Treatment Of Power Plant Recirculating Cooling Drainage By Fenton's Reagent Preoxidation Combined With Powdered Activated Carbon Adsorption

The effect of different kinds of processes on the treatment of recirculating cooling drainage which is from a power plant in Tianjin was investigated in this thesis.The aim is to removing organics in the wastewater,the effluent should meet the Discharge Standard of Pollutants for Municipal Wastewater Treatment Plant?DB12/599-2015?issued by Tianjin government.First,the Fenton's reagent oxidation and PAC adsorption methods for organics removal were studied respectively.It was found that the best efficiency was achieved when pH value of the raw water was 5.0,the molar ratio of H₂O₂ to Fe²⁺was 1 and the H₂O₂ dosage was 300 mg/L when the reaction time was 60 min.At this condition,the removal rate of NPOC is about 60%.The result was verified by an orthogonal experiment.However,it was found that the two processes still had some problems such as poor treatment effect and high chemicals cost.Therefore,after further analysis of the molecular weight of the recirculating cooling drainage,the combined process was optimized to improve the removal efficiency.The Fenton's reagent preoxidation-PAC adsorption combined process was developed as well as optimized and the influence factors of this process were tested.The results showed that the best efficiency was achieved when pH value of raw water was unchanged,the molar ratio of H₂O₂ to Fe²⁺was 1 and the H₂O₂ dosage was 25mg/L,at this condition,the removal rate of NPOC is about 68%.For two different quality of raw wasterwater,taken of different time,under the optimum conditions with PAC dosage of 0.15 g/L and 0.29 g/L,the results obtained from four-stage countercurrent adsorption process showed that it was stable and the removal effect was good.In addition,the process was low in operation cost and the effluent quality could meet the discharge standards with a slow membrane fouling rate.In summary,the Fenton's reagent preoxidation-PAC adsorption combined process was effective and economical in removing the organic in the recirculating cooling drainage from the power plant.