Reducing ammonia emission from poultry manure composting via struvite formation

Composting can provide a viable alternative for poultry manure management in the Fraser Valley of British Columbia, Canada. However, it has a high potential for ammonia emission because of the high nitrogen content of poultry litter. The objective of this study was to reduce ammonia emission by precipitating ammonia into struvite before it can volatilize from the composting matrix. Nitrogen transformation occurs during composting, but struvite formation can help to conserve nitrogen, and does not allow a large amount of nitrogen to be released into the environment as ammonia or nitrate, because ammonium‐nitrogen becomes bound in struvite. It would also be possible to remove phosphorus from the manure. A laboratory‐scale experiment was conducted to examine the feasibility of struvite formation during poultry manure composting. Magnesium and phosphate salts were supplemented to create favorable conditions to form struvite. Results indicated that ammonia emission was reduced by 40% to 84%, while the nitrogen retention in compost was enhanced. The struvite formed in compost was confirmed by means of X‐ray diffraction; and scanning electron microscopy with energy dispersive X‐ray spectroscopy. Copyright © 2007 Society of Chemical Industry     

Dissolution of phosphate rock during the composting of poultry manure: an incubation experiment

Dissolution of phosphate rocks (PRs) during composting with poultry manure was examined using a radioactive³²P labelled synthetic francolite and North Carolina phosphate rock (NCPR) through laboratory incubation experiments. Francolite or NCPR was mixed with different poultry manure composts at a rate equivalent to 5 mg P g^–1 and the dissolution was measured after 60 and 120 days incubation by a sequential phosphorus (P) fractionation procedure.The use of³²P labelled francolite showed that in manure systems, PR dissolution can be measured more accurately from the increases in NaOH extractable P (NaOH-P) than from the decreases in HCl extractable P (HCl-P) in the PR treated manure over the control. The dissolution measurements showed that approximately 8 to 20% of francolite and 27% of NCPR dissolved during incubation with poultry manure composts in the presence of various amendments. Addition of elemental sulphur (S°) to the compost enhanced the dissolution of PRs. The results provide no evidence for the beneficial effect of protons (H⁺), produced during the nitrification of NH ₄ ⁺ in manure composts, on PR dissolution. The low level of dissolution of PR in poultry manure composts was attributed mainly to the high concentration (4.8 × 10^–2 mol L^–1) of calcium (Ca²⁺) in manure solution.     

Levels of ATP in different organic wastes under composting conditions

BACKGROUND: The concentration of ATP in selected samples from the composting process of several organic wastes (municipal solid wastes, wastewater sludge, animal by‐products and cow manure) has been determined in order to characterize the aerobic biological activity of such wastes. RESULTS: The values obtained ranged from 0 (in old stable compost from cow manure) to 0.07 µmol ATP g^?1 dry matter in thermophilic samples of municipal solid wastes composting. In general, it was found that ATP levels were in agreement with the stage of the composting process (initial stage, thermophilic period and maturation). On the other hand, ATP concentration correlated well (P < 0.05) with the overall respiration activity during a complete composting process of municipal solid waste at full scale. CONCLUSION: ATP concentration can be used to determine the biological activity of organic solid wastes in different stages of their biological treatment and to predict compost stability prior to soil application. Copyright © 2008 Society of Chemical Industry     

去除牛粪厌氧生物转化过程中的H2S

The main aim of this research was the experimental study at lab scale to check the absorption technolOgytor the in situ removal of H2S from biogas during anaerobic digestion process.The reagent FeCll was used to check the removal efficiency of H,S produced from dairy manure during anaerobic bioconversion process.The expenments werc conducted under mesophilic conditions.Thc composition of biogas was analyzed by gas chromatography analyzer equipped with flame photometer and thermal conductivity detectors.Experimental results under the same conditions demonstrate that high concentration of HES in the form of FeS can be removed totally from the biogas using FeCl3 dosing with in anaerobic batch digester.     

猪粪原料沼气工程系统中的原核微生物群落结构

采集了中国不同地区的13个猪粪原料沼气工程系统的沼液,利用16S rRNA基因扩增子高通量测序技术研究了原核微生物群落组成及多样性。结果表明,Firmicutes是猪粪原料沼气工程系统中的主导微生物,其次为Bacteroidetes、Proteobacteria和Chloroflexi。在相似的温度条件下,铵态氮与磷酸盐的比例是影响猪粪原料沼气工程系统原核微生物群落结构及多样性的主要因素。较高的铵磷比会富集Firmicutes门的菌群,尤其是Clostridium sensu stricto属;而较低的铵磷比则有利于Bacteroidetes和Proteobacteria。不同营养类型产甲烷菌对高浓度铵态氮耐受程度不同（氢营养型产甲烷菌 >Methanosarcina >Methanosaeta）,影响着产甲烷菌群落组成。产甲烷菌和互营菌的群落组成是影响沼气发酵产气效率的重要生物因素,高比例的氢型产甲烷菌和丙酸互营菌更有利于提高产甲烷效率。     

牛粪与稻草混合堆肥理化性质转变特征

以奶牛粪便和稻草秸秆为原料,进行高温好氧堆肥过程中物料理化特性转变的研究。研究结果表明,堆肥物料先后经历了升温期、高温期和降温期。高温阶段堆体温度达到57℃,高温期维持9d;经降温期充分腐熟,堆肥物料中的有机质含量明显降低。堆肥过程结束后,堆肥产品中的TN、NO3--N、TP和速效磷等含量均有增加,增幅分别为22.45%、41.46%、68.98%和13.60%;堆肥物料中营养元素的植物利用有效性得到提高。经过高温好氧堆肥处理后,牛粪可实现无害化、稳定化和资源化。     

Biogas potential and microbial population distributions in flushed dairy manure and implications on anaerobic digestion technology

BACKGROUND: There remain technological deficiencies in the economical anaerobic digestion of the entire flow of flushed dairy manure on farms within cold climates. In order to develop an anaerobic digester tailored for this purpose, this study investigated the distributions of biomass and biogas generated in three particle‐size‐characterized zones of flushed dairy manure. RESULTS: Results demonstrate that comparable biogas generations are equally distributed between the solids and liquid phases of flushed dairy manure, implying that at least 50% of methane generation might be lost when utilizing existing processes that only selectively handle the liquid or solids phases. Microscopic and kinetic studies show that the majority of microorganisms in the manure are attached to the surface of undigested dairy manure fibrous solids. In particular, greater than 70% of acetate‐utilizing methanogens were found closely associated with the indigestible solids. This high microbial affinity to the dairy manure solids phase can be traced back to the selection pressure driven bacterial immobilization mechanism in cattle rumen. CONCLUSION: This study shows that dairy manure fibrous solids have the potential to act as effective natural biomass carriers for high rate and simultaneous methanation of both solids and liquid phases of flushed dairy manure in one digester. Copyright © 2010 Society of Chemical Industry     

Effect of retention time and organic loading rate on anaerobic acidification and biogasification of dairy manure

Vast amounts of animal manure produced from concentrated animal feeding operations have the potential to be converted into economic gain if the proper processing technology is employed. Anaerobic digestion (AD) is an effective way to convert organic wastes including animal manure into profitable by‐products as well as to reduce the pollution of water, air, and soil caused by these wastes. Two‐phase AD of manure offers several advantages over conventional one‐phase AD. Solids reduction through hydrolysis/acidification might be very significant for animal manure which contains high amounts of solids. However, to date, studies of two‐phase AD of animal manure have been limited to screened manure. Therefore, this study investigated the two‐phase AD of dairy manure with particular emphasis on the effects of retention time and organic loading rate (OLR) on anaerobic acidification and biogasification of unscreened dairy manure. The results indicated that pre‐acidification of dairy manure in daily‐fed continuously‐mixed reactors with no recycle led to significantly high reduction efficiencies of volatile solids and, thus, biogas production in the subsequent methanogenic reactor especially at OLRs of 4–10 g VS dm^?3 day^?1. However, the extent of the stimulation in the biogas production relative to corresponding feed samples was quite variable (between 6.9 and 64.7%) for different solids retention times and OLR combinations. A relatively lower performance was observed for the high OLRs (20–30 g VS dm^?3 day^?1) used which was attributed to the possible wash‐out of the acidifiers at the considerably low retention times (1.25–4 days) used. Copyright © 2004 Society of Chemical Industry     

Changes in physicochemical properties and gaseous emissions of composting swine manure amended with alum and zeolite

Ammonia emissions from composted swine manure and the resulting physicochemical changes were monitored to determine the effectiveness of adding alum and zeolite during the composting process, as well as the most effective addition method. The two amendments reduced ammonia emissions 85?C92%, with the finished compost retaining three-fold more NH ₄ ⁺ -N than the unamended control. The addition of zeolite sequestered 44% of the retained NH ₄ ⁺ -N at zeolite exchange sites. The addition of amendments did not appear to significantly affect microbial activity, because the patterns of CO₂ emissions, total organic carbon (TOC) reduction, and the ratio of humic acid to TOC of amended and unamended composts were very similar. The final respiration rates and Solvita? maturity index indicated that the finished compost was well matured and aged. Alum has a high potential to reduce ammonia emissions and concomitantly enhance fertilizer N value. Zeolite further reduces ammonia emissions, and improves fertilizer quality, by serving as a slow-release N source.     

Effect of composting time on phosphate exchangeability

Because of their high concentrations in organic matter and nutrients, composts have been used as soil amendments for years. However, information on their P availability is scarce. The effect of the composting time on phosphate exchangeability of composts was assessed on three substrates (House Refuse Compost, HRC; Sewage Sludge Compost, SSC; and Food Waste Compost, FWC) using the isotopic exchange kinetic method proposed by Fardeau (1996). Results were then interpreted by a pluricompartmental analysis and compared to those yielded by a sequential extraction. Preliminary results confirmed that the isotopic exchange kinetic method was appropriate to assess phosphate exchangeability of composts. Composts were shown to have a low buffering capacity (r(1)/R) for inorganic P (P_i) and high concentration in water extractable P_i (Cp) and in P_i isotopically exchangeable within 1 min (E_1min) compared to soils. Their concentra tion in P_i isotopically exchangeable between 1min and 3 months (E_{i1min–3months}) and in P_i which cannot be exchanged within three months (E_>3months) was a function of their origin. Composting of HRC, SSC, and FWC, systematically led to decreases in Cp and E_1min with time and in some cases to increases in E_{i1min–3months} and/or in E_>3months. These changes were related to the leaching of water soluble P_i from the HRC and FWC composts and, for the SSC and FWC composts, to the formation of phosphate precipitates with Ca, Mg and/or Fe during composting. Most of the changes in P_i exchangeability occurred during the first month of composting, i.e., during the most intense period of organic matter mineralisation. The slight increase in total organic P content observed after 180 d of composting in FWC and SSC indicates that the immobilisation of P in orga nic forms was not a major pathway for P transformation.     

原核微生物菌群的空间分异增强秸秆-猪粪混合发酵效率

秸秆与禽畜粪便混合发酵既可增强反应器稳定性又能提高发酵产气效率。然而关于秸秆附着菌群、发酵液菌群的时空动态变化,以及它们与产气效率、环境变量的关系仍然未被全部揭示。采用16S rRNA基因扩增子高通量测序技术,对这一问题进行了研究。结果显示,秸秆猪粪混合发酵能够改善沼气发酵的效率。原核微生物群落在空间上的差异分布可能有助于提升系统的效率。在产气高效的系统中,秸秆吸附菌群如Treponema、Clostridium Ⅲ、Alkaliflexus 和 Fibrobacter是主要的纤维素降解菌,提供底物给产酸菌。丙酸是发酵液中含量最丰富的挥发性脂肪酸（VFAs）,Pelotomaculum可能是该系统主要的丙酸氧化菌,它们与Methanoculleus、Methanosarcina和Methanosaeta协同作用通过二氧化碳/氢营养型和乙酸营养型产甲烷途径,将包括丙酸在内的VFAs最终转化成甲烷。参与氨基酸代谢的Aminobacterium和Cloacibacillus广泛分布于发酵液中,表明蛋白质是一种重要的发酵底物,说明VFAs尤其是丙酸和氨基酸的互营代谢可能是秸秆猪粪混合发酵系统的重要过程。这些结果表明,功能菌群的空间分化、稳定的秸秆降解菌群和发酵液菌群的弹性变化有助于维持秸秆猪粪混合发酵系统的稳定性和提高发酵效率。     

Interactions of aerobically decomposed cattle manure and nitrogen fertilizer applied to soil

Inorganic N fertiliser may be applied to soil in addition to cattle manure by smallholder farmers in developing countries: (a) to complement fertilization; (b) to control a possible immobilisation of N by the manure; and (c) to eliminate the risk of yield depression due to lack of plant available N. The aim of this study was to find out if and how much N was immobilised by cattle manure, if and when remineralisation of N will take place and, if added N has an effect on decomposition of cattle manure in soil. A laboratory study was conducted applying inorganic N fertiliser to soil (NH4NO3 equivalent to 30, 60 and 120 kg N ha-1) together with four cattle manures with different C/N ratios (9–18). CO2–C mineralisation and changes of inorganic N in soil were determined over 60 d. Immobilisation of fertiliser N occurred with manure having the lowest C/N ratio but not with the manures having a higher C/N ratios. Maximum immobilization of fertiliser N (23–36%) occurred within 21 d and thereafter N was mineralised. Carbon dioxide evolution decreased in cattle manure-amended soil at increasing rates of N fertiliser, but decomposition was still higher than from the unamended control. None of the manure treated soils had significantly different contents of inorganic N after 2 months of incubation. It was not possible to use the C/N ratio of aerobically decomposed cattle manure as a tool to predict mineralization or immobilization of N. It was concluded that aerobically decomposed solid cattle manures do not contribute to the N supply of crops in the short term but can immobilize fertiliser N applied at the same time.     

Ozonation of swine manure wastes to control odors and reduce the concentrations of pathogens and toxic fermentation metabolites

The use of ozone for the remediation of nuisance odorous chemicals in liquid swine manure slurry was investigated. Gaseous ozone was bubbled directly into stored swine manure slurry in a continuously stirred batch reactor. One‐liter samples of swine slurry were ozonated to achieve ozone dosages of 1.0, 2.0 and 3.0 g ozone/liter of waste. Olfactometric determinations demonstrated a significant reduction in odors in ozonated samples as compared to raw and oxygenated samples. Volatile fatty acids, nitrate, phosphate and ammonia concentrations were unchanged by ozonation. The biochemical oxygen demand (BOD) and the chemical oxygen demand (COD) were essentially unaffected by ozonation. The concentrations of odorous phenolic microbial metabolites (e.g., phenol, p‐cresol and p‐ethylphenol) and odorous indolic microbial metabolites (e.g., 3‐methylindole and indole) were reduced to non‐detectable levels by ozonation. Hydrogen sulfide concentrations were reduced slightly by the process, with a concurrent increase in the sulfate concentration. E. coli counts were reduced by a factor of three log units and total coliforms showed a one log decrease in concentration after treatment with ozone at 1.0 g/L.

The results of this study demonstrate clearly that at the pH values studied (ca. 7), ozonation is effective for the elimination of the malodors associated with stored swine slurry and for killing potentially pathogenic bacteria, without increasing the concentrations of major pollutants of current concern, (i.e., nitrate and phosphate) and without oxidizing ammonia, which is a major plant nutrient.     

The influence of ammonium and methods for removal during the anaerobic treatment of poultry manure

The addition of exogenous NH₄Cl to poultry manure and synthetic medium was used to study the effect of ammonia-nitrogen on the activity and composition of a methanogenic consortium. Results indicated that the production of biogas and methane was not affected by the variation in NH₄Cl concentration within the range 2–10 g dm⁻³ (0·5–2·6 g N-NH₄ dm⁻³). At higher values of ammonium (10–30 g dm⁻³ or 2–8 g N-NH₄ dm⁻³) a significant decline in both parameters (by 50–60% for biogas and 80–90% for methane) was observed. A significant decrease in the numbers of bacteria of all physiological groups (especially proteolytic and methanogenic) was observed when more than 30 g NH₄Cl dm⁻³ (7·8 g N-NH₄ dm⁻³) was added to the fermentation medium. The addition of 10% (w/v) of powdered phosphorite ore enhanced the production of biogas and methane at NH₄Cl concentrations up to 30 g dm⁻³, and also changed the composition of the methanogenic consortium. A partial recovery in the numbers of proteolytic and methanogenic bacteria coupled with the decrease in the density of sulphate-reducers was observed. High concentrations (more than 50 g dm⁻³) of NH₄Cl seemed to cause irreversible inhibition of methanogenesis which could not be eliminated by the addition of phosphorites. ©1997 SCI     

Nitrogen balance and accumulation pattern in three contrasting prairie soils receiving repeated applications of liquid swine and solid cattle manure

The expansion of intensive livestock operations in western Canada has increased concerns about overloading of nutrients in manured lands. The magnitude of nutrient accumulation and its distribution in the soil profile varies with soil-climatic conditions. The objective of this study was to determine loading and distribution of manure-derived nitrogen (N) in the soil profile as influenced by repeated manure applications. Four field experiments were conducted at three sites (Dixon, Melfort and Plenty) in Saskatchewan under longer-term manure management. The four field experiments provide contrasts in soil type, climatic conditions, manure type, application and cropping history to enable the effect of these factors to be evaluated. Liquid hog manure (LHM—Experiment 1) and solid cattle manure (SCM—Experiment 2) treatments were applied annually over 8 years at Dixon (Black Chernozemic loam soil—Udic Boroll in sub-humid climate), while only LHM was applied at Plenty (Dark Brown Chernozemic heavy clay soil—Typic Boroll in semi-arid climate) over 6 years (Experiment 3), and at Melfort (Dark Gray Luvisol silty clay loam soil—Mollic Cryoboralf in humid climate) over 5 years (Experiment 4). Soil samples were collected in the spring and autumn of 2003 and 2004, and were analyzed for organic N, ammonium-N (NH₄⁺-N) and nitrate-N (NO₃⁻-N) concentrations. Plant samples were collected to determine the impact of manure application rate on plant N uptake and crop N removal. The annual application of LHM (37,000 L ha⁻¹ yr⁻¹) and SCM (7.6 Mg ha⁻¹ yr⁻¹) at agronomic rates at Dixon (added N balances crop demand for that year), or larger rates of LHM (111,000 L ha⁻¹) applied once every 3 years (Melfort) did not significantly elevate NO₃⁻-N in soil compared to the unfertilized control. Lower crop removal and reduced leaching of NO₃⁻-N due to drier conditions as occurred at the Plenty site contributed to greater accumulation of nitrate in the top 60 cm at equivalent rates compared to the other two sites. At large manure rates, excess N from the balance estimates could not be accounted for in soil organic N and was assumed to be lost from the soil-plant system. At the Dixon LHM site, deep leaching of NO₃⁻-N was observed at the excessive rate (148,000 L ha⁻¹ yr⁻¹) up to the 150 cm depth, compared to the control. At Dixon, the large annual application rate of SCM (30.4 Mg ha⁻¹ yr⁻¹) did not significantly increase NO₃⁻-N in the 0–60 cm soil compared to the control, which was attributed to lower mineralization of organic N from the SCM. Over the short and medium term, LHM application at large rates every year poses a greater risk for loading and deep migration of NO₃⁻-N in soil than large rates of SCM. Larger single applications made once every 3 years were not associated with accumulation or deep leaching. To prevent loading, rates of applied manure nitrogen should be reduced when crop N removal potential is diminished by high frequency of drought.     

去除牛粪厌氧生物转化过程中的H2S

The main aim of this research was the experimental study at lab scale to check the absorption technology for the in situ removal of H2S from biogas during anaerobic digestion process. The reagent FeCl3 was used to check the removal efficiency of H2S produced from dairy manure during anaerobic bioconversion process. The experiments were conducted under mesophilic conditions. The composition of biogas was analyzed by gas chromatography analyzer equipped with flame photometer and thermal conductivity detectors. Experimental results under the same conditions demonstrate that high concentration of H2S in the form of FeS can be removed totally from the biogas using FeCl3 dosing with in anaerobic batch digester.     

Reducing ammonia emissions by cooling of manure in manure culverts

Temperature is one of the most important factors affecting ammonia volatilization from manure. The objective of this study was to investigate the possibility of reducing ammonia emissions from a pig house equipped with a cooling system with cooling coils mounted in the concrete floor of the manure culvert (beneath the slatted floor). Three cooling levels were used.The ammonia emission was reduced at two of the levels and increased at one of the levels. The reductions in ammonia emission were explained by the cooling effect, but also by periodly low ambient temperatures. The study showed that cooling pig manure is an effective measure of reducing ammonia emissions. Since the regular manure culvert floor temperatures (during the control periods) were low throughout the study, only low absolute emission reductions were obtained during the cooling periods, and the full potential of the cooling system as an emission-reducing measure could thus not be seen.