Best Management Practices (BMPs) for Mitigating Ammonia Emissions from Livestock Operations

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Best Management Practices (BMPs) for Mitigating
Ammonia Emissions from Livestock Operations
Pius Ndegwa Biological Systems Engineering
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Strategies for Reducing Ammonia Losses

• Reducing NH3 or NH4 formation or production.
• Reducing volatile N species (Mostly NH3 But also
  NH4).
• Physical containment of NH3 or NH4 after their
  formation.

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Strategy 1 - Reducing NH3 or NH4 Production
Diet Changes

• First line of defense in reducing ammonia loss is
  reducing excretion!

IN
OUT
Balance!
Amino Acid Phenylalanine
Protein Amino acids Combo
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Strategy 1 - Dietary Changes Non-Ruminants

• Avoid over-feeding proteins!
• Nutrient balance An average of 8 reduction in N
  excretion per unit of crude protein (CP)
  reduction (substitution with AA).

IN
OUT
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Strategy 1 - Dietary Changes Ruminants

• Avoid over-feeding proteins.
• Reduce N excretion by
• Reducing CP in the diet.
• Ruminal N balance Feed optimal ruminally
  degradable proteins (RDP) and supplement/w RUP or
  with ruminally-protected AA.
• Decreasing RUP during late lactation.

OUT
IN
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Strategy 2 Reducing Volatile N Species (NH3 But
also NH4)

• Urine-feces segregation, inhibition of urea
  hydrolysis.
• pH reduction.
• Binding ammonium.
• Bioconversion to non-volatile N species.

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Strategy 2 Urine-feces segregation, inhibition
of urea hydrolysis

• Urease enzyme is only in feces but NOT in urine.
• Reducing contact between feces and urine thus
  minimizes urea hydrolysis to ammonium N thus
  mitigating ammonia loss from separated urine.

• Urine-feces segregation reduce NH3 emissions from
  the barns by about 50 compared to the
  conventional manure handling systems.

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Strategy 2 pH reduction

• Acidification

Animal Species Agent or substance Emissions reduction ()
Cattle and pig Sulfuric acid 14-100
Cattle Hydrochloric acid 90
Cattle and pig Phosphoric acid 50
Pig Phosphoric acid 90
Broiler Alum 89
Cattle Alum 91-98
Cattle Calcium chloride 71-78
Poultry and cattle Calcium chloride 10-15
Cattle Monocalcium phosphate monohydrate 87
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Strategy 2 Binding ammonium

• This category of substances have a high affinity
  for holding onto NH4 ions thus reducing NH3
  volatilization through decreased concentration of
  free NH4 ions

Animal Species Binding Agent Emissions reduction ()
Poultry Zeolite 1.5-96
Pig Zeolite 71
Pig Sphagnum moss 80-99
Poultry Sphagnum moss 24
Pig Saponins (yucca extract) 23
Pig Alliance 24
Poultry De-Odorase 50
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Strategy 2 Binding ammonium

• Selection of appropriate application methods for
  effective use of these additives is very
  important. Currently, there is a lack of
  standardized application and evaluation protocols
  for these additives.

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Strategy 2 Bioconversion to non-volatile N
species

• Transformation of volatile N species to
  non-volatile species is a major biological
  treatment process comprising of coupled
  nitrification and denitrification processes.
• When designed and ran appropriately, these
  systems can reduce NH3 losses by as high as 99.
• It appears that the major hindrance is the
  economics of installing and operating the
  systems.

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Strategy 3 Physical containment of NH3 or NH4
after their formation.

• Emissions capture and treatment
• Filtration and biofiltration
• Impermeable and permeable covers
• Land application strategies

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Strategy 3 Biofilters

• Biofilter performances range is fairly wide
  9-100
• Wide range of biofilter-materials
• Need for optimum moisture
• Residence time difference
• Ammonia load difference
• Microbial community establishment
• Bottom Line Well designed and ran systems can
  effectively mitigate NH3 emissions from livestock
  operations.

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Strategy 3 Impermeable covers

• These are physical covers to contain the
  emissions.
• Impermeable covers trap released gases and thus
  are regularly used in conjunction with
  biofilters.

Inflatable
Floating
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Strategy 3 Permeable covers

• Permeable covers trap and bio-transform NH3 just
  like biofilters.
• Examples of materials used for permeable covers
  straw, cornstalks, peat moss, foam, geotextile
  fabric, and Leca rock.

No Support
Straw Application
Supported
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Permeable Impermeable Covers Performances
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Permeable Impermeable Covers Performances

• Impermeable covers are generally more effective
  (up to 100) than permeable covers in NH3
  mitigation.
• However, costs for covers vary widely depending
  on the material used and the method of
  application.
• Important to consider
• The length of the time the cover will be in
  place.
• Need for biofilters to clean up the gases trapped
  under impermeable cover.
• Excessive NH3 and other gaseous emissions may
  occur during land application.
• Removal and clean-up of the material left behind
  when the useful life of the cover is over.

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Strategy 3 Land Application Practices

• Significant NH3 volatilization can occur when
  manure is surface-spread to fertilize crop and
  pasture fields.
• Minimizing time of manure exposure on the ground
  surface is the most effective strategy for
  reducing NH3 emissions during or after field
  application of manure.

Tank Injector
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Land Application Performances
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Land Application Practices

• Direct manure injection or manure incorporation
  into the soil are the most effective (up to 98)
  for mitigating NH3 emissions.
• The extra costs of injection or incorporating
  manure into the soil may be recaptured
• In terms of better crop yields because of more
  efficient utilization of the applied manure.
• Environmental benefits accruing from reduced NH3
  volatilization, as well as cost that may be
  incurred in litigating NH3 emissions.

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REFERENCES
Ndegwa PM, A. Hristov, J. Arogo, R. Sheffield. A
review of ammonia emissions mitigation strategies
from concentrated animal feeding operations.
Biosystems Engineering 100(4)453-469. POINTS
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