弱酸性条件下丙酸富集培养物的降解特性

为阐明厌氧生物处理系统中pH降低对丙酸降解的影响，考察了弱酸性条件下丙酸富集培养物的降解特征.在污泥接种量为0.22g MLVSS/L，初始丙酸浓度为1000mg/L条件下，对照组（pH7.0）的丙酸能够被该富集培养物快速降解，在接种第6d时，丙酸去除率达到了98.5%.当pH从7.0分别降低至6.5和6.0时，丙酸降解速度立即下降.但经过2~3d的适应后，丙酸降解速率恢复到对照的水平，并分别在培养至第8d和9d时其去除率达到了97%以上.当pH为5.5时，丙酸降解被完全抑制.在整个实验过程中，均未检测到氢气，而乙酸也只有在培养初期有过短暂的积累.该结果表明，在该丙酸富集培养物中，产甲烷菌对弱酸性环境具有更好的耐受性和适应性.

Degradation characteristics of a propionate enriched culture at slightly acidic conditions

To clarify the effects of pH on propionate degradation in an anaerobic system, the degradation characteristics of a propionate enriched culture at slightly acidic conditions were investigated. Under the biomass of 0.22g MLVSS/L and initial propionate of 1000mg/L conditions, propionate was rapidly oxidized at pH7.0 (control) and propionate removal achieved 98.5% after 6days cultivation. pH decrease, from 7.0 to 6.5 and 6.0, resulted in propionate removal rate was decreased instantaneously. But propionate degradation rate was recovered to the value at pH 7.0 after 2~3 days adaptation. Propionate removal at pH 6.5 and pH 6.0 were reached above 97% after 8 days and 9 days cultivation, respectively. Propionate was hardly decomposed at pH 5.5 during the whole cultivation. During the whole experiment, no hydrogen was detected and acetate was transient accumulation in the early culture. These results indicated methanogens were more acid resistance than propionate-oxidizing bacteria.