Methane Emissions from Manure Storages

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The objectives of this study were to measure methane emissions from liquid manure stored on two farms (farm A
and farm B) in eastern Canada and to evaluate the effect of various mitigation strategies on methane emissions. It was found that manure from farm B (manure B) emitted methane soon after it was loaded to the storage pilots at 10°C and 20°C. It produced twice as much methane at 20°C as at 10°C. Manure from farm A (manure A) produced 3% and 54% of the methane emitted by manure B at 10°C and 20°C, respectively, over the 370‐day monitoring period. Additionally, manure A produced methane after a lag phase of about 250 days at 20°C, which, on most farms, is longer than the storage period between land applications. The important difference between the two farms shows the large error that would arise from estimating methane production using a single emission factor for all farms within a region.

Quantification of ammonia and hydrogen sulfide emitted from pig buildings in Korea

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Extensively modern pig production practices degrade the air quality in pig buildings and thereby pose a health risk to the pigs and farm workers (Whyte, 1993; Pearson and Sharples, 1995). To address these environmental problems, the U.S. and Europe are imposing more stringent regulations on aerial contaminants both within and from pig houses (Wathes et al., 1998; Gay et al., 2003). Aerial contaminants generated in the pig buildings are classified into gases, particulates and airborne microorganisms (Wathes, 1994). Representative gaseous compounds in the pig building are ammonia and hydrogen sulfide which are generated by the pigs themselves or by decomposing manure and easily adsorbed onto airbourne dust particles derived from feedstuffs (Bottcher, 2001). If ammonia and hydrogen sulfide are adsorbed onto fine dust particles such as PM2:5, they pose seriously adverse health effects on both pigs and workers because they penetrate the respiratory system (Donham et al., 1986). These gases promote a deterioration of equipment in the pig buildings (Ni et al., 2000b), elicit serious complaints from neighbors if the odors are emitted outdoors (Ni et al., 2000a), and can potentially damage ecosystems by soil acidification, water eutrophication and global warming (Harssema et al., 1981; van Breemen et al., 1982; Buijsman and Erisman, 1988). For pigs, ammonia concentrations above 100 ppm have been shown to cause a decline in feed consumption and daily weight gain (Stombaugh et al., 1969) and concentrations in the range of 50275 ppm lowered the ability of the pigs to clear bacteria from their lungs (Curtis et al., 1977). Concentrations of hydrogen sulfide below 10 ppm have no adverse health effect on pig growth (Curtis et al., 1977), but concentrations of 502100 ppm, 10021000 ppm, and 1000 ppm cause chronic, subacute, and acute intoxication, respectively (Smith et al., 1979). The Korea Ministry of Environment restricts livestock facilities, including pig buildings, to maximum levels of 1 ppm for ammonia and 0.02 ppm for hydrogen sulfide, based on a mandate to lessen odor emissions (KME, 2004). Prior to devising abatement techniques to prevent these environmental and hygiene problems caused by ammonia and hydrogen sulfide emitted from pig buildings, it is essential to accurately determine their concentrations. To date, there is no such field data from pig buildings in Korea. Therefore, the aim of this study was to provide both pig producers and governmental regulators in Korea empirical information on the concentrations and emissions of ammonia and hydrogen sulfide in the different types of pig buildings, and to compare values from Korean pig buildings to those in other countries. Concentrations of ammonia and hydrogen sulfide in the pig buildings averaged 7.5 ppm and 286.5 ppb and ranged from 0.8 to 21.4 ppm and from 45.8 to 1235 ppb, respectively. The mean emissions of ammonia and hydrogen sulfide per pig (normalized to 75 kg liveweight) and area (m²) from pig buildings were 250.2 and 37.8 mg/h/pig and 336.3 and 50:9mg/h/m², respectively. Ammonia and hydrogen sulfide concentrations and emissions were higher in the pig buildings managed with deep-pit manure systems with slats and mechanical ventilation than in other housing types.

For more information the full article can be found at http://www.sciencedirect.com/science/journal/03014797

Simultaneous Chemical and Sensory Characterization of Volatile Organic Compounds and Semi- Volatile Organic Compounds Emitted from Swine Manure using Solid Phase Microextraction and Multidimensional Gas Chromatography–Mass Spectrometry–Olfactometry

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In this research, a solid phase microextraction (SPME) and novel multidimensional gas chromatography–mass spectrometry–olfactometry (MDGCMS- O) system were used to simultaneously identify volatile organic compounds and related odors emitted from swine manure. It was found that nearly 68% of the compounds for which reaction rates with OH·radicals are known had an estimated atmospheric lifetime.

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

Ammonia Emissions Affected by Airflow in a Model Pig House: Effects of Ventilation rate, Floor Slat Opening, and Headspace Height in a Manure Storage Pit

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Laboratory experiments were performed to study the influence of airflow on ammonia emissions from pig house
slurry in a model growing/finishing pig house with slurry in the pit and a clean slatted floor with various opening areas, 100%, 33.3%, and 16.7%. It was found that the NH3 emission rate was more sensitive to the ventilation rate than to the slatted floor opening ratio and air headspace height in the pit. In addition, the NH3 emission rate was much more sensitive to variations in the ventilation rate at low ventilation rates than at high ventilation rates. Similar sensitivity responses were obtained for both slatted floor opening ratio and air headspace height.

Nitrogen removal from purified swine wastewater using biogas by semi-partitioned reactor

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The processes for traditional nitrogen removal from wastewater consist principally of two sub-processes, nitrification and denitrification. In the nitrification process ammonium (NH4+) is oxidized generally to nitrate (NO3-) by autotrophic bacteria; in the subsequent denitrification process, NO3- is reduced to dinitrogen gas (N2) by heterotrophic bacteria. The latter process requires electron donors like organic carbon sources for the heterotrophic microbial reaction. It is reported that CH4 is useable for the denitrification under circumstantially micro-aerobic conditions in the presence of CH4 and O2. Denitrification using CH4 has been experimentally applied to wastewaters that do not contain sufficient organic carbon for denitrification, such as landfill leachate (Werner and Kayser, 1991), nitrified municipal wastewater (Houbron et al., 1999), and ground water (Eisentraeger et al., 2001). Methane is present at high concentration in biogases produced in anaerobic waste treatment reactors and landfills, which would make it substantially less expensive to use than introduced chemicals. While use of CH4 for denitrification would be advantageous at such sites from the point of view both of carbon source reuse and cost reduction, it has not yet been in actual use. Both NO3- and NH4+ are frequently contained in the wastewater targeted for nitrogen removal using CH4 such as effluent from aerobic reactors treating animal wastewater, owing to the imperfect nitrification that occurs due to high and varying N concentrations (Tanaka et al., 1999). Therefore, simultaneous removal of NO3- and NH4+ would be necessary for practical application of nitrogen removal using CH4. However, there are few studies with actual wastewater. In this study, a novel type of reactor, a semi-partitioned reactor (SPR) was operated with a varying gas supply rate and was used to create a biological reaction using methane and oxygen in the water phase. The SPR then discharged the unused gases separately. Successful removal of NO3- and NH4+ was observed when biogas and air of 1 L/min was supplied to an SPR of 9 L water phase with a NO2,3-N and NH4+ –N removal rate of 0.10 g/L/day and 0.060 g/L/day, respectively. The original biogas contained an average of 77.2% methane, and the discharged biogas from the SPR contained an average of 76.9% of unused methane that was useable for energy like heat or electricity production. Methane was contained in the discharged air from the SPR at an average of 2.1%. When gas supply rates were raised to 2 L/min and the nitrogen load was increased, NO3- concentration was decreased, but NO2- accumulated in the reactor and the NO2,3-N and NH4+ –N removal activity declined. To recover the activity, lowering of the nitrogen load and the gas supply rate was needed. This study shows that the SPR enables nitrogen removal from purified swine wastewater using biogas under limited gas supply condition.

For more information the full article can be found at http://www.sciencedirect.com/science/journal/09608524

Development of a Dynamic Model to Predict PM10 Emissions from Swine Houses

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The objective of this study was to characterize the main input variables for modeling emissions of particulate matter with a mass median diameter ≤10 μm (PM10) from swine facilities using a databased model. The simulation of the PM10 emission rate resulted in a mean percentage error per data set of 21 to 39%, whereas the average simulated and measured emission rate per data set differed by about 4 to 19%.

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

Interactive effects of dietary crude protein and fermentable carbohydrate levels on odour from pig manure

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Odour nuisance from pig production facilities is a growing topic due to increasing complaints of neighbours
of these facilities. Reduction in odour nuisance plays an important role for strategies concerning where to permit
pig production facilities to be located and determines the maximum size of the facilities. The main objective in this study was to determine the effects of different combinations of dietary CP and FC on odour emission, odour strength,
odour offensiveness and ammonia emission from pig manure. It was shown that dietary crude protein and fermentable carbohydrates did have an interactive effect on odour concentration and emission from the manure of finishing pigs. herefor, dietary strategies to alter odour production from pig manure should therefore focus simultaneously on both crude protein and fermentable carbohydrates.

Control of H2S emission from swine manure using Na-nitrite and Na-molybdate

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Emission of gaseous and odorous compounds from livestock operations can be a major impediment to the expansion of these facilities, especially in locations close to the populated areas. O’Neill and Phillips have shown that more than 168 compounds produced either by chemical reactions or by microbial activities are responsible for the odorous emissions from livestock operations. Some of the major odour contributors identified included ammonia (NH3), hydrogen sulphide (H2S), volatile fatty acids, p-cresol, indole, skatole, and diacetyl . Hydrogen sulphide is produced as a result of bacterial reduction of sulphate and decomposition of sulphur-containing organic constituents of the manure under anaerobic conditions. Hazardous H2S levels can be generated in swine confinement buildings during the pulling of manure pit plugs, manure agitation and pump out, operation and maintenance of manure handling equipment and drainage lines, and power washing. In a previous study conducted in Saskatchewan, Chénard et al. demonstrated that such activities could cause short-term spikes of H2S to levels above 500 μLLˉ¹ within the building airspace. Considering the odorous, toxic and corrosive nature of H2S, and severe health problems associated with the presence of H2S, a variety of approaches aimed to control the production and emission of H2S in livestock facilities have been investigated. These include application of various pit additives and chemicals, as well as the treatment of emitted air in biofilters. The oil industry is also concerned with the biogenic production of hydrogen sulphide (H2S). Previous studies have shown that H2S in oil reserves can be controlled effectively using nitrite and molybdate salts. Therefore, in this study the effects of the addition of nitrite and molybdate on reducing the emission of H2S from swine manure slurry was investigated in the laboratory and semi-pilot scale systems. Addition of 80mM nitrite or 2mM molybdate (final concentration in the manure slurry) to fresh manure in the laboratory scale closed systems (125mL and 4 L) reduced the concentration of H2S in the headspace gas from 1500 μLLˉ¹ to 10 μLLˉ¹ which maintained during the remaining period of trials (40–60 days). With aged manure, similar results were achieved with a lower level of nitrite (10 mM). Simultaneous or sequential additions of nitrite and molybdate to fresh manure had similar effects. Contrary to the systems simulating biological conditions in oil reservoirs in which simultaneous addition of nitrite and molybdate has been reported to have a synergistic effect, no synergism was observed when nitrite and molybdate were added to the manure simultaneously. Experiments with fresh manure slurry in the semi-pilot scale systems (200 L) confirmed the effectiveness of this approach in which addition of 80mM nitrite or 2mM molybdate or a combination of 80mMnitrite and 2mM molybdate decreased the concentration of the H2S in the headspace gas from an initial value of 500μLLˉ¹ to a low level in the range 2–25μLLˉ¹ and maintained these low levels during the remaining period of trials (16 days). The concentration of ammonia (NH3) in the headspace gas of the treated systems was similar to that observed in the control system (untreated), indicating that the treatment did not have an effect on the level of present NH3. Although the addition of nitrite or molybdate reduced emissions of H2S from swine manure and the associated health and safety concerns, it had little impact on the intensity of odour in the headspace gas samples from the semi-pilot scale system.

For more information the full article can be found at http://www.sciencedirect.com/science/journal/03043894

Methane and Carbon Dioxide Emission from Two Pig Finishing Barns

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This article presents a field study of CH4 and CO2 emission from two 1100-head mechanically ventilated pig (Sus scrofa) finishing barns (B1 and B2) with shallow manure flushing systems and propane space heaters from August 2002 to July 2003 in northern Missouri. It was found that the CH4 and CO2 released from the flushing lagoon effluent were equivalent to 9.8 and 4.1% of the CDFB CH4 and CO2 emissions, respectively.

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

The electronic nose – a new tool to help manage farmyard odours

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Farm smells are not simply a sum of all odorous compounds
found within them, but result from interactions
among complex mixtures of hundreds of compounds. In addition to the molecules themselves, odour generation is
also influenced by many environmental factors such as temperature,
air flow speed and relative humidity. However, while Yang and his research team consider
their system a useful tool in supporting livestock and poultry
farm odour management, and point out that is easier and
cheaper to operate than using olfactometry or a human
panel, they admit that any electronic nose is limited on the
farm in that it can only detect odour events at one point.
It therefore cannot provide overall odour mapping around
livestock facilities, which is necessary for an overall odour
management strategy. Yang and his research team thus foresee the need for
a wireless electronic nose network, combined with an air
dispersion model on each farm, which would be able to
monitor odour strengths on the basis of odour emission
rates, topography and meteorological data.