Research On The Treatment Of Membrane Filtration Concentrate Rejected By Coagulation-clarification And Fenton Oxidation

As increasingly strict emission standard of landfill leachate was made, membrane technology was widely used because of its good treatment effect. However, a large amount of liquid membrane filter (the concentrate) was produced in the process of membrane technology. The concentrate which contains high concentrations of organic matter, ammonia nitrogen, salt pollution and poor biodegradability was difficult to be disposed. In addition, the treatment is expensive. These disadvantages had become the bottleneck problem of application of membrane technology in landfill leachate.In this paper, the combined process of coagulation-Fenton clarification was applied. According to the characteristics of concentrate which were remained in NF+RO membrane filtration in ZhangZhou Kowloon Ridge landfill,the dosage of PAC, PAM, FeSO4·7H2O, H2O2 and their influence have been studied in concentrate processing technology. On the basis of experimental results, the pilot process had been run.The pilot results showed that the optimal dosage of PAC and PAM was 1100 mg/L and 10 mg/L, respectively, in coagulation reaction.The optimal dosage of FeSO4·H2O and H2O2 was 1 g/L and 3 mL/L in Fenton reaction, respectively, on the basis of these results, the landfill leachate NF+RO mixed concentrate pilot process was implemented. Meanwhile, the operating parameters of mechanical stirring clarification+Fenton+vertical flow sedimentation processes were designed in pilot operation..The optimal operation onditions of pilot process were determined as follows:dosage of PAC, PAM, FeSO4 and H2O2 was 2000 mg/L,9 mg/L,1.6 g/L,8 ml/L, respectively, under the control of the influent flow rate of 5 m3/h, water inflow of 40 m3/d, mixer frequency of 50 Hz and enhance impeller frequency of 45 Hz. the concentrate removal of CODcr and colorimeter were 45% and 50% after treatment of mechanical stirring clarification and Fenton process, respectively, and then through the vertical flow sedimentation tank, the average concentration of CODcr was 350 mg/L and colorimeter was 24. The CODcr and colorimeter removal efficiency were up to 76.8% and 95.4%,respectively,under optimal pilot process.Finally, Through economic benefit estimate the treatmentcost of membrane filtration concentrate was 35.85 yuan/m3.