Biological Stability Of Reclaimed Water And Removal Of Organic Matter By Uultrafiltration-Ozone Treatment

Biological stability is one of the most important aspects for reclaimed water safety. Because in reclaimed water have many kinds of organic matter, when the reclaimed water distribution systems in the process, can cause of microbes grows again in the distribution systems, that in turn would lead to corrosion of pipe materials and deterioration of water quality in distribution systems. At present, the Assimilable Organic Carbon (AOC) have been widely used considered as indexes which can measure biological stability and bacterial regrowth of water. When concentrations of AOC is controlled under thresholds, biological stable reclaimed water which does not support bacteria regrowth will be prepared. At present, the research of reclaimed water AOC few reports.This paper studies on the microbial regrowth in the different reclaimed water distribution systems,use the G3strains (Pseudomonas saponiphila G3) from the reclaimed water. Removal capability of organic matters by water purification processes and changes of biological stabiliy in the reclaimed water distribution systems are investigated. Deeply discuss the ultrafiltration-ozone oxidation process to remove the organic characteristics. Main contents and results are summarized as follows:1) Studies on two different pipe materials of PVC tube and stainless steel tube on the reclaimed water distribution systems microbial regrowth. The results show that, the stainless steel tube wall of the biomass is far lower than the PVC tube wall in biomass. In the reclaimed water distribution systems use process,on the wall gradually forming a biological membrane, lead to corrosion of pipe materials and deterioration of water quality in distribution systems, At the same time, puts forward several control pipe network in microbial regrowth measures.2) Through the comparison of the drinking water determination method AOC. Get a bacteria and used in the reclaimed water AOC determination, and to identify strains, and finally determined for Pseudomonas saponiphila G3bacteria. Studies on the different environmental factor influence of the G3and growth of G3strains of different strains of the organic matter used.Through the G3strains of organic carbon number of units of the standard material utilization. Final determination of the yield of the reclaimed water AOC coefficient is3.8×106CFU/μg acetic acid carbon, used in the test for vaccination concentration gasoloid density was exceed104CFU/mL, training for25℃temperature.3) Uses the molecular weight distribution and3-D fluorescence detection means, research the ultrafiltration-ozone oxidation regeneration water disposal techniques to renewable water DOC, UV254and AOC removal mechanism.The results show that ultrafiltration of recycled water removal efficiency of DOC is better, the removal rate is41%, UV254to remove is worse, while high molecular weight of recycled water (>10kDa) removal rate as high as81%of the AOC; Ozone oxidation of recycled water to remove DOC is worse, but to UV254the removal rate is34%, and ozone oxidation make renewable water high molecular weight (>10kDa) and medium molecular weight (1kDa-10kDa) AOC declined obviously, and small molecular weight (<1kDa) AOC concentration significantly increased to501μg/L acetic acid, the carbon74%.4) Research by the organic characteristics AOC characterization of different Organic matter content index, molecular weight distribution and the influence of the growth of G3strains.The results show that, Different treatment process AOC and DOC differences is larger, the characterization of main and organic matter AOC small molecular weight related organisms. AOC is the growth of the bacteria is one of the important factors, but to control water to keep or regeneration AOC can cause the growth of the bacteria limit concentration is more difficult. Need through the different combination process, effective control of the water out of the factory AOC concentration., from the start control and in the distribution network to choose the hig quality steel tubes, regular cleaning pipe network, control the bacteria to regrowth, access to safe reclaimed water.