Studies On The Culture Identification And Quantitative Detection Method Of Typical Enteric Pathogenic Bacteria In Wastewater Reuse

Biololgical safety has become a focus in wastewater recycling which is one of the effective methods to resolve water resource problem. As typical enteric pathogenic bacteria, the Salmonella and Shigella can cause quite a few human diseases, such as typhoid fever, acute gastroenteritis, bacteremia, septicemia and bacillary dysentery. So the detection of the typical enteric pathogenic bacteria is wating to be studied.First of all, the feasibility about the membrane filtration and the MPN method to detect the typical enteric pathogenic bacteria was studied. Then, the improved MPN method was adopted to quantitatively detect the typical enteric pathogenic bacteria in treated wastewater and reuse water for four months. As a compare, fecal coliforms and fecal strepfococcus were detected by membrane filtration method simultaneously to study the pathogenic pollution characteristic of the wastewater reuse.(1) In the membrane filtration method, the pathogen can not be counted accurately because of the weak rejection of the agar; this method is just suitable for qualitative research.(2) The improved MPN method in which PCR was used instead of the biochemical tests and serological identification to identify pathogen is quick and applicable to quantitative detection of pathogen. The culture effects of MM enriched broth was the best at 42℃for 24 hours.(3) Measurements by the improved MPN method showed that, in the treated wastewater, the standard deviation of faecal coliforms is 753 cfu/mL, the streptococcus faecalis is 392 cfu/mL, the Salmonella is 587.75 MPN/L, the Shigella was not be detected.(4) In the reuse water, the standard deviation of faecal coliforms is 354.87 cfu/L, the streptococcus faecalis is 232.71 cfu/L and 106.49cfu/L, both the Salmonella and Shigella were not be picked up. The high quality of the reuse water was maked out of the lower measurements than the treated wastewater.(5) Regression analyses and statistical comparisons of the Salmonella and the fecal coliforms, fecal strepfococcus showed that the correlation coefficient between the Salmonella and the faecal coliforms (0.853 (p<0.01)) is stronger than the Salmonella and the faecalis(0.753 (p<0.05)).(6) The shigella was not be detected both in the treated wastewater and reuse water, it indicated that the water samples were lightly be polluted by it. The method detecting the shigella should be discussed further because of the big volume water samples during the testing. At the same time, more and long-term researches should be put in practice, if we adopt the improved MPN method for the assessment of bacteriological risk of water environment.