Micro-electric Field-zero-valent Iron Enhanced Hydrolytic Acidification Performance For Chemical Wastewater

The hydrolysis acidification process has advantages of low investment, strongadaptability and easy management. Therefore it is now being more and more widelyused in the pretreatment of organic chemical wastewater. However, because theorystudy is lacking and paremeter is in perfection, it also faces problems of poor treatmenteffect. Although a number of studies on adding zero-valent iron to the traditionalanaerobic reactor to enhance the effect of anaerobic digestion have been presented,little has been known about using electric field to strengthen the zero-valent ironhydrolysis acidification by now.The biodegradability of industrial wastewater mixture was improved with theaddition of zero-valent iron（ZVI） and micro-electric field which enhanced the effectof hydrolytic acidification. The experiments were carried out simultaneously in fourreactors: micro-electric field–zero-valent iron（ZVI） anaerobic reactor (R1),micro-electric field anaerobic reactor (R2), zero-valent iron anaerobic reactor (R3) andregular anaerobic reactor (R4). It is demonstrated that micro-electric field–zero-valentiron facilitated hydrolytic acidification evidently, with a TOC removal rate of70%athydraulic retention time (HRT) of81h and BOD5/CODCrfrom0.15to0.41. As a result,the biodegradability of wastewater was significantly improved.Based on theses experiments, it was operated under a condition of continuous waterinput. Various effect factors such as hydraulic retention time, reflux ratio, currentintensity, electrode distance, initial pH and zero-valent iron dosage of themicro-electric field-zero-valent iron anaerobic reactor operation were inspected, andthe feasible condition was confirmed. It studied the improvement of wastewaterbiodegradabitlity before and after the reaction. The results showed that under the sameprocess, the effect of hydrolysis acidification in the micro-electric field-zero-valentanaerobic reactor was better than in the traditional anaerobic reactor. The optimaloperation parameters of the micro-electric field-zero-valent iron anaerobic reactorwas that the optimal hydraulic retention time was24h, reflux ratio was5:1, currentintensity was10mA, electrode distance was1cm, initial pH was7~7.5and zero-valentiron dosage was5~7g. The wastewater was treeated7days under these conditions withimproving BOD5/CODCrfrom0.18to0.42and great improvement of the effluentbiodegradability. It was studied that the bacteria community in the micro-electric field-zero-valent iron anaerobic reactor for hydrolysis acidification, using PCR-DGGE technique. It found that there was significant change of the bacteria abundance,especially for the hydrolysis acidification bacteria. It proved that the micro-electricfield and zero-valent iron advanced the hydrolysis acidification according tomicrobiology.