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.     

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     

厌氧消化过程氨抑制解除技术研究进展

厌氧消化在处理有机废物的同时可产生大量的甲烷资源,是能源可持续发展的重要处理技术。作为微生物生长的营养物质之一,氨在厌氧消化过程中发挥重要作用,然而高浓度氨会抑制微生物活性,造成厌氧消化系统的失效。在总结国内外研究进展的基础上,讨论了氨抑制的形成机理及氨对产甲烷菌的抑制作用,并分别从氨浓度和微生物两个角度总结了当前解除氨抑制的技术和方法,为厌氧消化的工程应用和进一步氨抑制研究提供参考和建议。     

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.     

铁元素对厌氧氨氧化菌脱氮效能的影响

厌氧氨氧化工艺是治理水体氮污染的一种绿色、高效新型生物技术。然而,厌氧氨氧化菌世代时间长,对环境敏感性高,致使厌氧氨氧化系统启动缓慢、运行稳定性较低,进而导致厌氧氨氧化工艺在实际应用中受限。铁不仅是环境中普遍存在的金属元素,也是微生物生长所需的必要营养元素之一。本文综述了铁元素价态及投加量对基于厌氧氨氧化反应的废水脱氮工艺启动及运行过程中含氮污染物去除效果,分析铁元素存在时,铁/氮元素的反应途径、厌氧氨氧化菌生长速率、颗粒形成以及微生物群落组成演变等方面的作用关系,旨在深入探究和阐释元素铁对于厌氧氨氧化菌脱氮性能的内在作用机制,为实现工程化利用铁强化厌氧氨氧化系统脱氮过程、提高微生物活性提供科学指导。     

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     

Application of A/O‐MBR for treatment of digestate from anaerobic digestion of cow manure

BACKGROUND: Anaerobic digestion (AD) is widely used as an animal manure bioconversion technology. However, the effluent obtained from the digester during the wet‐AD process requires to be treated carefully before discharge if AD technology is to be developed as an effective and environmentally advantageous animal manure treatment. RESULTS: An anoxic/aerobic‐membrane bioreactor(A/O‐MBR) system has been developed for digestate treatment in an AD system treating cow manure. The performance of the A/O‐MBR system in terms of removal of nitrogen, COD and phosphorus were investigated. Results indicated that the average removal efficiencies of NH₄‐N⁺, COD and PO₄^3?‐P were 98.1%, 96.3% and 76.6%, respectively. The fouled membrane from the A/O‐MBR system was cleaned effectively using NaOH and a 30h soak time. CONCLUSION: This study suggests that it is technically feasible to use the A/O‐MBR for the treatment of digestate from a cow manure AD system, and can provide an environmentally acceptable way for the application of wet‐AD in animal manure treatment. Copyright © 2010 Society of Chemical Industry     

The value of poultry manure for wetland rice grown in rotation with wheat

Poultry manure applied alone or in combination with urea at different N levels was evaluated as a N source for wetland rice grown in a Fatehpur loamy sand soil. Residual effects were studied on wheat which followed rice every year during the three cropping cycles. In the first year, poultry manure did not perform better than urea but by the third year, when applied in quantities sufficient to supply 120 and 180 kg N ha^–1, it produced significantly more rice grain yield than the same rates of N as urea. Poultry manure sustained the grain yield of rice during the three years while the yield decreased with urea. Apparent N recovery by rice decreased from 45 to 28% during 1987 to 1989 in the case of urea, but it remained almost the same (35, 33 and 37%) for poultry manure. Thus, urea N values of poultry manure calculated from yield or N uptake data following two different approaches averaged 80, 112 and 127% in 1987, 1988 and 1989, respectively. Poultry manure and urea applied in 1:1 ratio on N basis produced yields in between the yields from the two sources applied alone. After three cycles of rice-wheat rotation, the organic matter in the soil increased with the amount of manure applied to a plot. Olsen available P increased in soils amended with poultry manure. A residual effect of poultry manure applied to rice to supply 120 or 180 kg N ha^–1 was observed in the wheat which followed rice and it was equivalent to 40 kg N ha^–1 plus some P applied directly to wheat.     

秸秆与猪粪混合高固厌氧消化产气性能及关键微生物分析

高固厌氧消化（HS-AD）是处理木质纤维素类原料和其他高固含率有机原料的有效方式之一。本文以节能高效为出发点,研究秸秆和猪粪为混合原料,两者不同配比（秸秆/猪粪的质量比2∶1、1∶1和1∶2）条件下,反应器的运行情况及关键微生物变化情况。结果表明：原料的配比对高固厌氧消化的产气量有明显影响。相比于其他两组实验,秸秆和猪粪的配比为2∶1时,累计产气量最大为229.66L,最终甲烷含量稳定在60.7%左右,转化为单位VS产甲烷量为131.8mL/g VS。同时,反应过程中液相性质（pH、VFA、TIC）的变化,也说明秸秆和猪粪配比为2∶1时,运行平稳且产气较好。另外,微生物分析结果显示,秸秆和猪粪配比为2∶1的实验组,在实验启动的前期,甲烷八叠球菌（Methanosarcinaceae）的相对丰度较高,并且细菌和古菌群落的丰富度和多样性都优于其他两组。     

对畜禽粪便发酵腐熟指标判定的探讨

以猪粪为例,通过加入腐熟剂发酵与自然发酵对比,探讨了畜禽粪便好氧发酵堆肥腐熟度的判定指标。实验表明,松散度、感官气味、温度、pH值、含水量、铵态氮、碳氮比、蛋白酶活性、大肠杆菌数、蛔虫卵死亡率、种子发芽率等可作为判定畜禽粪便腐熟度的指标,另外,重金属和抗生素也应作为重要指标进行检测,随着研究的深入还应从生物学、物理学、生物化学等方面综合判断。     

Applications of yeast physiology for improvements in the brewing process

Ammonia inhibition of unacclimated anaerobic mesophilic mixed cultures was studied in batch mode. Bacterial growth rate and specific acetate-uptake rate were affected by the concentration of un-ionised ammonia (UAN) in a three-stage pattern: initial inhibition, plateau and final inhibition stage. The un-competitive inhibition model provided the most reasonable data fit. The stage pattern of inhibition suggested that more than one mechanism of UAN inhibition are acting on the mixed culture. The effects of UAN on the length of initial lag-time also followed a three-staged curve. High concentration of UAN resulted in acetate release. The biological basis and origin of the acetate release were not determined.     

采用畜禽粪便原料生产有机无机复混肥工艺、设备探讨

根据畜禽粪便物料特性和工程实践经验,提出实用的有机无机复混肥加工工艺和设备系统,并对配套关键设备的技术要求分别进行了具体的描述。认为：好氧发酵宜采用槽式和条垛式发酵组成的“二阶段堆肥”工艺;建立以平模制粒技术为核心的有机无机复混肥连续制肥系统,利于降低能耗,改善生产环境。     

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.     

Characteristics of the pH-influenced adaptation of methanogenic sludge to ammonium toxicity

Increasing ammonium-nitrogen concentrations caused failure of methanogenesis at 1900-2000 mg dm^?3. After an adaptation period characterised by an almost nil methane production, methanogenesis appeared to be possible at even higher concentrations. A kinetic analysis of methane production during the adaptation process indicated that the adaptation was the result of a metabolic change in the methanogenic bacteria already present, rather than of growth of new bacteria. A high pH value causing toxic concentrations of un-ionised ammonia during the adaptation period appeared to result in a decreased maximum specific methanogenic activity of the adapted sludge. A low pH value during the adaptation period resulted in a retarded degradation of propionic acid, probably due to inhibition of the hydrogen consuming methanogenic bacteria by undissociated volatile fatty acids, but this did not result in a decreased maximum specific methanogenic activity in the adapted sludge. The maximum specific methanogenic activity at an ammonium-nitrogen concentration of 2315 mg dm^?3 after adaptation as a percentage of that at 1000 mg dm^?3 before adaptation was 31, 65 and 61% for a pH during the adaptation period of 7.6, 7.25 and 7.0 respectively. Except for the sludge which was maintained at pH 7.6 during the adaptation period, after adaptation the maximum specific methanogenic activity at an ammonium-nitrogen concentration of 2315 mg dm^?3 was higher than the maximum specific methanogenic activity at an ammonium nitrogen concentration of 1900 mg dm^?3 before adaptation.     

挥发性脂肪酸和氨氮对污泥厌氧消化中病原指示微生物灭活的影响

通过外源添加不同浓度挥发性脂肪酸(VFA)和氨氮,模拟研究剩余污泥固态中温(35℃)厌氧消化条件下,VFA和氨氮浓度对病原指示微生物灭活效果的影响。试验结果表明:经过VFA组持续8 d和氨氮组持续28 d的厌氧消化后,消化液中的总大肠杆菌和粪大肠杆菌的杀灭率均达到99.9%以上;且初始VFA和氨氮浓度越高,消化系统中病原指示微生物的灭活效果越好。厌氧消化结束后,高浓度VFA组和氨氮组粪大肠杆菌均在检测限以下,表明剩余污泥固态厌氧消化中产生的高浓度VFA和氨氮能够提高剩余污泥消化残渣的生物安全性。     

Hydrogen production during the anaerobic acidogenic conversion of glucose

Experiments on hydrogen production using chemostat‐type anaerobic digesters were conducted. The results indicate that the anaerobic acidogenic conversion of glucose can produce hydrogen. The hydrogenic activity of acclimated anaerobic sewage sludge is high at a short solids retention time (SRT) and low pH. At pH 5.7, SRT 0.25 days and an organic loading rate of 416 mmol‐glucose dm⁻³ day⁻¹, each mole of glucose in the mesophilic acidogenic reactor can produce 1.7 mol of hydrogen; each gram of biomass produces 0.456 mole of hydrogen per day. Moreover, the hydrogen productivity of the sludge is comparable to that of an enrichment culture. © 1999 Society of Chemical Industry