The Experimental Study On Advanced Treatment Of Coking Wastewater Based On Fenton Oxidation-coagulation

The study mainly aims at treatments of coking wastewater in which the concentration of turbidity, COD, and ammonia nitrogen is higher than the nation discharge standard after biochemical treatment. On the foundation of investigation the methods of advanced treatment for coking wastewater, the methods such as Fenton oxidation, coagulation and combined process have been put forward. This study tries to find out a reasonable advanced process to dispose coking wastewater in an efficient and lower cost manner.The whole experiment includes three steps. Firstly, the best experimental conditions of coagulation using PAC and PFS with coagulant aid (PAM) are studied. The second part is to study the best experimental condition of Fenton oxidation. Finally, on the best experimental conditions of Fenton oxidation-coagulation, the removal effect of turbidity, COD, and ammonia nitrogen is studied. The experiment results show that, on the best experiment conditions of PFS coagulation(PFS's dosing quantity is 150mg/L, pH is 7, the temperature is 30℃, PAM's dosing quantity is 3mg/L), the removal rate of turbidity, COD, and ammonia nitrogen is respectively 96.16%,78.28% and 38.94%. On the best experiment conditions of PAC coagulation(PAC's dosing quantity is 100mg/L, pH is 7, the temperature is 30℃, PAM's dosing quantity is 2mg/L), the removal rate of turbidity, COD, and ammonia nitrogen is respectively 97.76%, 77.26% and 40.38%. On the best experiment conditions of Fenton oxidation (Fe2+'s dosing quantity is 1000mg/L, H2O2's dosing quantity is 832.5mg/L, pH is 3, the time of oxidation is 2h), the removal rate of turbidity, COD, and ammonia nitrogen respectively is 97.42%,92.75% and 47.96%. On the conditions of Fenton oxidation combined with PAC coagulation(Fe2+'s dosing quantity is 500mg/L, H2O2's dosing quantity is 416.25mg/L, pH is 3, the time of oxidation is 30min, PAC's dosing quantity is 100mg/L), the removal rate of turbidity, COD, and ammonia nitrogen respectively arre 94.58%, 69.77% and 39.49%. The outflow of COD can meet the first order of industrial wastewater discharge standard, and the outflow of turbidity and ammonia nitrogen can meet the second order of industrial wastewater discharge standard (GB8978-1996).