Chitnis V, Chitnis S, Vaidya K, Ravikant S, Patil S, Chitnis D S
Department of Microbiology and Immunology, Choithram Hospital and Research Centre, Indore 452001, India.
Water Res. 2004 Jan;38(2):441-7. doi: 10.1016/j.watres.2003.09.038.
Hospital effluent with its high content of multidrug resistant (MDR) enterobacteria and the presence of enteric pathogens could pose a grave problem for the community. It was planned at our tertiary care hospital in central India to study the population changes at various steps of effluent treatment plant (ETP) like collection, aeration, clarification, liquid sludge, dried sludge, high-pressure filter and treated wastewater. The study included viable bacterial counts, coliform counts, staphylococcal, enterococcal, Pseudomonas and multiple drug resistant (MDR) gram negative bacterial counts in the different stages of ETP. In order to study the distribution of bacteria as free floating in liquid and adherent to suspended particles, enumeration of the bacteria in the filterate and the sediment was also carried out. The effluent input showed 55% of the 8.6 x 10(6)/ml bacteria as coliforms and E. coli which was a typical of fecal flora. The prevalence of MDR coliforms was 0.26%. The substantial reduction (> 3log) was seen for the effluent coming from the clarifier. The bulk of the bacteria in the hospital effluent remains firmly adhered to solid particles; aeration and clarification removes bulk of the bacteria by physical processes like flocculation. The treated liquid effluent still contains sizeable loads of MDR bacteria and inactivation by procedure such as chlorination is required. The bacteria get concentrated in sludge and a greater concentration of chlorine is required for decontamination.
医院污水中含有高含量的多重耐药（MDR）肠杆菌且存在肠道病原体，这可能给社区带来严重问题。印度中部的一家三级护理医院计划研究污水处理厂（ETP）各个环节（如收集、曝气、澄清、液体污泥、干污泥、高压过滤和处理后的废水）中的菌群变化。该研究包括对ETP不同阶段的活菌计数、大肠菌群计数、葡萄球菌、肠球菌、假单胞菌和多重耐药（MDR）革兰氏阴性菌计数。为了研究细菌在液体中自由漂浮以及附着在悬浮颗粒上的分布情况，还对滤液和沉积物中的细菌进行了计数。污水输入显示，每毫升8.6×10⁶个细菌中有55%为大肠菌群和大肠杆菌，这是典型的粪便菌群。多重耐药大肠菌群的流行率为0.26%。来自澄清池的污水出现了大幅减少（>3个对数）。医院污水中的大部分细菌仍牢固地附着在固体颗粒上；曝气和澄清通过絮凝等物理过程去除大部分细菌。处理后的液体污水仍含有大量的多重耐药细菌，需要通过氯化等程序进行灭活。细菌会在污泥中浓缩，去污需要更高浓度的氯。
