微好氧水解酸化在石化废水预处理中的应用研究

应用微好氧水解酸化技术对北方某石化污水厂进行了改造,投产后对其进行了跟踪监测.结果表明,在进水COD为490.3~673.2 mg·L-1,水力停留时间(HRT)为24 h以及溶解氧(DO)控制在0.2~0.35 mg·L-1条件下,监测阶段内COD的平均去除率为11.7%,出水和进水相比,BOD5/COD提高了12.4%,UV254值降低了11.2%,挥发性脂肪酸(VFA)浓度升高了23.0%.相对分子质量分布测定和好氧生物降解性试验结果表明:石化废水采用微好氧水解酸化预处理后,小分子有机物(1×103)所占比例由59.5%提高至82.1%,而大分子有机物(100×103)所占比例由31.8%降低到14.0%.经微好氧水解酸化预处理后降解性有显著提高,原水COD经48 h好氧处理可降至102.2 mg·L-1,而微好氧水解酸化出水COD经48 h好氧处理可降解至71.5 mg·L-1.微好氧水解酸化出水的SO2-4浓度(930.7±60.1)mg·L-1]高于进水(854.3±41.5)mg·L-1],表明微好氧环境对硫酸盐还原菌(SRB)有抑制作用.由于硫酸盐的还原受到抑制,减少有毒和恶臭类气体产生,改善了周围环境.

Application of Micro-aerobic Hydrolysis Acidification in the Pretreatment of Petrochemical Wastewater

Micro-aerobic hydrolysis acidification technology was applied in the reconstruction of ananaerobic hydrolysis acidification tank in a north petrochemical wastewater treatment plant.After put into operation, the monitoring results showed that the average removal rate of COD was 11.7% when influent COD was 490.3-673.2mg·L^-1, hydraulic retention time (HRT) was 24 and the dissolved oxygen (DO) was 0.2-0.35mg·L^-1.In addition, the BOD₅/COD value was increased by 12.4%, the UV₂₅₄removal rate reached 11.2%, and the VFA concentration was increased by 23.0%.The relative molecular weight distribution(MWD) results showed that the small molecule organic matter(<1×10³)percentage was increased from 59.5% to 82.1% and the high molecular organic matter(>100×10³) percentage was decreased from 31.8% to 14.0% after micro-aerobic hydrolysis acidification.The aerobic biodegradation batch test showed that the degradation of petrochemical wastewater was significantly improved by the pretreatment of micro-aerobic hydrolysis acidification.The COD of influent can be degraded to 102.2mg·L^-1 by 48h aerobic treatment while the micro-aerobic hydrolysis acidification effluent COD can be degraded to 71.5 mg·L^-1on the same condition.The effluent sulfate concentration of micro-aerobic hydrolysis acidification tank (930.7±60.1) mg·L^-1]was higher than that of the influent (854.3±41.5)mg·L^-1], indicating that sulfate reducing bacteria (SRB) was inhibited.The toxic and malodorous gases generation was reduced with the improvement of environment.