积极发展农村沼气工程

沼气是一种清洁卫生的能源。通过沼气这个中心环节,使农业废弃物得到充分利用。本工程以较小的投入获得了较多的产出,既提高了经济效益,又有利于改善生态环境,保护农业生态平衡。鄞县甲村乡上李家村沼气工程的建设,不仅改变了农村燃料结构,为农村提供了清洁卫生的新能源,还减轻了农业废弃物对环境的污染,促进农业废弃物的资源化利用,为发展生态农业创造了条件。     

规模化沼气工程消化效率及碳减排核算

规模化沼气工程的产气核算尚无明确标准和评价方法,已严重影响政府补贴政策的落实,并一定程度上加大了沼气工程的运营压力。以山东民和沼气工程为案例,对原料及各级反应罐消化液的理化性质和产甲烷潜力进行了研究,提出了基于产甲烷潜力变化率的物料生物降解性变化率(biochemical degradation rate, BDR)间接核算法。该方法可对规模化大型沼气工程的沼气产量及碳减排进行核算。结果显示,基于BDR法核算的沼气产量与实际上报的沼气产量相差2.3%,碳减排量与监测报告中的数值相差6.3%。BDR法不仅能够准确地对沼气工程的产气量及碳减排进行核算,同时也可为产气的测量、报告与核证提供数据基础。该方法可满足当前沼气转型升级建设实行先建后补的政策投资需求。     

西子生态农场的综合开发利用研究

介绍了西子生态农场建设的情况。农场采用德国引进的固液分离技术处理畜禽粪便,制取沼气,沼气发电用于整个农场。沼液,沼渣得到综合利用、整个农场实现污水循环使用,取得了良好的经济效益。,社会效益和生态效益,具有推广价值。     

我国餐厨垃圾厌氧处理技术现状分析及建议

随着我国餐厨垃圾排放量的持续增加,已造成严重的环境污染防控压力。为促进我国餐厨垃圾的资源化利用和无害化处理处置,在文献调研的基础上,梳理了我国大中型餐厨沼气工程的发展现状,分析了导致沼气产率低、沼气回用量大等餐厨沼气亟待解决的低经济效益难题的根本原因,并结合实际情况提出餐厨垃圾厌氧消化技术相关的建议,以期为我国提高餐厨垃圾的资源化、无害化处理能力和水平提供参考。     

日本开发成功用生鲜垃圾制氢和沼气的装置

日产业技术综合研究所采用生鲜垃圾高效生产氢和沼气装置，氢和沼气可用于燃料电池。该装置使两类微生物分两个阶段使有机物分别生成氢和沼气。在残羹剩饭中掺上水，放入微生物发酵，从而生成氢；提取氢后，将剩下的液体移到另外的容器，用另一种微生物发酵，提取沼气。与传统生鲜垃圾生成沼气装置相比，它处理速度快，能源回收率由45％提高到55％。每天可处理生鲜垃圾、食品废弃物60kg，垃圾纸5kg，提取氢0．5m^3，沼气5-10m^3。     

小球藻(Chlorella vulgaris)净化沼液和提纯沼气

为了研究同时提纯沼气和净化沼液的可能,利用沼液作为小球藻(Chlorella vulgaris)的培养基,同时把沼气中的CO2作为小球藻培养的碳源。在无菌培养条件下,得出了最适生长条件为沼液浓度50%、初始pH值6.0、接种小球藻干重为0.20 mg/mL、光质为红光。在此条件下沼液中的COD、TN、TP和BOD5的去除率分别达到了88.5%、91.2%、95.3%和87.6%,沼气中甲烷含量由原先的40%提升到60.2%。很好地同时解决了沼气品质低下和高浓度污染物沼液污染环境的问题。     

加热位置对沼气罐温度场影响的实验和模拟

为了使沼气罐内有一个相对均匀的温度环境、提高沼气的产气效率,通过改变沼气罐内的加热位置,找出能使沼气罐内温度场均匀的加热位置,减小罐内温度梯度过大对发酵造成的影响。用实验研究和数值模拟相结合的方法,研究沼气罐内的温度场分布情况,结果表明,中部加热较上部加热和下部加热能取得良好的罐内温度场,温度梯度较小,使罐内上、中、下各部分温度分别维持在33.95、34.02和33.6℃,比传统的采用下部换热能取得更好的温度场。     

绍兴兰亭生态试验场将成为兰亭风景区的延伸

绍兴市环境保护局已于1989～1993年完成《兰亭生态试验场的建设与研究》课题,并通过验收和专家鉴定。 该生态试验场共占地1.73公顷,位于绍兴县西南的兰亭镇境内,与著名的兰亭风景区隔河相望,且有桥相通。 整个生态试验场以沼气工程为纽带,以饲养鸡、鸭、猪为主,兼养水产,种植瓜果花木,开展多种经营。场内以饲养鸡,鸡粪喂猪,猪粪产沼气,沼液喂猪和养鱼,沼渣肥田等,提高了饲料蛋白的多次利用率、有机废弃物的综合利用率,同时提高了生物的转化率。创年产值达10万元。 为使生态试验与兰亭风景区相协调,不仅在场内开辟经济庭园,种植瓜果,而且建设小花圃,内栽较     

酒精废水EIC处理技术及综合利用

介绍了旋流内循环（EIC）厌氧反应器处理高浓度酒精废水的方法及效果，用EIC反应器代替UASB处理工艺，具有污染物去除率高、沼气产生量大等优点，产生的沼气用于发电供热，取得了良好的经济效益、环境效益和社会效益。     

猪场废水处理中的沼气热电联产工程案例分析

中高浓度畜禽废水处理中的沼气热电联产是保障沼气工程常年稳定运行的有效手段.以典型猪场废水处理沼气热电联产工程为案例,在工程介绍的前提下,引入相关数学模型,对沼气热电联产相关工艺参数进行了计算分析,结果表明,该工程沼气产量最高为1 678 m3/d,沼气发电机组发电效率为31.3％,发热效率为38.8％,总发电效率为70.1％,该沼气工程投资回报期为3.6年;CSTR厌氧罐秋季可达温度为24.3℃,冬季为15.9℃,CSTR厌氧罐内温度分布为秋季罐内平均温度(T)5.4(换热器顶部温度)=25.4℃,平均温度梯度grad1=1.83℃/m,grad2=0.80℃/m;冬季(T)5.4=19.6℃,(grad)1=1.44℃/m,(grad)2=1.06℃/m;通过参数分析,搅拌器宜尽可能置于换热器所在区域,并控制进水量稳定以保证CSTR厌氧罐的消化效果.     

垃圾填埋场甲烷氧化菌及甲烷通量的研究

采用静态箱法、滚管计数法和气相色谱法,对6个不同封场时间填埋区的甲烷通量、覆土层甲烷氧化菌数量和甲烷氧化速率的变化趋势进行了测定,并分析了它们与封场时间、植被覆盖率等因素之间的相关性。结果发现6个填埋区甲烷通量的变化范围在-0.34～5.31 mg/(m2.h)之间;覆土层甲烷氧化菌的数量范围为3.10×107～20.77×107 cfu/g干土,甲烷氧化速率在1.65×10-8～4.34×10-8mol/(h.g)之间。覆土层甲烷氧化菌的数量与甲烷氧化速率呈正相关,但前者并不是后者的决定性因素;甲烷通量高时可刺激甲烷氧化菌数量及氧化速率的提高,且三者均与封场时间呈显著负相关,与植被覆盖率呈负相关;当含水率大于15%时,随着覆土层含水率的增加,甲烷氧化速率呈下降趋势;覆土pH、有机质和铵态氮与甲烷氧化速率等无明显相关性。提高覆土层的甲烷氧化速率可有效减少垃圾填埋场的甲烷排放。     

Methane oxidation by Dutch grassland and peat soil microflora

The ability of Dutch grassland soil and Dutch peat soil for methane oxidation was investigated. The kinetics of methane oxidation by soil from different depths were determined in batch cultures incubated with 1; 10; 100; and 10,000 ppmv methane, respectively. All 4 applied concentrations of methane were degraded by both types of soil. Thereby, the highest oxidative activities were observed between 5 and 10 cm soil depth. Most importantly, these experiments demonstrated that this soil acts as a sink for methane even at concentrations well below 1 ppmv. Especially at higher methane concentrations (100 - 10,000 ppmv) much higher degradation rates were found in the peat soil. This also correlates with the higher methane production rates which had been observed in peat soil.     

污泥与餐厨垃圾联合厌氧发酵产氢余物产甲烷条件优化研究

研究了21、37和47 d产甲烷物料代替新鲜污泥接种于污泥与餐厨垃圾联合厌氧发酵产氢余物的厌氧发酵产甲烷情况,发现接种47 d产甲烷物料的消化系统在最佳接种量50%条件下的产甲烷效能显著优于接种新鲜污泥的消化系统,不仅提高了产甲烷率,还大大缩短了消化时间。并且3种消化系统产甲烷率和比产甲烷率均为47 d37 d21 d,分别为3.78、3.88、6.15 mL/g和0.172、0.277、0.559 mL/(g·d),完成产甲烷过程的消化时间为47 d37 d21 d。在一定的消化时间范围内,产甲烷菌被驯化时间越长,接种于产氢余物中的产甲烷效能越好。     

Methane emission from lakes

A physico-chemical model to describe methane and carbon dioxide emission from lakes was developed. The model describes the emission by diffusion, bubbles and plants. The intensity of the fluxes can be calculated either for total or particular emission in dependence on gas bubbles composition. It was found, that diffusional (Q) and bubble (J) fluxes depend on the methane molar ratio (X) in bubbles as follows: [formula: see text]. The model allows to estimate the role of the methane oxidation by atmospheric oxygen in the total methane flux. It was shown, that the methane oxidation does not influence much methane fluxes to the atmosphere for most of the experimentally observed situations.     

昆明市污水排水系统产甲烷规律的模拟实验研究

通过对昆明市餐饮和居民生活污水厌氧模拟实验研究,初步探讨生活污水中CH4的产生规律,实验结果表明,在自然条件下,餐饮和居民生活污水中产生的甲烷浓度最大值分别为1.63 mg/L和3.82 mg/L。并且将COD、硫酸盐、硫化物、TN的浓度变化与甲烷浓度变化进行Pearson简单相关性分析,结果表明,1/COD、COD/硫酸盐和1/TN与甲烷在置信度为0.01时极显著相关,硫化物与甲烷在置信度为0.05时不相关;COD、硫酸盐和TN浓度的变化对生活污水中甲烷的产生起关键性作用。对居民生活污水中甲烷产生规律进行温度和pH控制分析研究,实验结果表明,生活污水在25~30℃时,24 h内甲烷产生量最大值为8.6494 mg/L,明显大于其他温度段的甲烷产生量;在pH为7~8之间时,甲烷的产生量在24 h内达到的最大值为3.0477 mg/L,明显高于其他pH控制段的甲烷产生量。     

Reconstruction of the methane fluxes from the west Siberia gas fields by the 3D regional chemical transport model

A 3D mesoscale tropospheric photochemical transport model of high spatial resolution has been developed and used for assessment of the methane concentrations and methane emission in the West Siberian region of intensive mining of natural gas and oil deposits. The model is validated against the measurements of methane concentration at the surface and in the lower troposphere collected during July 1993 and June 1996 experiments. Comparison of the simulated and observed concentrations allowed to estimate that during the above periods the average natural methane fluxes were as high as 65 mg m⁻² day⁻¹. The anthropogenic methane fluxes (leakage from gas deposits) integrated over model domain during the same time period were about 20% of the total methane emission from relevant areas.     

渗滤液回流对不同填埋结构甲烷变化规律的影响研究

建立了大型模拟填埋试验装置,研究了渗滤液回流对不同填埋结构甲烷变化规律的影响.每周对填埋气体中甲烷浓度进行监测.结果表明:厌氧填埋中回流操作使甲烷浓度峰值提前了147 d,峰值为59.6%(体积分数,下同);准好氧填埋中回流操作使甲烷浓度峰值提前259 d,峰值为44.7%.回流操作使甲烷产气高峰提前,增加产气量,加快填埋垃圾稳定,减轻渗滤液污染.厌氧填埋中进行回流操作有利于甲烷的回收利用;准好氧填埋结构可有效减少甲烷的排放,减小对环境的危害.稳定期的垃圾填埋体进行回流产生一定的甲烷,但浓度较低,最高仅26.0%,没有利用价值.     

Theoretical consideration of methane emission from sediments

A stationary theory of gas emission from sedimentary (active) layers of wetlands is developed. The theory takes into account methane generation in a sedimentary layer (W1) and its depth dependence, (W1(z)), the solubility, determined by Henry's constant (K1), and the mobility of methane molecules set by the methane diffusion coefficient (D1). The exponential dependence of methane generation rate decay with depth is considered in more detail. The penetration of atmospheric nitrogen into the active layer is also taken into consideration. It is shown that the value of diffusion methane flux from sedimentary layers is proportional to square root(K1D1P0W10) where P0 characterizes the atmospheric pressure and W10 characterizes the maximum generation rate. Coefficients relating the diffusion methane flux to the square root(K1D1P0W10) value are calculated for the different depth dependencies of methane generation rate. The values of these coefficients are not much different from unity for most real cases.     

Influence of plants on the methane emission from sediments

The previous theory [Chem. Global Change Sci. 3 (2001) 33; Chemosphere 50 (2003) 191] of methane emission is applied to vegetated sediments. The presence of roots in a sediment is taken into account. It is assumed that methane and nitrogen enter a sediment through channels existing in plants and roots. The rate of methane and nitrogen transport through plants and roots is proportional to the difference in concentrations in the layer and on the upper surface. It is established that as the vegetation density increases, the rate of methane transport increases so that with sufficient vegetation density, almost all methane passes to the atmosphere through plants. In this case, the value of bubble emission decreases to zero. The nitrogen transport rate through plants first increases and then decreases with increasing the vegetation density. The theory qualitatively and quantitatively describes the dependence of methane concentration on depth in the presence of plants. A comparison with the available experimental data on dissolved methane concentration and bubble composition indicates satisfactory agreement.     

甲烷氯化物废水治理工艺的技术应用

在氯碱工业加工过程中会产生大量的甲烷氯化物废水,废水中含有大量的甲烷氯化物,该类废水不易处理,极大地影响了后续废水处理工作的开展。本文以某司甲烷氯化物具体试验为例,探讨高分子吸附剂在甲烷氯化物废水处理过程中的应用,在利用高分子吸附剂进行吸附的同时通过蒸汽吹脱使树脂中富集下来的甲烷氯化物得到分离回收,从而实现了废水的资源化,达到治废与资源利用的双重效果。