Degradation of O-chlorophenol by Immobilized Photosynthetic Bacteria in SBR

In order to investigate the photosynthetic bacterial biodegradation property of o-chlorophenol, preparation of immobilized photosynthetic bacteria gelatinous pellets and application in the Sequencing Batch Reactor (SBR) were studied respectively. Rhodopseudomonas palustris PSB-ID being immobilized with sodium alginate as immobilizing carrier and activated carbon as additive material, the optimal conditions of immobilized microorganism gelatinous pellets preparation had been determined through orthogonal experiments. The biodegradation efficiency of immobilized cells and free cells were studied compared with each other. The results show that the optimum conditions for the immobilization arc as follows: activated carbon concentration 1 %, sodium alginate concentration 3 %, PSB-ID cells / investment materials 1/20. Under the chosen conditions, the biodegradation rate of o-chlorophenol by the immobilized photosynthetic bacteria gelatinous pellet was 72.6 % after 7 days culture. It's indicated that immobilized cells have higher o-chlorophenol degradation ability than free cells, by testing comparison. The immobilized photosynthetic bacteria gelatinous pellets were added to the SBR. The effects of reaction parameters(immobilized gelatinous pellets addition, aeration rate) on o-chlorophenol degradation efficiency in the reactor were studied respectively. The results showed that, under dark aerobic condition, the optimum technological conditions for the bioreactor with effective volume 5 L were as follows: immobilized gelatinous pellets addition 20 g, aeration rate 100 L.h(-1) Under this condition, bioreactor system could treat the o-chlorophenol wastewater effectively and steadily, with the removal rate of 65 % or so. This study provides a comparatively reliable parameter for the o-chlorophenol industrial wastewater treatment by the photosynthetic bacteria.