垃圾填埋层通风对循环渗滤液的硝化与反硝化作用

Nitrification and Denitrification of Recirculated Leachate by Aerated Landfill Layers

渗滤液循环回灌填埋层同时去除其中的碳、氮污染物的前提是层内必须存在好氧、兼性、厌氧混合代谢条件.通过对比间歇强制通风和强化自然通风这两种使填埋层内形成混合代谢条件的实验发现:两者均可使填埋层具有去除回灌渗滤液中化学耗氧量CODCr和氨氮的能力,间歇强制通风的去除负荷为CODCr165 g/(m2.d),氨氮7.5 g/(m2.d);强化自然通风则为CODCr480 g/(m2.d),氨氮16 g/(m2.d).填埋层对氨氮硝化形成的硝态氮的反硝化能力与回灌渗滤液中生物可利用碳BC与氨氮之比BC/N有关,当此比值大于4.5时,间歇强制通风填埋层可达到几乎完全的反硝化水平.但强化自然通风填埋层中,即使当BC/N大于7.5时,流出液中硝态氮仍大于50 mg/L,主要原因是层内存在持续有氧的区域,阻碍了对其的完全反硝化.

To simultaneous remove CODCr and NH4^＋-N in the leachate by recirculation, co-existence of aerobic, facuhative and anaerobic metabolism in landfill layer should be provided. Intermittent forced aeration and natural ventilation were utilized to study the multiple metabolisms in the simulated landfill columns. Results showed that both of them could assist in removing CODCr and NH4^＋ -N in the recirculated leachate, in which 165 g/（m^2·d） of CODCr and 7.5 g/（m^2·d） of NH4^＋ -N could be eliminated by the column with forced aeration, and 480 g/（m^2·d） of CODCr and 16 g/（m^2·d） of NH4^＋ -N eliminated by the column with natural ventilation. Denitrification of NOx^- was related to the ratio of biodegradable carbon to NH4^＋ -N in the recirculated leachate. When the ratio was up to 4.5 in the column with forced aeration, almost all NO, was denitrified, while for natural ventilation, even the ratio increased to more than 7.5, NOx^- in the leachate effluent was still above 50 mg/L, which was mainly contributed to the denitrification inhibition due to the persistent existence of aerobic zone.