The Experimental Study For Recycling Sludge Water Safely In Water Plant

About 3%~10% of sludge water was to be produced in water plant, reusing this part of water can not only save the water resource, but also protect the env-ironment. Water treatment plants ecycle or reintroduce a variety of residual stre-ams back into their treatment plants. Some of these flows may enriched suspend-ed particles, organic matters, pathogens and some metals from raw water, while others may be quite harmless,will affect water quality in the factory. Therefore, it is necessary to assessment the characteristics of sludge water and to carry out the corresponding to study of the reusing of sludge safety.From the physical, chemical and biological to evaluate the characteristics of sludge water in the typical south water plant. Found that the sludge water quality of sedimentation tank is quite harmless for for directly reusing, while the security problems of the sand filter backwash water are not prominent, can be directly reused.Sand filter backwash water can reduce the zeta potential of particle surface of the flocs, to improve the coagulation conditions, reduce the turbidity of the water after sidimenting. But the equilizational reusing of Sand filter backwash water, the reusing ratio should be strictly controlled. Under normal operating conditions, the reusing ratio to less than 6% is appropriate; in case of some unforeseen circumstances,it need to increase the proportion of reflux, and the instantaneous reflux ratio should be no more than 20%, otherwise this will cause greater impact on water quality.The test result of the sedimentation without chemical addition of sludge water of the sedimentation tank show that, after half an hour sedimenting, turb-idity removal efficiency of between 92.6% to 99.8%, CODMn removal rate at 51.2%~94.3%, ammonia nitrogen removal rate at 21%~37%, The use of sedimentation on recycle streams has been shown to be effective in removing turbidity particles count and CODMn.Particles count and turbidity reductions were enhanced significantly with the addition of ployer. Compared with the without addition of ployer, At the solid content ratio of 0.281%, both the turbidity and particles count of supernatant reduced from 9.85NTU to 3.41NTU and 42597 to 2222; At the solid content ratio of 0.261%, both the turbidity and particles count of supernatant reduced from 7.89NTU to 4.87 NTU and 34859 to 22780.The presence of suspended solids will impact on the chlorine demand largely, along with turbidity increasing, the chlorine demand increasing. the chlorine demand varied from 0.2mg/L at the turbidity of 1.41NTU to 0.9mg/L at the turbidity of 93NTU, increase of 4.5 times. Other oxidation should be considered because of the disinfection by-products. Continuous membrane filtration (CMF) can effectively remove the stability of bacteria, algae, suspended solids and turbidity, can realize the security of Sludge reuse.