电子供体对地下水中高氯酸盐生物去除的影响研究

通过静态实验,考察了电子供体类型及用量对厌氧条件下微生物去除地下水中高氯酸盐的影响.结果表明,电子供体醋酸盐和H₂的加入,可以明显提高ClO₄^-的去除率,驯化后的微生物去除ClO₄^-的速率比未加入电子供体时提高约1.4~3倍.Monod动态模型能很好地拟合两种电子供体环境下ClO₄^-的微生物去除过程,分别以醋酸盐和H₂作为电子供体时,基质半饱和常数K_s为12.6 mg·L^-1和2.2 mg·L^-1,最大比基质消耗速率V_m为0.45 d^-1和0.08 d^-1.动力学参数表明,本实验条件下,异养型混合菌去除ClO₄^-的效果明显优于自养型混合菌;在少数受高浓度ClO₄^-污染的地下水环境中,为了提高ClO₄^-的去除速率只有通过增加菌体浓度或提高微生物酶的活性来实现.随着电子供体醋酸盐用量增加,ClO₄^-的(比)消耗速率逐渐增大.当初始CH₃COO^-与ClO₄^-的比例为3.80 mg(COD)/mg(ClO₄^-)时,比消耗速率v最大(0.27 d^-1).

Electron donors for the biological removal of perchlorate in groundwater

Effects of different types and concentrations of electron donors on anaerobic biological perchlorate reduction in groundwater were studied in batch experiments. The results show that addition of acetate and hydrogen as electron donors can significantly improve the removal efficiency of perchlorate. The removal rate of perchlorate increases by about 1.4 to 3 folds than no addition of electron donor after acclimation. Monod dynamic model fits well the data of biological reduction of perchorate using acetate and hydrogen as the electron donors. The parameters of K_s (half-saturation constant) are 12.6 mg·L^-1 and 2.2 mg·L^-1, while V_m (maximum specific reduction rate) are 0.45 d^-1 and 0.08 d^-1, respectively, which indicate that perchlorate removed by mixed cultures of heterotrophic is more effective than mixed cultures of autotrophic under the conditions of this study. In a few environmental areas with underground water highly contaminated by perchlorate, enhancement of the reduction rate of perchlorate can be only achieved by increasing the cell concentration or the activity of microbial enzymes. With the increasing of electron donor concentrations, the reduction rate of perchlorate increases gradually. The highest specific reduction rate of perchlorate (0.27 d^-1) was achieved at the initial ratio of 3.80 mg(COD)/mg(perchlorate).