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。     

剩余污泥与生活有机垃圾联合厌氧消化产沼气研究

以污水处理厂剩余污泥和生活垃圾为发酵原料,研究了不同原料配比对厌氧消化过程及消化效率的影响。结果表明,剩余污泥和生活垃圾联合厌氧发酵可以提高垃圾的消化效率,当剩余污泥和生活垃圾TS比为1∶4时厌氧消化效果最好,经过66 d消化后,COD去除率为59.79%,TS去除率为56.92%,VS去除率为66.87%。     

TS对牛粪与有机垃圾联合厌氧消化特性的影响研究

在中温(37℃)条件下,对牛粪和有机垃圾进行了为期90 d的连续式厌氧消化试验研究。结果表明:在CSTR厌氧发酵反应器中,牛粪与有机垃圾等比例连续式联合厌氧发酵,当系统水力停留时间低于12.5 d,且TS含量高于16.89%时,系统反应条件开始受到限制,TS含量越高,反应受限程度越大;反应末期pH下降,主要因为末期TS含量增高,系统有机负荷增加,厌氧消化反应无法正常进行,导致挥发酸积累;TS含量为15%是系统最佳的固体浓度,产气效率最高;挥发性脂肪酸(VFA),COD在一定时候均会达到饱和状态,使得反应高效率进行,而NH3-N成为制约因素,含量随着物料的添加一直升高,最终导致消化系统氨中毒,使得反应无法进行。     

有机垃圾高温厌氧消化中试验研究

采用高温厌氧消化处理方法对城市生活有机垃圾进行了中试试验研究.其有机垃圾产气量73.4m3/t,产气速率0.52m3/m3.d,COD去除率48.8%.结果表明,高温厌氧消化处理是城市生活有机垃圾较好的处理方式之一.有机垃圾不仅可以得到处理,最大限度地减少其污染环境;同时,还可以产生一定的经济效益和巨大的环境效益.这种垃圾处理方式值得应用和推广.     

不同预处理剩余污泥的中温厌氧消化试验研究

设计单因素试验,考察了热处理时间和碱投加量对剩余污泥有机质溶出和厌氧消化产沼气的影响。结果表明:加热和碱预处理均可明显地促进有机质溶解和提高厌氧产气效率;与原污泥相比,高温处理20 min后,剩余污泥可溶性有机质和累积厌氧产气量达到最高,分别为2 550 mg/kg和3 275.33 mL,较对照污泥分别增加了7.4倍和34.15%;高浓度CaO(6%和10%)处理后,剩余污泥中STOC浓度分别达到3 280 mg/kg和3 340mg/kg,较对照污泥STOC浓度(305 mg/kg)提高了9.75和9.95倍;CaO预处理对污泥厌氧消化影响较复杂,表现为低浓度促进产气和高浓度抑制产气;2%CaO处理下,累积产气量比对照提高了39.87%;6%和10%CaO处理下,累积产气量低于对照污泥。     

好氧预处理对沈阳市城市生物有机垃圾厌氧消化的影响

以沈阳市生物有机垃圾和秸秆（质量比10：1）为原料,先对物料进行为期一周的好氧堆肥,然后进行50d的中温（37℃）厌氧消化;为进行实验对照,未处理的原料直接进行厌氧消化。实验结果表明：消化初期,预处理物料的pH值高于未处理的物料;两者所产沼气的甲烷平均含量相同,均为65．2％（v／v）;在厌氧消化的前30d内．预处理物料的产气速度比未处理物料的产气速度快了近10％;两者的挥发性有机物生物降解率非常相似,预处理约为59．6％,未处理为60％。     

进料浓度和水力停留时间对分类有机垃圾厌氧消化性能的影响

针对分类有机垃圾在高含固率条件下厌氧消化时存在的负荷高、易酸化等问题,文章提出了通过延长水力停留时间（HRT）来调节有机负荷率的方法,研究了不同进料浓度和HRT组合条件下分类有机垃圾的厌氧消化性能。研究结果表明：在不同进料浓度和HRT组合下,分类有机垃圾厌氧消化的产气性能无显著差异,单位挥发性固体（VS）产甲烷率为300～330 mL/（g·d）,甲烷含量可达到56%;VS降解率均能达到70%以上,实现了有机物的高效降解;厌氧消化系统稳定性良好,各项指标均在合理范围内。     

我国城市生活垃圾厌氧消化处理的探讨

分析了我国城市生活垃圾处理现状及存在问题，探讨了以厌氧消化技术为主的城市生活垃圾处理方式，为解决我国的城市生活垃圾问题提供参考。     

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)。     

果蔬废弃物与剩余污泥协同厌氧消化特性研究

为了提升污泥的厌氧消化效率,文章从改善原料碳氮比入手,在温度为35℃,挥发性固体(VS)浓度为4%条件下,将果蔬废弃物与污泥按不同VS比例复配,并进行协同厌氧消化产甲烷潜力实验。实验结果表明:在厌氧消化过程中,不同配比实验组的pH值、氨氮浓度和挥发性脂肪酸浓度均在适宜的范围内;不同配比实验组的累积产甲烷量由高到低依次为6∶4,5∶5,4∶6,3∶7,8∶2,7∶3,2∶8,1∶9和9∶1,其分别比纯污泥组提高了516%,485%,430%,360%,335%,330%,290%,144%和-64%。通过Gomperzt修正方程拟合发现,果蔬废弃物与污泥协同厌氧消化的最佳VS配比为6∶4,此时体系的单位VS理论甲烷产率和单位VS最大甲烷日产量分别为114.05mL/g和14.61 mL/(g·d),分别比纯污泥组提高了422%和353%。     

混合比对市政污泥与餐厨垃圾二级高温共消化的影响

研究不同混合比下市政污泥与餐厨垃圾二级高温共消化的情况。实验分别采用污泥与餐厨TS之比为3∶1,4∶1,5∶1的3种混合比,主要考查了混合比对二级反应罐的影响。研究表明,不同的混合比对各反应罐达到稳定时出料的COD浓度、VS的含量及其去除率、日产气量以及产气中甲烷含量等都有一定的影响,混合比为3∶1,4∶1,5∶1的反应罐稳定时出料的COD浓度分别为13 500,10 000,23 000mg/L,混合比为4∶1时,出料COD浓度最低。稳定时VS的含量随着混合比的增加而升高,分别为0.034 7,0.039 6,0.045 6g/g物料,VS的去除率分别为42.8%,26.7%,5.2%;稳定时各反应罐的日产气量随着混合比的升高而降低,分别为12 000,5 500,4 500mL,产气中甲烷含量分别为92.49%,91.55%,88.69%。     

Enhanced methane fermentation of municipal sewage sludge by microbial electrochemical systems integrated with anaerobic digestion

Sewage sludge from a municipal wastewater treatment plant was fed into a microbial electrochemical system, combined with an anaerobic digester (MES-AD), for enhanced methane production and sludge stabilization. The effect of thermally pretreating the sewage sludge on MES-AD performance was investigated. These results were compared to those obtained from control operations, in which the sludge was not pretreated or MES integration was absent. The soluble chemical oxygen demand (SCOD) in the raw sewage sludge after pretreatment was 31% higher than the SCOD in untreated sludge (5804.85 mg/L vs. 4441.46 mg/mL). The methane yield and proportion of methane in biogas generated by the MES-AD were higher than those of the control systems, regardless of the pretreatment process. The maximum methane yield (0.28 L CH₄/g COD) and methane production (1139 mL) were obtained with the MES inoculated with pretreated sewage sludge. Methane yield and production with this system using pretreated sewage were 47% and 56% higher, respectively, than those of the control (0.19 L CH₄/g COD, 730 mL). Additionally, the maximum SCOD removal (89%) and current generation were obtained with the MES inoculated with a pretreated substrate. These results suggested that sewage sludge could be efficiently stabilized with enhanced methane production by synergistic combination of MES-AD system with pretreatment process.     

超声波促进污泥厌氧消化的研究

介绍了超声波的作用机理，指出在污泥厌氧消化过程中，污泥水解是限速步骤，在厌氧消化前，对污泥进行超声波破解预处理，促使细胞壁破裂，细胞内含物溶出，可以加速污泥的水解过程，从而达到缩短消化时间，减少消化池容积，提高沼气产量的目的。     

Heat and energy requirements in thermophilic anaerobic sludge digestion

The heating requirements of the thermophilic anaerobic digestion process were studied. Biogas production was studied in laboratory experiments at retention times from 1 to 10 days. The data gathered in the experiments was then used to perform a heat and energy analysis. The source of heat was a conventional CHP unit system. The results showed that thermophilic digestion is much faster than mesophilic digestion and therefore produces more biogas in a shorter time or at smaller digester volumes. The major part of the heating requirements consisted of sludge heating. The heat losses of the digester were only 2–8% of the sludge heating requirements. The heating requirements in thermophilic digestion are about twice those of mesophilic digestion. Therefore a CHP unit system cannot cover all of the needs for successful operation of thermophilic digestion. Heat regeneration was introduced as a solution. Heat is regenerated from the sludge outflow at a temperature of 50–55 °C and transferred to the cold inflow sludge at a temperature of 11 °C. Enough heat is regenerated in a conventional counter flow heat exchanger to bring the thermophilic process to the same level as the mesophilic one. Considering the smaller digester volumes and the relatively small investment in the regenerative equipment, the construction of thermophilic digestion systems may be a very good alternative to conventional mesophilic sludge digestion systems.     

Effects of solid retention time on anaerobic digestion of dewatered-sewage sludge in mesophilic and thermophilic conditions

Anaerobic digestion of dewatered-sewage sludge using continuous stirred tank reactors (CSTRs) in duplicates was evaluated under thermophilic (50 °C) and mesophilic (37 °C) conditions over a range of nine solid retention times (SRTs). The 35- and 30-day SRTs were designed to simulate a full-scale plant operation while 25-, 20-, 15- and 12-day SRTs were planned to evaluate process performance at the various SRTs. The 9-, 5- and 3-day SRTs were performed to push the reactors to extend their degradation capacity and test the threshold for process imbalance. The corresponding organic loading rates (OLR) varied from 1.6 to 20.5 kg VS m^?3 day^?1. Biogas production rate could be tripled when the SRT was shortened from 30 to 12 days and more than doubled from 35- to 15-day SRT because of a concomitant increase in OLR. In general, higher biogas productivity was realized under thermophilic, but methane yields were comparable due to the higher methane content in the biogas under mesophilic digestion. The methane content in biogas fluctuated between 55 and 65% and the methane yield ranged from 0.314 to 0.348 Nm³ CH₄ kg VS_added^?1 day^?1 for both thermophilic and mesophilic digestion. The VS-reduction at 12- and 15-day SRT ranged from 45 to 52% and there was no accumulation of VFAs. Increasing concentrations of VFAs, decreasing concentration of partial alkalinity and decrease in pH were noted as signs of reactor instability. Process imbalance started at 9-day SRT, souring of the reactors, cell wash-out and foaming was noted as the principal causes of process failure under both thermophilic and mesophilic conditions. This study projected the possibility of using CSTRs in treating dewatered-sewage sludge at a shorter SRT to achieve reasonable biogas production and VS-reduction without encountering adverse operation conditions as foaming and wash-out of cells.     

Principles and potential of the anaerobic digestion of waste-activated sludge

When treating municipal wastewater, the disposal of sludge is a problem of growing importance, representing up to 50% of the current operating costs of a wastewater treatment plant. Although different disposal routes are possible, anaerobic digestion plays an important role for its abilities to further transform organic matter into biogas (60–70 vol% of methane, CH₄), as thereby it also reduces the amount of final sludge solids for disposal whilst destroying most of the pathogens present in the sludge and limiting odour problems associated with residual putrescible matter. Anaerobic digestion thus optimises WWTP costs, its environmental footprint and is considered a major and essential part of a modern WWTP. The potential of using the biogas as energy source has long been widely recognised and current techniques are being developed to upgrade quality and to enhance energy use. The present paper extensively reviews the principles of anaerobic digestion, the process parameters and their interaction, the design methods, the biogas utilisation, the possible problems and potential pro-active cures, and the recent developments to reduce the impact of the problems. After having reviewed the basic principles and techniques of the anaerobic digestion process, modelling concepts will be assessed to delineate the dominant parameters. Hydrolysis is recognised as rate-limiting step in the complex digestion process. The microbiology of anaerobic digestion is complex and delicate, involving several bacterial groups, each of them having their own optimum working conditions. As will be shown, these groups are sensitive to and possibly inhibited by several process parameters such as pH, alkalinity, concentration of free ammonia, hydrogen, sodium, potassium, heavy metals, volatile fatty acids and others. To accelerate the digestion and enhance the production of biogas, various pre-treatments can be used to improve the rate-limiting hydrolysis. These treatments include mechanical, thermal, chemical and biological interventions to the feedstock. All pre-treatments result in a lysis or disintegration of sludge cells, thus releasing and solubilising intracellular material into the water phase and transforming refractory organic material into biodegradable species. Possible techniques to upgrade the biogas formed by removing CO₂, H₂S and excess moisture will be summarised. Special attention will be paid to the problems associated with siloxanes (SX) possibly present in the sludge and biogas, together with the techniques to either reduce their concentration in sludge by preventive actions such as peroxidation, or eliminate the SX from the biogas by adsorption or other techniques. The reader will finally be guided to extensive publications concerning the operation, control, maintenance and troubleshooting of anaerobic digestion plants.     

氨化预处理玉米秸秆与餐厨垃圾混合两相厌氧消化性能研究

研究了玉米秸秆与餐厨垃圾混合两相厌氧消化性能。秸秆与餐厨垃圾混合比例(TS/TS)分别为4∶1,3∶1,2∶1,1∶1,1∶2,1∶3,1∶4,分别进行氨化预处理和未预处理两相对比试验。结果表明:酸化阶段的水解酸化类型以混合型为主,预处理组的产酸总量和溶解性COD分别比未预处理组高了3.1%~25.4%和3.0%~27.6%,预处理组中混合比例1∶4条件下产酸最高,达到9 044.2 mg/L。在产甲烷阶段,预处理组和未预处理组最高累积产气量分别为16 305 mL和14 615 mL。随着秸秆含量逐渐增加,预处理组T90比未预处理组提前2 d。氨化预处理秸秆对秸秆与餐厨混合两相厌氧消化起到促进作用。