 2003. EPA 841-B-03-004.
- ^
a
b
U.S. Natural Resources Conservation Service (NRCS). Washington, DC.
"National Conservation Practice Standards."
National Handbook of Conservation Practices. Accessed 2015-10-02.
- ^
"Integrated Pest Management Principles"
.
Pest Control and Pesticide Safety for Consumers
. EPA. 2017-06-27.
- ^
a
b
U.S. Environmental Protection Agency (EPA). Washington, DC.
"Protecting Water Quality from Agricultural Runoff."
March 2005. Document No. EPA 841-F-05-001.
- ^
U.S. Natural Resources Conservation Service (NRCS). Fort Worth, TX.
National Conservation Practice Standard: Contour Farming."
[
permanent dead link
]
Code 330. June 2007.
- ^
NRCS.
National Conservation Practice Standard: Mulching."
[
permanent dead link
]
Code 484. September 2008.
- ^
NRCS.
"National Conservation Practice Standard: Nutrient Management."
[
permanent dead link
]
Code 590. August 2006.
- ^
NRCS.
National Conservation Practice Standard: Pest Management."
[
permanent dead link
]
Code 595. July 2008.
- ^
EPA.
"Integrated Pest Management Principles."
March 13, 2008.
- ^
Tietz, Jeff (December 14, 2006).
"Boss Hog"
(PDF)
.
Wetlands Preserve
. Retrieved
March 5,
2016
.
- ^
"Waste Pesticide Management"
(PDF)
.
Oregon.Gov
. State of Oregon Department of Environmental Quality Land Quality Division Hazardous Waste Program. Archived from
the original
(PDF)
on 2 February 2017
. Retrieved
5 October
2016
.
- ^
"Animal Feeding Operations"
.
National Pollutant Discharge Elimination System
. EPA. 2017-01-17.
- ^
"antibiotic-resistant soil bacteria: Topics by WorldWideScience.org"
.
worldwidescience.org
. Retrieved
2023-03-21
.
- ^
Bank, European Investment (2023-02-27).
"Microplastics and Micropollutants in Water: Contaminants of Emerging Concern"
.
- ^
Dairy Waste Anaerobic Digestion Handbook
Archived
October 15, 2013, at the
Wayback Machine
- ^
"Agricultural Waste"
.
usatanksales.com
. Archived from
the original
on 2013-12-10
. Retrieved
2013-10-15
.
- ^
"Managing Fire water and major spillages - Environment Agency Guidance note PPG18 ( retrieved 19 April 2009)"
(PDF)
. Archived from
the original
(PDF)
on 19 December 2007.
External links
[
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]