黑龙江省生物质废弃物厌氧消化产沼气技术现状及发展趋势

面对金融危机,扩大内需,以沼气为核心的农村能源结构的调整和环境的改善是解决农村问题的关键.黑龙江省生物质能源丰富,由于受冬季低温的限制,严重制约了生物质能源的转化,特别是沼气能源的推广应用.低温发酵是制约北方农村沼气的重要的亟待解决的关键问题和技术瓶颈.其核心技术是如何实现低温条件下厌氧消化处理生物质废弃物高效转化,提高沼气的单位产量.本文针对黑龙江省,现有沼气应用技术发展现状及存在的问题,提出了适合寒地的沼气应用的新理论、新技术及新工艺,并对今后的发展趋势进行深入的探讨和分析.     

厌氧消化消化残留液中游离氨基酸含量的测定

采用ＧＣ－９Ａ气相色谱仪进行三种不同原料厌氧消化残留液中游离氨基酸珠测定。实验结果表明,鸡粪厌氧消化残留液中游离氨基酸种类最多,且含量较其他两种残留液高,鸡粪残留液更适于再利用。     

淀粉酶活在厌氧消化过程中的变化研究

本文研究了淀粉酶在厌氧消化过程听变化规律及对沼气形成的影响关系，结果表明，糖化型淀粉酶活性与沼气产量是相关性，酶活高峰期也就是产气高峰，糖化型淀粉酶在此时酶活高达４２１９ｍｇ葡萄糖／１００ｍｌ．ｈｏｕｒ，发酵结束后酶活高于原料中的酶活，其酶主要来自发酵原料。     

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。     

大型奶牛场粪便厌氧消化工程的研究

本文报导了大型牛场粪便厌氧消化工程研究的概况。该工程针对牛粪草多、浮渣多的特点设计了除长草、除浮渣装置。以保证了厌氧消化的稳定运行。工程每天可处理奶牛粪便８０余吨、鸡粪及工业发酵废渣２０余吨,生产沼气供应２８６８户职工家庭作燃气使用,平均沼气率为１．２ｍ＾３／ｍ＾３．ｄ。经后处理的发酵残留物被充分利用,制成肥料、绿色营养土和鱼饵,这样既免除了二次污染,又提高了工程的经济效益。该工程为我国大中型沼气     

温度和化学预处理对玉米秸厌氧消化产气量的影响

提出通过中温消化和化学预处理相结合的方法提高玉米秸的厌氧消化产气量。研究了中温和常温条件下,不同负荷率对玉米秸产气量的影响,以及经氢氧化钠、氨水与尿素处理后玉米秸主要成份的变化规律及其对产气量的影响。结果显示,中温消化产气量比常温提高了139．2％～281.8％,消化时间减少了8～16d;除尿素外,氢氧化钠和氨处理都可不同程度地提高玉米秸的产气量;中温消化时,氢氧化钠处理玉米秸的产气量比未处理玉米秸提高了77．0％,比常温消化的未处理玉米秸提高了263．6％。把中温消化和化学处理结合起来是提高玉米秸厌氧消化效率和产气量的有效方法。     

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。     

厌氧氨氧化生物脱氮技术的研究进展

厌氧氨氧化是指在厌氧条件下,厌氧氨氧化混合菌直接以NH4 为电子供体,以NO3-或NO2-为电子受体,将NH4^ 、NO3-或NO2-转变成N2的过程。厌氧氨氧化作为一种新型的污水处理工艺具有较高的理论意义和良好的应用前景。本文主要阐述了厌氧氨氧化生物脱氮技术原理、厌氧氨氧化的可能途径、方法及其应用现状,并且讨论了厌氧氨氧化反应的微生物学机理和厌氧氨氧化工艺的开发,提出了今后研究的主要方向。     

厨余垃圾厌氧消化合成高附加值化学品的研究进展

厨余垃圾在生活垃圾中占比巨大,已对食品安全、自然资源可持续利用和环境造成了不利影响,故亟须实现厨余垃圾的有效处理及利用。目前处理厨余垃圾最常用的方式主要包括填埋与焚烧,但存在易产生二次污染、耗能大等问题,阻碍了其大规模应用。厨余垃圾具有有机质含量高的特性,通过生物炼制合成高附加值化学品(如有机酸等),不仅可实现产品的清洁生产,也可提高厨余垃圾的经济价值。本文首先概括了国内外厨余垃圾的处理现状及处理方法,其中厌氧消化法可清洁生产高附加值产品,展示出巨大的研究潜力。因此,对厌氧消化厨余垃圾合成化学品进展进行详细综述,最后对构建人工混菌培养体系和生物膜调控在厨余垃圾生物制造领域的应用提出了展望。     

厌氧氨氧化反应器的启动研究

目的：对UASB-生物膜反应器进行厌氧氨氧化反应的启动研究。方法：以自配含氨氮和亚硝氮的废水为进水,以氧化沟工艺城市污水处理厂回流污泥为接种污泥。结果：反应器内部菌群进行了竞争,在运行至第66d时氨氮、亚硝酸盐氮的去除率分别达到了60.4%、58.7%,同时有硝酸盐氮生成,表明厌氧氨氧化反应已经成为反应器内的主导反应。结论：厌氧氨氧化反应器实现了快速启动。     

Effect of substrate concentration on dry mesophilic anaerobic digestion of organic fraction of municipal solid waste (OFMSW)

The influence of total solid contents during anaerobic mesophilic treatment of the organic fraction of municipal solid waste (MSW) has been studied in this work. The work was performed in batch reactors of 1.7L capacity, during a period of 85-95 days. Two different organic substrate concentrations were studied: 931.1 mgDOC/L (20% TS) and 1423.4 mgDOC/L (30% TS). Experimental results showed that the reactor with 20% total solids content had significantly higher performance. Thus, the startup phase ended at 14 days and the total DOC removal was 67.53%. The startup in reactor R30 ended at 28 days obtaining 49.18% DOC removal. Also, the initial substrate concentration contributed substantially to the amount of methane in the biogas. Hence, the total methane production in the methanogenic phase was 7.01 L and 5.53 L at the end of the experiments for R20 and R30, respectively.     

Influence of inoculum on performance of anaerobic reactors for treating municipal solid waste

The influence of bovine rumen fluid inoculum during anaerobic treatment of the organic fraction of municipal solid waste (MSW) was studied in this work. The parameters adopted for evaluation were the biostabilization constant of total volatile solids (TVS) and the biostabilization time of the chemical oxygen demand (COD) applied to the reactors. The work was realized in four anaerobic batch reactors of 20 l capacity each, during a period of 365 days. The proportions between MSW/inoculum loaded in the reactors were Reactor A (100%/0%), Reactor B (95%/5%), Reactor C (90%/10%) and Reactor D (85%/15%). The necessary time for biostabilization of half of the applied COD was 459, 347, 302 and 234 days and the average of methane concentration in the biogas produced was 3.6%, 13.0%, 25.0% and 42.6% for Reactors A, B, C and D, respectively. The data obtained affirm that the inoculum used substantially improved the performance of the process.     

Enhancement of dry anaerobic batch digestion of the organic fraction of municipal solid waste by an aerobic pretreatment step

The start-up of the dry anaerobic batch digestion by the BIOCEL-concept of the organic fraction of municipal solid waste (MSW) is unbalanced when a methanogenic inoculum (digested sewage sludge) is added to a total solids concentration of 35%. The unbalanced conditions are the result of the rapid degradation of easily-degradable compounds which are present in the organic fraction. Enhancement of the first start-up of the dry batch digestion was tried by applying an aerobic partial-composting step. By this aerobic treatment the easily degradable compounds are removed. After the composting step the anaerobic digestion will be limited by the conversion of the ligno-cellulose part of the organic fraction. It appeared that at least 19·5% of the volatile solids (VS) should be converted during the aerobic composting period before acid formation in the digestion was in balance with the methane formation. This amount of aerobically degraded VS means a 40% loss of potential biogas. The loss of a part of the biogas is a major drawback to the partial composting as a method for enhancing the start-up of the dry anaerobic digestion. A shorter composting period which is combined with another start-up method might be a feasible method to decrease the energy input of the dry digestion process.     

Effect of fermentation temperature on hydrogen production from cow waste slurry by using anaerobic microflora within the slurry

We examined hydrogen production from a dairy cow waste slurry (13.4 g of volatile solids per liter) by batch cultures in a temperature range from 37 to 85°C, using microflora naturally present within the slurry. Without the addition of seed bacteria, hydrogen was produced by simply incubating the slurry, using the microflora within the slurry. Interestingly, two peaks of fermentation temperatures for hydrogen production from the slurry were observed at 60 and 75°C (392 and 248 ml H₂ per liter of slurry, respectively). After the termination of the hydrogen evolution, the microflora cultured at 60°C displayed hydrogen-consuming activity, but hydrogen-consuming activity of the microflora cultured at 75°C was not detected, at least for 24 days. At both 60 and 75°C, the main by-product was acetate, and the optimum pH of the slurry for hydrogen production was around neutral. Bacteria related to hydrogen-producing moderate and extreme thermophiles, Clostridium thermocellum and Caldanaerobacter subterraneus, were detected in the slurries cultured at 60 and 75°C, respectively, by denaturing gradient gel electrophoresis analyses, using the V3 region of 16S rDNA.     

Two stage anaerobic baffled reactors for bio-hydrogen production from municipal food waste

A two-step anaerobic baffled reactor (ABR-1 and ABR-2) for H₂ production from municipal food waste (MFW) was investigated at a temperature of 26 °C. In ABR-1, the average yield of H₂ at an HRT of 26 h and OLR of 58 kg COD/m³ d was 250 ml H₂/g VS removed. As unexpected; the H₂ production in the ABR-2 was further increased up to 370 ml H₂/gVS removed at a HRT of 26 h and OLR of 35 kgCOD/m³ d. The total H₂ yield in the two-step process was estimated to be 4.9 mol H₂/mol hexose. The major part of H₂ production in the ABR-1 was due to the conversion of COD_particulate (36%). In the ABR-2 the H₂ yield was mainly due to the conversion of COD in the soluble form (76%). Based on these results MFW could be ideal substrate for H₂ production in a two-step ABR processes.     

Two-phase anaerobic fermentation of liquid swine waste to methane

Two-phase anaerobic digestion of liquid swine manure has been developed with options for single-cell protein (SCP) or methane production. In the acidogenic phase at two to four days retention time, and 2.5-7.0% dry matter (DM) concentration, 8-46% of the volatile solids was solubilized. Maximum reactor capacity was 3.86 g/L at 7.0% DM concentration, but optimal operation was achieved at 4.5% DM concentration at four days retention time. The second methanogenic phase was operated continuously and had a maximum specific methane production rate of 0.70 L/L day at 12 days retention time. With recirculation, the rate was 1.16 L/L day at 8.5 days retention time with 52.7% conversion of organic matter. Maximum digestibility was 66% of the lignin free organic matter.     

Thermophilic anaerobic digestion of source-sorted organic fraction of municipal solid waste

The influence of different organic fraction of municipal solid wastes during anaerobic thermophilic (55 degrees C) treatment of organic matter was studied in this work: food waste (FW), organic fraction of municipal solid waste (OFMSW) and shredded OFMSW (SH_OFMSW). All digester operated at dry conditions (20% total solids content) and were inoculated with 30% (in volume) of mesophilic digested sludge. Experimental results showed important different behaviours patterns in these wastes related with the organic matter biodegradation and biogas and methane production. The FW reactor showed the smallest waste biodegradation (32.4% VS removal) with high methane production (0.18 LCH4/gVS); in contrast the SH_OFMSW showed higher waste biodegradation (73.7% VS removal) with small methane production (0.05 LCH4/g VS). Finally, OFMSW showed the highest VS removal (79.5%) and the methane yield reached 0.08 LCH4/g VS. Therefore, the nature of organic substrate has an important influence on the biodegradation process and methane yield. Pre-treatment of waste is not necessary for OFMSW.     

MSW干式厌氧发酵过程中颗粒度影响研究

不同颗粒度干式厌氧发酵处理生物废弃物,对发酵过程有着重要影响,试验表明：不同颗粒度对pH值变化影响较大,较小颗粒度发酵初期下降较快,较大颗粒度pH值变化不显著,而ORP差异比较明显,颗粒度越小,ORP下降越快;蛋白质和还原糖在匀浆状态下初期含量很高,而中后期无太大差异;纤维素酶在高破碎的情况下具有很强的活性,中后期减弱,而果胶酶活力在处理1中初期上升较快,随后变化不显著;VS和CODcr的去除率为处理2效果最好;从产气总量和产气速率比较,处理2为最佳,所产甲炕含量也为最高。     

Characterization of polysaccharidase activity optima in the anaerobic digestion of municipal solid waste

Summary Cellulolytic enzymes from a laboratory anaerobic digester fed municipal solid waste were examined with respect to pH and temperature. The pH optimum was pH 6.6, considerably lower than the pH range in which digesters are normally operated (pH 7.2–7.6). The optimum temperature was between 50 and 60°C, rather than the 35–37°C range in which most digesters are controlled.     

利用餐厨垃圾循环半连续厌氧发酵产氢研究

利用餐厨垃圾采用半连续厌氧发酵进行产氢的研究。实验结果表明以高温(100℃)预处理15 min的厌氧活性污泥为种泥,在温度37℃,pH 6.0左右,较宽的稀释率(1.0~4.0 d-1)范围内,均能较好的实现厌氧发酵产氢。在稀释率D=2.4 d-1下,流出液中乙醇、乙酸、丙酸、丁酸和戊酸的质量分数分别为5.6%、29.6%、5.4%、58.5%和0.9%,产氢过程属于典型的丁酸型发酵,最终氢气的体积分数可达60%,氢气的产生速率为5.49 m3/(m3.d)。将厌氧发酵液相产物作为稀释液返回到反应器中,反应器的产氢能力大幅度的提高,当回流比R=0.8时,最大产氢速率可达10.9 m3/(m3.d),最终氢气的含量可达65%,厌氧发酵反应器的产氢能力提高了约130%。