Research On The Degradation And Mechanism Of Mordant Orange â…  By Bio-Degradating Promoting By Internal Electrolysis

Current dye wastewater discharge, with high content of nondegradable toxic substances, can hardly meet the discharge standards, which has become a serious problem. In order to study the deep-treatment of dye wastewater, a technology for degradating Mordant Orangeâ… in water by biological-physico-chemical combination craft consisted of aerobic and micro-electrolysis was studied. As a result, the theoretical basis to develop an efficient and economical craft of deep-treatment of dye wastewater was erected.Physico-chemical craft and biological-physico-chemical combination craft was separately applied to treat Mordant Orangeâ… in water. As to the physico-chemical craft, the degradation effects of Mordant Orangeâ… with micro-electrolysis and micro-electrolysis-UV were compared. The effects of volume ratio of Fe to C, initial pH and hydraulic retention time (HRT) on the further treatments of Mordant Orangeâ… with combination craft were investigated. The experiment result showed that : The removal rates of color and Mordant Orangeâ… were found to be 98.14% and 93.29%, respectively, when the following optimal condition was used: dye concentration of 100mg/L with a pH of 5.0,vollum rate of Fe to C 1:2,rate of air/water 15:1 and an internal electrolysis hydraulic retention time of 40min. Compared with internal electrolysis, obvious effects of ultra-violet on the further removal of color and Mordant Orangeâ… were not found. In biological-physico-chemical process, effect of reflux ratio in different system hydraulic retention time(HRT) on the degradation of Mordant Orangeâ… was focused. When the system hydraulic retention time (HRT) was 6h, the reflux ratio was 2, the removal rates of color and TOC were up to 95.32% and 79.44% , respectively. While further decreasing the system hydraulic retention time (HRT) to 4h, the removal rates of color and TOC can also be found to be 89.86% and 77.28%, respectively.The possible transformation of Mordant Orangeâ… in combination craft analyzed by UV-Vis, HPLC and LC-MS was as followed: Mordant Orangeâ… was converted to P-phenylenediamine, 5-Aminosalicylic acid and their cleavage products-acid and aldehyde of six carbon in micro-electrolysis process, then these products were returned to aerobic process to be further used by microorganisms. 2,3-dihydroxy -4-amino adipic acid was used most slowliest by microorganisms among the acid and aldehyde of six carbon, and was mainly converted to 2,3-epoxy-2-cyclobutene ether, which can be detected in final discharge.Based on the redevelopment of traditional treatment processes, the economic cost of the additional deep-treatment was estimated. Additional investment was cumulated to about 1600,800 yuan, while the additional average operating cost was about 1.32 yuan per ton. So the purpose of developing a time-saving, economic and effective craft was achieved.