NH3 Abatement Research Articles

Evaluation of the performance of new plastic packing materials from plastic waste in biotrickling filters for odour removal

The gas emissions from wastewater treatment plants (WWTPs) contain multiple chemical compounds, such as H2S, NH3 and volatile organic compounds (VOCs), which can cause odour nuisance and health hazards. Biological technologies, such as biotrickling filters (BTFs), are preferred due to their cost-effectiveness and eco-friendliness. The selection of the packing materials in these bioreactors is crucial due to their high purchase cost, frequent replacement and impact on the gas-liquid mass transfer. This research aims at evaluating the NH3, H2S and VOC abatement performance of novel packing materials from plastic byproducts from the water cycle at different gas residence times (EBRT). The experimental set-up consisted of three BTFs of 2 L of working volume constructed with three different packing materials: commercial Pall rings (control), recycled plastic (from bottle caps), and extruded recycled plastic materials in the form of an optimised 3D-printed carrier. The three BTFs supported a complete removal of H2S and NH3 at EBRTs of 30, 15, 10 and 6 s, and VOCs removal above 90 % at EBRTs of 30 and 15 s. The extruded recycled plastic materials in the form of optimised 3D-printed carrier supported toluene and α-pinene removals of 100 % at EBRTs of 30 and 15 s. The genus Thiobacillus was identified in the three BTFs. This research confirmed the potential of reused and recycled plastics from the integral water cycle as a packing material in BTFs devoted to odour treatment.

Ammonia emission factors from cattle production systems in Ireland – a review

Ammonia (NH3) emissions from livestock production contribute to environmental pollution. To address this challenge, the European Union (EU) National Emission Reduction Commitments Directive 2016/2284 (NECD) sets NH3 reduction targets for EU member states. In order to achieve these targets, several strategies have been evaluated under Irish conditions. A compilation of emission factors (EFs) from studies which evaluated these strategies is necessary to assess their effectiveness. This paper reports NH3 EFs from cattle production under Irish conditions. The results from the review show that the mean EFs from the deposition of dung, urine and urea applied to urine patches on grasslands were 4%, 9% and 8% total nitrogen (TN), respectively. EFs from the application of urea to urine patches were reduced by 28% after the addition of the urease inhibitor N-(n-butyl) thiophosphoric triamide (NBPT) to urea. The mean EF of 28% TN reported for urea fertiliser was almost 7 times higher than calcium ammonium nitrate (CAN). The inclusion of urease inhibitors with urea fertilisation on grassland led to EF reduction of up to 86%. The mean EFs from cattle houses, concrete yards, slurry storage pits and slurry landspreading were approximately 13%, 35%, 60% and 59% total ammoniacal nitrogen (TAN), respectively. The most effective NH3 abatement strategies for concrete yards and slurry storage were immediate cleaning of concrete floors (up to 89% reduction) after excreta deposition and the application of chemical amendments (sulphuric acid, acetic acid, alum and ferric chloride) to slurry in storage pits (up to 98% reduction), respectively. Low-emission spreading strategies and slurry acidification were effective at abating EFs after slurry application to land.

Traceability of atmospheric ammonia in a suburban area of the Beijing-Tianjin-Hebei region

Ammonia (NH3) is one of the most important sources that have been linked to the formation of PM2.5. Therefore, it is important to study the source contributions to atmospheric NH3 for air pollution control. Here we used 15N natural abundance (expressed by δ15N) values to quantify the source contributions to atmospheric NH3 in the Beijing-Tianjin-Hebei (BTH) region, which suffers from the country's worst air pollution. Results showed that from 2017 to 2019, the annual mean δ15N-NH3 value at the livestock site (−27.5 ± 6.0 ‰) was lower than at cropland (−20.7 ± 6.0 ‰) and rural residential sites (−22.1 ± 7.4 ‰), while their concentrations were the opposite. Seasonal mean δ15N-NH3 values were the highest in winter and lowest in summer, whereas monthly mean δ15N-NH3 values were the highest in January and lowest in June. The isotope mixing model results showed that agricultural sources account for 64.5 ± 13.5 % of year-round total NH3 emissions, while industrial and other sources contributed 27.4 and 8.1 %, respectively. However, the contribution of industrial sources was higher than that of agricultural sources in January. Our results indicated that the contribution of agricultural sources has decreased after the implementation of air pollution control policies in this region suggesting that NH3 abatement from agricultural sources is effective. However, further refinement of agricultural emission abatement measures will be required, accompanied by a greater focus on controlling winter non-agricultural sources.

Low-temperature NH3 abatement via selective oxidation over a supported copper catalyst with high Cu+ abundance

Selective catalytic NH3-to-N2 oxidation (NH3-SCO) is highly promising for abating NH3 emissions slipped from stationary flue gas after-treatment devices. Its practical application, however, is limited by the non-availability of low-cost catalysts with high activity and N2 selectivity. Here, using defect-rich nitrogen-doped carbon nanotubes (NCNT-AW) as the support, we developed a highly active and durable copper-based NH3-SCO catalyst with a high abundance of cuprous (Cu+) sites. The obtained Cu/NCNT-AW catalyst demonstrated outstanding activity with a T50 (i.e. the temperature to reach 50% NH3 conversion) of 174°C in the NH3-SCO reaction, which outperformed not only the Cu catalyst supported on N-free O-functionalized CNTs (OCNTs) or NCNT with less surface defects, but also those most active Cu catalysts in open literature. Reaction kinetics measurements and temperature-programmed surface reactions using NH3 as a probe molecule revealed that the NH3-SCO reaction on Cu/NCNT-AW follows an internal selective catalytic reaction (i-SCR) route involving nitric oxide (NO) as a key intermediate. According to mechanistic investigations by X-ray photoelectron spectroscopy, Raman spectroscopy, and X-ray absorption spectroscopy, the superior NH3-SCO performance of Cu/NCNT-AW originated from a synergy of surface defects and N-dopants. Specifically, surface defects promoted the anchoring of CuO nanoparticles on N-containing sites and, thereby, enabled efficient electron transfer from N to CuO, increasing significantly the fraction of SCR-active Cu+ sites in the catalyst. This study puts forward a new idea for manipulating and utilizing the interplay of defects and N-dopants on carbon surfaces to fabricate Cu+-rich Cu catalysts for efficient abatement of slip NH3 emissions via selective oxidation.

Nitrogen management to minimize yield-scaled ammonia emission from paddy rice in the Middle and Lower Yangtze River Basin: A meta-analysis

Paddy fields in China contributed to one third of the global cropland ammonia (NH3) emission inventory, while rice accounted for half of cereal consumption, necessitating exhaustive considerations of the balance between NH3 emissions abatement and food demand. The concept of yield-scaled emission intensity (emissions per unit crop production) has the potential to guide sustainable intensification strategies, yet its application to NH3 emissions remains poorly understood. Here, by constructing novel crop-specific models for single rice production and NH3 emissions in the Middle and Lower Yangtze River Basin (LYRB) as a case study, the relationships between fertilizer N application and yield-scaled NH3 were estimated. Contrary to our hypothesis of a tipping point, our results showed that yield-scaled NH3 curves could not directly identify optimal nitrogen (N) rates. However, the benefit of lower N fertilizer rate on NH3 abatement consistently outweighed the risk of yield loss. The exponential relationships between yield-scaled NH3 and N surplus allowed us to estimate the N surplus criterion as 15.6 kg N ha−1 (or 190 kg N ha−1 fertilizer N rate) for the LYRB. Under the N surplus criterion, NH3 emissions can be reduced by 23–27% without severely impacting rice yield, compared to the N rate required for the highest yield. Moreover, five major controlling factors for yield-scaled NH3 were estimated by random forest models, ranked in order of importance as N rate, total N, K rate, mean annual precipitation, and soil organic carbon. Among the agricultural practices (irrigation, tillage, and fertilizer management), deep placement was the most effective measure to reduce yield-scaled NH3, showing 48% reduction potential, followed by proper N splitting frequency (43%). Overall, this study highlights the efficacy of N application optimization and targeted farm management in mitigating NH3 emission while maintaining crop productivity.

Environmental risk of microplastics after field aging: Reduced rice yield without mitigating yield-scale ammonia volatilization from paddy soils

Microplastics (MPs, <5 mm) are enriched in paddy ecosystems as emerging environmental pollutants. Biochar (BC) is a controversial recalcitrant carbon product that poses potential environmental risks. The presence of these two exogenous organic substances has been demonstrated to have impacts on soil nitrogen cycling and crop production. However, the after-effects of MPs and BC on soil ammonia (NH3) volatilization and rice yield after field aging remain unexplored. In this study, two common MPs, including polyethylene (PE) and polyacrylonitrile (PAN), and BC were selected for rice growing season observations to study the impacts on soil NH3 volatilization and rice yield after field aging. The results showed that the reduction of cumulative soil NH3 losses by MPs was around 45% after one-year field aging, which was within the range of 40–57% in the previous rice season. Abatement of NH3 volatilization by MPs mainly occurred in basal fertilization and was related to floodwater pH. Besides, the reduction rate of NH3 volatilization by BC and MPs + BC was enhanced after field aging (63% and 50–57%) compared to that in the previous rice season (5% and 11–19%), with the abatement process occurring in the first supplementary fertilization. There was a significant positive correlation between cumulative NH3 volatilization and soil urease activity. Notably, field aging removed the positive effect of MPs and MPs + BC in reducing yield-scale NH3 losses in the previous rice season (∼62%). Furthermore, despite BC affecting rice yield insignificantly after field aging, the presence of MPs led to a significant 17–19% reduction in rice yield. Our findings reveal that differences in the after-effects of BC and MPs in field aging emerge, where the negative impacts of MPs on soil NH3 abatement and crop yield are progressively becoming apparent and should be taken into serious consideration.

An acid rain–friendly NH3 control strategy to maximize benefits toward human health and nitrogen deposition

Ammonia (NH3) abatement remains controversial in China owing to its effectiveness in reducing PM2.5 pollution and nitrogen deposition but with the potential risk of promoting acid rain formation, necessitating scientific guidance. Here, we propose a novel method for designing an NH3 control strategy to mitigate both air pollution and nitrogen deposition without significantly exacerbating acid rain. This method involves extending the response surface model (RSM) to deposition using a delicately developed polynomial response function of deposition (i.e., dep-RSM). The Yangtze River Delta (YRD) dep-RSM application reveals that 16 out of 41 cities have NH3 control potentials from 15 % to 71 %. Excellent NH3 control potentials have been noted between April and June (78 %–92 %). From 2013 to 2017, the effective SO2 and NOx control significantly reduced wet sulfur and oxidized nitrogen deposition, providing considerable NH3 abatement potentials (15 %–24 %) to further reduce PM2.5 and nitrogen deposition by up to 2 % and 9 %, respectively, without acid rain exacerbation (the wet neutralization factor was maintained). Additionally, 57 % and 73 % NH3 emission reduction potentials were obtained under acid rain constraints with 75 % and 86 % reductions in the other precursors to reduce the average PM2.5 concentration below 25 and 15 μg/m3, and an additional 8408 and 14,459 premature deaths could only be avoided at an extra cost of 8.7 and 19.7 billion CNY, respectively. Meanwhile, the N deposition considerably reduced by 10 and 13 kgN/ha·yr. However, the YRD region could still simultaneously obtain substantial amounts of PM2.5 and N deposition mitigation using the strategy proposed herein. The expanded optimization system can be directly adopted by policymakers to implement coordinated control in regions or countries facing the same NH3 control conundrum.

Ammonia in urban atmosphere can be substantially reduced by vehicle emission control: A case study in Shanghai, China

To investigate the impact of emission controls on ammonia (NH3) pollution in urban atmosphere, observation on NH3 (1 hr interval) was performed in Shanghai before, during and after the 2019 China International Import Expo (CIIE) event, along with measurements on inorganic ions, organic tracers and stable nitrogen isotope compositions of ammonium in PM2.5. NH3 during the CIIE period was 6.5±1.0 µg/m3, which is 41% and 32% lower than that before and after the event, respectively. Such a decrease was largely ascribed to the emission controls in nonagricultural sources, of which contribution for measured NH3 in control phase abated by ∼20% compared to that during uncontrol period. Molecular compositions of PAHs and hopanes further suggested a dominant role of the reduced vehicle emissions in the urban NH3 abatement during the CIIE period. Our results revealed that vehicle exhaust emission control is an effective way to mitigate NH3 pollution and improve air quality in Chinese urban areas.

Transient kinetic analysis of passive SCR systems for NH3 abatement from natural gas fueled heavy duty engines over dual-layer ASC catalysts: An experimental and modelling study

Air-to-fuel ratios fluctuating around the stoichiometric value enable the best CH4, NOX and CO abatement performance of the three-way catalytic converters implemented in NGVs after-treatment systems; however, this leads to undesired NH3 production and potential slip under rich combustion conditions. An additional Passive SCR catalytic device placed downstream of the TWC, based on a dual-layer SCR+PGM configuration, could represent the solution.Through both transient experimental tests and modelling analysis, we demonstrate that effective NH3 abatement is achieved at low temperatures by its adsorption onto the SCR catalyst during the rich phases, and its further consumption by NO+O2 under lean conditions. Differently, at high temperatures NH3 is efficiently and selectively converted to nitrogen by direct oxidation through a redox reaction mechanism. The developed model can predict the performances of both fresh and aged catalysts under the transient rich-lean cycling experimental conditions investigated.

Volatilisations of ammonia from the soils amended with modified and nitrogen-enriched biochars

Biochar’s capacity to abate NH3 emissions from fertilised agricultural soils may be enhanced through both modifications and formulation of slow-release biochar-based N fertilisers but there is a dearth of data in this area. Sulphuric acid (H2SO4), hydrogen peroxide (H2O2) and potassium hydroxide (KOH) were used to modify biochars which are denoted as BSAD, BHPO and BKOH, respectively. Nitrogen (N) enrichment was performed using urea and ammonium nitrate and the enriched biochars are denoted as BUR and BAN, respectively. The biochars were characterised by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), Fourier-transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS). The ammonia abatement potentials of both the modified and N-enriched biochars were assessed in the incubation experiments which lasted for 30 days. Urea was used as a control while non-modified biochar (PrBC) was included for comparison. Compared to the control, PrBC, BKOH, BHPO, BSAD, BUR and BAN attenuated gaseous NH3 emissions by 57.62%, 63.06%, 73.23% and 74.85%, 79.93% and 82.88%, respectively. Biochar modifications increased the content of oxygen containing surface groups especially carboxyl and sulphoxide in the case of BSAD as depicted from the instrumental analysis data, which most probably increased the sorption of NH3 and its transformation to nitrates thus, resulting in a higher NH3 abatement capacity than that of PrBC. XPS data indicated that N-enrichment resulted in reactions of N with the surface groups of biochar which slowed its release, concomitantly lowering NH3 volatilisation better than even the modified biochars.

Costs and benefits of ammonia abatement in Australia

The abatement of ammonia (NH3) emissions has attracted much attention globally given its increasingly dominant roles in ecosystem sustainability and human health. The potential, costs and benefits of NH3 abatement in Australia, the driest inhabited continent in the world, are less known. We mapped the latest spatial-temporal NH3 emissions in Australia and assessed the feasibility of NH3 abatement. Results show that annual NH3 emissions in Australia ranged 1.2–1.4 Tg N yr-1 in response to agricultural activities and climate variability during 2014–2019. Intensive animal and cropping systems occupy ∼13% of Australia's land but contribute 60% of NH3 emissions. The mitigation potential of Australian agricultural NH3 emissions is 32% (21–47%), with implementation cost estimated at 0.3 (0.1–0.9) billion US dollars (USD), equivalent to only one-tenth of the total mitigation benefit at 3.1 (0.5–7.6) billion USD. The societal benefits of mitigating NH3 emissions in terms of ecosystem sustainability (0.6–6.2 billion USD) are higher than human health benefits (0.8–1.9 billion USD) due to the small human population and the uniqueness and significance of Australia's biodiversity. Mitigating NH3 emissions in Australia should be prioritized to the animal and cropping systems to achieve the low-hanging fruit. Cost-effectiveness mitigation of NH3 will require integration with the current climate policy.

Comprehensive quantification of global cropland ammonia emissions and potential abatement

Ammonia (NH3) emissions mostly from agriculture result in air pollution and degrade human health. However, a full picture of soil NH3 emissions and associated abatement in cropping systems are not well understood. Here we present a thorough analysis of cropland NH3 emissions, discuss mitigation potential and assess associated abatement costs. Global cropland NH3 emissions account for 26% of total soil nitrogen losses, and are estimated as 22.8–31.2 Tg N yr−1 during 1996–2013 with the increase rate of 1.6% yr−1. Our results also show that, with no increase in nitrogen fertilizer, climate change can contribute to an additional 10% increase in cropland NH3 emissions in 2100 compared to the 2010 baseline. Instead, our scenario analysis show, cropland NH3 emissions will decline by 26% from 2010 to 2100 given a 0.5% yr−1 decrease in N fertilizer (with current technology and agricultural management level), considering the facts stronger control policies are expected to occur worldwide including Western Europe, the United States of America and China. The most ambitious management (with all known mitigation practices) can reduce cropland NH3 emissions by up (71%, 17.6 Tg N yr−1) at an abatement cost of US$524 billion. Our findings indicate that cropland NH3 emissions can be mitigated through adoption of appropriate human management practices with considerable economic costs, providing a critical reference for the future NH3 abatement strategies.

Emerging Porous Materials and Their Composites for NH3 Gas Removal.

NH3, essential for producing artificial fertilizers and several military and commercial products, is being produced at a large scale to satisfy increasing demands. The inevitable leakage of NH3 during its utilization, even in trace concentrations, poses significant environmental and health risks because of its highly toxic and reactive nature. Although numerous techniques have been developed for the removal of atmospheric NH3, conventional NH3 abatement systems possess the disadvantages of high maintenance cost, low selectivity, and emission of secondary wastes. In this context, highly tunable porous materials such as metal–organic frameworks, covalent organic frameworks, hydrogen organic frameworks, porous organic polymers, and their composite materials have emerged as next‐generation NH3 adsorbents. Herein, recent progress in the development of porous NH3 adsorbents is summarized; furthermore, factors affecting NH3 capture are analyzed to provide a reasonable strategy for the design and synthesis of promising materials for NH3 abatement.

Mitigating Nitrogen Emissions From Dairy Farming Systems in China

Dairy farming intensification results from the increasing demand for dairy products being met by increasing livestock populations, which places huge pressure on resources and the environment due to poor manure management. In this study, we first quantify the nitrogen (N) flows of two typical dairy manure management systems: “Ganqingfen” system and slurry-based system, based on a substance (N) flow analysis method. Second, the effects of ammonia (NH3) abatement technologies on N recycling efficiency (NRE) and N losses are evaluated for the two systems through a scenario analysis. Furthermore, we explore the mitigation potential of integrated crop and dairy production systems using a scenario analysis of a concatenation of mitigation techniques. The results indicate that the ratio of returned manure N in the “Ganqingfen” and slurry-based manure systems are 32% and 34% of feed N, respectively. N losses from manure management are 56.8–59.5% of total N excretion, of which approximately 50% is emitted as NH3. The scenario analysis indicates that implementation of single or combined NH3 abatement measures can reduce NH3 emissions by 2–56%, whereas nitrous oxide emissions (N2O) can increase depending on the specific measures. Total losses can be reduced from 80.4-83.5 kg N·head-1 to 49.2-55.7 kg N·head-1. Regarding integrated crop and dairy production systems, as the level of scenario optimization improves, resource use (e.g. land use and chemical fertilizer use) and N losses (particularly NH3 emissions) are decreased, while the NRE improves. The results of this study provide insights into the N flow and losses of typical dairy manure management systems in China, as well as effective measures towards the sustainable development of integrated crop and livestock production systems.

Abatement of ammonia emissions from dairy cow house concrete floor surfaces through additive application

Winter housing of dairy cows and beef cattle is common practise in north-western European countries such as the UK and Ireland. In cattle housing, urine and dung are deposited over a large floor surface area from which ammonia (NH3) emissions may rapidly occur. The application of additives to this emitting layer has the potential to significantly reduce NH3 volatilisation from cattle housing surfaces. A dynamic flow-through chamber based study was carried out to determine the NH3 abatement potential of 10 additives applied to dairy cow slurry covered concrete surfaces under simulated northwest European winter housing conditions. Peak NH3 fluxes for control (slurry only) treatments occurred at approximately 3–5 h post slurry application, peaking at 133 mg [NH3–N] m−2 h−1. Acidifiers offered the most potential for cost-effectively abating NH3 emissions from slurry-fouled surfaces by increasing the NH4+:NH3 ratio. Experimental data suggests that targeting a slurry pH of 6 at the housing floor stage can significantly reduce NH3 emissions from fresh excreta. Of the tested additives, alum was the most successful at abating NH3 emissions from slurry; particularly after 6 h (76% NH3 abatement), where the efficacy of alum was greatest relative to the other acidifiers. Alum was followed by calcium chloride (69%) and sulphuric acid (41%). Actisan, a commercially available bedding disinfectant was another successful NH3 abatement option (59% after 6 h). Caution is needed in extrapolating results from this chamber-scale study to cow house scale as spatial and temporal variability of excreta deposition and climatic factors create additional complexity.

Impact of rainfall to the effectiveness of pig slurry shallow injection method for NH3 mitigation in a Mediterranean soil

Ammonia emission from fertilized cropping systems is an important concern for stakeholders, particularly in regions with high livestock densities producing large amounts of manure. Application of pig slurries can result in very large losses of N through NH3 volatilization, thus decreasing the N use efficiency (NUE) of the applied manure. Shallow incorporation has been shown to significantly abate these losses. In this field study, we assessed the impact of contrasting weather conditions on the effectiveness of shallow injection to abate NH3 emissions from pig slurry application to a Mediterranean soil. As potential trade-offs of NH3 abatement, greenhouse gas emissions were also measured under conditions of high soil moisture. Compared with surface application of slurry, shallow injection effectively and significantly decreased NH3 losses independently of weather conditions, but reductions of NH3 emission were greater after heavy rainfall. In contrast, under these conditions, shallow injection triggered higher emissions of N2O and CH4. Our findings reinforce the idea that any single-pollutant abatement strategy needs to be designed and assessed in a regional context and considering potential trade-offs in the form of other pollutants.

Evaluating the potential of dietary crude protein manipulation in reducing ammonia emissions from cattle and pig manure: A meta-analysis

Dietary manipulation of animal diets by reducing crude protein (CP) intake is a strategic NH3 abatement option as it reduces the overall nitrogen input at the very beginning of the manure management chain. This study presents a comprehensive meta-analysis of scientific literature on NH3 reductions following a reduction of CP in cattle and pig diets. Results indicate higher mean NH3 reductions of 17 ± 6% per %-point CP reduction for cattle as compared to 11 ± 6% for pigs. Variability in NH3 emission reduction estimates reported for different manure management stages and pig categories did not indicate a significant influence. Statistically significant relationships exist between CP reduction, NH3 emissions and total ammoniacal nitrogen content in manure for both pigs and cattle, with cattle revealing higher NH3 reductions and a clearer trend in relationships. This is attributed to the greater attention given to feed optimization in pigs relative to cattle and also due to the specific physiology of ruminants to efficiently recycle nitrogen in situations of low protein intake. The higher NH3 reductions in cattle highlights the opportunity to extend concepts of feed optimization from pigs and poultry to cattle production systems to further reduce NH3 emissions from livestock manure. The results presented help to accurately quantify the effects of NH3 abatement following reduced CP levels in animal diets distinguishing between animal types and other physiological factors. This is useful in the development of emission factors associated with reduced CP as an NH3 abatement option.

Flue-gas desulfurization gypsum effects on urea-degrading bacteria and ammonia volatilization from broiler litter

A major concern of the broiler industry is the volatilization of ammonia (NH3) from the mixture of bedding material and broiler excretion that covers the floor of broiler houses. Gypsum has been proposed as a litter amendment to reduce NH3 volatilization, but reports of NH3 abatement vary among studies and the mechanism responsible for decreasing NH3 volatilization is not well understood. The goal of this study was to evaluate the effect of adding 20 or 40% flue-gas desulfurization gypsum (FGDG) to broiler litter on pH, electrical conductivity (EC), water potential, urea-degrading bacteria abundance, NH3 and carbon dioxide (CO2) evolution, and nitrogen (N) mineralization in several 21-d experiments. The addition of FGDG to broiler litter increased EC by 24 to 33% (P < 0.0001), decreased urea-degrading bacteria by 48 to 57% (P = 0.0001) and increased N mineralization by 10 to 11% (P = 0.0001) as compared to litters not amended with FGDG. Furthermore, the addition of FGDG to broiler litter decreased NH3 volatilization by 18 to 28% (P < 0.0001), potentially resulting from the significantly lower litter pH values compared to un-amended litter (P < 0.0001). Findings of this study indicate that amending broiler litter with 20% FGDG can decrease NH3 volatilization and increase the fertlizer value of broiler litter.

Assessing ammonia emission abatement measures in agriculture: Farmers' costs and society's benefits – A case study for Lower Saxony, Germany

Ammonia (NH3) emissions have adverse impacts on the environment and, being a precursor for fine particulate matter, also on human health. About 95% of NH3 emissions in Germany originate from agriculture, mainly from livestock husbandry. This case study is aimed at presenting an approach that evaluates NH3 emission abatement measures in agriculture regarding their abatement costs for farmers and their benefits for the society in terms of avoided external costs of health damages and loss of terrestrial biodiversity. Following the impact-pathway chain, an economic-ecological farm model for estimating NH3 emission reductions and abatement costs was combined with an environmental impact assessment model for estimating the benefits for human health and biodiversity. The case study analysed a variety of manure storage cover and application techniques in Lower Saxony, a region in the north-west of Germany with the highest livestock density in Germany and high NH3 emissions. In the reference situation, the damage costs of NH3 emissions were EUR 2.7 billion. The implementation of concrete storage covers and slurry injection, the most effective measures, reduced NH3 emissions by 25% and achieved net benefits of EUR 505 million. Farmers' abatement costs averaged over all farms ranged from EUR 3.6 to 6.8 per kilogramme NH3 reduced. The abatement costs per farm type ranged from EUR 2.4 to 16.6 for floating plastic covers and from EUR 2.2 to 11.4 for concrete covers. The abatement costs for floating plastic covers were lower for grazing livestock specialists, while the abatement costs for concrete covers were lower for pig specialists, poultry specialists and mixed farms. Farm type specific abatement costs for manure application techniques ranged from EUR 4.5 to 9.6 per kilogramme NH3 reduced with little variation between trailing shoe and cultivator/injector techniques. Abatement costs for trailing shoe application were lower than for cultivator/injector application for grazing livestock specialists, poultry specialists and mixed farms. The average benefits per kilogramme NH3 reduced were EUR 14.1 for health and EUR 10.4 for biodiversity, totalling EUR 24.5. As the benefits exceed the abatement costs for all measures analysed in this study, principally, they can be recommended for implementation. However, the variation in abatement potentials and costs per farm type indicate differences in suitability. While manure covers should above all be implemented by pig specialists because of their high abatement potential, manure application techniques should be implemented by grazing livestock specialists. Among manure storage covers, floating plastic covers are more favourable for grazing livestock specialists, whereas concrete covers are more suitable for all other farm types. The analysis with the farm model was considered more appropriate than recent analyses at technical or macroeconomic level, because the abatement costs reflect differences in farm types, detailed production processes and farmers' profit-maximising behaviour. Overall, it can be concluded that an assessment of NH3 emission abatement measures should be carried out for farm types and should consider impacts of NH3 emission abatement both on human health and biodiversity. The presented modelling approach enables to estimate abatement costs for farm types and benefits for human health and biodiversity. Cost-efficient NH3 emission abatement measures tailored to farm types can be identified and farm type specific regional abatement strategies can be developed.

Modeling analysis of energy requirement in aqueous ammonia based CO2 capture process

Aqueous ammonia is a promising alternative absorbent for CO2 capture from the flue gas of coal-fired power plants. The efficiency penalty of aqueous ammonia based CO2 capture process, however, is considerably heavy, resulting from the energy requirement for CO2 regeneration and NH3 abatement cycle. The paper focused on the whole process including CO2 absorption, CO2 regeneration, CO2 compression, NH3 abatement and NH3 recovery process, and analyzed the effects of operating parameters on the energy requirement of this process with a validated and reliable model. The sensible heat, stripping heat and desorption heat were calculated to gain insights into the regeneration process. The orthogonal analysis method was then adopted to find out the achievable minimum energy requirement for CO2 capture. The minimum energy requirement was identified as 2.89MJ/kg CO2 for CO2 regeneration process and 4.07MJ/kg CO2 for the whole process.