臭氧/UASB/接触氧化处理医药废水

医药废水是一种浓度高、可生化性差的难降解废水。采用臭氧/UASB/接触氧化工艺处理,调试及运行结果均表明,系统对BOD5和COD的去除率分别达到98.0%和97.0%以上,运行稳定,出水水质达到《污水综合排放标准》(GB 8978—1996)的二级标准,运行费用为3.21元/m3。     

预处理/AO工艺处理牛仔布废水

介绍了牛仔布染整废水处理系统运行调试中污泥的培养及驯化，分析了运行过程中遇到的问题，提出了影响牛仔布染整废水生化处理系统的因素及相应的控制措施。实践表明，预处理／AO工艺的出水水质达到了国家《纺织染整工业水污染物排放标准》(GB 4287-1992)中的一级标准。     

Enhanced granulation by natural ionic polymer additives in UASB reactor treating low-strength wastewater

Effect of natural ionic polymer additives on granulation in lab-scale UASB reactors treating low-strength synthetic wastewater (COD 750-850 mg/L) was examined. The organic loading rate was 1.477+/-0.118 kgCOD/m3/day. Under identical conditions four similar reactors were operated in parallel with the following additives: control with no additive, anionic part of Reetha (Sapindus trifoliata) extract, cationic part of Reetha extract, and Chitosan. By the end of the study period, Chitosan as an additive produced largest granules with mean size of 0.15 mm closely followed by the cationic fraction of the Reetha extract with mean size of 0.144 mm, and anionic fractions of the Reetha extract with 0.139 mm. Control reactor with no additives had the smallest size granules with mean size of 0.128 mm. The fraction of granules in the sludge bed of size >0.1 mm showed similar trend. The largest granule size observed in the reactors with additives was 4-5mm as compared to 2 mm in the control reactor. Cationic polymers were more effective additives for enhancing sludge granulation. Exo-cellular protein, lipid, sugar and total polymer increased with granulation in the reactors. A COD removal efficiency of 95-98% was achieved in all the reactors.     

UASB反应器处理甲醇废水的研究

采用单段UASB工艺处理甲醇废水,以颗粒污泥为接种污泥,在容积负荷为18 kg-COD/(m3.d)、污泥负荷为1.098 kgCOD/(kgVSS.d)的条件下,反应器运行平稳,对COD的去除率>90%,且处理全程始终未出现挥发性脂肪酸的积累现象。当外加碱度(以CaCO3计)降低到119 mg/L时,反应器内的pH值仍可保持稳定。甲醇在转化为甲烷的生物化学过程中,以直接还原成甲烷为主要途径,而通过形成乙酸再转化为甲烷并不是主要途径,因此甲醇废水的厌氧生物处理通常并不存在由脂肪酸的积累引起的毒性作用和pH的急剧变化所导致的运行不稳定。     

Mechanisms and models for anaerobic granulation in upflow anaerobic sludge blanket reactor

Upflow anaerobic sludge blanket (UASB) reactor has been employed in industrial and municipal wastewater treatment for decades. However, the long start-up period required for the development of anaerobic granules seriously limits the application of this technology. In order to develop the strategy for rapid UASB start-up, the mechanisms for anaerobic granulation should be understood. This paper attempts to provide a up-to-date review on the existing mechanisms and models for anaerobic granulation in the UASB reactor, which include inert nuclei model, selection pressure model, multi-valence positive ion-bonding model, synthetic and natural polymer-bonding model, Capetown's model, spaghetti theory, syntrophic microcolony model, multi-layer model, secondary minimum adhesion model, local dehydration and hydrophobic interaction model, surface tension model, proton translocation-dehydration theory, cellular automaton model and cell-to-cell communication model. Based on those previous works, a general model for anaerobic granulation is also proposed. It is expected that this paper would be helpful for researchers to further develop a unified theory for anaerobic granulation and technology for expediting the formation of the UASB granules.     

小型啤酒厂污水处理技术

对小型啤酒厂污水处理的常用技术与方法进行了评介,并推荐了较为先进且适用性强的ＳＢＲ和ＵＡＳＢ法。     

Formation and impact of granules in fostering clean energy production and wastewater treatment in upflow anaerobic sludge blanket (UASB) reactors

Anaerobic reactors have acquired a new relevance in recent years due to their ability to generate methane from biodegradable wastewaters—thereby producing clean energy. Methane capture in this manner also prevents the escape of the greenhouse gas to the atmosphere which otherwise occurs when anaerobic conditions develop in drains and outfalls carrying wastewater. Of all the different types of anaerobic reactors in vogue - anaerobic filter, downflow fixed-film reactor, expanded fluidized-bed anaerobic reactor, etc. - the upflow anaerobic sludge blanket (UASB) reactor is arguably the most widely used. Nearly 80% of the world's anaerobic wastewater treatment systems are estimated to be based on the UASB technology. The functioning of a UASB reactor revolves round its sludge bed which gets expanded as the wastewater is made to flow vertically upwards through it. It is the microflora attached to the sludge particles which acts upon the wastewater. Hence the quality of biofilms sported by the sludge particles, and the intimacy of the sludge-wastewater contact are the factors which, principally, govern the success of a UASB reactor. Very early in the development of UASB technology it was realized that granular sludge of appropriate particle size, particle density, and microfilm characteristics enhances the reactor efficiency in terms of the rate as well as the extent of wastewater treatment. From then onwards efforts have been made by scientists across the world to understand the factors which shape the granules and the manner in which the granules contribute to wastewater treatment. The state-of-the-art is presented in this paper.     

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。     

Treatment of a combined dairy and domestic wastewater in an up-flow anaerobic sludge blanket (UASB) reactor followed by activated sludge (AS system)

The feasibility of using an up-flow anaerobic sludge blanket (UASB) reactor followed by activated sludge (AS system) for the treatment of wastewater discharged from dairy factory was explored. The UASB reactor was operated at a hydraulic retention time (HRT) of 24 h and organic loading rates (OLRs) ranging from 1.9 to 4.4 kgCOD/m³.d. The average total chemical oxygen demand (COD_total) and total biological oxygen demand (BOD_5total) concentrations of the UASB reactor effluent were 1385 and 576 mg/l, corresponding to percentage removal of 69% and 79%, respectively. Total suspended solids (TSS) and volatile suspended solids (VSS) removal averaged above 72% and 75%, respectively. Residual phosphorous and oil and grease concentrations of the UASB reactor effluent were 8.2 and 44 mg/l, corresponding to percentage removal values of 63% and 83%, respectively. This good performance could be attributed to the relatively long sludge residence time (SRT = 76 d) imposed to the reactor. Total and faecal coliform counts were reduced in the treated effluent by a value of 1.07 and 0.9 log₁₀, respectively. The net sludge yield coefficient was found to be 0.2 g VSS per g COD_total removed per day, corresponding to 20% of the total influent COD imposed to the UASB reactor. The volatile solids / total solids (VS/TS) ratio of 0.66 of excess sludge revealed its good quality. Preliminary batch experiments of the AS system treating UASB reactor effluent indicated first-order removal kinetics between total organic carbon (TOC) and contact time. The TOC removal reached 80%, resulting in only 47 mg/l in the final effluent at a HRT of 2.0 h. Accordingly, the AS system was operated at a HRT of 2.0 h. The system achieved a substantial reduction of COD_total, BOD_{5 total}, TSS and oil and grease resulting effluent quality with residual values of only 35.0, 7.0, 14.0 and 2.8 mg/l, respectively. The geometric mean of total and faecal coliform counts was reduced by a value of 1.28 and 1.64 log₁₀, respectively. Based on these results, it is recommended to use of an integrated system consisting of a UASB reactor followed by the AS system for the treatment of a combined dairy and domestic wastewater to produce a good effluent quality complying with the standards for discharge into agricultural drains.