Zur Reaktionstechnik der anaeroben Fermentation

Chemical reaction engineering of anaerobic fermentation. Anaerobic fermentation has already been used for more than 50 years for the disposal of excess activated sludge. In recent years, increasing costs and considerable problems encountered in connection with the disposal of activated sludge have encouraged the development of anaerobic processes for the treatment of industrial waste water. Various aspects which have to be taken into account when planning a digester plant are discussed. Reduction in residence time with concomitant increase of biogas production rate is possible by retention of biomass. In this way catabolic performances are obtained comparable to those of aerobic high capacity activated sludge plants. Anaerobic waste treatment appears so far to be a real purification method because the predominant part of the organic pollution (more than 95%) is eliminated under energy saving conditions. The by-product biogas contributes to the energy self-sufficiency of the process.     

ACIDOGENIC FERMENTATION OF LIGNOCELLULOSIC SUBSTRATE WITH ACTIVATED SLUDGE

The lignocellulosic residues accumulated in municipal solid waste and agro-residues represent potential organic fractions preferably to be treated by anaerobic digestion in an energy recycle and/or value-added-product-type solid waste disposal system. Hydrolysis and acidification are predominant reactions in organic fermentation. Owing to the complicated physiochemical structures, the initial hydrolysis and acidification of the lignocellulosic residues into soluble forms are critical to the anaerobic digestion of the residues. This research focused on the promotion of solid-state acidogenic fermentation of two natural lignocellulosic residues in a pure form from the tobacco industry and urban turf grass by a combined pretreatment and thermophilic co-digestion with concentrated activated sludge from a biological municipal wastewater treatment plant. Laboratory-scale experiments were conducted in a batch and semi-continuous mode, with and without leachate recirculation. The results showed that the mechanophysicochemical pretreatment (roll milling-freezing-thawing-alkali wetting agent), followed by thermophilic co-digestion with activated sludge, substantially increased the solubility and fermentation efficiency of the natural lignocellulosic residues, leading to value-added utilization of these residues. In addition, leachate recycling appeared to be beneficial to acidogenesis.     

Pollution control in palm oil mills in Malaysia

Pollution prevention approaches are being adopted by more and more mills. Digested POME increasingly is being used successfully as a fertilizer/soil conditioner, resulting in significant savings in imported fertilizers. Studies also have shown that energy can be obtained from biogas generated from anaerobic digestion of POME; in fact, electricity from POME has become a reality. These technological developments and the increasing awareness of the economic value of POME have made it a valuable, renewable resource.     

酒糟沼气化利用的基础研发

酒糟是酒精工业和酿酒工业的废弃物,通过厌氧发酵不仅可以解决酒糟废弃物污染的问题,还可以提供能源,并且经厌氧发酵后的沼液、沼渣还可以用作生物肥。开展了中温（37℃）条件下的酒糟厌氧发酵产生沼气研究,并分析了厌氧发酵前后物料组成变化及酒糟沼液作为生物液态肥的可行性。结果表明：四种酒糟的沼气产量从高到低依次为玉米燃料乙醇酒糟、酱香型白酒酒糟、浓香型白酒酒糟、木薯燃料乙醇酒糟,对应的产气量分别为607.4、578.7、434.2、122.3 ml·g^-1（以VS计）;各酒糟厌氧发酵产沼气的甲烷体积分数均在60%～70%之间;酒糟的沼气产量与其VS降解率呈正比;酒糟发酵液各元素及离子含量符合生物液态肥标准,是一种很好的生物液态肥原料。     

城市生活垃圾处理技术研究进展

我国现在对城市生活垃圾处理的技术主要是焚烧、堆肥、填埋。资源化与综合利用是我们奋斗的目标。通过开展新技术,采用适合我国城市生活垃圾特点的处理方法,垃圾焚烧余热利用和填埋气体回收利用,以及有机垃圾高温堆肥和厌氧消化制沼气等;提倡垃圾综合利用。垃圾分类收集应与垃圾处理工艺相衔接,积极发展有机垃圾生物处理技术,提倡采用综合处理方式。     

有机废物厌氧消化系统预处理装置工况优选的实验研究

现存于农村的厌氧消化装置大都是单相常温的,不但浪费原料而且产气量较低,难以保证用户供暖需求.研究设计了一套两相有机废物厌氧消化系统,针对预处理装置及其测控系统进行了实验研究,得出了可保证预处理装置原料利用率最高时的最优条件,使得后续厌氧消化系统的产气量得以保障.     

Effect of sodium dodecyl benzene sulfonate (SDBS) on the performance of anaerobic co-digestion with sewage sludge,food waste,and green waste

Abstract

The anionic detergent sodium dodecyl benzene sulfonate (SDBS) inhibits anaerobic solid waste fermentation process in mesophilic anaerobic digesters. In this study, the effect SDBS on the performance of anaerobic digestion (AD) of mixture of sewage sludge, food waste, and green waste serving as substrate was investigated. The batch experiments were conducted with five SDBS concentrations namely 0, 0.01, 0.02, 0.05, 0.1, and 0.2?g/g (SDBS/dry sludge) under mesophilic condition (37?±?1?°C) and lasted for 63?days. The results showed that the presence of SDBS remarkably increased the release of protein and carbohydrate, and resulting in the serious accumulation of volatile fatty acids (VFAs), especially for propionate accumulation. Likewise, the observed variations in enzyme activities associated with different stage of AD revealed that methanogenesis was quite sensitive to SDBS and inhibited by the increase of SDBS addition. Meanwhile, the presence of SDBS decreased the pH value and the concentration of free ammonia, but increased the concentration of NH₄⁺-N. Furthermore, the production of biogas was reduced by SDBS. In conclusion, SDBS addition has a negative impact on anaerobic co-digestion. On the one hand, methanogens were severely inhibited and biogas yield decreased remarkably, on the other hand, the accumulation of VFAs was excessive. Thus, the presence of surfactant (SDBS) in the municipal organic waste should be concerned during the waste disposal via anaerobic digestion process.     

餐厨垃圾与污泥两相中温厌氧消化试验研究

研究了混合比例和污泥停留时间对餐厨垃圾与污泥联合两相中温厌氧消化过程的影响。相较于餐厨垃圾与污泥TS比为1∶3的条件,TS比为1∶1时两相系统具有更好的产气效果、有机物去除效果和运行稳定性。随着SRT的延长,两相系统有机负荷逐步降低,产甲烷速率相应降低,单位体积进料产沼气量以及有机物去除率逐步提高。在餐厨垃圾与污泥TS比为1∶1的条件下,两相厌氧消化系统最佳SRT为25 d（产酸相和产甲烷相分别为5 d和20 d）;此时,沼气中甲烷含量高达71％,产甲烷速率和甲烷产率分别为0．7 L/L＆#183;d和0．69 L/gVS去除,两相系统VS去除率达到64．7％。     

污泥中蛋白类物质厌氧转化影响因素及其促进策略研究进展

蛋白类物质是剩余污泥中的主要有机组分（占有机质的50%～60%）,是污泥厌氧消化产沼气的主要底物,其降解率的提升将对剩余污泥厌氧转化效率的提升和脱水性能的强化起到决定性作用。本文首先重点归纳了蛋白质的厌氧转化机制,蛋白质的厌氧降解主要包括蛋白质水解与氨基酸代谢两个重要的步骤,蛋白质的结构与氨基酸组分差异将决定其厌氧转化性能。其次总结了污泥中蛋白类物质厌氧转化的影响因素,包括蛋白质来源、污泥中其他有机物如多糖、无机物如微细砂（二氧化硅）和金属离子、代谢产物如氨氮等。在此基础上归纳了污泥中的蛋白类物质厌氧转化的促进研究,破坏蛋白质的构象、二级结构与氢键网络等将有效强化其厌氧转化性能,其中高温热水解技术能够发挥有效的作用并得到了广泛应用。最后,系统性总结了污泥中蛋白类物质的前沿解析方法包括氨基酸测定方法、荧光光谱法和宏蛋白组学。明晰污泥中蛋白类物质的厌氧转化机制和限制性因素,不仅可以从源头上强化剩余污泥的厌氧转化效率,完善污泥厌氧消化过程中的氮循环理论,还可能从减少亲水性物质的角度改善其后续的脱水性能。     

Membrane systems for the recovery of energy carriers from products of organic waste recycling

One of the most promising technologies for separating energy carriers from renewable feedstocks is the biological recycling of organic waste to derive gas (biogas, biohydrogen) or liquid mixtures that contain methane and hydrogen or lower alcohols, respectively. This technology has many advantages: low power consumption, high ecological safety, high level of organic waste recycling, affordability, and ease of implementation and control. The main practical problem of the microbiologic recycling of biomass is the low calorific value of resulting gas and liquid mixtures for their use as energy carriers, because products of bioconversion are diluted aqueous organic mixtures and/or gas mixtures containing a significant amount of ballast CO₂. In the capacity of promising systems for separating energy carriers from gas mixtures, we discuss conventional membrane systems and propose original gas-liquid membrane contactors (MCs), which do not require the precompression (additional energy consumption) of the initial gas mixture. After the stage of separation, for example, of biogas, resulting commercial-purity methane (>95%) can be injected into the pipeline network or supplied to a receiver. Our low energy consumption membrane system was designed on the basis of developments of the Topchiev Institute of Petrochemical Synthesis of the Russian Academy of Sciences in cooperation with microbiologists and experts in bioengineering. MCs were prepared of nonporous highly permeable asymmetric membranes based on polyvinyltrimethylsilane (PVTMS) with a CO₂ permeance of more than 15 l/(m² h kPa), which completely meets the requirements on a highly permeable and, at the same time, sterile barrier. Composite membranes based on a glassy polymer with high internal free volume, i.e., polytrimethylsilylpropyne (PTMSP), which are now being produced on a laboratory scale, are regarded as promising for MCs. The use of membrane methods, i.e., pervaporation and membrane separation of the organic component of the vapor phase, is also promising for separating liquid energy carriers (bioalcohols) from dilute aqueous organic solutions (the range of concentrations of organic substances is 1–7%) that are derived by biofermentation. It is shown that organophilic membranes based on PTMSP can be advantageously employed for the continuous extraction of liquid energy carriers from products of biomass conversion.     

Preservation of mesophilic mixed culture for anaerobic palm oil mill effluent treatment by convective drying methods

While anaerobic digestion is a reliable method that treats the waste and produces renewable biomethane fuel, the necessary sludge in liquid form is difficult to handle due to the constant biogas generation. Therefore, this study investigates the possibility of convective air drying, namely heat pump and hot air circulation oven as preservation methods for anaerobic microbial sludge. Drying was conducted at various temperatures, ranging from 22 to 70°C. The study found that heat pump drying at 22°C resulted in highest chemical oxygen demand removal of 55.3% as well as the least log reduction in methanogens and anaerobes at 1.4 and 2.4, respectively.     

餐厨垃圾厌氧发酵过程的影响因素硏究

餐厨垃圾虽是废物,但经过厌氧发酵,可以产生发酵产物和沼气,厌氧发酵可以将有机垃圾变废为宝,同时获得清洁能源,减少碳排放,取得良好的社会和经济效益。在本文中,对餐厨垃圾厌氧沼气发酵系统进行了全面的研究,通过探讨食物垃圾物理组成,研究影响餐厨垃圾厌氧发酵的各种因素,通过研究找出餐厨垃圾厌氧发酵的最佳反应条件,进行餐厨垃圾厌氧发酵实验室测试得出实验结论。     

高含固率污泥厌氧消化系统的启动方案与试验

高含固污泥厌氧消化技术是目前国内外的研究热点。该文以上海市白龙港污水处理厂脱水污泥稀释而成的含固率为10%的污泥作为研究对象,对高含固污泥厌氧消化技术进行了初步的探讨。试验结果表明,厌氧消化系统的进泥含固率升高至10%后,每投入1 m3的污泥产气约16~18 m3沼气,远高于现有浓缩污泥厌氧消化系统的产气率(8~10 m3沼气/m3污泥)。高含固率污泥厌氧消化系统推荐采用清水启动策略,即消化罐内介质的初始状态为清水(二沉池出水),之后以不同投配率投加原污泥,避免系统启动过程中的VFA的积累,尤其是丙酸含量的积累。该研究成果不仅可为该污水处理厂现有污泥厌氧消化系统未来的扩建改造服务,而且可为国内同类工程提供借鉴和示范。     

A novel combination of methane fermentation and MBR — Kubota Submerged Anaerobic Membrane Bioreactor process

Methane fermentation is considered one of the best placed biological processes to reduce volume of organic waste while keeping small sludge production and recovering energy. One of the disadvantages of early anaerobic digestion technologies was the long hydraulic retention time thus large capacity tanks were required to hold slow growing methanogenic bacteria. New technological attempts such as upflow anaerobic sludge blanket (UASB), fixed or fluidised bed and membrane bioreactor (MBR) appeared as countermeasures.Kubota’s submerged anaerobic membrane biological reactor (KSAMBR) process has been developed in the last decade and successfully applied in a number of full-scale food and beverage industries. It consists of a solubilization tank and a thermophilic digestion tank, the latter incorporating submerged membranes. The biogas generated can be utilized for water heating via boilers. Both permeate and waste anaerobic sludge are further treated in wastewater treatment facilities.One of the main advantages of KSAMBR is that membranes retain the methanogenic bacteria while dissolved methane fermentation inhibitors such as ammonia are filtered out with the permeate. This makes the KSAMBR process very stable. Furthermore, the digester volumes can be scaled down to 1/3 to 1/5 of the conventional digesters provided that biomass is 3 to 5 times as concentrated.Applications include stillage treatment plants for Shouchu (Japanese spirits made from sweet potato, rice or other grains), potato processing sites, sludge liquor and food factory treatment plants.In summary, it is believed that KSAMBR offers the best possible solution combining the benefits of methane fermentation process with the performance of membrane technology. More details will be presented in the proceedings paper and in the presentation.     

基于沼气的热电气联供系统全工况模型与性能分析

为了解决我国城镇化进程中日益增长的能源需求,高效循环利用有机废弃物,缓解农村环境污染问题,构建了基于沼气的内燃机热电气联供系统,将生物质厌氧发酵、内燃机热电联产、补充热源、用户侧需求等有机联系起来建立系统全工况动态数学模型,并以兰州地区5户建筑面积226.8 m²的新农村建筑为例,进行系统全年逐日供需能量平衡分析及性能分析。结果表明：寒冷地区新农村建筑负荷与商业建筑存在明显不同,冬夏季热负荷差异大,全天电负荷波动很明显;在充分考虑厌氧发酵生物质能源转化效率、热量传输及换热效率和火电厂发电效率的情况下,联供系统全年一次能源利用率为37.85%;与传统农村分供系统相比,系统一次能源节约率为17.12%。系统性能分析结果可为我国生物质沼气集中热电联产在村镇的规模化应用提供一定理论依据。     

改性污泥填埋的稳定化

该文以上海老港填埋场55#单元的矿化污泥填埋区和固化污泥填埋区中分别经矿化垃圾和固化剂改性的填埋污泥为研究对象,对填埋过程中污泥的含水率、有机物含量、渗沥液成分和产气量的变化进行了分析。结果表明矿化垃圾和固化剂的添加可以加快填埋初期污泥的降解,且矿化垃圾的促进稳定效果更好;改性剂的添加可以明显缩短渗沥液有机污染物浓度达到峰值的时间;添加矿化垃圾可以为填埋污泥创造更好的产甲烷环境。     

水热预处理对剩余污泥有机物释放的影响

针对剩余污泥中有机能源利用率低的问题,研究了水热预处理对剩余污泥有机物释放及污泥厌氧消化过程中累积产气量的影响。结果表明:水热处理是一种有效的污泥预处理方法,当水热温度为200℃、水热时间为1 h时,污泥减量度达76.56%,污泥SCOD为原泥的34倍,大大减少了污泥固相有机物含量。经水热处理后,污泥厌氧消化最大产气量为2 950 m L,较原泥提高了69%;厌氧消化后,水热预处理污泥SCOD减少量为原泥的30倍。     

对垃圾填埋场生物气体控制的研究

垃圾的处理是世界各国的重要问题.在各种处理技术中,填埋是处理最为经济的方法.填埋场对环境的潜在危害之一就是其生物气体(主要包括二氧化碳和甲烷)的逸出.甲烷是一种主要的温室气体,同时也是一种可燃气体.旧式垃圾填埋场对环境的负面影响及人们对可再生能源的认识使填埋场生物气体的回收利用引起了越来越多的关注.以抚顺市榆林垃圾填埋场为研究对象,对其生物气的成份,含量进行了分析,对结果进行了讨论,并对其作为能源的潜在性进行了评估.     

玉米秸秆高浓度厌氧发酵的启动过程特性

高浓度厌氧发酵具有单位体积产气率高、原料处理量大、需水量小、能耗低等优点,同时存在启动难和易酸化的问题。以玉米秸秆为原料,研究秸秆高浓度发酵过程接种物、分批进料结合渗滤液回流对启动的影响。结果表明,分批进料结合渗滤液回流工艺可有效实现高浓度厌氧发酵系统的稳定启动,反应器启动运行22 d,以污泥为接种物的秸秆累积产沼气量为43.54 ml·（g TS）^-1,以湿法发酵的沼液为接种物的秸秆累积产沼气量为115.15 ml·（g TS）^-1。与以厌氧污泥为接种物的发酵系统相比,以湿式发酵沼液为接种物的高浓度厌氧发酵系统秸秆微观结构变化更明显,主要表现为半纤维的溶解;荧光原位杂交技术（FISH）结果也表明两种接种物系统的甲烷菌形态存在明显差异。     

A review of chemical absorption of carbon dioxide for biogas upgrading

Significant attention has been given to biogas production, purification and upgrading as a renewable and clean fuel supplement. Biogas is a product of an anaerobic digestion process comprising methane, carbon dioxide, and trace amounts of other gases. Biogas purification removes trace gases in biogas for safe utilisation. Biogas upgrading produces methane-rich biogas by removing bulk carbon dioxide from the gas mixture. Several carbon dioxide removal techniques can be applied for biogas upgrading. However, chemical absorption of carbon dioxide for biogas upgrading is of special significance due to its operation at ambient or near ambient temperature and pressure, thus reducing energy consumption. This paper reviews the chemical absorption of carbon dioxide using amine scrubbing, caustic solvent scrubbing, and amino acid salt solution scrubbing. Each of these tech-niques for biogas upgrading is discussed. The paper concludes that an optimised implementation of the chemical absorption techniques for biogas upgrading requires further research.