剩余污泥处置的减量化发展方向

当今世界上应用最广泛的三类剩余污泥处置方法（土地利用，填埋和焚烧）都存在各自的不足，可将污水处理作为生产过程看待，运用“清洁生产”的理念从源头治理，使剩余污泥的处置朝着减量化的方向发展，并指出了今后剩余污泥处置的优先顺序应为减量化，资源化、无害化。     

剩余污泥资源化利用技术研究进展

介绍了剩余污泥处理处置的现状,梳理了国内外剩余污泥资源化方法,包括制备建筑材料、能源利用、制备吸附材料、土地利用、制备微生物絮凝剂等技术。在综合了国内外剩余污泥资源化利用技术的基础上,提出了剩余污泥的应用前景。     

微氧颗粒污泥强化剩余污泥与餐厨垃圾协同消化

为确定剩余污泥高效消化的有效方式,采用不接种颗粒污泥(NOGS)和接种颗粒污泥(GS)的EGSB反应器处理含固率为10%的剩余污泥。在27～33℃的中温条件下,当回流量为10 L/h、液体上升流速为1. 5 m/h、消化时间为21 d时,对比NOGS-EGSB厌氧消化剩余污泥、GSEGSB厌氧消化剩余污泥、GS-EGSB厌氧消化热水解(90℃、45 min)的剩余污泥(+后期微氧)和GS-EGSB微氧消化剩余污泥(+后期餐厨垃圾协同消化)的运行效果。结果表明,EGSB反应器中回流形成的适度搅拌能强化对剩余污泥的处理。高活性颗粒污泥内丰富的微生物菌群的集群协同作用保证了对剩余污泥的高效处理效果。热水解能够强化剩余污泥中微生物的溶胞效果,提高微生物细胞中有机物的溶出率,但微氧曝气对溶出后有机物的降解更有效。微氧EGSB反应器能够高效处理剩余污泥,少量餐厨垃圾的加入能够促进剩余污泥的消化。高活性颗粒污泥、微氧曝气、餐厨垃圾协同消化是EGSB反应器高效处理剩余污泥的关键因子。     

化工生化剩余污泥稳定化研究

化工企业在生产过程中不可避免地产生大量生化剩余污泥,相较于市政剩余污泥,此类污泥含有更多的有机物,更加难处理。为此,利用自主研发的剩余污泥稳定化处理技术,对华南某化工厂的生化剩余污泥开展工业侧线试验,取得了较好的效果。在稳定剂/MLVSS=0.70、反应温度为175℃、反应时间为2 h的最佳处理条件下,化工生化剩余污泥的稳定化率可达到66%以上,减量率达到98.9%以上,泥饼含水率在60%以下;污泥脱水液pH呈中性,BOD5/COD在0.3以上,属于易生化处理的污水,且该股水量较少,可直接送至污水厂进行处理。     

剩余污泥生态稳定化技术研究

剩余污泥的处理与处置已经引起广泛关注,但现行技术的高投资和运行费用又限制了该问题的彻底解决。本文提出了污泥的生态稳定法,利用人工湿地技术对污泥进行稳定化、无害化处理,并兼对渗滤液进行处理。初步试验结果表明,对剩余污泥进行生态稳定化处理在技术上可行。     

冷冻预处理对剩余污泥性质的影响研究

为了提高污泥的有机物溶出率,以利于后续生物处理,采用冻/融技术对城市污水厂的剩余污泥进行预处理,考查了冷冻时间对污泥理化特性的影响。结果表明,冻/融处理可以破解污泥,将固体物质转化为液相成分。随着冷冻时间的增加,污泥pH值下降,SCOD和碱度上升;冷冻污泥的SS和VSS值与冷冻时间相关。粒径分布和微观结构观察也证实了污泥絮体已被破坏。与混合污泥(初沉污泥+剩余污泥)相比,剩余污泥粒径分布的变化更加显著。剩余污泥和混合污泥经过冻/融(72h/3h)处理后,有机物溶出效果较好,污泥的物理特性也得到了改变。     

低温热水解提高污泥厌氧消化性能的研究

先将剩余污泥进行低温热水解预处理,其后测定生物化学甲烷势（BMP）来研究热水解对剩余污泥厌氧消化性能的影响。结果表明：污水厂剩余污泥经低温热水解处理可使污泥固体溶解和水解,从而提高剩余污泥厌氧消化性能。最适宜的热水解条件为70℃,24 h,此时剩余污泥TCOD去除率由18％提高到30％,热水解处理后沼气产量提高63％。     

超声及碱处理促进剩余污泥水解的试验研究

剩余污泥水解是解决污水处理厂生物脱氮除磷的碳源不足和实现污泥资源化的重要途径。采用3个平行反应器,在35℃、厌氧条件下研究了剩余污泥以及经过超声预处理和碱处理(pH=10±0.1)的剩余污泥的水解过程。结果表明:超声预处理以及碱处理均能促进剩余污泥的水解,它们对污泥的平均比降解速率较原污泥可分别提高39.4%和93.9%,SCOD的平均溶出速率可分别提高92.9%和150.4%。另外,碱处理后水解对剩余污泥的降解比超声预处理的更快、更彻底。根据污泥比降解速率、SCOD溶出速率以及营养物释放速率大小,可认为水解过程分多阶段进行,其中污泥比降解和SCOD溶出速率在第Ⅰ阶段(0～2d)最大,磷释放速率在第Ⅱ阶段(4～6d)最大。透射电镜扫描结果表明:剩余污泥水解的次序为EPS、胞内物质、细胞壁。     

污泥处理处置技术及其存在问题初探

阐明了污泥处理处置对污水处理厂、人类生活环境的重要性。介绍了传统处理处置技术的优缺点,分析了制约我国污泥处理处置技术的三大因素,对污泥处理处置技术未来的发展和资源化利用进行了简单的展望,认为只有解决了三大制约因素并引入清洁生产的概念,污泥才能真正走上减量化、无害化、资源化的道路。     

常温下剩余污泥水解酸化强化方法研究进展

剩余污泥的处理与处置是污水处理的重要环节,常温下对剩余污泥直接破解以促进水解酸化是污泥处理的有效方法,这种方法无需污泥脱水,而且能提高污泥絮体的降解率,并实现资源化利用.但这种方法存在投资大、运行费用高和难以稳定控制等问题,尚未实现大规模的工程应用.对目前研究较多的污泥机械处理、酸碱处理、超声破解和臭氧氧化等技术的作用原理、处理效果和应用前景进行了综述和分析,并提出了多种技术的组合是提高污泥处理效率的最有效方法.     

Investigation of bacterial community in activated sludge with an anaerobic side-stream reactor (ASSR) to decrease the generation of excess sludge

The goal of this study was to investigate the bacterial community in activated sludge with an anaerobic side-stream reactor (ASSR), a process permitting significant decrease in sludge production during wastewater treatment. The study operated five activated sludge systems with different sludge treatment schemes serving as various controls for the activated sludge with ASSR. Bacterial communities were analyzed by denaturing gradient gel electrophoresis (DGGE), sequencing and construction of phylogenetic relationships of the identified bacteria. The DGGE data showed that activated sludge incorporating ASSR contained higher diversity of bacteria, resulting from long solids retention time and recirculation of sludge under aerobic and anaerobic conditions. The similarity of DGGE profiles between ASSR and separate anaerobic digester (control) was high indicating that ASSR is primarily related to conventional anaerobic digesters. Nevertheless, there was also unique bacteria community appearing in ASSR. Interestingly, sludge in the main system and in ASSR showed considerably different bacterial composition indicating that ASSR allowed enriching its own bacterial community different than that from the aeration basin, although two reactors were connected via sludge recirculation. In activated sludge with ASSR, sequences represented by predominant DGGE bands were affiliated with Proteobacteria. The remaining groups were composed of Spirochaetes, Clostridiales, Chloroflexi, and Actinobacteria. Their putative role in the activated sludge with ASSR is also discussed in this study.     

Production of polyhydroxyalkanoates (PHA) by activated sludge treating municipal wastewater: effect of pH,sludge retention time (SRT), and acetate concentration in influent

In this paper, the production of biodegradable plastics polyhydroxyalkanoates (PHA) by activated sludge treating municipal wastewater was investigated. The effect of three operational factors, i.e. the acetate concentration in influent, pH, and sludge retention time (SRT) were studied. Sludge acclimatized with municipal wastewater supplemented with acetate could accumulate PHA up to 30% of sludge dry weight, while sludge acclimatized with only municipal wastewater achieved 20% of sludge dry weight. It was found that activated sludge with an SRT of 3 days possessed better PHA production capability than sludge with an SRT of 10 days. Sludge acclimatized under pH 7 and 8 conditions in sequencing batch reactors (SBRs) exhibited similar PHA production capability. However, in PHA production batch experiments, pH value influenced significantly the PHA accumulation behavior of activated sludge. When pH of batch experiments was controlled at 6 or 7, a very low PHA production was observed. The production of PHA was stimulated when pH was kept at 8 or 9.     

Biological hydrolysis and acidification of sludge under anaerobic conditions: the effect of sludge type and origin on the production and composition of volatile fatty acids

New wastewater treatment processes resulting in considerably reduced sludge production and more effective treatment are needed. This is due to the more stringent legislations controlling discharges of wastewater treatment plants (WWTPs) and existing problems such as high sludge production. In this study, the feasibility of implementing biological hydrolysis and acidification process on different types of municipal sludge was investigated by batch and semi-continuous experiments. The municipal sludge originated from six major treatment plants located in Denmark were used. The results showed that fermentation of primary sludge produced the highest amount of volatile fatty acids (VFAs) and generated significantly higher COD- and VFA-yields compared to the other sludge types regardless of which WWTP the sludge originated from. Fermentation of activated and primary sludge resulted in 1.9-5.6% and 8.1-12.6% COD-yields, soluble COD (SCOD)/total COD (TCOD), in batch experiments, respectively. The COD-yields for primary, activated and mixed sludge were 19.1%, 6.5% and 21.37%, respectively, in semi-continuous experiments operated at solids retention time (SRT) of 5d and temperature of 37 degrees C. The benefit of fermentation for full-scale application was roughly estimated based on the experiments performed in semi-continuous reactors. The results revealed that even though the VFA production of primary sludge was higher compared to activated sludge, substantial amounts of VFA could be produced by fermentation of activated sludge due to the substantially higher production of activated sludge in WWTPs.     

城市污水处理厂剩余污泥厌氧消化试验研究

以北京市某污水处理厂的剩余污泥为研究对象，对该污泥的理论产气量进行了估算，考察了投加接种污泥和未投加接种污泥条件下污泥厌氧消化的产气情况，并分析了污泥消化前、后的泥质特点。结果表明：与未接种条件相比，污泥厌氧消化前采用投加接种污泥的方式可大大促进消化反应的进行，加快污泥的产气速率，使厌氧消化周期缩短近1／4，但对污泥的总产气量影响较小；在厌氧消化正常运行条件下，污泥产气量达到总产气量的90％时所需反应时间约为16d，可将其作为污泥厌氧消化工艺较为理想的消化周期；剩余污泥的消化性能差、产气率低、试验产气量占理论产气量的比例〈50％，在工程上单独的剩余污泥不宜采用厌氧消化工艺处理。     

以中国钢铁生产为例谈清洁生产与可持续发展

介绍了清洁生产的定义以及与可持续发展的关系，分析了钢铁工业清洁生产的成绩，并指出了仍然存在的不足，总结了清洁生产实施中存在的问题，说明了我国推行清洁生产的形势和前景。     

Co-conditioning and dewatering of chemical sludge and waste activated sludge

The conditioning and dewatering behaviors of chemical and waste activated sludges from a tannery were studied. Capillary suction time (CST), specific resistance to filtration (SRF), and bound water content were used to evaluate the sludge dewatering behaviors. Zeta potentials were also measured. Experiments were conducted on each sludge conditioned and dewatered separately, and on the sludge mixed at various ratios. Results indicate that the chemical sludge was relatively difficult to be dewatered, even in the presence of polyelectrolyte. When the waste activated sludge was mixed with the chemical sludge at ratios of 1:1 and 2:1, respectively, the dewaterability of chemical sludge improved remarkably while the relatively better dewaterability of the waste activated sludge deteriorated only to a limited extent. As the mixing ratios became 4:1 and 8:1, the dewaterability of the mixed sludge was equal to that of the waste activated sludge. The optimal polyelectrolyte dosage for the mixed sludge was equal to or less than that of the waste activated sludge. It is proposed that the chemical sludges act as skeleton builders that reduce the compressibility of the mixed sludge whose dewaterability is enhanced. Bound water contents of sludge decreased at low polyelectrolyte dosage and were not significantly affected as polyelectrolyte dosage increased. Advantages and disadvantages of co-conditioning and dewatering chemical sludge and waste activated sludge were discussed.     

腐殖土活性污泥技术的除污效能及除臭效果

阐述了腐殖土活性污泥工艺的基本原理，从微生物菌群结构、除污效能、控制恶臭气体及改善污泥沉降和脱水性能等方面介绍了该工艺的特性，同时说明了该技术的典型工艺流程及设计参数。实践表明，腐殖土活性污泥工艺可强化对氮、磷的去除，使污泥脱水性能大大改善，实现污水处理流程的无臭化。     

Moisture distribution in activated sludges: a review

The dewatering of residual sludges is a current problem due to the huge production of this waste. Activated sludges are generally hard to dewater, and the design and the control of the separation operations are often quite difficult. In order to better understand this problem, pertinent indices are needed. The knowledge of how water is distributed within activated sludge is an interesting approach. Current literature dealing with this topic is, however, relatively difficult to apply. This work presents a review of the problem of moisture distribution classification and measurement within activated sludge. The main techniques used for this analysis are compared and discussed in detail. The estimation of the water binding energy is also extremely commented upon. Finally, the paper discusses the utility of this type of analysis to examine the conditioning and dewatering of activated sludge.     

Cultivation of anaerobic granular sludge in UASB reactors with aerobic activated sludge as seed

Methanogenic bacteria of 10⁸ g SS⁻¹ in the activated sludges from an aeration tank treating sewage and from a secondary sedimentation tank of an activated sludge plant treating textile dyeing wastewater were enumerated by the Most Probable Number (MPN) technique. By using the two activated sludges as the seed material, anaerobic granular sludges were obtained at 35°C in two lab-UASB reactors having volumes of 29 and 481, and treating a glucose molasses solution of 1000–3500 mg COD 1⁻¹ and citrate wastewater of 20,000–36,000 mg COD 1⁻¹ respectively. The characteristics of granulation using the activated sludge as the seed were similar to those using digested sewage sludge as the seed. It is shown that activated sludge is readily available seed material for an anaerobic reactor. The growth of methanogenic bacteria in the activated sludge can be attributed to the existence of some anaerobic nuclei in the activated sludge flocs. The factors for the cultivation of granular sludge by using the activated sludge are also discussed.     

Feasibility of using a chlorination step to reduce excess sludge in activated sludge process

The ultimate disposal of excess sludge generated from activated sludge processes has been one of the most challenging problems for wastewater treatment utilities. Previous work has shown that excess sludge can be minimized successfully by using sludge ozonation to dissolve it into substrates to be oxidized in the aeration tank. However, this approach is a costly option. Therefore, as an alternative solution, we propose to use chlorination to replace ozonation in excess sludge minimization in the light of operational cost. To investigate the feasibility of this low cost approach, this paper mainly focuses on the effect of chlorination on sludge reduction rate, formation of trihalomethanes, sludge settleability, and effluent quality. Two identical activated sludge membrane bioreactors were continuously operated with synthetic wastewater under the same operation conditions for several months. During this period, one pilot unit was used as the reference system without chlorination of excess sludge, while another served as a testing unit, where excess sludge was taken out for conducting chlorination at a dose of 133mg/g MLSS every day and the chlorinated liquor was then returned to the aeration tank. The sludge production rate and the water quality of both the units were analyzed daily. It was observed that the sludge production could readily be reduced by 65% once the chlorination treatment was involved. However, the chlorination treatment also resulted in poor sludge settleability as well as significant increase of soluble chemical oxygen demand in the effluent, which creates potential difficulties in the operation of a conventional treatment plant with gravity clarifiers. However, it has been demonstrated that by integrating the immersed membrane into the activated sludge process these difficulties can be overcome effectively.