Lime Treatment Of Secondary Treated Sewage Effluent For Power Station Cooling Water

The water shortage especially in northern province is a serious problem in our country which water resources are scarce. The wastewater reuse technology is the mainly method to alleviate it. The projects in several years have proven the available in technology of wastewater reuse. The water used in industry has taken the large proportion in water consume, especially in Thermal Power Sation's cooling water. Because the quality demand of cooling water is not strict, the second class effluent of Waste Water Treatment Plant can achieve requirements of that by appropriate treatment.In the dissertation, on the base of mechanism analysis about advanced treatment Sewage Effluent technology by lime, the optimum dose of lime which lime coagulating technology treats secondary treated sewage effluent were studied.The experimental results showed that: the optimum dose of lime was 445 mg/L to 500 mg/L,the optimum dose of PFS was 0.26mmol/L to 0.32mmol/L,this dose had higher efficiency than others;the removing rate of alkalinity was about 84%, the removing rate of the total water rigidity and calcium rigidity were about 68% and 60%, the turbidity removing rate was more than 90%, the removing rate of CODCr was about 40%, the removing rate of NH₃-N was lower, about 10%; The PAM which added 0.1 mg/L to 0.3 mg/L can make sedimentation velocity faster, which benefits clarification processing; the removing rate by the different order of added was not obvious, but it had higher efficiency than other orders that lime was added at first, followed coagulant, then coagulant aid.Finally, a project which the author was participated in about advanced treatment Sewage Effluent technology by lime and reused for cycle cooling water in power plant is explained.