羟胺抑制协同pH调控对人工快渗系统短程硝化的影响

The effect of hydroxylamine inhibition and pH control on achieving shortcut nitrification in constructed rapid infiltration system

针对人工快渗系统(CRI)总氮去除率低的问题,研究了羟胺抑制协同pH调控对人工快渗系统实现由全程硝化向短程硝化转化的可行性,探讨了其对系统内氮素污染物迁移转化和硝化功能菌空间分布及活性的影响.结果表明,0.5 mmol·L^(-1)羟胺连续添加13 d后可实现CRI系统短程硝化的快速启动,氨氮去除率、亚硝氮积累率分别为91.1%、77.9%,经16 d不添加羟胺运行后氨氮去除率、亚硝氮积累率分别降低3.9%、9.8%,此时调控进水pH至8.4,氨氮去除率和亚硝氮积累率均超过90%,CRI系统短程硝化效果显著且稳定性较高.羟胺对硝化菌具有选择性抑制,对AOB和NOB产生明显抑制的浓度分别为0.7、0.5 mmol·L^(-1),羟胺浓度为1.0 mmol·L^(-1)时AOB和NOB活性均被严重抑制且解抑较难;pH调控对短程硝化的影响主要与游离氨(FA)的抑制作用有关,对AOB和NOB产生明显抑制的FA浓度分别为26.5、5.6 mg·L^(-1),NOB比AOB对FA的敏感性更高.

The study focused on the conversion from complete nitrification to shortcut nitrification in the constructed rapid infiltration（ CRI） system by hydroxylamine inhibition and pH control,as well as their impact on nitrogen conversion,nitrifying bacteria spatial distribution and activity,in order to improve TN removal rate in the system. Results show that the ammonia nitrogen removal rate and nitrite nitrogen accumulation rate were 91.1% and 77.9%respectively via adding 0.5 mmol·L^（-1）hydroxylamine for 13 days since the shortcut nitrification in CRI system occurred. Without adding hydroxylamine for16 days,the ammonia nitrogen removal rate and nitrite nitrogen accumulation rate were reduced by 3.9% and 9.8% respectively. The ammonia nitrogen removal rate and nitrite accumulation rate were both above 90% when the influent pH increased to 8.4,and the efficiency of shortcut nitrification in CRI system was stable. The nitrifying bacteria was selected by hydroxylamine inhibition,and their apparent inhibition concentrations on AOB and NOB were0.7 and 0.5 mmol·L^（-1）respectively. When the hydroxylamine concentration was 1.0 mmol·L^（-1）,the activities of AOB and NOB were severely inhibited and difficult to recover. PH control on shortcut nitrification was mainly related to free ammonia（ FA） inhibitions,as their concentrations were 26.5 and 5.6mg·L^（-1）respectively to inhibit AOB and NOB activity. Compared with AOB,NOB was more sensitive to FA.