采用生物膜培养反应器(RAB)模拟给水管网系统,研究了pH和温度对硝化作用的影响.结果表明,较低水温(15℃)对硝化作用的影响不明显,而在较高水温(30℃)下模拟管网中明显地发生了硝化作用.较低水温(15℃)下,提高水的pH对硝化作用的影响较小,而在较高水温(30℃)情况下提高水的pH对硝化作用具有明显的控制效果.在较高水温时,pH由7.5±0.22提高到9.3±0.24,反应器中余氯胺浓度平均升高0.76 mg/L,生物膜和出水中的氨氧化细菌(AOB)浓度分别降低0.6 lgMPN/cm2和1.4 lg MPN/mL,水中异养细菌降低98 CFU/mL.2种pH条件下反应器出水亚硝酸氮浓度较进水分别提高4倍和3倍.而在较低水温(15℃)条件下,pH由7.4±0.15提高到9.3±0.26时,反应器出水氯胺浓度、亚硝酸氮和氨氮浓度变化都不大,水中异养细菌浓度稳定.
The effect of pH and temperature on the controlling of nitrification was evaluated using rotating annular bioreactors(RABs),which were applied to simulate the drinking water distribution system.The results showed that elevated pH had little effect on nitrification occurrence at low temperature(15℃),however the pH controlling effect on nitrification was obvious at high temperature(30℃).With pH increasing from 7.5±0.22 to 9.3±0.24 at high temperature(30℃),the residual chloramines concentration increased to 0.76 mg/L,and the AOB concentration in the biofilm and bulk water reduced 0.6 lg MPN/cm2 and 1.4 lg MPN/mL respectively,the heterotrophic bacteria concentration in bulk water reduced 98 CFU/mL.With pH increasing from 7.4±0.15 to 9.3±0.26,compared with the influent nitrite concentration,the effluent nitrite concentration increased four and three times respectively at different pH levels.The effluent residual chloramines,nitrite nitrogen,ammonia nitrogen concentrations varied slightly compared with influent at low temperature(15℃),and the effluent heterotrophic bacteria concentration was also stable.