Will additional straw bedding in buildings housing cattle and pigs reduce ammonia emissions?

Posted in: Environment by admin on January 1, 2009 | No Comments

Buildings housing livestock are the second largest source of ammonia (NH3) emissions from UK agriculture. In the UK c. 42% of NH3 emissions from buildings are from those in which cattle and pigs are bedded on straw. Additional straw may reduce NH3 emission by reducing airflow across surfaces soiled by urine, and by immobilization of ammonium–N.

The object of this study was to quantify the effects of increasing straw use on NH3 emission from buildings housing cattle or pigs. The extra straw was applied in increments of up to 100%, either over the entire floor (broadcast) or targeted to the areas where most excreta were deposited. An increase of 33% straw, broadcast over the entire floor, reduced NH3
emission from cattle by 50%, but greater addition did not give any further significant reduction. However, for pigs only the broadcast addition of 100% more straw reduced NH3 emission and then by only c. 20%.

Targeted use of an additional 33% straw reduced emission from cattle by 22%, compared with broadcasting the same quantity of straw, but further additions of targeted straw use did not increase abatement. When the straw was targeted in the pig buildings there was no benefit from using additional straw. Thus optimum results may be obtained from an addition of 33% extra straw, targeted to the soiled areas for cattle, but 100% extra straw broadcast over the whole floor for pigs.

For more information the full article can be found at  http://www.sciencedirect.com/science/journal/15375110

Assessing the ventilation effectiveness of naturally ventilated livestock buildings under wind dominated conditions using computational fluid dynamics

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A computational fluid dynamics (CFD) model was developed to investigate the natural ventilation of a climatic livestock building under different wind incidences (WIs) for three different inlet opening areas. A 1⁄2 scale experimental duopitch building was employed to validate, both qualitatively and quantitatively, the CFD predictions of airflow distribution. To improve the applicability of CFD to building design, a thermal comfort index called the ‘‘minimum comfort temperature’’ was used in this study.

Results showed that ventilation rates were not at their highest when wind was blowing normal to the building because a considerable quantity of the flow exited the building via short-circuiting. However, the greatest ventilation homogeneity was experienced when the wind was blowing normal to the building, because of the formation of two
wind-driven vortices within the building. Results also showed that the highest level of environmental heterogeneity occurs at WIs of 10–40° because the primary vortex only occupies a portion of the total building volume. It was also found that in some circumstances the ventilation rate determined from the flow rate through the building openings may not accurately represent the actual ventilation rate of a building, and measurements/simulations of contaminant decay may form a more accurate measure of ventilation rate.

Greenhouse Gas Microbiology in Wet and Dry Straw Crust Covering Pig Slurry

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Liquid manure (slurry) storages are sources of gases such as ammonia (NH3) and methane (CH4). Danish slurry storages
are required to be covered to reduce NH3 emissions and often a floating crust of straw is applied. This study investigated whether physical properties of the crust or crust microbiology had an effect on the emission of the potent greenhouse gases CH4 and nitrous oxide (N2O) when crust moisture was manipulated (“dry”, “moderate”, and “wet”). The dry crust had the deepest oxygen penetration (45 mm as compared to 20 mm in the wet treatment) as measured with  microsensors, the highest amounts of nitrogen oxides (NO2 – and NO3–) (up to 36 μmol g–1 wet weight) and the highest emissions of N2O and CH4. Fluorescent in situ hybridization and gene-specific polymerase chain reaction (PCR) were used to detect occurrence of bacterial groups. Ammonia-oxidizing bacteria (AOB) were abundant in all three crust types, whereas nitrite-oxidizing bacteria (NOB) were undetectable and methane-oxidizing bacteria (MOB) were only sparsely present in the wet treatment. A change to anoxia did not affect the CH4 emission indicating the virtual absence of aerobic methane oxidation in the investigated 2-mo old crusts. However, an increase in N2O emission was observed in all crusted treatments exposed to anoxia, and this was probably a result of denitrification based on NOx – that had accumulated in the crust during oxic conditions. To reduce overall greenhouse gas emissions, floating crust should be managed to optimize conditions for methanotrophs.

For more information the full article can be found at https://www.agronomy.org/publications/jeq

User-Friendly Air Quality Monitoring System

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The objective of the study was to produce a reliable and cost‐effective hardware and software system for measuring environmental variables in a commercial livestock building and thus improve building environments and reduce pollutant emissions. It was found that this special software greatly simplified data management and reporting. The improvements over the old system have reduced the labor input required for operating the system and enables producers and consultants to reduce worker OH&S risks, improve environmental outcomes, and potentially improve production efficiency.

For more information the full article can be found at http://asae.frymulti.com/toc.asp

Performance of a Pilot-Scale Air Sparged Continuous Flow Reactor and Hydrocyclone For Struvite Precipitation abd Removal From Liquid Swine Manure

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The objective of this research was to test a pilot‐scale air sparged tank reactor (ASTR) and the ASTR in
combination with a hydrocyclone (called the pilot‐scale ASTR‐hydrocyclone system) on two swine manure slurries for
struvite‐based (MgNH4PO4‐6H2O) phosphorus removal and recovery. It was found that in a typical Iowa deep-pit swine production facility (10,000 head/year) the annual cost of struvite‐based phosphorus removal using the struvite-based phosphorus removal system would be approximately $8.88/finished pig or $0.035/L manure slurry treated ($0.134/gal). This cost often exceeds producer’s profit margins and is not currently economically viable.

For more information the full article can be found at http://asae.frymulti.com/toc.asp

Effects of management, environmental and temporal factors on mortality and feed consumption in integrated swine fattening farms

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The aim this study is to assess the effects of environmental, management, housing and temporal factors on two production parameters that impact the costs in all-in all-out swine fattening systems: mortality and feed consumed per marketed hog. The study also aims to estimate the contribution of the finishing herd and batch to the total variability of mortality and feed consumed per marketed hog. The study, conducted under ‘real field’ conditions, confirmed the negative effect of non-pelleted feed on average feed intake per marketed hog. The considerable effect of particular origin farms on mortality risk suggest including this data on further research. A high level of care provided by the farmers to the pigs contributed to reduce the risk of mortality. Both mortality and feed performance were influenced by the season and the year but the effect of the year on feed intake was modified by the average final weight of the batch and its level of mortality. Our results suggest that a constant effect of ‘the farm itself’ on mortality would be small or non-existent. On the other hand, by investigating and improving permanent farm characteristics a substantial profit is expected in the long run as a result of lower feed costs. However management factors at the individual batch level had the greatest impact on mortality and feed intake in all-in-all-out fattening farms. Also, uncertainty about mortality and feed intake tended to be higher in cold template periods than in other months. 

For more information the full article can be found at http://www.journals.elsevierhealth.com/periodicals/livsci

Observations on microbial activity in acidified pig slurry

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Acidification of pig slurry to pH 5.5 is used as a measure to reduce ammonia emission from pits and storages. The slurry is acidified with sulphuric acid in a process tank and pumped back to the slurry pits or to a storage tank. We investigated the effect of acidification on microbial activity. Oxygen consumption rate, methanogenesis and sulphate reduction were all reduced by more than 98% in the stored acidified slurry compared to untreated slurry. Despite higher sulphate concentration, the microbial metabolism was greatly compromised or absent in the acidified slurry. This could be explained by the high concentration of protonized short-chained volatile fatty acids in the acidified slurry (approximately 25 mM, compared to untreated slurry <0.1 mM), which act as an uncoupling agent of the cell membrane potential and thereby arrest microbial metabolism. In total the consequences of slurry acidification are greatly reduced production rates and loss of sulphide and methane, and eliminated loss of ammonia. On the other hand, increased volatilization and loss of smelly fatty acids is to be expected.

For more information the full article can be found at  http://www.sciencedirect.com/science/journal/15375110

Applying with style

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Two award-winning farmers talk about their different manure application styles

Doing the right thing

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Meadowlane Farms adds a waste application business to its environmentally responsible portfolio.

Going Big with Digesters

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Chilean hog producer Agricola Super has gone big with its manure management program, installing eight digesters, and it has reaped the benefits in reduced odor complaints and marketable greenhouse gas-reduction credits. The credits can be sold to other greenhouse gas producing industries as a way to mitigate their emissions and meet goals set by the Kyoto Protocol. In a 2004 deal, Agricola Super sold credits worth 1.75 million metric tons of greenhouse gas emissions to Calgary, Canada-based power producer TransAlta Corp for $9 million. In addition, Tokyo Electric Power Co will purchase credits from Agricola worth two million metric tons of greenhouse gas over a nine-year period from 2004 to 2012. The price was not disclosed.