余氯对城市污水处理厂生化系统的影响研究

Study on the effect of residual chlorine on biochemical system of municipal wastewater treatment plant

新冠疫情会使含氯消毒剂的使用增多,最终可能进入污水处理厂影响生物处理效果。探讨不同浓度的余氯(游离氯和化合氯)对活性污泥处理效果的影响,并观察活性污泥的性能和微生物多样性。结果显示,与未投加余氯相比,投加游离氯浓度大于等于3mg/L或投加化合氯浓度大于等于5mg/L时,出水水质出现显著增加,且化合氯对COD和TN去除抑制作用大于游离氯,对TP去除抑制作用小于游离氯。投加余氯后,活性污泥的沉降性能良好,但芽孢杆菌属(Bacillus)的相对丰度随着游离氯投加量的增加而减少,当化合氯投加量超过1mg/L时,芽孢杆菌属(Bacillus)几乎消失。芽孢杆菌属(Bacillus)的变化导致活性污泥脱氮效率的降低,且化合氯抑制细菌脱氮功能高于游离氯。

Chlorine-containing disinfectants were used increasedly due to the outbreak of2019-nCoV,which may affect biological treatment after entering sewage treatment plants.In this study,the effects of different concentrations of residual chlorine(free chlorine and combined chlorine)on activated sludge were investigated,and the performance and microbial diversity of activated sludge were observed.The results showed that when the concentration of free chlorine was more than 3 mg/L or the concentration of combined chlorine was more than 5 mg/L,the water quality of effluent significantly increased.The inhibitory effect of combined chlorine on the removal of COD and TN was greater than that of free chlorine,and the inhibitory effect on TP was opposite.After addition of residual chlorine,the sedimentation performance of activated sludge was well.But the relative abundance of Bacillus decreased with the increase of the free chlorine dosage and Bacillus almost disappeared when the combined chlorine dosage was more than 1 mg/L,which reduced the denitrification efficiency of activated sludge.The inhibition of bacterial denitrification by combined chlorine was higher than that by free chlorine.