吸附-预沉淀MBR工艺处理生活污水及膜污染控制效果

Domestic wastewater treatment and membrane fouling control by an innovative MBR system combined with adsorption and rough-sedimentation

膜污染是限制膜生物反应器(MBR)广泛应用的主要因素之一。针对MBR处理生活污水过程中存在的硝化效果不稳定与膜污染问题,提出了一种新型的MBR系统:通过吸附-预沉淀实现进水中碳氮的分离和单独处理,不仅提高了污染物去除效果,且能够有效控制膜污染。研究结果表明,吸附-预沉淀可以去除进水中约89.7%的有机物,系统出水COD、NH+4-N平均浓度为24 mg/L、0.78 mg/L,去除率分别为95.9%和98.1%。MBR中碳氮比的降低和硝化细菌比例的增加大大降低了MBR内MLSS、EPS和SMP含量,平均浓度分别为5 185 mg/L、41 mg/g MLSS和2.62 mg/g MLSS。在膜通量为4 L/(m2·h)条件下,TMP可稳定保持在20 kPa左右。通过吸附-预沉淀过程可有效控制MBR中的膜污染。

Membrane fouling is one of the main factors limiting the widespread application of membrane bioreactor （MBR）. Aiming at the instable nitrification and membrane fouling of traditional MBR, an innovative MBR system combined with an adsorption and a rough sedimentation chamber was extensively investigated for domestic wastewater treatment and membrane fouling control. Experimental results revealed that pollutants removal was improved and the membrane fouling was also effectively reduced with the separation of organics and nitrogen. Approximately 89.7% of the organics in influent was removed in the adsorption and rough sedimentation, thus improved the nitrification ＂in MBR. Effluent COD and NH4＋ -N were averaged at 24 mg/L, 0. 78 mg/L, respectively, corresponding to the removal of 95.9% and 98. 1%. On the other hand, the concentrations of MLSS, EPS, and SMP were obviously reduced due to the decrease of carbon to nitrogen ratio and the increase of nitrifying bacteria, resulting to the average values of 5 185 mg/L,41 mg/g MLSS and 2.62 mg/g MLSS. As a con- stant flux about 4 L/（m2 · h） applied, the TMP was kept around 20 kPa. To sum up, the separation of carbon and nitrogen helped improve pollutants removal and control the membrane fouling.