酸碱调控污泥厌氧发酵实现乙酸累积及微生物种群变化

摘要：【目的】通过对污泥厌氧发酵pH调控,研究挥发性脂肪酸的累积、产酸微生物种群变化及产氢产乙酸菌群对乙酸产生的贡献。【方法】测定不同pH条件下污泥厌氧发酵过程中挥发性脂肪酸的累积;分别应用末端限制性片段长度多态性（T-RFLP）和荧光原位杂交技术（FISH）分析产酸系统中微生物种群结构的变化及产氢产乙酸菌的数量。【结果】 pH为10.0时,有机酸和乙酸的产率在发酵结束时分别达到652.6 mg COD/g-VS和322.4 mg COD/g-VS,显著高于其它pH条件。T-RFLP结果表明,pH值为12     

多级逆流工艺促进城市污泥厌氧发酵生产挥发性脂肪酸

采用一种新型的厌氧发酵工艺——多级逆流发酵工艺对城市污泥进行厌氧发酵, 实现高效产挥发性脂肪酸的目的。结果表明, 实验条件下应用多级逆流发酵工艺, 挥发性脂肪酸浓度与产率分别达到(10.5±0.5) g/L和0.20 gVFAs/ gVS, 与普通厌氧发酵工艺相比, 分别提高了31%和54%。此外, 在多级逆流工艺中, 底物有机质去除率可达50%, 较普通厌氧发酵提高了37%。进一步分析多级逆流工艺产酸的机制, 发现产酸效率的提高在于降低了发酵产物对厌氧产酸细菌的抑制效应, 并且工艺的VFAs产率以及有机质去除率分别取决于第一级和第三级厌氧发酵过程。因此, 城市污泥采用多级逆流工艺厌氧发酵不仅能够有效促进挥发性脂肪酸的生成, 而且能够较大程度上提高污泥中有机质的去除率。     

城市污泥添加厨余垃圾厌氧发酵产挥发性脂肪酸的研究

为了考察污泥产酸工业化的可行性和添加食品废弃物对污泥产酸的影响,本实验在实验室的基础上进行扩大研究,考察了不同的底物总固体浓度对产挥发性脂肪酸的影响.结果显示添加厨余垃圾之后挥发性脂肪酸的累积量可达到17.62g/L.综合产挥发性脂肪酸效果、底物降解效果和产率等情况建议在较大规模的生产过程中选择130g/L的底物浓度为...     

城市污泥中邻苯二甲酸酯(PAEs)的厌氧微生物降解

邻苯二甲酸酯(PAEs)是城市污泥中普遍存在的一类具有内分泌干扰性作用的有机污染物.研究污泥厌氧生物处理过程中PAEs的微生物降解对保障污泥农用的安全性十分必要.本文以污泥中两种主要的PAEs——邻苯二甲酸二丁酯(DBP)和邻苯二甲酸(2-乙基己)酯(DEHP)为研究对象,通过比较PAEs在污泥厌氧消化系统与发酵产氢系统中降解过程的差异及系统污泥特性的变化,分析不同污泥厌氧生物处理系统中影响PAEs降解的可能因素.结果表明: 在污泥厌氧发酵系统中,DBP在6 d内降解率达99.6%, DEHP在整个14 d的培养期间也降解了46.1%;在发酵产氢系统中,在14 d培养过程DBP的降解率仅为19.5%,DEHP则没有明显的降解.与厌氧消化系统相比,PAEs在发酵产氢系统中的降解受到明显抑制,这与发酵产氢过程中微生物量下降、革兰氏阳性菌/革兰氏阴性菌(G⁺/G^-)和真菌/细菌变小及挥发性脂肪酸(包括乙酸、丙酸及丁酸)浓度升高有关.     

活性污泥产酸发酵研究进展

有机物的厌氧生物处理一般经过三个阶段:水解阶段、产酸发酵阶段和产甲烷阶段;研究证明,产酸相不同发酵类型的形成对产甲烷相乃至整个工艺的稳定运行具有至关重要的作用,此外,污泥厌氧消化过程所产生的大量的挥发性脂肪酸(VFAs),如乙酸、丙酸、丁酸及戊酸等,还可作为化工原料用于发酵工业生产各种高附加值产品.近年来,产酸发酵受到越来越多的关注,该文主要对污泥产酸阶段的产酸发酵类型、产酸发酵细菌的生态学、产酸过程的影响因素和生态因子以及产酸发酵的液相末端产物VFAs的测定方法进行了论述.     

餐厨垃圾协同剩余污泥发酵产酸的生物过程与影响因素研究进展

资源化利用是应对餐厨垃圾(Kitchen waste,KW)和剩余污泥(Excess sludge,ES)快速增加的有效方法,而厌氧发酵获得挥发性脂肪酸(Volatile fatty acids,VFAs)是其中的重要方式之一,但单一底物限制了VFAs的高效生产.近年来,不同底物厌氧共发酵产生VFAs被广泛研究与应用,...     

不同生境微生物转化H2/CO2产乙酸及其在合成气发酵中应用

【目的】合成气发酵对大力开发可再生资源和促进国家可持续发展具有重要意义,研究旨在探究不同生境微生物转化H2/CO2产乙酸及其合成气发酵的潜力。【方法】采集剩余污泥、牛粪、产甲烷污泥和河道底物样品在中温(37 °C)条件下生物转化H2/CO2气体,将来源于牛粪样品的H2/CO2转化富集物用于合成气发酵,通过454高通量技术和定量PCR技术分析复杂微生物群落的组成,GC气相色谱法检测气体转化产生的挥发性脂肪酸(VFAs)浓度。【结果】牛粪和剩余污泥微生物利用H2/CO2气体生成乙酸、乙醇和丁酸等,最高乙酸浓度分别为63 mmol/L和40 mmol/L,明显高于河道底物和产甲烷污泥样品的最高乙酸浓度3 mmol/L和16 mmol/L。牛粪和剩余污泥微生物中含有种类多样化的同型产乙酸菌,剩余污泥中同型产乙酸菌主要为Clostridium spp.、Sporomusa malonica和Acetoanaerobium noterae,牛粪中则为Clostridium spp.、Treponema azotonutricium和Oxobacter pfennigii。【结论】同型产乙酸菌的丰富度和数量两个因素都对复杂微生物群落转化H2/CO2产乙酸效率至关重要;转化H2/CO2得到的富集物可用于合成气发酵产乙酸和乙醇,这为基于混合培养技术的合成气发酵提供了依据。     

碱-组合工艺预处理剩余污泥研究进展

城市污泥在进行厌氧发酵处理时,所需时间长、SS降解率低、产气量也低,难以有效达到污泥减量化的目的(VS去除率30％左右).污泥的厌氧发酵包括水解、酸化、产乙酸、产甲烷的过程.研究发现在污泥进行厌氧发酵过程中固态有机物的水解、酸化是限速步骤,因此为了促进污泥的水解、酸化,使更多的固体有机物转化为水溶性的有机物,进而提高厌氧发酵的效率实现污泥的减量化、无害化和资源化利用,对污泥预处理是必须的.该文着重介绍了NaOH及其组合工艺对污泥预处理的影响.     

不同生境微生物转化H_2/CO_2产乙酸及其在合成气发酵中应用（英文）

【目的】合成气发酵对大力开发可再生资源和促进国家可持续发展具有重要意义,研究旨在探究不同生境微生物转化H_2/CO_2产乙酸及其合成气发酵的潜力。【方法】采集剩余污泥、牛粪、产甲烷污泥和河道底物样品在中温(37°C)条件下生物转化H_2/CO_2气体,将来源于牛粪样品的H_2/CO_2转化富集物用于合成气发酵,通过454高通量技术和定量PCR技术分析复杂微生物群落的组成,GC气相色谱法检测气体转化产生的挥发性脂肪酸(VFAs)浓度。【结果】牛粪和剩余污泥微生物利用H_2/CO_2气体生成乙酸、乙醇和丁酸等,最高乙酸浓度分别为63 mmol/L和40 mmol/L,明显高于河道底物和产甲烷污泥样品的最高乙酸浓度3 mmol/L和16 mmol/L。牛粪和剩余污泥微生物中含有种类多样化的同型产乙酸菌,剩余污泥中同型产乙酸菌主要为Clostridium spp.、Sporomusa malonica和Acetoanaerobium noterae,牛粪中则为Clostridium spp.、Treponema azotonutricium和Oxobacter pfennigii。【结论】同型产乙酸菌的丰富度和数量两个因素都对复杂微生物群落转化H_2/CO_2产乙酸效率至关重要;转化H_2/CO_2得到的富集物可用于合成气发酵产乙酸和乙醇,这为基于混合培养技术的合成气发酵提供了依据。     

化工上的应用

372354利用温州蜜柑皮发醉甲烷的研究.1.在产酸发酵中由温州蜜柑皮生产挥发性脂肪酸〔日〕/Kashiwagi,S,…了公害一一985,20(6)一257~267〔译自CBA-1986,(8),3217〕 产酸的细菌在其适应的厌氧条件下可将温州蜜柑皮转化为挥发性脂肪酸。为了从原始消化污泥巾消除产申烷细菌,要使     

厌氧消化酸抑制研究进展

厌氧消化工艺目前已广泛应用于各类废水的处理处置过程中,但在实际运行中,受消化条件和物料性质的影响,消化系统经常遭受由挥发性脂肪酸积累过多导致的酸抑制问题,引发产气量下降、产甲烷率降低等问题。近年来,有研究者发现,挥发性脂肪酸的种类和浓度及pH、温度是影响酸抑制的主要因素。基于此,相关研究者分别尝试了添加碱性化学药剂和微量元素及利用生物强化技术与微生物电化学技术来解除酸抑制的尝试,并都取得了不错的效果。本文综述了厌氧消化过程中酸抑制的产生过程、抑制机理及恢复方法,以期为解决厌氧消化酸抑制问题提供参考。     

有机溶剂对污泥厌氧发酵产酸的影响

有机酸是重要的化工原料,从市政污泥厌氧发酵过程提取有机酸、用于生产高附加值的产品可以实现废物资源化,本研究在确定最佳有机溶剂和萃取剂的基础上,考察了有机溶剂对城市污泥厌氧发酵生产有机酸的影响.结果表明,较合适的溶剂和萃取剂分别为磺化煤油和三烷基氧膦.少量磺化煤油对城市污泥发酵产生产有机酸有一定促进作用.     

厌氧发酵液中溶解性有机物对活性污泥合成聚羟基脂肪酸酯影响的研究进展

利用活性污泥微生物将剩余污泥发酵液中的挥发性脂肪酸(Volatile fatty acids,VFAs)转化为聚羟基脂肪酸酯(Polyhydroxyalkanoates,PHA)是目前环境生物技术领域的研究热点.但针对发酵液中非VFAs物质(主要是溶解性有机物,Dissolved organic matter,DOM)...     

Anaerobic digestion: microbial and biochemical aspects of volatile acid production

Summary The production of organic acids has been tested with bacterial flora selected from a municipal sludge digestor. In order to elucidate the basic mechanisms by which glucose is converted to volatile fatty acids, the examination of non-methanogenic bacteria was attempted. Both lactate-producers and lactate-utilizers were found among these bacteria. When mixed isolates were used as the inoculum, the accumulation of lactic acid and its further conversion to propionic and butyric acids was demonstrated at a carbon conversion rate of about 0.75. It is therefore suggested that this metabolic sequence may occur as a normal process in acidogenic fermentation, which is the first step in anaerobic digestion.     

Combined removal of nitrate and carbon in granular sludge: Substrate competition and activities

Granular sludge from an upflow anaerobic sludge blanket reactor treating synthetic waste water containing a mixture of volatile fatty acids and nitrate showed a removal efficiency of nearly 100% for both nitrogen and carbon. This activity was achieved by a combined process of denitrification and methanogenesis under conditions of surplus carbon. Under batch conditions the two processes proceeded clearly separated in time with first denitrification dominating and excluding methanogenesis. However, as soon as nitrate was depleted, methane production was initiated, showing that the inhibition of methanogenesis by nitrate was reversible. Of the volatile fatty acids supplied to the reactor, i.e. acetate, propionate, and butyrate, the denitrifying population clearly preferred butyrate and propionate even though acetate could also be metabolized. Consequently, growth of syntrophic volatile fatty acid degraders was suppressed by the denitrifiers in cases of low C:N ratios in the medium, leaving acetate as the major substrate for methanogenesis.Abbreviations UASB upflow anaerobic sludge blanket - COD chemical oxygen demand - VFA volatile fatty     

Anaerobic biohydrogen production from monosaccharides by a mixed microbial community culture

Monosaccharides (e.g. glucose and fructose) are produced from the hydrolyzation of macromolecules, such as starch, cellulose, hemicellulose and lignin, which are abundant in various industrial wastewaters. The elucidation of anaerobic activated sludge microbial community utilizing monosaccharides will lay an important foundation for the industrialization of biohydrogen production. In this study, the hydrogen production by a mixed microbial culture on four monosaccharides (glucose, fructose, galactose and arabinose) was investigated in a batch cultures. The mixed microbial culture was obtained from anaerobic activated sludge in a continuous stirred-tank reactor (CSTR) after 29 days of acclimatization. The results indicated that glucose had the highest specific hydrogen production rate of 358 mL/g.g mixed liquid volatile suspended solid (MLVSS), while arabinose had the lowest hydrogen production rate of 28 mL/g.gMLVSS. Glucose also possessed the highest specific conversion rate to hydrogen of 82 mL/g glucose, while fructose had the highest specific conversion rate to liquid product of 443 mg/g fructose. Arabinose had the lowest conversion rates to both liquid products and hydrogen. Metabolic pathways and fermentation products were the major reasons for the difference in hydrogen production from these four monosaccharides. The complex fermentation pathways of arabinose reduced its hydrogen production efficiency and a long acclimation period (over 68 h) was required before the anaerobic activated sludge could effectively utilize arabinose in batch cultures.     

Stability and reproducibility of low-temperature anaerobic biological wastewater treatment

The reproducibility of low-temperature anaerobic biological wastewater treatment trials was evaluated. Two identical anaerobic expanded granular sludge bed bioreactors were used to treat synthetic volatile fatty acid-based industrial wastewater under ambient conditions (18-20 degrees C) and to investigate the effect of various environmental perturbations on reactor performance and microbial community dynamics, which were assessed by chemical oxygen demand removal or effluent volatile fatty acid determination and terminal restriction fragment length polymorphism analysis, respectively. Methanogenic activity was monitored using specific methanogenic activity assays. Reactor performance and microbial community dynamics were each well replicated between Reactor 1 and Reactor 2. Archaeal dynamics, in particular, were associated with reactor operating parameters. Terminal restriction fragment length polymorphism data suggested dynamic acetoclastic and hydrogenophilic methanogenic populations and were in agreement with temporal specific methanogenic activity data. Putative psychrophilic populations were observed in anaerobic bioreactor sludge for the first time.