厌氧消化法处理畜禽粪的研究

本文报导了２个沼气工程的概况。其一是上海跃进农场的装置１２８ｍ３的上流式厌氧污泥床（ＵＡＳＢ）,该装置于１９８５年建成,已正常运行８年。用于处理２万羽鸡的粪水,２０～２４℃发酵,共产气４５万ｍ３。平均产气率１．３５ｍ３／ｍ３．ｄ。ＣＯＤ去除率８８％。产生的沼气供应１２０户居民使用。其二是上海星火农场沼气站,该站为处理２７００头奶牛的粪便,于１９９１年建成了２７００ｍ３上流式全混合型厌氧消化装置,日处理牛粪便８０吨,鸡粪２０吨,２５～３１℃发酵。至１９９６年底,共产气３６０万ｍ３,供应了３０００户职工及１０个集体单位使用。发酵残留物全部进行了综合利用,不但净化了环境而且创造了较好的经济效益。２个工程长期稳定运行的结果表明,沼气工程的工艺设计先进,设备配套齐全,可为全国畜禽粪的处理提供供鉴。     

厌消化法处理畜禽粪的研究

本文报导了２个沼气工程的概况。其一是上海跃进农场的装置１２８ｍ６３的上流式厌氧污泥床,该装置于１９８５年建成,已正常运行８年。用于处理万羽鸡的粪水,２０－２４℃发酵,共产气４５万ｍ６３。平均产气率１．３５ｍ＾３／ｍ＾３．ｄ。ＣＯＤ去除率８８％。产生的沼气供应１２０户居民使用。     

淀粉污水处理工程的设计和运行

淀粉污水采用厌氧－接触氧化－气浮综合处理,在水温２０℃、ＣＯＤ为９１６７ｍｇ／Ｌ条件下,厌氧段的容积负荷为９．２ｋｇＣＯＤ／ｍ＾３·ｄ,ＣＯＤ去除率为８４．７％好氧段的容积负荷为１．９ｋｇＣＯＤ／ｍ＾３·ｄ,ＣＯＤ的去除率为６４．１％,ＣＯＤ总去除率为９４．６％、ＢＯＤ的总去除率为９７％。工程总投资约为３００万元,日处理浓污水４００ｍ＾３,污水处理费为１．０￣１．２元／ｍ＾３。     

维生素C废水处理工程的技术改造及其效果

中原制药厂引进国外技术与设备生产葡萄糖,山梨醇,Ｖｃ等系列产品,日排废水７０００ｍ＾３左右,为了使废水达标排放,对引进处理工艺进行了合理的改造,改造后使容积负荷从３．０ｋｇＣＯＤ／ｍ＾３．ｄ提高到５．０ｋｇ／ＣＯＤ／ｍ＾３．ｄ,沼气产率从１．０ｍ＾３／ｍ＾３．ｄ,提高到３．０ｍ＾３／ｍ＾３．ｄ并最终达到了环保排放的要求。     

无土地毯式草皮的研究

利用无纺织物作培养基,采用先进的无土培植技术培植地毯式草皮。试验结果表明：在培养基质的垫底处理中,以水泥板作垫底草毯生长最好。无纺织物地毯式草皮生长周期为２０－２５天,盖度８０－９５％,每ｍ＾２草皮的叶面积７．８－９．０ｍ＾２,地上部分鲜重为０．７－０．８ｋｇ／ｍ＾２,草毯运动重量为３．４６ｋｇ／ｍ＾２。草毯铺地后不经过恢复期,直接进入生长,１０天后即可投入使用。     

生物燃气技术及工程的发展现状

生物燃气俗称沼气,是微生物群体在厌氧条件下协同发酵可降解有机废弃物的产物,传统能源供应的萎缩和增加可再生能源在能源消费中份额的需求使沼气的重要性越来越突出。经过不断研究与工程实践,已经开发出了不同的发酵工艺处理生活垃圾和工农业生产废弃物等有机质生产生物燃气,其中全混式中温发酵占主导地位,欧洲的技术处于领先水平,特别是德国的沼气发电、热电联产。结合作者多年沼气研究积累的经验,综述了沼气技术的最新进展,包括厌氧发酵菌群、消化反应器结构和发酵工艺,沼气生产和应用等,指出了今后发展的重点和方向。     

高温厌氧消化液二次厌氧消化产气特性的研究

目的:对高温厌氧消化后产生的消化液进行二次厌氧消化降解的可行性研究.方法:采用经阶段性高温厌氧发酵后的消化液为原料,利用实验室自制的小型厌氧发酵装置进行中温35±2℃条件下厌氧发酵实验,测定产气量、甲烷含量和COD值.结果:经中温厌氧二次发酵30d后,消化液中的COD平均降幅达28 150ng/L,说明经阶段性高温厌氧发酵后的消化液可继续进行中温厌氧二次发酵,同时,从产气特性各指标可以看到,300g的消化液在中温条件下发酵30d后的总产气量平均为523ml,沼气中甲烷含量达到55%,沼气质量好.结论:高温厌氧消化后产生的消化液可以进行二次厌氧消化降解.     

改革流加糖工艺提高谷氨酸发酵水平的研究

采用天津短杆菌Ｔ６－１３经多年经后的３２８＾＃菌株,以淀粉糖为糖质材料,生物素亚适量,当发酵残糖约为６０ｇ／Ｌ时,流加糖,效果好。在２００ｍ＾３发酵罐生产中,流加糖浓度分别为３００ｇ／Ｌ和４５０ｇ／Ｌ发酵周期３２小时,平均产酸分别达１０２．３ｇ／Ｌ和１１５ｇ／Ｌ,糖酸转化率５５．５％,提取收率９５．８％;单罐产理论谷氨酸由１６．２４吨提高至１８．２０吨。     

八大公山自然保护区森林土壤动物群落多样性的初步研究

对八大公山自然保护区森林土壤动物群落的多样性进行了初步研究,共获得２７类土壤动物,隶属５门１２纲,其中螨类、弹尾类、线虫类和线蚓类为优势类群,占全捕量的８８．６７％,是该区土壤动物的主体。土壤动物密度与土壤类型和土壤性质有一定的关系,主要土壤类型层中动物密度为：黑色石灰土中１２５．６万个／,棕色石灰土中１０４．３万个／ｍ＾３,山地生草黄棕壤中９１．３万个／ｍ＾３,山地黄棕壤中７４．２万个／ｍ＾３。     

畜禽粪便和粪水厌氧消化技术分析与展望

随着我国畜禽养殖集约化程度的不断提高,畜禽粪污导致的环境污染已成为畜禽养殖业发展面临的重要制约因素。粪污通过厌氧消化可回收能源、生产沼肥和消灭病原菌,避免对环境产生危害,是畜禽粪污处理和资源利用技术链条的核心环节。根据原料性质的差异,将粪污区分为畜禽粪便与养殖废水,分别探讨了这两种处理对象厌氧消化处理的不同技术难点和发展方向。针对畜禽粪便,重点探讨了高含氮粪便厌氧消化过程中存在的氨抑制问题及解除氨抑制的方法;针对养殖废水,介绍了废水处理与回用标准,比较分析了升流式厌氧污泥床、厌氧膜生物反应器、厌氧折流板反应器和自搅拌厌氧折流板反应器等几种代表性的和新型的废水厌氧处理工艺,并展望了技术的创新发展,旨在为畜禽粪便和养殖废水的厌氧消化及废水回用技术的发展提供参考。     

Production of biogas from solid organic wastes through anaerobic digestion: a review

Anaerobic digestion treatments have often been used for biological stabilization of solid wastes. These treatment processes generate biogas which can be used as a renewable energy sources. Recently, anaerobic digestion of solid wastes has attracted more interest because of current environmental problems, most especially those concerned with global warming. Thus, laboratory-scale research on this area has increased significantly. In this review paper, the summary of the most recent research activities covering production of biogas from solid wastes according to its origin via various anaerobic technologies was presented.     

Anaerobic digestion of municipal solid waste and agricultural waste and the effect of co-digestion with dairy cow manure

Anaerobic digestion of dairy cow manure (CM), the organic fraction of municipal solid waste (OFMSW), and cotton gin waste (CGW) was investigated with a two-phase pilot-scale anaerobic digestion (AD) system. The OFMSW and CM were digested as single wastes and as combined wastes. The single waste digestion of CM resulted in 62m(3) methane/ton of CM on dry weight basis. The single waste digestion of OFMSW produced 37m(3) methane/ton of dry waste. Co-digestion of OFMSW and CM resulted in 172m(3) methane/ton of dry waste. Co-digestion of CGW and CM produced 87m(3) methane/ton of dry waste. Comparing the single waste digestions with co-digestion of combined wastes, it was shown that co-digestion resulted in higher methane gas yields. In addition, co-digestion of OFMSW and CM promotes synergistic effects resulting in higher mass conversion and lower weight and volume of digested residual.     

Elevated methane emissions from a paddy field in southeast China occur after applying anaerobic digestion slurry

One hundred million tons of farm stalk waste and livestock and poultry excrement are used every year in China for the production of clean energy (biogas) by anaerobic digestion. Consequently, a large amount of fermented liquid is produced, and if disposed of improperly, it will result in secondary pollution. Agricultural application of this anaerobic slurry as a liquid fertilizer would reduce possible eutrophication of water sources from random slurry discharge and supply a superior organic fertilizer for farming. This study investigated the effect of applying anaerobic digestion slurry as a liquid fertilizer on the methane emitted from a paddy field. A two‐year (2008–2009) field experiment replacing chemical fertilizer with liquid fertilizer from anaerobically digested pig manure slurry was conducted in a paddy field in Yixing, Jiangsu, China. A static closed chamber method was used to measure methane fluxes over the period from June 2008 to October 2009. All fertilizer treatments increased methane emissions relative to untreated controls, with increases in methane ranging from 40–70% in 2008 to 48–84% in 2009. Paddy fields treated with anaerobically digested pig manure slurry had greater methane emissions (8–84% in 2008 and 3–26% in 2009) than those treated with chemical fertilizer. This suggests that the anaerobic digestion slurry would increase methane emission and so is unsuitable as a liquid fertilizer in paddy fields without development of cultivation practices to limit these emissions.     

添加厨余垃圾对剩余污泥厌氧消化产沼气过程的影响

为提高剩余污泥厌氧消化的沼气产量和甲烷含量,研究了厨余垃圾的不同添加量对剩余污泥厌氧消化性能的影响。结果表明,在35℃下,随着剩余污泥中厨余垃圾添加量的增加,厌氧消化系统中碳氮质量比（C／N）、胞外多聚物（EPS）等生理生化指标均有不同程度的改善。其中当剩余污泥与厨余垃圾质量比为2：1时,混合有机废弃物中沼气产量和甲烷含量均达到最大值,每克挥发性固体（VS）产生了156．56mL沼气,甲烷体积分数为67．52％,分别比剩余污泥单独厌氧消化时的产气量提高了5倍和1．5倍。     

Anaerobic waste digestion in Germany – Status and recent developments

Anaerobic treatment processes are especially suited for the utilization of wet organic wastes from agriculture and industry as well as for the organic part of source-separated household wastes. The anaerobic degradation is a very cost-effective method for treating biogenic wastes because the formed biogas can be used for heat and electricity production and the digester residues can be recycled to agriculture as a secondary fertilizer. The anaerobic technology will be used today also for the common treatment of wastes together with renewable energy crops in order to reduce the CO₂-emissions according the Kyoto protocol. Various process types are applied in Germany which differ in material, reaction conditions and in the form of the used reactor systems. The widespread introduction of anaerobic digestion in Germany has shown that biogenic organic wastes are a valuable source for energy and nutrients. Anaerobic waste treatment is done today in approx. 850 biogas plants on small farm scale as well as on large industrial scale with the best beneficial and economic outcome. Due to some new environmental protection acts which promote the recycling of wastes and their utilization for renewable energy formation it can be expected that several hundreds new biogas plants will be built per year in Germany. For using the synergetic effects of a combined fermentation of wastes and energy crops new process types must be developed in order to optimize the substrate combinations and the process conditions for maximum biodegradation.     

Optimization of biogas production from co-digestion of whey and cow manure

Anaerobic co-digestion is effective and environmentally attractive technology for energy recovery from organic waste. Organic, agricultural and industrial wastes are good substrates for anaerobic co-digestion because they contain high levels of easily biodegradable materials. In this paper enhancement of biogas production from codigestion of whey and cow manure was investigated in a series of batch experiments. The influence of whey ratio on specific biogas production in a mixture with cow manure was analyzed at 35 and 55°C, for different initial pH values and for different concentrations of supplemental bicarbonate in experiments carried out over 12 days. Good biogas production (6.6 dm³/dm³), methane content (79.4%) in a biogas mixture and removal efficiencies for total solids (16%) were achieved at optimum process conditions (temperature of 55°C, 10% v/v of whey and 5 g/dm³ NaHCO₃ in the initial mixture). In order to validate optimized conditions for co-digestion of whey and cow manure in the one-stage batch process, the experiments were performed within 45 days. The high biogas production (21.8 dm³/dm³), a good methane content (78.7%) in a biogas mixture as well as maximum removal efficiencies for total solids (32.3%), and chemical oxygen demand (56.3%), respectively indicate that whey could be efficiently degraded to biogas in a onestage batch process when co-digested with cow manure.     

Continuous biomethanization of agrifood industry waste: A case study in Spain

The anaerobic digestion technology is a biological treatment widely used to reduce the pollution load of wet waste biomass. In this work we present the results obtained by performing extensive experiments of anaerobic digestion of slaughterhouse waste, tomato industry waste and olive oil industry waste in continuous mode, which were designed to demonstrate that anaerobic digestion is an effective technology from an environmental and economic point of view.Biogas yields obtained are between 35.22 and 5.45 Nm³ biogas/m³ olive oil industry waste and tomato industry waste respectively and the slaughterhouse wastes achieve intermediate production, 30.86 Nm³ biogas/m³ municipal slaughterhouse waste and 22.53 Nm³ biogas/m³ Iberian pig slaughterhouse waste. Moreover, it possible to degrade between 63.46 and 75.3% of the initial organic matter.If these results are analyzed, the environmental, energetic economic benefits of anaerobic digestion can be quantified. Biomethanation of all these wastes generated annually in Extremadura could prevent the emission of 134,772 t of equivalent carbon dioxide, generate an energy similar to that provided by 2826 toe and reach payback times from 3.29 to 3.75 years for anaerobic digestion plant designed to treat the wastes generated by a medium-sized industry. So, we have fulfilled all the planned aims.     

Fungal fermentation on anaerobic digestate for lipid-based biofuel production

Background

Anaerobic digestate is the effluent from anaerobic digestion of organic wastes. It contains a significant amount of nutrients and lignocellulosic materials, even though anaerobic digestion consumed a large portion of organic matters in the wastes. Utilizing the nutrients and lignocellulosic materials in the digestate is critical to significantly improve efficiency of anaerobic digestion technology and generate value-added chemical and fuel products from the organic wastes. Therefore, this study focused on developing an integrated process that uses biogas energy to power fungal fermentation and converts remaining carbon sources, nutrients, and water in the digestate into biofuel precursor-lipid.

Results

The process contains two unit operations of anaerobic digestion and digestate utilization. The digestate utilization includes alkali treatment of the mixture feed of solid and liquid digestates, enzymatic hydrolysis for mono-sugar release, overliming detoxification, and fungal fermentation for lipid accumulation. The experimental results conclude that 5 h and 30 °C were the preferred conditions for the overliming detoxification regarding lipid accumulation of the following fungal cultivation. The repeated-batch fungal fermentation enhanced lipid accumulation, which led to a final lipid concentration of 3.16 g/L on the digestate with 10% dry matter. The mass and energy balance analysis further indicates that the digestate had enough water for the process uses and the biogas energy was able to balance the needs of individual unit operations.

Conclusions

A fresh-water-free and energy-positive process of lipid production from anaerobic digestate was achieved by integrating anaerobic digestion and fungal fermentation. The integration addresses the issues that both biofuel industry and waste management encounter—high water and energy demand of biofuel precursor production and few digestate utilization approaches of organic waste treatment.

     

Application of the IWA ADM1 model to simulate anaerobic co-digestion of organic waste with waste activated sludge in mesophilic condition

Anaerobic digestion model no. 1 model of international water association was applied to a full scale anaerobic co-digestion process for the treatment of the organic fraction of municipal solid wastes along with activated sludge wastes originating from a municipal wastewater treatment plant. This operation was carried out in a digester of 2000 m(3) in volume. It is operates at an average hydraulic retention time of 26.9 days with an average organic loading rate of 1.01 kg TVS/m(3) day, at a temperature of 37 degrees C with an average gas production rate of 0.296 m(3)/m(3) day. The aim of the present study is to compare the results obtained from the simulation with the experimental values. The simulated results showed a good fit for pH, methane and carbon dioxide percentages, biogas volume, chemical oxygen demand, total volatile fatty acids, inorganic nitrogen and inorganic carbon.     

Biogas technology in sub-Saharan Africa: status, prospects and constraints

Africa is a continent with abundant, diverse and un-exploited renewable energy resources that are yet to be used for improving the livelihood of the vast majority of the population. The production of biogas via anaerobic digestion of large quantities of agricultural residues, municipal wastes and industrial waste(water) would benefit African society by providing a clean fuel in the form of biogas from renewable feedstocks and help end energy poverty. Biogas technology can serve as a means to overcome energy poverty, which poses a constant barrier to economic development in Africa. Anaerobic digestion of the large quantities of municipal, industrial and agricultural solid waste in developing countries present environmental conditions that make use of anaerobic biotechnology extremely favourable under perspective of sustainable development. However, the use of biogas is not widespread in Africa. There are many reasons of economic, technical and non-technical nature for the marginal use of biogas in Africa. The key issue for biogas technology in Africa is to understand why large scale-up has not occurred despite demonstration by several programmes of the viability and effectiveness of biogas plants. This article provides knowledge-based review of biogas technology status, constraints and prospects in Africa. In addition, recommendations to overcome the technological and non-technological challenges to commercialise biogas are discussed. Recommendations for large scale adoption for biogas technology include establishing national institutional framework, increasing research and development, education and training and providing loans and subsidies and major policy shift in the energy sector. The conclusion is that biogas technology must be encouraged, promoted, invested, researched, demonstrated and implemented in Africa.