Anaerobic Digestion Of Manure Research Articles

Influence of zero valent iron nanoparticles and magnetic iron oxide nanoparticles on biogas and methane production from anaerobic digestion of manure

In this study, nanoparticles (NPs) were hypothesized to enhance the anaerobic process and to accelerate the slurry digestion, which increases the biogas and methane production. The effects of NPs on biogas and methane production were investigated using a specially designed batch anaerobic system. For this purpose, a series of 2 L biodigesters were manufactured and implemented to study the effects of the nanoparticles of Iron (Fe) and Iron Oxide (Fe3O4) with different concentrations on biogas and methane production. The best results of NPs additives were selected based on the statistical analysis (Least Significant Difference using M-Stat) of biogas and methane production, which were 20 mg/L Fe NPs and 20 mg/L Fe3O4 magnetic NPs (p < 0.05). The aforementioned NPs additives delivered the highest biogas and methane yields in comparison with their other concentrations (5, 10 and 20 mg/L), their salt (FeCl3) and the control. Furthermore, the addition of 20 mg/L Fe NPs and 20 mg/L Fe3O4 magnetic NPs significantly increased the biogas volume (p < 0.05) by 1.45 and 1.66 times the biogas volume produced by the control, respectively. Moreover, the aforementioned additives significantly increased the methane volume (p < 0.05) by 1.59 and 1.96 times the methane volume produced by the control, respectively. The highest specific biogas and methane production were attained with 20 mg/L Fe3O4 magnetic NPs, and were 584 ml Biogas g−1 VS and 351.8 ml CH4 g−1 VS, respectively compared with the control which yielded only 352.6 ml Biogas g−1 VS and 179.6 ml CH4 g−1 VS.

German Electricity Balancing Market for Small Manure Plants

AbstractIn order to exploit the theoretical potential of small manure anaerobic digestion (AD) plants for flexible power generation, the technical retrofitting and the prospective additional revenue generated by direct marketing is assessed for two different manure AD plants by means of a profitability analysis. Due to the variation in the economic profitability by the individual direct marketing models, the economy of three plants was simulated in four different scenarios: basic feed‐in tariff, direct marketing, electricity balancing market, and flexible operation. Economical operations were calculated and the additional revenue for small manure AD plants taking part in the direct marketing system was calculated.

Potentialities of biogas installation in South African meat value chain for environmental impacts reduction

Livestock farming in South Africa has expanded significantly, and thus there is a corresponding increasing need to properly manage the generated waste streams. Anaerobic digestion to produce biogas is becoming an increasingly popular technology choice for the treatment of organic wastes and wastewater. Energy production from the anaerobic digestion of manures and slaughterhouse wastes would reduce untreated waste disposal and provide additional income. This study investigated biogas plants potentialities to reduce emissions from poor waste management both at the feedlot and at the abattoir stage of the South Africa beef and pork value chain. Electricity generation from the biogas, and possibly usage of co-produced heat would further reduce GHG emissions by about 1.56 Mt CO2eq per year, reducing the carbon footprints of beef and pork by 10% and 30% respectively. Even more significant reductions of both AC and EU impacts should be achievable by avoiding mostly landfilling of wastes and over-fertilization of soils. Furthermore, the produced biogas, burned for generating electricity and heat used within the industries themselves, might make them self-sufficient from the national grid. The nutrient-rich digestate would be similar in quantity to imported fertilizers, reducing the cost of importing and possibly generating additional income.

Temperature and pH effect on methane production from buffalo manure anaerobic Digestion

Temperature and pH effect on methane production from buffalo manure anaerobic Digestion

Temperature and pH effect on methane production from buffalo manure anaerobic Digestion

Temperature and pH effect on methane production from buffalo manure anaerobic Digestion

Orchard and horticulture systems in Spanish Mediterranean coastal areas: Is there a real possibility to contribute to C sequestration?

Agriculture in the Mediterranean basin is currently contributing to greenhouse gas emissions (GHG) and in the future is expected to be strongly affected by climate change. Increasing soil organic carbon (SOC) via soil organic matter (SOM) improvement is widely regarded as a way to both mitigate and adapt to climate change. Using as a case study the Mediterranean coastal area in Spain, which is regarded as one of the most intensively managed areas in Europe for orchards and horticultural cropping, we analyzed the potential for climate change mitigation of introducing different practices that are expected to increase SOC. We selected both as a single measure and in combination, cover cropping and application to the soil of the available underutilized exogenous organic matter (EOM), treated (e.g. composted or digested) or non-treated. These practices were compared against a baseline scenario that intended to reflect the current practices in the area (e.g. all livestock manure produced in the area is applied to the agricultural soil). We carried out a modelling exercise at the regional scale using the agricultural activity data and current climatic conditions as inputs. Modelling runs were performed coupling a widely used dynamic model of SOC turnover (RothC) with a model to simulate the GHG emissions from EOM processing or storage prior to soil application (SIMSWASTE).Results indicate that the most promising practice, considered as a single measure and with respect to the baseline, was introducing cover crops in woody cropping systems. This practice resulted in an increase of 0.44MgCha−1 yr−1 during the first 20 years (range 0.41–0.52MgCha−1 yr−1) and led to a total SOC accumulation of about 30TgC after 100 years. Amendment of all agricultural land with available underutilized EOM resulted in an increase of up to 0.09MgCha−1 yr−1 (range 0.07–0.16MgCha−1 yr−1) as a single measure (urban waste) and 0.13MgCha−1 yr−1 (range 0.11–0.21MgCha−1 yr−1) as a combined measure (urban waste and composted agroindustry by-products), leading to a total SOC accumulation of about 7TgC (urban waste) and 10Tg C (urban waste and composted agroindustry by-products) after 100 years. Manure anaerobic digestion or composting as a single measure did not result in significant SOC changes but, if GHG emissions and savings from manure storage and processing management stages are considered, they could help to reduce about 4.3 (anaerobic digestion) or 1.1Tg CO2eq yr−1 (composting) in the study area, which represents a significant amount compared with total agricultural emissions in Spain.

Ammonia inhibition on hydrogen enriched anaerobic digestion of manure under mesophilic and thermophilic conditions

Capturing of carbon dioxide by hydrogen derived from excess renewable energy (e.g., wind mills) to methane in a microbially catalyzed process offers an attractive technology for biogas production and upgrading. This bioconversion process is catalyzed by hydrogenotrophic methanogens, which are known to be sensitive to ammonia. In this study, the tolerance of the biogas process under supply of hydrogen, to ammonia toxicity was studied under mesophilic and thermophilic conditions. When the initial hydrogen partial pressure was 0.5 atm, the methane yield at high ammonia load (7 g NH4+-N L−1) was 41.0% and 22.3% lower than that at low ammonia load (1 g NH4+-N L−1) in mesophilic and thermophilic condition, respectively. Meanwhile no significant effect on the biogas composition was observed. Moreover, we found that hydrogentrophic methanogens were more tolerant to the ammonia toxicity than acetoclastic methanogens in the hydrogen enriched biogas production and upgrading processes. The highest methane production yield was achieved under 0.5 atm hydrogen partial pressure in batch reactors at all the tested ammonia levels. Furthermore, the thermophilic methanogens at 0.5 atm of hydrogen partial pressure were more tolerant to high ammonia levels (≥5 g NH4+-N L−1), compared with mesophilic methanogens. The present study offers insight in developing resistant hydrogen enriched biogas production and upgrading processes treating ammonia-rich waste streams.

Phosphorus Uptake by Potato from Fertilizers Recovered from Anaerobic Digestion

The rising costs of fertilizers have encouraged the development of technologies to recover nutrients from dairy, cattle, swine, and poultry operations. Field experiments were conducted in the Columbia Basin of Washington to assess the yield of potato (Solanum tuberosum L.) to application of P‐enriched materials recovered from anaerobic digestion of manure. Four rates of P from five sources, three recovered from anaerobic digesters (AD), AD‐dairy P‐enriched fine solids (ADD), AD centrifuged poultry solids (ADP), and AD dairy struvite‐P (ADS) compared to a commercial poultry fertilizer (PBP) were compared to mono‐ammonium phosphate (MAP) and non‐amended control (No‐P). Fertilized treatments had higher yields than the No‐P treatment. Phosphorus source and application rate had significant effects on petiole P concentrations. Increases in petiole P concentrations averaged 300 to 500 mg kg−1 tissue with each rate increase for MAP and ADS. Tuber yields among P fertilizers and rates of P application were not significant but were different between years, averaging 2 and 10 Mg ha−1 fresh weight higher than the No‐P treatment. Tuber size distribution showed a significant shift from smaller tubers &lt;170 g to the 285+ g tuber classes. The P recovery efficiency averaged 42% among treatments receiving 56 kg P2O5 ha−1 and declined to 22% for higher rates of ADS, ADD, and MAP. Recoveries were lowest for poultry derived materials, ranging 20 to 30%. The P fertilizer sources evaluated performed similarly when equal rates of P were applied and method of application was comparable. Phosphorus recovered from anaerobic digesters can effectively substitute for commercial mined P fertilizers. Potato yields among recovered P fertilizers and rates of P application were not significantly different. Recovered P fertilizer performed similarly when equal rates were applied and method of application was comparable.

The effect of magnesium as activator and inhibitor of anaerobic digestion

Anaerobic digestion stands as a key technology in the emerging green energy economy. Mg2+ has been identified as an important element to improve digesters methane production; however the inhibition risk that high Mg2+ concentrations can cause to the AD process must also be considered when dosing Mg reagents and wastes containing Mg2+. Despite its importance, Mg2+ stimulation and inhibition mechanisms as well as threshold values are scarce in the literature. This research paper investigates the impact (stimulation and inhibition) of Mg2+ on pig manure anaerobic digestion. Mathematical modelling was used to better understand the interaction between substrate, inoculum and magnesium, where Mg2+ inhibition was modelled by a n-component non-competitive inhibition function. Modelling was done on absolute curves rather than specific methane productions curves (new approach) to account for the lower background methane production of the inoculum as the Mg2+ concentration increased. Results showed that no stimulation or inhibition occurred between 40 (native concentration) and 400mgMg2+L−1, while minor and major inhibition were observed at 750 and 1000mgMg2+L−1, and at 2000 and 4000mgMg2+L−1, respectively. Mg2+ half maximal inhibition concentration was estimated at 2140mgMg2+L−1 with an inhibition order of 2. The latter indicates that Mg2+ inhibition is a progressive rather than a steep inhibition mechanism.

Health risk assessment of heavy metals in soil-plant system amended with biogas slurry in Taihu basin, China.

Biogas slurry is a product of anaerobic digestion of manure that has been widely used as a soil fertilizer. Although the use for soil fertilizer is a cost-effective solution, it has been found that repeated use of biogas slurry that contains high heavy metal contents can cause pollution to the soil-plant system and risk to human health. The objective of this study was to investigate effects of biogas slurry on the soil-plant system and the human health. We analyzed the heavy metal concentrations (including As, Pb, Cu, Zn, Cr and Cd) in 106 soil samples and 58 plant samples in a farmland amended with biogas slurry in Taihu basin, China. Based on the test results, we assessed the potential human health risk when biogas slurry containing heavy metals was used as a soil fertilizer. The test results indicated that the Cd and Pb concentrations in soils exceeded the contamination limits and Cd exhibited the highest soil-to-root migration potential. Among the 11 plants analyzed, Kalimeris indica had the highest heavy metal absorption capacity. The leafy vegetables showed higher uptake of heavy metals than non-leafy vegetables. The non-carcinogenic risks mainly resulted from As, Pb, Cd, Cu and Zn through plant ingestion exposure. The integrated carcinogenic risks were associated with Cr, As and Cd in which Cr showed the highest risk while Cd showed the lowest risk. Among all the heavy metals analyzed, As and Cd appeared to have a lifetime health threat, which thus should be attenuated during production of biogas slurry to mitigate the heavy metal contamination.

Continuous anaerobic digestion of swine manure: ADM1-based modelling and effect of addition of swine manure fibers pretreated with aqueous ammonia soaking

Anaerobic digestion of manure fibers presents challenges due to their low biodegradability. Aqueous ammonia soaking (AAS) has been tested as a simple method to disrupt the lignocellulose and increase the methane yield of manure fibers. In the present study, mesophilic anaerobic digestion of AAS pretreated manure fibers was performed in CSTR-type digesters, fed with swine manure and/or a mixture of swine manure and AAS pretreated manure fibers (at a total solids based ratio of 0.52 manure per 0.48 fibers). Two different simulations were performed. In the first place, the Anaerobic Digestion Model 1 (ADM1) was fitted to a manure-fed, CSTR-type digester and validated by simulating the performance of a second reactor digesting manure. It was shown that disintegration and hydrolysis of the solid matter of manure was such a slow process that the organic particulate matter did not significantly contribute to the methane production. In the second place, ADM1 was used to describe biogas production from the codigestion of manure and AAS pretreated manure fibers. The model predictions regarding biogas production and methane content were in good agreement with the experimental data. It was shown that, AAS treatment significantly increased the disintegration and hydrolysis rate of the carbohydrate compounds of the fibers. The effect of the addition of AAS treated fibers on the kinetics of the conversion of other key compounds such as volatile fatty acids was negligible.

Economics of GHG emissions mitigation via biogas production from Sorghum, maize and dairy farm manure digestion in the Po valley

The Greenhouse gas (GHG) emissions and economic feasibility of electricity production from the anaerobic digestion of different substrates are studied in this paper. Three realistic substrate options for the climatic and soil conditions of a modelled farm in the Po Valley in Italy are analysed: manure from a dairy farm, Sorghum and maize.A detailed cost analysis is performed with field data provided by farmers and suppliers and literature sources. The capital costs (CAPEX) and the operational costs (OPEX), disaggregated by their components, are presented. Investment payback time is then calculated for the different substrates and technologies, while taking into account the Italian government feed-in tariff scheme for biogas plants implemented in 2013.In the specific conditions assumed, electricity production via anaerobic digestion of manure and co-digestion of manure with at most 30% Sorghum (no till) provide both GHG savings (in comparison to the Italian electricity mix) and profit for economic operators.The anaerobic digestion of silage maize or Sorghum alone, instead, provides no (or very limited) GHG savings, and, with the current feed-in tariffs, generates economic losses.Both economic and environmental performance are improved by the following practices: cultivating Sorghum instead of maize; implementing no till agriculture; and installing gas-tight tanks for digestate storage. A tool allowing a customised calculation of the economic performances of biogas plants is provided.

Chemical and biological assessment of endocrine disrupting chemicals in a full scale dairy manure anaerobic digester with thermal pretreatment

Concentrated animal feeding operations are important sources of estrogens and their conjugates, which are introduced into the environment through manure land application. In this study, concentrations of estrogens were measured in an anaerobic co-digestion system with thermal pasteurization pretreatment. Free estrogens (estrone (E1), 17α-estradiol (E2α), 17β-estradiol (E2β), estriol (E3)) were analyzed by gas chromatography with mass spectrometry (GC/MS), and conjugated estrogens (sulfate- and glucuronide-conjugates) were analyzed by liquid chromatography with tandem mass spectrometry (LC/MS/MS). Additionally, yeast estrogen screen assay was used to determine the estrogenic potential of the manure. The total hormone concentrations (mainly E1, E2α, E2β, and sulfated estrogens) were observed at concentrations up to a total of 7100ng/L in the liquid fraction, while free estrogen levels were 630ng/kg in the solid fraction of the untreated manure. The total hormone concentration did not decrease significantly during digestion, however, the relative composition of the estrogens changed from E2α (65%) being the predominant species before digestion to mostly E1 (72%) after digestion. This conversion process has important implications because E1 is more estrogenic than E2α. Total E2 equivalents associated with E1, E2α and E2β concentrations as determined by GC/MS indicate that E1 is the most important contributor to the endocrine-disruption activity of the treated manure.

Effect of domestication on microorganism diversity and anaerobic digestion of food waste.

To accomplish the rapid start-up and stable operation of biogas digesters, an efficient inoculum is required. To obtain such an inoculum for food waste anaerobic digestion, we domesticated dairy manure anaerobic digestion residue by adding food waste every day. After 36 days, the pH and biogas yield stabilized signifying the completion of domestication. During domestication, the microbial communities in the inocula were investigated by constructing 16S rDNA clone libraries. We evaluated the effect of the domesticated inoculum by testing batch food waste anaerobic digestion with a non-domesticated inoculum as a control. The pH and methane yield of the digestion systems were determined as measurement indices. Domestication changed the composition and proportion of bacteria and archaea in the inocula. Of the bacteria, Clostridia (49.3%), Bacteroidales (19.5%), and Anaerolinaceae (8.1%) species were dominant in the seed sludge; Anaerolinaceae (49.0%), Clostridia (28.4%), and Bacteroidales (9.1%), in domestication sludge. Methanosaeta was the dominant genus in both of the seed (94.3%) and domestication (74.3%) sludge. However, the diversity of methanogenic archaea was higher in the domestication than in seed sludge. Methanoculleus, which was absent from the seed sludge, appeared in the domestication sludge (21.7%). When the domesticated inoculum was used, the digestion system worked stably (organic loading rate: 20 gVS/L; methane yield: 292.2 ± 9.8 mL/gVS; VS = volatile solids), whereas the digestion system inoculated with seed sludge failed to generate biogas. The results indicate that inoculum domestication ensures efficient and stable anaerobic digestion by enriching the methanogenic strains.

돼지분뇨 슬러리중의 고형물 농도수준과 분쇄 처리가 메탄 생성에 미치는 효과

최근 들어서 국내에서도 가축분뇨를 이용한 바이오가스화 시설이 늘어나고 있다. 국내에서 운용 중인 가축분뇨 혐기소화 시설이 모두 다 혐기소화 원료로서 돼지분뇨 슬러리를 이용하고 있다. 일반적으로 돼지분뇨 슬러리는 97%내외의 물과 3% 정도의 고형물로 구성된다. 돼지분뇨 슬러리에는 옥수수 입자등과 같이 돼지가 섭취한 사료 중에서 미처 소화되지 못하고 배설되는 고형성 물질이 함유되어 있다. 입자성 물질은 혐기소화 과정에서 바이오가스 생성효과를 낮추는 요인이 된다. 따라서 본 연구에서는 기계적 분쇄 처리에 의해 고형물의 입자 크기를 감소시킴에 따른 메탄 생성효과의 변화정도를 분석하였다. 또 한편으로는 돼지분뇨 슬러리중의 고형물 농도 수준이 메탄 생성량에 미치는 영향을 분석하였다. 그리고 각각의 실험조건에서 발생된 바이오가스 중에 포함된 메탄의 농도를 분석하였다. 실험결과, 입자성 고형물을 분쇄 처리함에 따라 돼지분뇨 슬러리중의 미세 입자 농도가 증가하였다. 또한 고형물을 분쇄 처리한 경우가 분쇄하지 않은 원 슬러리를 사용하는 경우보다도 메탄 생성량과 메탄 함량이 높게 나타났다. Recently, the number of anaerobic digestion facility for livestock manure is on the rise in Korea. All of the livestock manure anaerobic digestion facilities in operation use pig manure slurry as a substrate for anaerobic digestion. Generally, pig manure slurry is composed of 97% water and 3% solids. The particulate matter, such as corn in the form of particles that is undigested by pig is contained in the pig manure slurry. Particulate matter is a factor reducing the effectiveness of biogas production in the anaerobic digestion process. In this study, mechanical grinding treatment was applied to analyze the effect of methane production from pig manure slurry by reducing the particle size of the slurry. On the other hand, the effect of the solid concentration levels on methane production and methane content of the biogas was analyzed. The fine particle concentration in the pig manure slurry was increased by the mechanical grinding treatment. And methane production and methane content of the biogas were higher in grinded pig manure slurry than untreated raw slurry.

Enhancing recovery of ammonia from swine manure anaerobic digester effluent using gas-permeable membrane technology

Gas-permeable membrane technology is useful to recover ammonia from manure. In this study, the technology was enhanced using aeration instead of alkali chemicals to increase pH and the ammonium (NH4+) recovery rate. Digested effluents from covered anaerobic swine lagoons containing 1465–2097mgNH4+–NL−1 were treated using submerged membranes (0.13cm2cm−3), low-rate aeration (120mL airL-manure−1min−1) and nitrification inhibitor (22mgL−1) to prevent nitrification. The experiment included a control without aeration. The pH of the manure with aeration rose from 8.6 to 9.2 while the manure without aeration decreased from 8.6 to 8.1. With aeration, 97–99% of the NH4+ was removed in about 5days of operation with 96–98% recovery efficiency. In contrast, without aeration it took 25days to treat the NH4+. Therefore, the recovery of NH4+ was five times faster with the low-rate aeration treatment. This enhancement could reduce costs by 70%.

Substrate Type and Free Ammonia Determine Bacterial Community Structure in Full-Scale Mesophilic Anaerobic Digesters Treating Cattle or Swine Manure.

The microbial-mediated anaerobic digestion (AD) process represents an efficient biological process for the treatment of organic waste along with biogas harvest. Currently, the key factors structuring bacterial communities and the potential core and unique bacterial populations in manure anaerobic digesters are not completely elucidated yet. In this study, we collected sludge samples from 20 full-scale anaerobic digesters treating cattle or swine manure, and investigated the variations of bacterial community compositions using high-throughput 16S rRNA amplicon sequencing. Clustering and correlation analysis suggested that substrate type and free ammonia (FA) play key roles in determining the bacterial community structure. The COD: (C:N) ratio of substrate and FA were the most important available operational parameters correlating to the bacterial communities in cattle and swine manure digesters, respectively. The bacterial populations in all of the digesters were dominated by phylum Firmicutes, followed by Bacteroidetes, Proteobacteria and Chloroflexi. Increased FA content selected Firmicutes, suggesting that they probably play more important roles under high FA content. Syntrophic metabolism by Proteobacteria, Chloroflexi, Synergistetes and Planctomycetes are likely inhibited when FA content is high. Despite the different manure substrates, operational conditions and geographical locations of digesters, core bacterial communities were identified. The core communities were best characterized by phylum Firmicutes, wherein Clostridium predominated overwhelmingly. Substrate-unique and abundant communities may reflect the properties of manure substrate and operational conditions. These findings extend our current understanding of the bacterial assembly in full-scale manure anaerobic digesters.

Dairy manure resource recovery utilizing two-stage anaerobic digestion – Implications of solids fractionation

Dairy manure management is increasingly becoming an environmental challenge. In this regard, manure anaerobic digestion (AD) can be applied to address environmental concerns; however, dairy manure AD remains economically uncompetitive. Ongoing research is focused on enhanced resource recovery from manure, including maximizing AD methane yield through a novel multi-stage AD configuration. Research presented herein centered on the hypothesis that separately digesting fine and coarse solids from fermented dairy manure would improve methane production; the hypothesis was disproven. While maximum methane concentration was realized on fine solids, combined solids AD yielded enhanced VS destruction. The diverse combined-solids substrate enriched for a more heterogeneous bacterial/archaeal consortium that balanced fermentation and methanogenesis to yield maximum product (methane). However, results suggest that targeted AD of the fat-rich fine solids could be a more optimal approach for processing manure; alternate (non-AD) methods could then be applied to extract value from the fibrous fraction.

Comparison of anaerobic digestion characteristics and kinetics of four livestock manures with different substrate concentrations

Anaerobic digestions of pig manure (PM), dairy manure (DM), chicken manure (CM) and rabbit manure (RM) at initial volatile solid loading (VSL) of 8gVS/L, 16gVS/L, 32g VS/L, 64g VS/L were investigated under mesophilic conditions. The maximum methane yields of 410, 270, 377 and 323mL CH4/gVSadded for PM, DM, CM and RM were all obtained at initial VSL of 8gVS/L, respectively. The improvement of substrate concentration to 64gVS/L not only decreased the methane yield and biodegradability both by 22.4%, 37.3%, 49.1% and 34.6% for PM, DM, CM and RM respectively, but also reduced the methane content in final biogas production. The Cone model (R2: 0.9910–0.9974) showed a better fit to the experiment data and the calculated parameters indicated that anaerobic digestion of manures at higher loading has longer lag phase and lower hydrolysis rate.

Effects of Anaerobic Digestion and Solids Separation on Ammonia Emissions from Stored and Land Applied Dairy Manure

Field and laboratory studies were conducted to evaluate the effects of anaerobic digestion (AD) and solids-liquid separation on emissions during subsequent storage and land application. The lab storage tests were conducted for 21 days with manure samples obtained at the following four points in a full-scale AD system: raw manure (RM) delivery, raw manure supplemented with other substrates (AD influent), AD effluent, and AD effluent after solids-liquid separation (AD liquid effluent). Ammonia fluxes from stored AD effluent declined from 3.95 to 2.02 g m−2 day−1. Lower NH3 fluxes, however, were observed from AD liquid effluent (1.1 g m−2 day−1) and AD influent (0.25 g m−2 day−1). Ammonia emissions from full-scale manure storages were similar to those obtained in the lab. Results also indicated significantly lower volatile fatty acid (VFA) in AD effluent and AD liquid effluent compared with that from the AD influent, indicating significant reduction in odor generation potential due to AD and solids-liquid separation processes. Two manure application methods (surface application and manure injection) for both non-AD and AD manures were simulated in the lab and studied for 9 days. Surface-applied non-AD manure exhibited the highest NH3 flux (0.78 g m−2 day−1), while injected AD manure led to the lowest NH3 flux (0.17 g m−2 day−1). Similar NH3 emissions results were observed from the field studies. Overall, while AD of dairy manure resulted in significant increases in NH3 emissions from stored effluent, the AD process significantly reduced NH3 emissions following application of AD manure on land.