The Treatment Of Refractory Biodegradable Acidic Wastewater

This research focuses on the treatment of refractory biodegradable polyesterwastewater with high Cl—, phenolic compounds concentration, and other complicatedcomposition. Firstly, the four kinds of pretreatment processes (neutralization, Fenton,membrane diffusion dialysis, microelectrolysis) were sutdied, then microelectrolysisbiological treatment process was carefully studied because of its advatages.The experiment results show that when using Fenton oxidization pretreatmentprocess, with pH 3, FeSO₄·7H₂O concentration 0.8g/L , H₂O₂(30 % ) portion120mL/L,and reaction time 60min, COD removal efficiency was 60%,oxidizationefficiency was good but the additional efficiency of COD removal resulted fromferrous coagulation sedimentation was low.In the Fe-carbon-microelectrolysis pretreatment experiment, spiral scrap ironwas used as ferrous frame and gas was supplied to fluent activated carbonintermittently, thus solved the problem of jam, scrap iron agglomeration anddelamination existing in the traditional micro-electrolysis reactor, obtainned highpretreatment efficiency and operating agility. With influent pH 3 and HRT 6h, theremoval rate of COD_cr, volatile phenolic compounds and TP reached 66%, 60.2%,29% respectively. When pH was improved to 5.5 or higher, BOD/COD ratio increasedto 0.48 from 0.28.In the diffusion dialysis experiment, with distilled water/acid wastewater 1 andQ=600mL/h, 20% Cl—was separated from wastewater. However, some enteredrecycled acid through diffusion membrane at the same time, which brought manydifficulties to the utilization and treatment of recycled acid.In the micro-electrolysis-SBR treatment experiment, with influent 800mL daily,the effluent COD concentration was lower than 200mg/L and sludge settlingcharacteristics was good. According to the kinetics analysis, with the same organicpollutant load, the influent amount of micro-electrolysis-SBR was two times ofneutralization process or SBR process. Also, this process can improve the amount ofbiodegradable pollutant.Through this study, the proper treatment process for polyester wastewater wasdetermined, and some parameters affecting the treatment of refractory biodegradationacid wastewater with high phenolic compounds concentration and other complicatedcomposition were analyzed, too. Meantime, the micro-electrolysis reactor used in thisexperiment and gas sequencing supplying mode provided a new method to solve thoseproblems existing in the traditional micro-electrolysis reactor.