Reduction of ammonia emission by shallow slurry injection: injection efficiency and additional energy demand

Ammonia (NH3) emission from livestock production causes undesirable environmental effects and a loss of plant-available nitrogen. Much atmospheric NH3 is lost from livestock manure applied in the field. The NH3 emission may be reduced by slurry injection, but slurry injection in general, and especially on grassland, increases the energy demand and places heavy demands on the slurry injection techniques used. The reduction in NH3 emission, injection efficiency, and energy demand of six different shallow slurry-injection techniques was examined. The NH3 emission from cattle slurry applied to grassland was reduced by all the injectors tested in the study, but there were major differences in the NH3 reduction potential of the different types of injectors. Compared with the trailing hose spreading technique, the NH3 loss was reduced by 75% when cattle slurry was injected using the most efficient slurry injection technique, and by 20% when incorporated by the least efficient injection technique. The reduction in NH3 emission was correlated with injection depth and the volume of the slot created. The additional energy demand for reducing ammonia emissions by slurry injection was approximately 13 000 kJ ha(-1) for a 20% reduction and 34 000 kJ ha(-1) for a 75% reduction. The additional energy demand corresponds to additional emissions of, respectively, 5.6 and 14.5 kg CO2 per ha injected.     

Dependence of ammonia emissions from housing on the time cattle spent inside

Buildings housing cattle contribute 19% (42 kt NH3-N yr(-1)) of total UK ammonia (NH3) emissions. In the UK there is not usually an abrupt switch from cattle being kept inside to when they are turned out to graze 24 h a day. Moreover, during the summer dairy cows return to the farm twice a day to be milked and may spend some time inside buildings. Hence, there is uncertainty over the treatment of the transitional and summer periods when inventorying NH3 emissions. The aim of this study was to measure, under controlled and replicated conditions, the relationship between the number of hours cattle spend in buildings and the NH3 emissions from those buildings. Our results indicate that NH3 emissions decrease as the proportion of the day cattle spend in the buildings decreases, although the trend is not linear. Daily emission rates from cattle housed for 2 h ranged from 1.6 to 6.2 g NH3-N lu(-1) whereas emissions from cattle housed for 24 h ranged from 8.1 to 24.1 g NH3-N lu(-1). To significantly reduce NH3 emissions in comparison to those from buildings where cattle are housed for 24 h, the occupancy would have to be reduced to no more than 6 h each day. Thus, the strategy of extending the grazing season by allowing cattle to graze for c. 4 to 12 h during the winter is unlikely to reduce NH3 emissions from buildings or overall.     

3,4-Dimethylpyrazol phosphate effect on nitrous oxide, nitric oxide, ammonia, and carbon dioxide emissions from grasslands

Intensively managed grasslands are potentially a large source of NH3, N2O, and NO emissions because of the large input of nitrogen (N) in fertilizers. Addition of nitrification inhibitors (NI) to fertilizers maintains soil N in ammonium form. Consequently, N2O and NO losses are less likely to occur and the potential for N utilization is increased, and NH3 volatilization may be increased. In the present study, we evaluated the effectiveness of the nitrification inhibitor 3,4-dimethylpyrazol phosphate (DMPP) on NH3, N2O, NO, and CO2 emissions following the application of 97 kg N ha(-1) as ammonium sulfate nitrate (ASN) and 97 kg NH4+ -N ha(-1) as cattle slurry to a mixed clover-ryegrass sward in the Basque Country (northern Spain). After slurry application, 16.0 and 0.7% of the NH4+ -N applied was lost in the form of N2O and NO, respectively. The application of DMPP induced a decrease of 29 and 25% in N2O and NO emissions, respectively. After ASN application 4.6 and 2.8% of the N applied was lost as N2O and NO, respectively. The application of DMPP with ASN (as ENTEC 26; COMPO, Münster, Germany) unexpectedly did not significantly reduce N2O emissions, but induced a decrease of 44% in NO emissions. The amount of NH4+ -N lost in the form of NH3 following slurry and slurry + DMPP applications was 7.8 and 11.0%, respectively, the increase induced by DMPP not being statistically significant. Levels of CO2 emissions were unaffected in all cases by the use of DMPP. We conclude that DMPP is an efficient nitrification inhibitor to be used to reduce N2O and NO emissions from grasslands.     

Ammonia emissions from Swine waste lagoons in the Utah great basin

In animal production systems (poultry, beef, and swine), current production, storage, and disposal techniques present a challenge to manage wastes to minimize the emissions of trace gases within relatively small geographical areas. Physical and chemical parameters were measured on primary and secondary lagoons on three different swine farming systems, three replicates each, in the Central Great Basin of the United States to determine ammonia (NH3) emissions. Nutrient concentrations, lagoon water temperature, and micrometeorological data from these measurements were used with a published process model to calculate emissions. Annual cycling of emissions was determined in relation to climatic factors and wind speed was found the predominating factor when the lagoon temperatures were above about 3 degrees C. Total NH3 emissions increased in the order of smallest to largest: nursery, sow, and finisher farms. However, emissions on an animal basis increased from nursery animals being lowest to sow animals being highest. When emissions were compared to the amount of nitrogen (N) fed to the animals, NH3 emissions from sows were lowest with emissions from finisher animals highest. Ammonia emissions were compared to similar farm production systems in the humid East of the United States and found to be similar for finisher animals but had much lower emissions than comparable humid East sow production. Published estimates of NH3 emissions from lagoons ranged from 36 to 70% of feed input (no error range) compared to our emissions determined from a process model of 9.8% with an estimated range of +/-4%.     

Evaluation of zeolite for control of odorants emissions from simulated poultry manure storage

Poultry operations are associated with emissions of aerial ammonia (NH3), volatile organic compounds (VOCs), and odor, and the magnitude of emissions is influenced by manure management practices. As a manure treatment additive, zeolites have been shown to have the potential to control NH3. Because of their properties it is also expected that zeolites could effectively adsorb VOCs and odor. The effectiveness of zeolite in controlling odor and VOCs was qualitatively evaluated in this controlled laboratory study involving simulated poultry manure storage. In the first two trials, zeolite was topically applied on nearly fresh laying hen manure at the rates of 0, 2.5, 5, and 10% (by weight). In the third trial, zeolite was topically applied at 5% with each addition of fresh manure into the storage vessel. Headspace samples from the emission vessels were collected with solid phase microextraction (SPME) and analyzed on a multidimensional-gas chromatograph-mass spectrometry-olfactometry (MDGC-MS-O) system for identification and prioritization of poultry manure odorants. Acetic acid, butanoic acid, isovaleric acid, indole, and skatole were consistently controlled in the headspace, with the reduction rate being proportional to the zeolite application rate. Dimethyl trisulfide and phenol were consistently generated, and with a few exceptions, the rate of generation was proportional to the application rate. Average reduction of the odor caused by all odorants evaluated with SPME-GC-O was 67% (+/-12%) and 51% (+/-26%) for the two topical applications, respectively, while no significant reduction of VOCs and odor was detected for the layered application.     

Effects of reed straw, zeolite, and superphosphate amendments on ammonia and greenhouse gas emissions from stored duck manure

Stored poultry manure can be a significant source of ammonia (NH) and greenhouse gases (GHGs), including nitrous oxide (NO), methane (CH), and carbon dioxide (CO) emissions. Amendments can be used to modify physiochemical properties of manure, thus having the potential to reduce gas emissions. Here, we lab-tested the single and combined effects of addition of reed straw, zeolite, and superphosphate on gas emissions from stored duck manure. We showed that, over a period of 46 d, cumulative NH emissions were reduced by 61 to 70% with superphosphate additions, whereas cumulative NO emissions were increased by up to 23% compared with the control treatment. Reed straw addition reduced cumulative NH, NO, and CH emissions relative to the control by 12, 27, and 47%, respectively, and zeolite addition reduced cumulative NH and NO emissions by 36 and 20%, respectively. Total GHG emissions (as CO-equivalents) were reduced by up to 27% with the additions of reed straw and/or zeolite. Our results indicate that reed straw or zeolite can be recommended as amendments to reduce GHG emissions from duck manure; however, superphosphate is more effective in reducing NH emissions.     

Functional classification of swine manure management systems based on effluent and gas emission characteristics

Gaseous emissions from swine (Sus scrofa) manure storage systems represent a concern to air quality due to the potential effects of hydrogen sulfide, ammonia, methane, and volatile organic compounds on environmental quality and human health. The lack of knowledge concerning functional aspects of swine manure management systems has been a major obstacle in the development and optimization of emission abatement technologies for these point sources. In this study, a classification system based on gas emission characteristics and effluent concentrations of total phosphorus (P) and total sulfur (S) was devised and tested on 29 swine manure management systems in Iowa, Oklahoma, and North Carolina in an effort to elucidate functional characteristics of these systems. Four swine manure management system classes were identified that differed in effluent concentrations of P and S, methane (CH4) emission rate, odor intensity, and air concentration of volatile organic compounds (VOCs). Odor intensity and the concentration of VOCs in air emitted from swine manure management systems were strongly correlated (r2 = 0.88). The concentration of VOC in air samples was highest with outdoor swine manure management systems that received a high input of volatile solids (Type 2). These systems were also shown to have the highest odor intensity levels. The emission rate for VOCs and the odor intensity associated with swine manure management systems were inversely correlated with CH4 and ammonia (NH3) emission rates. The emission rates of CH4, NH3, and VOCs were found to be dependent upon manure loading rate and were indirectly influenced by animal numbers.     

Modelling the economic consequences of the EU Water Framework Directive for Dutch agriculture

The EU Water Framework Directive (WFD) requires member states to take measures to ensure that bodies of water will be in good chemical and ecological condition by 2015. Important measures to achieve this goal include reducing emissions of nitrogen (N) and phosphate (P₂O₅) from manure and mineral fertilizers into the environment. In regions with a high livestock density, this measure is expected to affect agricultural production and income. To quantify these effects, an environmental economic model is required that can assess alternatives capable of reducing N and P₂O₅ potential emissions to water. In this paper, we develop a model that is capable of analysing changes in potential emissions to water of N and P₂O₅ and apply it to the Netherlands, a country with large nutrient emissions. Compared to a 2015 reference scenario based on current efforts to reduce nutrient emissions, we found that the WFD measures will increase regional transport and export of manure and reduce the number of animals in the Netherlands. Fodder adjustments (defined as lower N and P₂O₅ input in purchased fodder) to decrease nutrient excretion in manure were a less attractive option than amongst others export, transportation of manure to another region, land use changes or reduction of the number of livestock. Compared to the reference scenario in 2015, total agricultural income will decrease by about €81.5 million per year (about €49/ha per year), although the effects will differ among parts of the Netherlands and agricultural sectors. The average predicted decrease in N emissions from agricultural sites, vulnerable to leaching into bodies of water will be almost 20% or approximately 14.7 kg N/ha per year. The reduction in N emissions to air from animal sheds, manure storage systems, application of animal manure and mineral fertilisers to the crops and grazing animals equals 6.5% or 5 kg ammonia (NH₃) per hectare.     

Oxygen distribution and potential ammonia oxidation in floating, liquid manure crusts

Floating, organic crusts on liquid manure, stored as a result of animal production, reduce emission of ammonia (NH3) and other volatile compounds during storage. The occurrence of NO2- and NO3- in the crusts indicate the presence of actively metabolizing NH3-oxidizing bacteria (AOB) which may be partly responsible for this mitigation effect. Six manure tanks with organic covers (straw and natural) were surveyed to investigate the prevalence and potential activity ofAOB and its dependence on the O2 availability in the crust matrix as studied by electrochemical profiling. Oxygen penetration varied from <1 mm in young, poorly developed natural crusts and old straw crusts, to several centimeters in the old natural crusts. The AOB were ubiquitously present in all crusts investigated, but nitrifying activity could only be detected in old natural crusts and young straw crust with high O2 availability. In old natural crusts, total potential NH3 oxidation rates were similar to reported fluxes of NH3 from slurry without surface crust. These results indicate that old, natural surface crusts may develop into a porous matrix with high O2 availability that harbors an active population of aerobic microorganisms, including AOB. The microbial activity may thus contribute to a considerable reduction of ammonia emissions from slurry tanks with well-developed crusts.     

Application technique and slurry co-fermentation effects on ammonia,nitrous oxide,and methane emissions after spreading: I. Ammonia volatilization

Ammonia emissions after spreading animal manure contribute a major share to N losses from agriculture. There is an increasing interest in anaerobic co-digestion of liquid manure with organic additives. This fermentation results in a change of physical and chemical parameters of the slurry. Among these are an increased pH and ammonium content, implying a higher risk of NH3 losses from fermentation products. To compare different application techniques and the effect of fermentation on NH3 volatilization, we used the standard comparison method and tested it for reliability. This method seems to be perfectly suited for experiments with a large number of treatments and replicates if prerequisites concerning the experimental layout are considered. We tested four different application techniques on arable and grassland sites. The more the substrate was incorporated into the soil or applied near the soil surface on the grassland site, the less NH3 was lost. Injection of the substrate reduced losses to less than 10% of applied NH4+ on both sites, whereas losses after splash plate application amounted to more than 30%. Trail shoe application on grassland performed as well as injection. Harrowing on arable land also reduced emissions efficiently, if harrowing occurred within the first 2 h after application. Emissions from trail hose-applied co-fermentation product were not greater than from unfermented slurry. Better infiltration of the less viscous substrate seemed to have compensated for the increased loss potential.     

Environmental bonds and the challenge of long-term carbon sequestration

The potential to capture carbon from industrial sources and dispose of it for the long-term, known as carbon capture and sequestration (CCS), is widely recognized as an important option to reduce atmospheric carbon dioxide emissions. Specifically, CCS has the potential to provide emissions cuts sufficient to stabilize greenhouse gas levels, while still allowing for the continued use of fossil fuels. In addition, CCS is both technologically-feasible and commercially viable compared with alternatives with the same emissions profile. Although the concept appears to be solid from a technical perspective, initial public perceptions of the technology are uncertain. Moreover, little attention has been paid to developing an understanding of the social and political institutional infrastructure necessary to implement CCS projects. In this paper we explore a particularly dicey issue--how to ensure adequate long-term monitoring and maintenance of the carbon sequestration sites. Bonding mechanisms have been suggested as a potential mechanism to reduce these problems (where bonding refers to financial instruments used to ensure regulatory or contractual commitments). Such mechanisms have been successfully applied in a number of settings (e.g., to ensure court appearances, completion of construction projects, and payment of taxes). The paper examines the use of bonding to address environmental problems and looks at its possible application to nascent CCS projects. We also present evidence on the use of bonding for other projects involving deep underground injection of materials for the purpose of long-term storage or disposal.     

Carbon monoxide from composting due to thermal oxidation of biomass

Emissions of carbon monoxide (CO) were observed from decomposing organic wastes and litter under laboratory, pilot composting plant, and natural conditions. Field studies included air from inside a compost heap of about 200 m3, emissions from composting of livestock wastes at a biologically operating farm, and leaf litter pile air samples. The concentration of CO was up to 120 micromol mol(-1) in the compost piles of green waste, and up to 10 micromol mol(-1) in flux chambers above livestock waste windrow composts. The mean CO flux rates were approximately 20 mg CO m(-2) h(-1) for compost heaps of green waste, and varied from 30 to 100 mg CO m(-2) h(-1) for fresh dung windrows. Laboratory studies using a temperature and ventilation-controlled substrate container were performed to elucidate the origin of CO, and included hay samples of fixed moisture content at temperatures between 5 and 65 degrees C, including nonsterilized as well as sterilized samples. The concentration of CO was up to 160 micromol mol(-1) in these experiments, and Arrhenius-type plot analyses resulted in activation energies of 65 kJ mol(-1) for thermochemically produced CO from the nonsterilized compost substrate. Sterilized samples showed dramatically reduced CO2 but virtually unchanged CO emissions, albeit at a slightly lower activation energy, likely a result of the high-temperature sterilization. Though globally and regionally these CO emissions are only a minor source, thermochemically produced CO emissions might affect local air quality in and near composting facilities.     

The setting of standards for agricultural nitrogen emissions: a case study of the Delphi technique

The Delphi technique is a means of aggregating the judgement of a panel of experts in order to improve the quality of decision-making. This paper provides a case study of the technique by undertaking a three-round Delphi study to determine a package of best available techniques to reduce nitrogen emissions from a poultry unit under the Integrated Pollution Prevention and Control Directive (IPPC). Forms of nitrogen addressed included ammonia (NH3), nitrous oxide (N2O) nitrogen oxides (NOx), dusts and nitrate (NO3-), with the study providing a means to prioritise the pollution concerns on different spatial scales. The priority pollutant issues were the contribution of NH3 to eutrophication, the global cooling effect of NH4+ aerosol, the role of NH4+ as a vector for atmospheric transport of NOx and SO2, the contribution of N2O to global warming, and NO3- leaching. Reduced nitrogen (NHx) was rated as a priority on all scales, while N2O and NO3- were rated as priorities only on global and local scales, respectively. The study indicated the need for abatement techniques at each stage of poultry rearing and waste management, with particular attention to reduce NH3 emissions, reflecting the priority pollutant concerns. Measures identified by the panel include maintenance of dry litter, low emission removal of litter from housing and storage of litter under cover. Once the litter has left the farm, this should either be used as a biofuel for electricity generation or rapidly incorporated into agricultural soils. The amounts and timing of manure application should be tuned to crop needs. Uncertainties in the Delphi technique limit its suitability as a stand-alone decision making tool. However, the Delphi technique proved useful in identifying priority pollutant issues, areas of agreement, disagreement and where information is lacking. This demonstrates its use when dealing with the complex issues of prioritising pollution issues and abatement approaches.     

Nitrogen cycling through swine production systems: ammonia, dinitrogen, and nitrous oxide emissions

Ammonia (NH(3)) emissions from animal systems have become a primary concern for all of livestock production. The purpose of this research was to establish the relationship of nitrogen (N) emissions to specific components of swine production systems and to determine accurate NH(3) emission factors appropriate for the regional climate, geography, and production systems. Micrometeorological instrumentation and gas sensors were placed over two lagoons in North Carolina during 1997-1999 to obtain information for determining ammonia emissions over extended periods and without interfering with the surrounding climate. Ammonia emissions varied diurnally and seasonally and were related to lagoon ammonium concentration, acidity, temperature, and wind turbulence. Conversion of significant quantities of ammonium NH(4)(+) to dinitrogen gas (N(2)) were measured in all lagoons with the emission rate largely dependent on NH(4)(+) concentration. Lagoon NH(4)(+) conversion to N(2) accounted for the largest loss component of the N entering the farm (43% as N(2)); however, small amounts of N(2)O were emitted from the lagoon (0.1%) and from field applications (0.05%) when effluent was applied nearby. In disagreement with previous and current estimates of NH(3) emissions from confined animal feeding operation (CAFO) systems, and invalidating current assumptions that most or all emissions are in the form of NH(3), we found much smaller NH(3) emissions from animal housing (7%), lagoons (8%), and fields (2%) using independent measurements of N transformation and transport. Nitrogen input and output in the production system were evaluated, and 95% of input N was accounted for as output N from the system.     

BACTERIAL POPULATIONS OF AQUATIC SYSTEMS RECEIVING DIFFERENT TYPES OF STRESS1

ABSTRACT: Bacterial populations in a fast flowing stream receiving chemical wastes and in a slower flowing pond receiving a thermal addition 3–5°C above ambient temperature were compared with populations in a nonpolluted converging stream and an adjacent unheated pond. Parameters measured were total aerobic heterotrophic bacteria, bacterial diversity, percent chromagens of the total bacterial populations, and water temperature. Analyses of monthly samples plated on dilute Standard Plate Count Agar indicated that chemical additives to the waste stream significantly decreased the percent of chromagenic bacteria, and that thermal stress significantly altered total counts and bacterial diversity in the flowing pond. The effects of potential pollutants on these aquatic systems were assessed and are discussed on the basis of results obtained over a 16-month period.     

The effect of biofuel production on swine farm methane and ammonia emissions

Methane (CH) and ammonia (NH3) are emitted to the atmosphere during anaerobic processing of organic matter, and both gases have detrimental environmental effects. Methane conversion to biofuel production has been suggested to reduce CH4 emissions from animal manure processing systems. The purpose of this research is to evaluate the change in CH4 and NH3 emissions in an animal feeding operation due to biofuel production from the animal manure. Gas emissions were measured from swine farms differing only in their manure-management treatment systems (conventional vs. biofuel). By removing organic matter (i.e., carbon) from the biofuel farms' manure-processing lagoons, average annual CH4 emissions were decreased by 47% compared with the conventional farm. This represents a net 44% decrease in global warming potential (CO2 equivalent) by gases emitted from the biofuel farms compared with conventional farms. However, because of the reduction of methanogenesis and its reduced effect on the chemical conversion of ammonium (NH4+) to dinitrogen (N2) gas, NH3 emissions in the biofuel farms increased by 46% over the conventional farms. These studies show that what is considered an environmentally friendly technology had mixed results and that all components of a system should be studied when making changes to existing systems.     

An economic evaluation of livestock odor regulation distances

Setback regulations-legislated distances that livestock production facilities must be removed from surrounding properties-are meant to mitigate odor impacts. If the setback length is too short, then there is evidence that surrounding properties and people suffer uncompensated damages. If, on the other hand, setback lengths are too long, then livestock producers may be paying more than that required to compensate for odor-related environmental damages. The purpose of this study is to assess the impact of Kentucky's livestock production facility setbacks on the value of surrounding properties and farm financial management decisions. This paper develops a model of the benefits of livestock odor reduction and the livestock odor abatement cost associated with setback lengths paid by producers. The results of this investigation indicate that the mandated setback lengths for Kentucky are too short. Livestock production firms are worse off under longer setback lengths, but the losses to surrounding home owners far exceed the firm gains at the mandated setbacks. A finding of this study is that the firm has no incentive to completely protect the legislated setback length. Livestock producers in compliance with the relevant setback length may feel protected from odor lawsuits despite damage being done to surrounding property. This suggests that the perceived threat of lawsuit is currently low in the state of Kentucky. Both industry and public goals could be met from further research including location and economic impact of livestock production.     

Characterization and dispersion modeling of odors from a piggery facility

Piggeries are known for their nuisance odors, creating problems for workers and nearby residents. Chemical substances that contribute to these odors include sulfurous organic compounds, hydrogen sulfide, phenols and indoles, ammonia, volatile amines, and volatile fatty acids. In this work, daily mean concentrations of ammonia (NH3) and hydrogen sulfide (H2S) were measured by hand-held devices. Measurements were taken in several places within the facility (farrowing to finishing rooms). Hydrogen sulfide concentration was found to be 40 to 50 times higher than the human odor threshold value in the nursery and fattening room, resulting in strong nuisance odors. Ammonia concentrations ranged from 2 to 18 mL m(-3) and also contributed to the total odor nuisance. Emission data from various chambers of the pig farm were used with the dispersion model AERMOD to determine the odor nuisance caused due to the presence of H2S and NH3 to receptors at various distances from the facility. Because just a few seconds of exposure can cause an odor nuisance, a "peak-to-mean" ratio was used to predict the maximum odor concentrations. Several scenarios were examined using the modified AERMOD program, taking into account the complex terrain around the pig farm.     

Avoided deforestation as a greenhouse gas mitigation tool: economic issues

Tropical deforestation is a significant contributor to accumulation of greenhouse gases (GHGs) in the atmosphere. GHG emissions from deforestation in the tropics were in the range of 1 to 2 Pg C yr(-1) for the 1990s, which is equivalent to as much as 25% of global anthropogenic GHG emissions. While there is growing interest in providing incentives to avoid deforestation and consequently reduce net carbon emissions, there is limited information available on the potential costs of these activities. This paper uses a global forestry and land use model to analyze the potential marginal costs of reducing net carbon emissions by avoiding deforestation in tropical countries. Our estimates suggest that about 0.1 Pg C yr(-1) of emissions reductions could be obtained over the next 30 to 50 yr for $5 per Mg C, and about 1.6 Pg C yr(-1) could be obtained over the same time frame for $100 per Mg C. In addition, the effects of carbon incentives on land use could be substantial. Relative to projected baseline conditions, we find that there would be around 3 million additional hectares (ha) of forestland in 2055 at $5 per Mg C and 422 million ha at $100 per Mg C. Estimates of reductions in area deforested, GHG mitigation potential, and annual land rental payments required are presented, all of which vary by region, carbon price paid, and time frame of mitigation.