[Capability and bacteria community analysis of an anaerobic baffled reactor treating soybean wastewater].

Capability and process characteristic of anaerobic baffled reactor (ABR) treating soybean wastewater were investigated in a 4-compartment ABR with an effective volume of 28 L. During an operation period of 100 days, the organic loading rate (OLR) increased by stages and its influence on the chemical oxygen demand (COD) removal efficiency was researched. The bacteria community structures in anaerobic activated sludge from different stages were also investigated by single-strand conformation polymorphism (SSCP) with the eubacterium universal primers SRV3-2P and BSF8/20, while the microbial genetic distance being analyzed by UPGMA communities clustering method. With an inoculated aerobic activated sludge of 18.0 g x L(-1) in terms of mixed liquor volatile suspend solid (MLVSS), the reactor started up at COD concentration of 2000 mg/L, hydraulic retention time (HRT) of 39.5 h and temperature of (35 +/- 1) degrees C for 31 d, the ABR achieved a stable state that resulted in 96% COD removal. When OLR increased stage by stage from 1.2 kg x (m3 x d)(-1) to 6.0 kg x (m3 x d)(-1), the reactor could performed steadily with a COD removal efficiency as high as 98%, and this indicated that compartmentalized ABR held a good performance during shock loadings. It was found that a step change in OLR had a remarkably effect on the structure and distribution of microbial communities in each compartment. With the organic loading rate increase, the genetic distances among the microbial communities in the compartments extended gradually, indicating that the specificity of microbial communities in each compartment was enhanced.