不同曝气强度下MBR污泥混合液可滤性分析

Analysis of Filterability of Mixed Liquor Under Variant Aeration Intensities in Membrane Bioreactor

研究了曝气强度对膜-生物反应器(MBRs)污泥混合液的可滤性的影响.2套MBRs采用曝气强度分别为500L/h及100 L/h恒流出水模式连续运行60 d,应用污泥混合液过滤装置测定污泥混合液的可滤性.结果表明:过高的曝气强度将恶化污泥混合液的可滤性,增加膜污染速率;曝气强度的增加将导致污泥混合液上清液中相对分子质量大于10 000的溶解性微生物代谢产物(SMP)浓度增加,此部分大分子有机物浓度的增加恶化了污泥混合液的可滤性;曝气强度大于500 L/d也将导致污泥絮体中1～10μm细小颗粒和胞外聚合物(EPS)含量的增加.

The influence of aeration intensity on the filterability of mixed liquor in membrane bioreactors （MBRs） has been studied. Two lab-scale MBRs with aeration intensities of 500 L/h and 100 L/h,respectively,were operated for 60 d with a constant permeating flux ,and the filtration tests for mixed liquor have been conducted to confirm the mixed sludge filterability. Experimental results show that excessive aeration intensity has negative impact on the filterability of the mixed sludge in MBR and increases the rate of membrane fouling. The increase of aeration intensity results in the increase of soluble microbial products （SMPs）with relative molecular weight over 10 000 in the supernatant,which significantly obstructs the filtration of the mixed sludge. Small particles with the size of 1-10 μm and EPS in flocs also increase when the aeration intensity is over 500 L/h.