Mechanistic insight into the biofilm formation and process performance of a passive aeration ditch (PAD) for decentralized wastewater treatment

• A Passive Aeration Ditch was developed to treat decentralized wastewater. • A model was developed to describe the process performance. • A high C/N ratio facilitates microbial growth but nitrification deteriorates. • A high salinity decreases both organic and nitrogen contaminants removal. Decentralized wastewater containing elevated salinity is an emerging threat to the local environment and sanitation in remote coastal communities. Regarding the cost and treatment efficiencies, we propose a passive aeration ditch (PAD) using non-woven polyester fabric as a feasible bubbleless aerator and biofilm carrier for wastewater treatment. Consideration has been first given to PAD’s efficacy in treating saline decentralized wastewater, and then to the impact of chemical oxygen demand-to-nitrogen (C/N) ratio and salinity on biofilm formation. A multispecies model incorporating the salinity effect has been developed to depict the system performance and predict the microbial community. Results showed that the PAD system had great capacity for pollutants removal. The biofilm thickness increased at a higher C/N ratio because of the boost of aerobic heterotrophs and denitrifying bacteria, which consequently improved the COD and total nitrogen removal. However, this led to the deterioration of ammonia removal. Moreover, while a higher salinity benefited the biofilm growth, the contaminant removal efficiencies decreased because the salinity inhibited the activity of aerobic heterotrophs and reduced the abundance of nitrifying bacteria inside the biofilm. Based on the model simulation, feed water with salinity below 2% and C/N ratio in a range of 1 to 3 forms a biofilm that can reach relatively high organic matter and ammonia removal. These findings not only show the feasibility of PAD in treatment of saline decentralized wastewater, but also offer a systematic strategy to predict and optimize the process performance.     

复合式生物膜反应器中生物膜的特性

传统的活性污泥工艺中加入废弃轮胎颗粒作为生物膜载体形成的复合式生物膜反应器。在颗粒浓度为４０ｇ／Ｌ时,稳定运行条件下在轮胎颗粒表面可形成约５０ｍｇ／ｇ的生物膜量,即在传统曝气池的２０００－３０００ｍｇ／Ｌ悬浮生长污泥的基础上,可增加２０００ｍｇ／Ｌ的附着生物膜量。     

有机碳源和溶解氧对亚硝酸盐生物硝化的影响研究

从城市污水处理厂的活性污泥中纯化分离到高活性硝化菌株N-20（Nitrobacter sp．）,在一种新型材料Carbon Foam的表面挂膜;通过对菌株N-20进行摇瓶试验,选择添加有机碳源的种类,将其在pH7．5～8．0、温度28℃的条件下,分别以NaNO2和K2HPO4为氮源和磷源,通过生物滤塔中的液相连续试验,考察在不同DO的条件下有机碳源对硝化作用的影响规律。结果表明,以葡萄糖作为有机碳源,DO≥2mg／L,葡萄糖低于20mg／L时,生物滤塔内可进行正常硝化,NO2^--N的硝化去除率维持在90％左右,随着葡萄糖浓度的增加,硝化去除率下降到70％;DO≤2mg／L,葡萄糖对硝化作用的抑制增强,当葡萄糖为200mg／L时,生物滤塔中NO^2-—N的硝化去除率仅为32％。     

生物技术处理废水的研究进展

随着经济的发展和人民生活水平的提高，所排放的废水日益增多，造成的环境危害也日趋严重。采用生物技术处理废水具有许多明显的优点。本文详细介绍了生物技术在废水处理中的应用进展及前沿动态。     

两段式生物膜-膜生物反应器的试验研究

试验对传统两段式生物反应器(TSBR)进行了改进，二段采用生物膜-膜生物反应器(BMBR)；在一段HRT=SRT=2．82～4．23h，二段HRT=6．44～9．66h、SRT→∞，每日空曝气8h的运行条件下，对该工艺进行了试验研究。结果表明，系统稳定后，出水水质稳定，CODc、NH4^ -N和TP的去除效率分别为95％、80%和60％以上，膜污染得到了有效控制。     

双循环两相生物处理工艺工程应用的探讨

探讨了新型生物脱氮除磷工艺--双循环两相(BICT)生物处理工艺的生产规模应用问题.通过在序批式活性污泥法基础上增设独立的生物膜反应器,实现微生物的分相培养,BICT工艺为提高系统的脱氮除磷能力,增强运行稳定性和可靠性创造了条件.技术经济比较分析说明,BICT工艺技术先进、运行稳定,投资及运行费用具有竞争力,在污水处理要求愈加严格的情况下,具有推广价值和应用前景.     

营养源对活性艳红脱色降解体系的影响研究

选择活性艳红X-3B为脱色和降解对象，将白腐真菌固定在生化填料上构建白腐真菌生物膜反应器，并以接种活性污泥的生物膜反应器为对照，考察了营养源对活性艳红脱色降解的影响。实验表明，对白腐真菌Shu-13采用查氏培养基预培养和在反应器中投加适量蔗糖及酱油废水，均能明显提高活性艳红X-3B的脱色率。城市污水中的营养源，不足以满足白腐真菌对活性艳红X-3B的脱色降解需要，白腐真菌Shu-13对富氮条件存在依赖性。在富营养条件下，白腐真菌Shu-13生物膜反应器对活性艳红X-3B的脱色效果明显优于活性污泥。营养源及其浓度、菌种是影响pH变化的重要因素，活性污泥和酱油曲霉生物膜反应器的出水pH变化规律，与Shu-13存在明显不同，Shu-13对活性艳红X-3B的脱色过程中发生了明显的降解作用，而这种作用对生物膜恢复其污染物净化功能是至关重要。另外，酱油废水中存在的酱油曲霉属于半知菌纲的白腐真菌，其对活性艳红X-3B也有较显著的脱色降解效果。     

Heavy metals and arsenic fixation into freshwater organic matter under Gammarus pulex L. influence

Organic sediments are a main sink for metal pollutants in aquatic systems. However, factors that make sediments a sink of metals and metalloids are still not clear. Consequently, we investigate the role of invertebrate shredders (Gammarus pulex L.) on quality of metal and arsenic fixation into organic partitions of sediment in the course of litter decay with laboratory microcosm experiments. During the decomposition of leaf litter, G. pulex significantly facilitated the development of small particles of organic matter. The capacity of metal fixation was significantly higher in smaller particles than leaf litter and litter residuals. Thus, G. pulex enhanced metal fixation into the organic partition of sediments by virtue of increasing the amount smaller particles in the aquatic system. Furthermore, invertebrates have a significant effect on formation of dissolved organic matter and remobilization of cobalt, molybdenum and cesium, but no significant effect on remobilization of all other measured elements.     

生物滴滤塔处理苯乙烯气流的工效和生物膜微群落的分析

采用培养驯化污泥菌种、类球形陶粒和循环液等构建生物滴滤塔.研究评价气体苯乙烯浓度、气体流量、循环液喷淋量对生物滴滤塔工效的影响,并对生物膜微群落中的微种群作了定性定量检测.当进口气体苯乙烯小于1 000 mg/m3、气体流量为200 L/h、循环液流量为10 L/h时,苯乙烯净化效率达90%以上,生化去除量为30 mg/(L·h);单位体积生物膜填料对苯乙烯的最大生化去除量为35 mg/(L·h).湿润生物膜微群落的优势菌种群包括恶臭假单胞菌、梭形芽孢杆菌、罗非氏不动杆菌等5种,恶臭假单胞菌等非芽孢杆菌的最大活菌数为5.5×107 CFU/g,并随生物滴滤塔运行时间延长有减少趋势.     

微生物磁效应及其强化废/污水生物处理的研究进展

介绍了微生物磁效应的现象、原理及其在强化废/污水生物处理过程应用的研究进展,包括磁场对微生物运动、微生物生长、微生物酶活力以及对活性污泥法或生物接触氧化法处理废/污水过程的影响。提出生物亲和亲水磁性填料以及磁粉的合理运用,可能是实现微生物磁效应在废/污水生物处理中应用的有效途径。