城市有机生活垃圾溶胞处理对其厌氧消化的影响机理

由于城市有机生活垃圾成分的复杂性和厌氧消化的限速步骤的影响,导致厌氧发酵的速度比较缓慢、产气量较少和工艺不稳定等问题。文章综述了国内外有机生活垃圾的各种溶胞处理技术,如物理法、化学法、生物法及其联合处理等方法,以便改善发酵物料的性质,消除厌氧发酵的限速步骤。研究认为,通过溶胞处理能够改善有机垃圾的物理化学性质如发酵物料的溶解度、酸碱度等,提高微生物对难降解有机物的分解,增加可溶性COD和挥发性酸的浓度,优化发酵细菌的代谢途径以及产物的组成等,从而增加生物气产量,缩短水力停留时间,强化厌氧发酵过程,减轻了后续处理的负担。     

高固体厌氧消化法处理城市垃圾

简要介绍了一种新型垃圾处理方法－高固体厌氧消化法的概念、优缺点、发展历史、现状及国内外几种典型的工艺方法。     

高固体厌氧消化法处理城市垃圾

简要介绍了一种新型垃圾处理方法──高固体厌氧消化法的概念、优缺点、发展历史、现状及国内外几种典型的工艺方法。     

温度对厨余垃圾高温厌氧消化及微生物群落的影响

使用全混流反应器(CSTR),研究53℃和60℃条件下厨余垃圾的处理效果,同时利用T-RFLP(末端限制性片段长度多态性)以及16S rRNA基因克隆文库的方法,对微生物群落结构进行跟踪解析.结果表明,在温度为53℃、挥发性总固体(VTS)负荷为4 g L-1 d-1时,处理性能稳定,有机酸积累少,产气率约为900 mL/g VTS;当温度升高至60℃时,TOC和有机酸积累,产气率显著下降.微生物群落分析结果表明,当温度从53℃升高至60℃后,细菌群落从以发酵产酸菌群为主转变为以各类发酵菌和有机酸氧化菌为主,产甲烷菌群落中乙酸营养型产甲烷菌比例下降,而氢营养型产甲烷菌比例升高.运行温度从53℃升高至60℃后厌氧处理能力下降的主要原因是乙酸营养型产甲烷菌比例下降,乙酸的消耗需要通过乙酸氧化菌和氢营养型的产甲烷菌的协同作用,产甲烷速率降低,从而导致处理能力下降.图3表3参50     

油脂去除对餐厨垃圾压滤液厌氧消化的影响

采用常温（25℃）厌氧消化工艺,通过设计两种不同的进料浓度和4个处理方式,研究了油脂的去除对餐厨垃圾压滤液厌氧消化产沼气的影响,并考察了消化过程中典型工艺参数pH值、挥发性脂肪酸（VFA）、CODCr、总磷等的变化规律.试验结果表明油脂对餐厨垃圾压滤液厌氧消化的产气前期有一定的抑制作用,但是整体抑制不明显.处理T1（未隔油餐厨垃圾滤液800 mL）、T2（隔油餐厨垃圾滤液800 mL）、T3（未隔油餐厨垃圾滤液500 mL）、T4（隔油餐厨垃圾滤液500 mL）的产气总量分别为：84357、55539、45031和31033 mL,其中T1的产气总量是T2的1.52倍;T3的产气总量是T4的1.45倍,结果表明餐厨垃圾滤液不需要经过隔油处理而直接可以用于厌氧消化产沼气.同时,当压滤液低浓度（T3、T4）时,产气差异小;高浓度（T1、T2）时,产气差异大.此外,在整个厌氧消化过程中,处理T1、T2、T3和T4的CODCr总去除率分别为80.44%、78.53%、79.67%和80.7%.     

牛粪和厨余垃圾联合厌氧消化试验

在37℃条件下对不同比例的牛粪和厨余垃圾进行为期50d的联合厌氧消化试验.结果表明:(1)牛粪与厨余垃圾质量比2/1和1/2联合厌氧消化的实际产气潜能为0.66和0.71L·g-1(以挥发性固体VS质量计),比加权计算值分别提高50%和29%;(2)4种比例物料的甲烷平均浓度约为50%～55%,其生物能范围为18.92～20.81MJ·m-3;(3)在联合厌氧消化过程中,牛粪和厨余垃圾质量比1/2物料的产气效率最高,反应前10d的产气量占总产气量的55.4%,前20d产气量占总产气量的92.2%;(4)纯牛粪、牛粪和厨余垃圾质量比2/1、牛粪和厨余垃圾质量比1/2及纯厨余垃圾4种比例物料厌氧消化的最终生物降解率分别为46.99%、53.31%、70.12%和66.25%.     

温度对填埋垃圾渗滤液特征的影响

温度对填埋场有机垃圾的厌氧降解具有十分重要的影响,因而对填埋场渗滤液特征也产生重要的影响。文章通过在常温及29~45℃范围内设置的6个不同温度下的模拟垃圾柱降解对照试验,分析研究了温度对填埋有机垃圾渗滤液特征的影响。结果表明,在垃圾降解适宜的温度范围(29~45℃)内,较高的温度对渗滤液COD衰减具有较大的促进作用,而保持恒定的温度比升高温度对渗滤液COD衰减的影响更加显著,但温度对垃圾降解渗滤液中氨氮影响并不明显。     

城市生活垃圾生命周期管理

生命周期评价是一种全面的环境管理工具,具有潜在的发展前景。０它通过对产品,产品系统,工艺活动整个生命周期的环境影响环境改善的机会进行评价。根据国际环境毒理与化学学会１９９３年和ＩＳＯ１４０００环境管理体系中关于生命周期评价的技术框架,本文应生命周期评价在城市生产垃圾管理系统中的作用及管理系统的清单分析,影响评价和改善评价进行研究。     

洛阳市城市生活垃圾成份分析

对洛阳市城市生活垃圾按季节进行了分类，分析了垃圾中碳、硫、挥发分、灰分及水分的含量，测定了垃圾发热量及部分化学元素的含量，为城市生活垃圾的处理提供了科学数据。     

添加剂对污泥厌氧消化性能的影响

在间歇培养条件下,研究了还原型辅酶Ⅱ（NADPH）、乙酰辅酶A（Acetyl Co A）和对氨基苯甲酸（PABA）3种添加剂对污泥厌氧消化性能的影响.结果表明,3种微生物活性促进剂均能促进污泥厌氧消化产气.其中,NADPH的促进效果最为显著,消化第35 d,产甲烷量比对照组高15.90%.在污泥含固率为3%、未调初始pH（pH=6.7）和温度35℃的厌氧消化条件下,NADPH的最佳添加量为50 mg.L-1,消化第36 d,污泥累积产甲烷量127.13 mL.g-1VSS.在含固率3%、初始pH=8.5、温度55℃和NADPH添加量为50 mg.L-1的工艺条件下,污泥厌氧产气效果最佳,消化第30 d时累积产甲烷量达158.02 mL.g-1VSS.     

城市有机生活垃圾厌氧发酵处理研究

在适当的PH值和搅拌条件下，研究了反应温度、总固体含量、pH值、碳氮比、碳磷比以及接种物量对有机牛活垃圾厌氧发酵产沼气的影响。实验结果表明：有机生活垃圾厌氧消化产沼气的适宜条件是：反应温度50～55℃，总固体含量23％～28％，pH=6．8～7．4，w(C)／w（N)=(20～30)，w(C)／w(P)=50，60％～75％的生物气，可实现能量回收；发酵剩余物可制有机肥，时间为15～20d。接种物量为25％～30％。在厌氧的条件下，可以制取含甲烷实现物质再利用。有机生活垃圾在厌氧消化反应器的停留时间为15～20d。     

Increasing the performance of anaerobic digestion: Pilot scale experimental study for thermal hydrolysis of mixed sludge

The performance of a pilot plant operation combining thermal hydrolysis (170°C, 30 min) and anaerobic digestion (AD) was studied, determining the main properties for samples of fresh mixed sludge, hydrolyzed sludge, and digested sludge, in order to quantify the thermal pretreatment performance (disintegration, solubilisation, and dewaterability) and its impact on the anaerobic digestion performance (biodegradability, volatile solids reduction, and digester rheology) and end product characteristics (dewaterability, sanitation, organic and nitrogen content). The disintegration achieved during the thermal treatment enhances the sludge centrifugation, allowing a 70% higher total solids concentration in the feed to anaerobic digestion. The digestion of this sludge generates 40% more biogas in half the time, due to the higher solids removal compared to a conventional digester. The waste generated can be dewatered by centrifugation to 7% dry solids without polymer addition, and is pathogen free.     

Degradation of polyacrylamide (PAM) and methane production by mesophilic and thermophilic anaerobic digestion: Effect of temperature and concentration

• PAM degradation in thermophilic AD in comparison with mesophilic AD. • PAM degradation and its impact on thermophilic and mesophilic AD. • Enhanced methane yield in presence of PAM during thermophilic and mesophilic AD. • PAM degradation and microbial community analysis in thermophilic and mesophilic AD. Polyacrylamide (PAM) is generally employed in wastewater treatment processes such as sludge dewatering and therefore exists in the sludge. Furthermore, it degrades slowly and can deteriorate methane yield during anaerobic digestion (AD). The impact or fate of PAM in AD under thermophilic conditions is still unclear. This study mainly focuses on PAM degradation and enhanced methane production from PAM-added sludge during 15 days of thermophilic (55°C) AD compared to mesophilic (35°C) AD. Sludge and PAM dose from 10 to 50 g/kg TSS were used. The results showed that PAM degraded by 76% to 78% with acrylamide (AM) content of 0.2 to 3.3 mg/L in thermophilic AD. However, it degraded only 27% to 30% with AM content of 0.5 to 7.2 mg/L in mesophilic AD. The methane yield was almost 230 to 238.4 mL/g VSS on the 8th day in thermophilic AD but was 115.2 to 128.6 mL/g VSS in mesophilic AD. Mechanism investigation revealed that thermophilic AD with continuous stirring not only enhanced PAM degradation but also boosted the organics release from the sludge with added PAM and gave higher methane yield than mesophilic AD.     

Fates and partitioning of heavy metals in municipal solid waste incineration process

The fate and partitioning of heavy metals (including Hg, Cd, Pb, Zn, As, Cr, Ni, and Cu) from MSW incinerators located in Taiwan were determined. Results of stack sampling indicate that most Hg and As (more than 80%) exists in the gas phase while other metals partition differently among bottom ash, fly ash, and flue gases. Removal efficiencies of existing air pollution control devices for Hg and As are lower (about 70%) than other metals. Bottom ash contains higher concentration of Cd compared with European incinerators. In addition, strong enrichment of Cd on fly ash particles is observed.     

Roles of acid-producing bacteria in anaerobic digestion of waste activated sludge

Three acid-producing strains, AFB-1, AFB-2 and AFB-3, were isolated during this study, and their roles in anaerobic digestion of waste activated sludge (WAS) were evaluated. Data of 16S rRNA method showed that AFB-1 and AFB-2 were Bacillus coagulans, and AFB-3 was Escherichia coli. The removal in terms of volatile solids (VS) and total chemical oxygen demand (TCOD) was maximized at 42.7% and 44.7% by inoculating Bacillus coagulans AFB-1. Besides, the optimal inoculum concentration of Bacillus coagulans AFB-1 was 30% (v/v). Solubilization degree experiments indicated that solubilization ratios (SR) of WAS reached 20.8%±2.2%, 17.7%±1.48%, and 11.1%±1.53%. Volatile fatty acids (VFAs) concentrations and compositions were also explored with a gas chromatograph. The results showed that VFAs improved by 98.5%, 53.0% and 11.6% than those of the control, respectively. Biochemical methane potential (BMP) experiments revealed that biogas production increased by 90.7% and 75.3% when inoculating with Bacillus coagulans AFB-1 and AFB-2. These results confirmed that the isolated acid-producing bacteria, especially Bacillus coagulans, was a good candidate for anaerobic digestion of WAS.

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厌氧折流板反应器(ABR)处理柠檬黄模拟废水的效果及产物分析

采用厌氧折流板反应器(ABR)处理柠檬黄模拟废水,研究在不同水力停留时间(HRT)下,ABR对柠檬黄及COD的去除效果,实验结果表明,HRT为30 h时,柠檬黄经ABR厌氧处理后的去除率达96.4%,COD去除率达97.9%.同时利用红外光谱、UV-Vis、离子色谱分析柠檬黄的降解产物.从红外光谱和UV-Vis分析得出,柠檬黄经ABR厌氧处理后偶氮键断裂,生成的芳香胺类化合物被进一步降解为含苯环、含萘环的化合物;离子色谱定性分析得出柠檬黄分子中的磺酸基转化成了硫酸根.     

Influencing mechanism of high solid concentration on anaerobic mono-digestion of sewage sludge without agitation

High-solids anaerobic digestion of sewage sludge was a promising process, but high solid concentration negatively influenced methane production. The influencing mechanism was systematically analyzed in this study through a series of static anaerobic digestion experiments at total solids (TS) contents of 3%–15%. The results showed that TS 6% was the boundary between low-solids and high-solids anaerobic digestion, and the accumulative methane yield decreased exponentially when TS increased from 6% to 15%. The performance of anaerobic digestion was directly determined by the efficiency of mass transfer, and the relation between methane yield and sludge diffusive coefficients was well described by a power function. Thus, the increasing TS resulted in an exponential increase in sludge viscosity but an exponential decrease in diffusive coefficient. The blocked mass transfer led to the accumulation of volatile fatty acids (VFAs) and free ammonia. Acetic metabolism was the main process, whereas butyric and propionic metabolisms occurred at the initial stage of high-solids anaerobic digestion. The concentration of VFAs reached the maximum at the initial stage, which were still lower than the threshold influencing methanogens. The concentration of free ammonia increased gradually, and the methanogenesis was inhibited when free ammonia nitrogen exceeded 50 mg·L⁻¹. Consequently, the deterioration of high-solids anaerobic digestion was related to the blocked mass transfer and the resulting ammonia accumulation.