Microbiological Safety Evaluation Of Reclaimed Water

As experiments indicating, reclaimed water is one of the best way of economizing water, promoting environment and solving the lacking -water problems. But there are a great deal of pathogenic microorganisms in sewage, which have caused infectious diseases broken. Reclaimed water, treated from sewage, can also menace public health. But there is no systemic evaluation of microbiogical safety for reclaimed water in the world. This study was aimed to develope the microbiological safety evaluation system for guiding the application of reclaimed water in the end.Microorganisms were isolatied and cultured from waste water and reclaimed water by ordinary culture, selective culture and sensitive cell culture. It's found there were no pathogenic microorganisms in sewage, but there were non-pathogenic bacteria, conditional pathogenic bacteria and bacteria phages, such as E.coli (10⁴cfu/mL), Streptococcus faecalis(≥2400 cfu/100mL), Vibrio vulnificus, Proteus vulgaris, Proteus mirabilis, Clostirdium perfringens (10²â€” 10³cfu/mL), Staphylococcus, T coliphage and f₂ coliphage (10²pfu/mL).To study the survival status of the pathogenic bacteria, enterovirus or indicator microorganisms in waste water, microorganisms were added into waste water, the initial concentration is 10³ — 10⁷cfu/L(or pfu/L), which was low-speed centrifugalized and high-pressure sterilized. The survival status was observed under different conditions by changing temperature, water quality and time. It's found survival status of the microorganisms were different with different species and conditions.A novel style of electropositive filter media particle was used to concentrate indicator virus such as f₂ coliphage, and enterovirus such as Polio virus, from sewage water, which was not pretreated at all. To improve the effect of concentration, we took an electropositive material into sewage water before concentration and observed the different outcome under the different conditions. The recovery of viruses (f₂ ,Polio virus) from large volume (20L) were all exceed 80%.Membrane biological reactor (MBR) with 0.20μm aperture was used to study the function of holding back the microorganisms, including enterobacteria, enterovirus and...