氯、亚氯酸盐控制氯胺消毒管网硝化作用效果

采用2台串联环状生物膜培养反应器(biofilm annular reactor,BAR)模拟氯胺消毒给水管网系统,通过对余氯、NH₄⁺-N、NO₂^--N、NO₃^--N、DO、异养菌(heterotropic,HPC)及亚硝化菌(amnoniu-oxidizing bacteria,AOB)等指标进行检测,共同评价氯和亚氯酸盐2种消毒剂对氯胺消毒管网中硝化作用的控制效果.试验结果表明,出厂水再投氯消毒可造成NH₄⁺-N降解,使得NO₂^--N和NO₃^--N产生积累;再投亚氯酸盐更易提高管网中余氯和DO的质量浓度,使得NO₂^--N和NO₃^--N质量浓度降低,可有效地控制硝化作用;与投加氯消毒时相比,投加0.6mg/L亚氯酸盐时,第1台BAR中悬浮和生物膜中HPC分别平均降低了2.58log和2.86log,悬浮及生物膜中AOB降低约1log,亚氯酸盐能对AOB起到控制灭活效果而等量氯对其几乎没有灭活效果.因此,在控制管网硝化作用方面,亚氯酸盐与氯胺联用的消毒效果优于氯与氯胺.

Disinfectant Efficacy of Chlorine and Chlorite in Nitrification Control in Water Distribution Systems

Two biofilm annular reactors(BAR) in series were investigated to compare the relative efficacy of chlorine and chlorite in nitrification by analyzing residue chlorine,NH+4-N,NO-2-N,NO-3-N,DO,HPC and AOB.The results showed that the concentration of NH+4-N was dropped and those of NO-2-N and NO-3-N were increased during the stage of adding chlorine.However,that was not happened by adding chlorite because of enhancing the effluent concentration of residue chlorine and DO.Consequently,the chlorite was more effective than chlorine in mitigating nitrification.Compared with equivalent chorine(0.6 mg/L),the suspended and attached HPC of the first BAR reduced 2.58 log and 2.86 log,respectively,both suspended and attached AOB declined 1 log using the chlorite.Therefore,the effect of chlorite is better than chorine combined with chloramine in mitigating nitrification in distribution systems.