蠕虫在膜生物反应器和活性污泥法中的污泥减量研究

通过长达345d的中试规模试验,研究比较了蠕虫在膜生物反应器(MBR)和活性污泥法(CAS)的生长状况及其导致的污泥减量效果.CAS中的蠕虫生长状况明显优于MBR的蠕虫生长状况.MBR曝气池中平均蠕虫密度(10条·mg-1)远低于CAS曝气池中平均蠕虫密度(71条·mg-1),并且CAS中蠕虫连续保持高密度(>30条·mg-1)生长达172d.CAS中红斑瓢体虫和仙女虫交替成为优势蠕虫.蠕虫生长对MBR的污泥产率(0 40kg·kg-1)和污泥沉降性能(污泥沉降指数133mL·g-1)影响很小,但却能显著减少CAS的污泥产率(0 17kg·kg-1)和改善污泥沉降性能(污泥沉降指数为60mL·g-1).仙女虫比红斑瓢体虫能更大地减少污泥产量和更好地改善污泥沉降性能.蠕虫生长不影响MBR的COD去除率和出水水质,但却显著影响CAS的COD去除率和出水水质.

Minimization of sludge production by Oligochaete in membrane bioreactor (MBR) and conventional activated sludge (CAS) processes

P_ilot scale experiments were carried out to compare sludge reduction induced by Oligochaete in a submerged membrane bioreactor (MBR) and a conventional activated sludge (CAS) reactor for 345 days. Worm growth in the CAS reactor was much better than in the MBR. The average worm density of the aeration tank in the CAS reactor was 71 total worms/mgVSS, much higher than that in the MBR (10 total worms/mg). Worms in the CAS reactor occurred nearly throughout the operating period and were continuously maintained at over 30 total worms/mg in the aeration tank for 172 days. The alternating dominance of worm types in both reactors changed between Aeolosoma and Nais, and the time of Aeolosoma dominance was longer than that of Nais dominance. Worm growth in the MBR contributed to neither sludge reduction nor improvement of sludge settling characteristics due to low density. Worm presence and bloom in the CAS reactor greatly decreased sludge yield and improved sludge settling characteristics at high density. Both the average sludge yield (0.17kg·kg^-1) and SVI (60mL·g^-1) in the CAS reactor were much lower than those in the MBR (0.40kg·kg^-1 and 133mL·g^-1). Nais had higher potential for sludge reduction than Aeolosoma. Worm growth had little impact on effluent quality in the MBR, but affected effluent quality greatly in the CAS reactor.