颗粒填料复合式膜生物反应器的长期运行特性

Performance of hybrid membrane bioreactor with suspended carriers during long-term operation

在实验室条件下,从有机物去除效果、透膜压差、污泥颗粒粒径和污泥混合液过滤阻力等方面对颗粒填料复合式膜生物反应器(HMBR)的长期运行特性进行了研究。结果表明,与普通MBR相比,HMBR可以显著减缓膜污染,延长稳定运行时间,减少膜组件的清洗频率,在本试验条件下,当膜通量分别为3.0、4.5和6.0 L/(m2.h)时,MBR的透膜压差增长率分别是HMBR的5.5、3.3和2.2倍;HMBR的有机污染物去除效果显著,COD平均去除率达到92.3%,但是由于颗粒填料对HMBR膜表面污泥沉积层的去除,HMBR对有机物的筛滤/吸附作用减弱,造成HMBR出水的COD浓度比MBR略高;随运行时间的增长,HMBR污泥颗粒粒径呈下降趋势,而污泥混合液的过滤阻力逐渐增大,由于颗粒填料对污泥絮体的剪切作用,以及污泥生物相的变化导致HMBR的污泥粒径下降趋势比MBR更为明显,粒径分布范围更窄,而且HMBR的污泥混合液过滤阻力增长速率略大于MBR。

Performance of hybrid membrane bioreactor （HMBR） with suspended carriers during long-term operation was studied under the lab conditions in such aspects as COD removal efficiency, transmembrane pressure （TMP）, sludge particle size distribution and filtration resistances of sludge suspension. Compared with MBR,HMBR showed great superiority in reducing membrane fouling and decreasing the cleaning frequency of membrane. When membrane flux was 3.0, 4.5 and 6.0 L/（m^2 · h） respectively,TMP increase rates of MBR were 5.5, 3.3 and 2.2 times of HMBR. The average COD removal rate of HMBR was 92.3% , and was slightly lower than MBR because the suspended carriers removed the cake layer deposited on the membrane surface of HMBR, which could reject/sorb the low molecular weight substances or submicron colloidal particles. The sludge particle size of HMBR diminished with operation time, while the filtration resistance of sludge suspension in HMBR increased with operation time. Due to the shear stress of suspended carriers imposed on the microbial flocs could induce the breakage of microbial flocs and thus release colloidal substance, the sludge particle size of HMBR was slightly smaller than MBR and the increase rate of filtration resistance of sludge suspension in HMBR was a little greater than MBR.