The Study Of Biological Stability Of Moupanshan Plant Conventional Water Purification Process

In2006, the new standers of living drinking water strengthened the requirements to total count of bacteria and coliform. It says that when total coliform.has been detected, Escherichia coli or thermotolerant coliforms should been tested. If coliform has not been detected, then the detection of Escherichia coli or thermotolerant coliforms is unnecessary. This showed the microbial indicators of drinking water has been more important.This paper selected a conventional water purification process in Mopanshan waterworks as object, studied the biological stability of the conventional water purification process. Measured the conventional water quality indicators of the raw water and the water was coagulated, sedimented, filtrated and disinfected.This paper evaluated the biological stability by Assimilable Organic Carbon (AOC)、Biodegradable Organic Carbon (BDOC) and Microorganism Available Phosphorus (MAP), then analyzed the correlativity between HPC as well as water temperature and the three biological stability indexs, studied if filter backwashing has effect on water biological stability.At the same time, this paper analyzed the dominant heterotrophic bacteria of the seven water samples in the conventional water purification process by pure culture as well as gram staining and simple molecular biology techniques. Gram staining and microscopic examination helped to observe the bacterial morphology, CR technology and DNA sequencing technology were used to classify and identify the bacteria in these seven water samples, NCBI-faste website helped match the DNA sequence, then obtained the dominant bacterial phylogenetic tree through Mega5.1.The results showed that, the raw water of Mopanshan waterworks was good, from April,2011to October,2012, the turbidity of raw water keet lower than3NTU, the TOC was lower than6mg/L, ammonia concentration was less than0.3mg/L. The biological stability of the raw water was well, during the experiment, AOC concentration was less than100μg/L,even lower than50μg/L in winter., BDOC concentration was3.3mg/L or less, the MAP concentration was not more than47.5ug/L. After coagulation-sedimentation-filtration-disinfection, the water can meet the requirements of the new standers of living drinking water. But the AOC of finished water was higher than the stander of biological stability(AOC<100μg/L). Coagulation and sedimentation made AOC concentration increase, filtration has a nice effect on decreasing AOC concentration, the dissolved phosphate can be removed through coagulation and sedimentation, Chlorine disinfection made organic macromolecules in water into small organic molecules, which was not conducive to the protection of water biological stability.