Effect of bacterial inoculum ratio in mixed culture for decolourization and detoxification of pulp paper mill effluent

BACKGROUND: Effluent released from industry is a mixture of various pollutants. For the degradation of complex pollutants, mixed bacterial cultures can be more effective than a single culture. This study investigated the balance of bacterial populations in a mixed culture for maximum reduction of pollutants. RESULTS: This study deals with the degradation and detoxification of pulp paper mill effluent (PPME) by three bacterial strains, i.e. Serratia marcescens, Serratia liquefaciens and Bacillus cereus in different ratios, and found that two ratios, 4:1:1 and 1:4:1, were effective for the degradation of PPME. These ratios reduced the various pollution parameters. Enzyme bioassay revealed that more enzyme was produced during degradation for the ratio 4:1:1. High performance liquid chromatography (HPLC) analysis showed that the ratio 4:1:1 degraded 95% of lignin and related compounds, and chlorophenols up to 98%, whereas ratio 1:4:1 reduced lignin by 84% and chlorophenols by 58% after 7 days incubation. Degradation products were confirmed by gas chromatography–mass spectrometry (GC‐MS) analysis. A seed germination bioassay on Phaseolous mungo L. revealed that toxicity was reduced by the ratio 4:1:1. CONCLUSION: Due to variable potential of different bacteria show variation in their growth pattern at any contaminated site. This study shows that an appropriate ratio of mixed cultures is required for maximum degradation and detoxification of PPME. Copyright © 2012 Society of Chemical Industry     

老污水处理厂技术改造与排放标准升级

21世纪初,上海对建于上世纪80年代的11座中心城区老污水处理厂进行了技术改造以提高排放标准,由于各厂的进出水水质、用地和设备等差异较大,针对各厂的实际情况采用了许多不同的技术改造路线和工艺。随着节能减排要求的提高,这些厂又将面临更高的排放标准,因此对前一次改造的经验和效果进行总结和回顾,可以为后续的改造提供参考。     

Thermophilic hydrogen production from starch wastewater using two-phase sequencing batch fermentation coupled with UASB methanogenic effluent recycling

The aim of this study was to evaluate the performance of thermophilic hydrogenesis coupled with mesophilic methanogenesis in which the effluent was recycled to the hydrogen reactor for starch wastewater treatment. With this system, the hydrogen production rate and yield were 3.45 ± 0.25 L H₂/(L·d) and 5.79 ± 0.41 mmol H₂/g COD_added respectively, and thus higher than the values of the control group without methanogenic effluent recycling. In addition, relatively higher contents of acetate and butyrate were obtained in the hydrogen reactor with recirculation. The methane reactors were operated with the effluent from the hydrogen reactor, and methane yield was stabilized at 0.21–0.23 L/g COD_removal in both. Analysis of the microbial communities further showed that methanogenic effluent recirculation enriched microbial communities in the hydrogen reactor. Two species of bacteria effective in hydrogenesis, Thermoanaerobacterium thermosaccharolyticum and Clostridium thermosaccharolyticum, dominated during hydrogen production, whereas archaea belonging to Euryarchaeota were detected and cultured in the methane reactor. The recycled effluent supplied alkaline substrates for the hydrogen producing bacteria. Alkali balance calculations showed that the amount of added alkali was reduced by 88%. This amount, required for hydrogen production from starch wastewater, was contributed by alkali in the methanogenic effluent, (2225 ± 140 mg CaCO₃/L), resulting in lower operational costs.     

谈混凝土植筋技术在污水处理工程的应用

结合实际工程介绍了混凝土植筋技术在污水处理工程中的应用,对混凝土植筋技术的施工特点、优缺点等进行了分析,并指出植筋技术在污水处理工程的应用越来越多,有全面取代水工构筑物各种预埋件的趋势。     

Experimental study of the relationship between separation performance and lengths of vortex finder of a novel de-foulant hydrocyclone with continuous underflow and reflux function

To solve the blockage and defer the fouling of sewage heat exchanger, a novel de-foulant hydrocyclone with continuous underflow and reflux function was proposed. Experimental results demonstrated that the novel hydrocyclone had a remarkable behavior on separating the sand (75–250 μm) and foulant (<4 mm). The continuous underflow and reflux function could significantly improve the separation efficiency by relieving the particle re-entrainment and eliminating the air core without increasing energy consumption (<17 kPa) and split ratio (<10%) considerably. Besides, the range of optimum vortex finder length was proportional to the particle density.     

Characterization of EfOM Fraction Responsible for Short-Term Fouling in Ultrafiltration

Based on our earlier diagnosis that hydrophobic and hydrophilic (HPO/HPI) acids are the primary cause of short-term fouling in the ultrafiltration of secondary effluent, the HPO/HPI acids were extracted and subsequently characterized in comparison with commercial organic materials. HPO/HPI acids isolated from secondary effluent contained significantly fewer complex mixtures than humic substances that have been implicated as the dominant foulants in the filtration of surface water using porous membranes. The physicochemical and spectroscopic characterization demonstrated that the aromaticity and apparent molecular weight of HPO/HPI acids were lower than that observed for other humic materials, while the oxygenated functional groups were relatively higher.     

环氧树脂玻璃钢防腐在丰特果蔬汁污水处理工程中的应用

介绍环氧树脂玻璃钢防腐施工工艺、控制过程及控制指标,总结环氧树脂玻璃钢防腐的优点。     

对竹园第-污水处理厂污泥产率的分析

根据上海市竹园第一污水处理厂的运行数据，研究了该厂的污泥产率。结果表明竹园第一污水处理厂每万吨水产泥率的变化范围为0．38—1．44tSS／万M2；剩余污泥的表观产率系数（Lobs）和合成产率系数（y）分别为0．56和0．58kgVSS／kgBOD，均在正常范围以内；衰减系数（虬）为0．006d-1；惰性ss产泥率的变化范围为0．20～0．50tSS／万M2。     

石化污水场金属管道及设备腐蚀原因探讨及对策

污水场金属设备及管道腐蚀严重,通过对相关污水水质、垢样成分和腐蚀类型的分析,得出在污水场金属管道及设备中存在铁细菌、硫酸盐还原菌的腐蚀和溶解氧的腐蚀。针对腐蚀产生的原因,提出了正确选用金属材料,改变腐蚀环境,采用耐腐蚀覆盖层,电化学保护,采用非金属材料等解决方案,通过一年的运行和监测,改造结果满足设计要求。