| Coal-chemical engineering wastewater is a biodegradable industrial wastewater, its biochemical effluent can hardly meet the national emission standards, especially the COD and Color. Based on the characteristics of coal-chemical engineering wastewater and the investigation about the methods of advanced treatment for coal-chemical engineering wastewater, coagulation, Fenton oxidation and Fenton oxidation-coagulation were used to dispose wastewater in the advanced treatment. A suitable treatment to dispose coal-chemical engineering wastewater in an efficient and lower cost way was expected to find.The whole study was divided into three parts. First, The effluent from secondary sedimentation tank of coal-chemical engineering wastewater was treated by the coagulation system posed by the coagulant, coagulant aid and adsorbent. Based on treatment effect, the best experimental conditions of coagulation were proposed. Second, the method of Fenton oxidation treatment was studied to determine the best experimental conditions. Finally, Fenton oxidation-coagulation precipitation method was studied.The result of the first part about coagulation experiment:the best coagulation conditions of PAC show that, the dose of PAC、PAM、Powdered activated carbon is350mg/L、2.0mg/L and1.0g/L respectively, pH is6.8～7.2and the precipitation time is30min, then the removal rate of COD、Color is61.62%and92.08%respectively. The best coagulation conditions of PFS show that, the dose of PFS、 PAM、Powdered activated carbon is500mg/L、4.0mg/L and1.0g/L respectively, pH is6.8～7.2and the precipitation time is30min. Then the removal rate of COD、 Color is64.55%and94.33%respectively. The best coagulation conditions of PAFC show that, the dose of PAFC、PAM、Powdered activated carbon is300mg/L、3.0mg/L and1.5g/L respectively, pH is8.0and the precipitation time is30min, then the removal rate of COD、color is61.20%and82.03%respectively.The result of the Second part about Fenton oxidation experiment:Fenton oxidation was used to dispose coal-chemical engineering wastewater in the advanced treatment. And Fenton oxidation reaction conditions can be Determined. The dose of H2O2and Fe2+were240mg/L and180mg/L respectively, and reaction time and pH were30min and3.0respectively.The result of the third part about Fenton oxidation-coagulation experiment: Based on Fenton oxidation experiment, the coagulation experiment was combined with Fenton oxidation. In the coagulation treatment, appropriate PAM dose was3.0mg/L and appropriate pH was8.0. Then the removal rates of COD、color、 volatile phenols、ammonia nitrogen were69.57%、89.49%、79.55%and6.20%respectively.Based on comparing effect and cost between the several advanced treatment above, Fenton oxidation-coagulation was accounted an efficient and lower cost method,which has a feasibility of practical application. |
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