枯草芽孢杆菌对微污染水体的净化作用

Use of Bacillus subtilis in purification of slightly-polluted water

采用投加枯草芽孢杆菌的水质净化方法,系统考察了在典型南方夏季气温下,封闭的模拟微污染水枯草芽孢杆菌净化体系中,投菌浓度、主要环境条件(pH和溶解氧)及其冲击对净化效果的影响.结果表明,枯草芽孢杆菌的最佳投菌浓度为3.2×105cfu·mL-1,适宜的环境条件为:pH5～7,溶解氧4～6mg·L-1.投菌9d后,CODMn、NH4+-N、NO2--N和NO3--N的去除率分别达到95.3%、96.7%、82.0%和28.6%,达到地表Ⅱ类水水质标准.水体的酸碱性变化会造成污染物去除率的显著波动,在pH低于4或高于9的冲击下,净化系统将崩溃且不可恢复;而溶解氧的降低对系统污染物去除率的影响较小,净化系统可以适应溶解氧短期的降低且其除污能力在溶解氧回升后可以恢复.本研究可为枯草芽孢杆菌在湖泊、水库等微污染水体的净化及修复应用提供基础依据.

Bacillus subtilis was employed to purify slightly-polluted water.The effects of bacteria concentration,pH and dissolved oxygen were systematically investigated in a closed and simulated Bacillus subtilis purification system in southern China in summer.The optimum operation conditions for the Bacillus subtilis purification were as follows：the Bacillus subtilis concentration was 3.2×105 cfu · mL-1,pH 5~7 and the dissolved oxygen 4~6 mg · L-1.Under such conditions,the removal efficiency of CODMn,NH＋4-N,NO-2-N and NO-3-N reached 95.3%,96.7%,82.0% and 28.6%,respectively,after a 9 day treatment.After treatment,the water could meet the National Standard Ⅱ for surface water quality.The pH exerted a significant effect on the performance of the purification system which could collapsed and be unrecoverable when pH was lower than 4 or higher than 9.The dissolved oxygen had a negligible effect on the system performance and the system could adapt well to a reduction in dissolved oxygen concentration;yet,the purification capacity of the system recovered to the original level after restoration of dissolved oxygen in the water.This study provides a theoretical and technical basis for the purification of lakes,reservoirs and other slightly-polluted water by Bacillus subtilis.