MBR处理低浓度稠油废水

为解决稠油废水达标排放问题,构建了一套中试实验装置,以经过除油、浮选和过滤预处理的富含溶解性有机化合物、氮磷缺乏的低浓度难生化稠油废水为原水,进行了187 d的连续运行,结果表明,经过厌氧和好氧生物处理后,出水COD可降至80~100 mg/L以下,再经膜过滤后COD降至60~80 mg/L,加入少量的粉末活性炭进行吸附处理后,出水COD可稳定在50 mg/L以下;水力停留时间从72 h降至30 h时,出水COD基本无变化;气相色谱-质谱分析表明该系统容易去除的有机物为酮类、醇类等物质,而烷烃(C17~C25)和芳烃等为本工艺难降解物质,通过膜生物反应器工艺优化或选择专门降解菌如Acinetobacter spp.进行处理可进一步降低出水COD的浓度。

Treatment of low concentration heavy oily wastewater by membrane bioreactors

To meet the stringent discharge standards, a field pilot study was conducted to treat heavy oily wastewater with rich dissolved recalcitrant organic compounds and low nutrient of nitrogen and phosphorus. The wastewater was pretreated by oil removing, flotation and filtration processes. Through 187 days continuous running, the COD concentration in the effluent was less than 100 mg/L after biological treatment, 60~80 mg/L after membrane filtration and lower than 50 mg/L after powdered activated carbon (PAC) adsorption. Changing HRT from 72 h to 30 h had no significant impact on COD removal performance. Gas chromatography-mass spectrometry (GC-MS) indicates that the MBR can completely remove ketones and alcohols. However, n-alkanes (C17~C25) and aromatic hydrocarbons are found to be refractory degradation, and their removal efficiency may be improved by optimizing the process or using some special degradation bacteria such as Acinetobacter spp.