生物产酸对木薯酒精废水发酵联产氢气和甲烷的影响

在温度为36.0±0.5℃,初始pH值为4.5,5.5,6.5和7.5条件下进行生物产酸过程,当初始pH值为6.5,获得最大生物产酸率为53.13%,产酸过程进行168 h后再进行厌氧消化过程。用修改的Modified Gompertz模型处理两级厌氧消化与直接厌氧消化的实验数据,获得最大比产气量、最大比产气速率和滞留时间等厌氧消化动力学参数。拟合结果表明,初始pH值为7.5,6.5和5.5实验组的两级厌氧消化比直接厌氧消化的产气效果好,初始pH值为4.5的两级厌氧消化产气效果相对较差。初始pH值6.5的实验组产气效果最优,以单位质量MLVSS计的最大比产氢量和最大比产甲烷量分别为90.63 mL/g和199.33 mL/g。以单位质量MLVSS计的最大比产氢速率和产甲烷速率分别为13.00 mL/(g·h)和1.37 mL/(g·h)。两级厌氧消化比直接厌氧消化处理木薯酒精废水的能源转化率提高了19.01%。     

厨余垃圾厌氧消化制取甲烷的影响因素研究

介绍我国厨余垃圾的现状及潜在危害,从垃圾性质(自身底物成分、C/N、颗粒大小)、工艺条件(温度、pH值、搅拌强度、添加金属离子、添加载体、接种量、挥发性脂肪酸含量)及工艺流程(预处理、消化气回流、先产氢再甲烷化、间断/连续式消化、干发酵后堆肥工艺及混合物料发酵工艺)等方面,综述了影响厨余垃圾厌氧消化的因素及优化厌氧消化的工艺条件,指出提高我国厨余垃圾厌氧消化技术需要解决的问题及今后的研究方向,并对我国城市生活垃圾综合处理提出合理性建议.     

有机垃圾组分中温厌氧消化产甲烷动力学研究

以土豆、生菜、瘦肉和花生油为原料,采用批式中温厌氧消化产甲烷实验,研究了城市生活有机垃圾中淀粉类、纤维素类、蛋白质类和脂类4种典型组分的厌氧消化产甲烷特性。利用修正Gompertz方程对累积产甲烷量进行拟合,并对厌氧降解过程用一级动力学进行分析。结果表明:土豆、生菜、瘦肉和花生油的最终甲烷产量为260.1、145.7、258.4和757.2mL·gVS~(-1),延滞期分别为0、1.3、1.6和13.1d,累积甲烷产量达到最终甲烷产量80%所需的时间分别为7.2、9.6、8.1和59.7d,可生物降解度分别为74%、31%、51%和85%。从厌氧消化过程中液相的挥发性脂肪酸浓度和气相的氢气浓度以及pH监测结果表明,所有厌氧消化过程均没有中间产物的积累,适合一级动力学方程。土豆、生菜、瘦肉和花生油的厌氧降解速率常数分别为0.183、0.147、0.190和0.020d~(-1)。     

城市生活垃圾和污水厂剩余污泥联合厌氧消化产气性能研究

以城市生活垃圾和污水厂剩余污泥为消化原料,在中温(35℃)条件下,采用序批式厌氧消化方式,研究了生活垃圾和剩余污泥不同混合比例下的厌氧消化产气性能,以及不同原料配比对厌氧消化过程及消化效率的影响。按照生活垃圾和剩余污泥VS比分别为1∶0(R1),2∶1(R2),1∶1(R3),1∶2(R4)和0∶1(R5),试验设置了5个试验组。研究结果表明:两种物料混合后有助于提高消化效果和产气性能,其中,当城市生活垃圾和剩余污泥VS比为2∶1时,系统厌氧消化效果最好,VS去除率为35.98%,单位VS产气量为348.84 m L/g,产气中甲烷含量为53.8%,消化时间较单纯生活垃圾厌氧消化缩短了9 d。说明一定比例的生活垃圾和剩余污泥联合厌氧消化是提高厌氧消化效率的有效途径。     

厌氧膜生物反应器处理垃圾渗滤液在高负荷下的连续运行性能研究

为解决常规厌氧工艺在处理垃圾渗滤液的运行过程中存在微生物流失和出水水质较差等问题,考察了浸没式平板厌氧膜生物反应器处理垃圾渗滤液的运行性能.以垃圾填埋场新鲜渗滤液为研究对象,在中温(37±1)℃条件下进行连续厌氧消化试验,容积负荷为9.5 kgCOD/(m3·d),反应器运行67 d.实验表明,在水力停留时间为10 d...     

微量金属元素对餐厨垃圾与牛粪联合厌氧消化效率影响

为了提高餐厨垃圾(FW)与牛粪(CM)联合厌氧消化效率,试验通过向批式厌氧消化体系中加入微量金属元素(Fe,Co,Ni),研究其对FW与CM联合厌氧消化性能的影响。结果表明:添加微量金属元素有利于维持系统稳定,提高产气效率。T1~T5的沼气总产量均达到4 000mL以上,较不添加微量元素处理(CK)增加55%左右,平均甲烷含量均在60%以上,较不添加微量元素处理(CK)增加20%左右。T1~T5的有机酸(VFAs)及氨氮含量变化较平稳,未出现酸累积及氨抑制现象,而CK的VFAs及氨氮含量呈现不断上升的趋势。加入微量金属元素后辅酶F420的吸光值开始上升,15 d以后吸光值稳定在0.55~0.65,而CK的吸光值呈现下降趋势。因此,添加微量金属元素是提高FW与CM联合厌氧消化效率的有效途径。     

畜禽粪便、污泥、农村垃圾中温联合厌氧消化技术研究

利用中温厌氧消化工艺,在CSTR反应器内对畜禽粪便、污水处理厂污泥及农村生活垃圾3种原料进行联合厌氧消化试验研究,重点探讨了3种原料的配比问题。结果表明,在温度为37℃,停留时间为20 d,粪便、污泥、垃圾TS之比为6∶3∶1,容积负荷为3.61 g/(L.d)的条件下,系统稳定性和处理效果都比较理想,单位VS的产气率为0.36～0.39 L/g,VS去除率为45.1%～49.4%。     

北京市餐厨垃圾产生状况及厌氧发酵产气潜力分析

随着餐饮行业的发展,越来越多的餐厨垃圾造成的污染成为我们亟待解决的问题.文章通过对北京市城区的餐馆进行实地调查,针对不同规模的餐馆,分别对其餐厨垃圾产生的数量、成分、性质及其收集处理方式、处理费用和最终用途进行了深入的调查分析;并对中国目前的管理政策进行了探讨.文章还通过批式厌氧消化实验对学校食堂的餐厨垃圾进行了产气潜力分析,结果显示在20g/L的容积污染负荷下,经过35 d的中温(35℃)消化,总产气量达到7 380 mL,总甲烷量达到4 023 mL,甲烷含量平均为54.51%,VS去除率为50%,产气率和产甲烷率分别达到369ml/g和201 ml/g,实验表明餐厨垃圾具有很好的产气性能,为进一步研究提供了理论基础.     

餐厨垃圾高温厌氧消化连续运行性能：有机物转化效率、发酵稳定性与代谢活性

在高温 (50±1)℃条件下处理实际工程的餐厨垃圾,采用全混式厌氧反应器（CSTR）进行了80 d的连续试验。试验以水力停留时间（HRT）20 d启动,HRT 15 d连续运行,研究了反应器启动和运行期间的发酵特性,解析了餐厨垃圾厌氧消化运行稳定性和代谢活性。试验结果表明,在HRT 15 d、有机负荷（OLR）为7.3 kg_COD/(m³∙d)的条件下,容积产甲烷率为2.2 L/(L∙d),挥发性固体（VS）的甲烷产率达到480 L/kg_VS左右,有机物转化率约为95%。批次试验表明,高温产甲烷菌代谢乙酸能力较强,在适宜pH下可承受10 000 mg/L的乙酸浓度。餐厨垃圾的高温降解速率快,10 d达到90%的产气,有承受更高负荷的可能。系统pH稳定在7.6 ~ 7.7,总氨氮和自由氨浓度低于抑制水平。研究结果表明,餐厨垃圾的高温厌氧消化可实现较高的产气潜力和有机物去除率,系统稳定性好且有机物转化效率高,具有应用于工程高温餐厨垃圾厌氧处理的潜力。     

水分选有机垃圾三种总固体厌氧消化产甲烷

以水分选城市生活有机垃圾(WS-OFMSW)为原料,采用35L厌氧反应器进行中温(30±2℃)批式厌氧消化,研究3种TSr分别为16.0%、13.5%和11.0%的样品对厌氧消化稳定性及性能的影响。结果表明,3种TSr均能实现稳定的产甲烷过程,pH自我恢复调节能力较强,在整个过程中没有产生挥发性脂肪酸抑制。较低的TSr有助于快速启动并缩短发酵周期,3种TSr厌氧消化分别于32、25和12d达到产气高峰。累积产甲烷量分别为273.1、283.0和313.7L·kgVS~(-1),平均甲烷浓度为64.6%、66.3%和65.7%。3种TSr厌氧消化的VS去除率分别为26.08%、35.76%和41.78%。通过该实验,获得相关的WS-OFMSW厌氧消化原始数据,为城市生活垃圾水分选技术的完善以及有机垃圾厌氧消化性能的提高指出了参考方向。     

餐厨垃圾SBMR-ASBR两相厌氧消化产气性能研究

以学校食堂餐厨垃圾为原料,考察餐厨垃圾在SBMR-ASBR反应器中产酸和产甲烷性能。结果表明:高负荷下启动酸化相有利于系统快速形成稳定的乙醇型发酵,且可以避开丙酸型发酵,在10 g/(L.d)负荷(以VS计)下,稳定状态产酸率平均达到55 000 mg/L,VFA中乙醇和乙酸分别平均稳定在27 000 mg/L和23 000mg/L,两者共占总VFA的91%;甲烷相可以稳定运行的最高负荷为5 g/(L.d)(以VS计),此时,系统整体处理能力为3.3 g/(L.d),单位容积产气率达到2.3 L/(L.d),甲烷含量在65%～70%,TS,VS去除率分别达到77%,83%。在实际工程中可以高负荷启动酸化相,有利于系统形成稳定的乙醇型发酵和高负荷运行的甲烷相。     

基于UASB反应器的厨余厌氧发酵产氢研究

针对目前厨余连续流发酵产氢处理负荷不高、产氢率较低的难题,采用UASB反应器进行厨余发酵产氢研究。在温度为30℃,进水COD浓度为2 000~10 000 mg/L,水力停留时间为2~6 h条件下,产氢速率最大达到17.04 L/(L.d)。反应器内有颗粒污泥的形成,平均生物量达到6.17 g/L,为氢气的产生提供了有利保障。当出水pH为4.2~4.4,碱度为260~340 mg/L的条件下,乙醇和乙酸占挥发酸总量的89.2%,形成稳定的乙醇型发酵类型,反应器最高处理负荷COD达到60 kg/(m3.d)。试验结果表明,UASB反应器具有更高的产氢效能和更加稳定的产氢效果,能够为厨余发酵产氢提供有利的保障。     

Biohydrogen using leachate from an industrial waste landfill as inoculum

Since hydrogen is a renewable energy source, biohydrogen has been researched in recent years. However, there is little data on hydrogen fermentation by a leachate from a waste landfill as inoculum. We investigated hydrogen production using a leachate from an industrial waste landfill in Kanagawa prefecture. The results showed no methane gas production and the leachate was a suitable inoculum for hydrogen fermentation. The maximum H₂ yield was 2.67 mol of H₂ per mol of carbohydrate added, obtained at 30 °C and initial pH 7. The acetate and butyrate production was significant when the H₂ yield was higher. The oxidation–reduction potential analysis of the culture suggested that hydrogen-producing bacteria in the leachate were facultatively anaerobic. Scanning electron microscope observations revealed hydrogen-producing bacteria comprised bacilli of about 2 μm in length.     

厨余和污泥不同混合比例碱处理产氢特性研究

以厨余垃圾和污泥为反应底物,加热预处理的污泥为发酵接种物,考察了碱处理下厨余与污泥不同混合比例的发酵产氢特性。结果表明:不同pH碱液对厨余垃圾进行预处理后,其效果以pH=13时最佳,预处理3h后SCOD和还原糖含量分别为31316.8mg/L和5.54mg/mL;碱预处理后的污泥与厨余联合发酵能够改善物料的营养平衡,缩短反应延迟时间到1h内;当厨余与污泥混和比例为5:1时为本试验最佳的试验条件,其氢气含量、比产氢速率峰值和氢产率分别为52.69%,1.73mL H_2/(h·gVS)和50.27mL H_2/gVS。     

狼尾草高底物同步糖化乙醇发酵全残留物产甲烷特性研究

以汽爆狼尾草的高底物浓度乙醇发酵全残留物为底物,进行甲烷潜力测试(BMP)以及单相全混式连续搅拌反应器(CSTR)厌氧消化实验,以验证乙醇发酵全残留物的产甲烷特性及残留物中各组分在生产清洁能源甲烷时的底物贡献率。经过50 d的BMP实验,甲烷产量最终达到884 mL,相应的甲烷产率为390.6 mL/g VS,其中纤维素和半纤维素在第10天达到产气高峰,累计产气量占全残留物累计产气量的48.2%,小分子酸和酶与酵母在第2天达到产气高峰,其产气量分别占全残留物累计产气量的22.4%和26.4%。随后使用CSTR反应器进行单相厌氧消化,有机负荷从1.5 g VS/(L·d)逐渐提升至3.5 g VS/(L·d),最终获得457.1 L/kg VS的甲烷产率和47.3%的挥发性固体(VS)去除率。结果表明:狼尾草作为一种木质纤维素原料,在获得满足工业蒸馏需求的乙醇浓度后,其发酵全残留物仍可作为良好的底物通过厌氧消化制取甲烷,不仅减少工艺的环境排放负荷,而且可提高原料的利用率。     

Viability of ultrasonication of food waste for hydrogen production

Batch anaerobic studies were conducted to study the effect of ultrasonication as a pre-treatment method for pulp waste prior to anaerobic hydrogen production. Pre-treatment was conducted by sonicating a 100 mL of pulp waste at different sonication times varying from 0.5 min to 30 min. The ultimate hydrogen production increased with increasing sonication time. The highest ultimate hydrogen production was achieved at a sonication time of 30 min and reflected an 88% increase over the unsonicated food waste, of 80 mL/g VS_added. The highest final VFAs concentration after fermentation (corresponding to 70% increase over the unsonicated food waste) was also achieved at a sonication time of 30 min. There were no significant differences between the acetate-to-butyrate ratios (HAc/HBu) for the all sonication times. The maximum hydrogen production rate at sonication time of 30 min was about 145% higher than that the unsonicated food waste.     

Effect of ammonia on biohydrogen production from food waste via anaerobic fermentation

The effect of different additive ammonia (0–10 g/l as nitrogen) on hydrogen production from the anaerobic batch mesophilic fermentation of food waste was studied at two feed-to-microorganism ratios (F/M), 3.9 and 8.0. Anaerobic sludge taken from an anaerobic digester was used as inoculum. The hydrogen yield at F/M 3.9 and 8.0 without additive ammonia was 77.2 and 51.0 ml-H₂/gVS, respectively. At F/M 3.9, the hydrogen production was enhanced by adding additive ammonia in the system when the total ammonia nitrogen (TAN) concentration was no higher than 6.0 g/l. A maximum hydrogen yield of 121.4 ml-H₂/gVS was obtained at a TAN concentration of 3.5 g/l. At F/M 8.0, the enhancement of hydrogen production was found in a narrower range of additive TAN concentrations, with a highest yield of 60.9 ml-H₂/gVS at the TAN of 1.5 g/l. Hydrogen production was inhibited at higher additive TAN concentrations for both F/M ratios. This study provides a novel strategy for controlling ammonia for production of hydrogen from food waste via anaerobic fermentation.     

Buffering and nutrient effects of white mud from ammonia–soda process on thermophilic hydrogen fermentation from food waste

Hydrogen production via anaerobic fermentation may suffer from instability or inhibition due to volatile fatty acids concentrations and inorganic elements deviations from optimality. A slight addition of white mud from ammonia–soda process (WMA) to the fermentation may show a feasible implement approach to use as buffer and inorganic nutrient. Batch tests were conducted to study the effect of the WMA addition on the hydrogen fermentation of food waste (FW) for the purpose of the maximum hydrogen yield (MHY) while achieving process stability and microbial germination through the endogenous alkalinity and inorganic elements of WMA. This was attributed to the existence of calcium, sodium, magnesium, potassium and alkali-rich materials, like calcium carbonate. 3 g of WMA addition to 200 g FW and fermentation time of 36 h resulted in obtaining the MHY of 145.4 mL H₂/g VS, with a corresponding lag-phase time of 3.0 h. Under these operating conditions, the fermentation process demonstrated one of the highest measured stability with final pH 5.3.     

Evaluation of hydrogen and methane production from municipal solid wastes with different compositions of fat,protein, cellulosic materials and the other carbohydrates

Municipal solid wastes (MSW) collected in Kyoto city were carefully separated, and the waste-type proportion in MSW was surveyed. A hydrogen/methane fermentation batch experiment was conducted under thermophilic condition using twenty different types of MSW components. Biodegradable wastes in the MSW almost consist of vegetable kitchen waste, and the characteristics of hydrogen and methane fermentation of MSW were similar to that of vegetable kitchen waste. Hydrogen production per g VS added was considerably positively correlated with easily degradable carbohydrates concentration and negatively correlated with cellulosic materials concentration. The various feedstocks could be classified into four groups according to nutrient composition (protein, fat, cellulosic materials and easily degradable carbohydrates), and the feedstocks belonging to carbohydrates rich group showed higher hydrogen yields than the other feedstocks. Rough hydrogen yield could be easily predicted by concentration of easily degradable carbohydrates.