低温下表面流人工湿地中氨氮型富营养化水体净化研究

以氨氮为主要氮组分的富营养化水体为研究对象,采用批量培养方式对比研究了6.8～7.2℃水温下浮水植物系统(2种水葫芦Eichhornia crassipes、浮萍Lemna minor)、泡沫板系统(无生命覆盖物系统)及空白系统(无覆盖物系统)的脱氮效果,并探讨了6.4～11.2℃水温下不同起始COD浓度(27～105 mg/L)对各污染物去除的影响.结果表明,溶解氧(DO)是影响NH₄⁺-N去除的关键因子之一,好氧时期各系统NH₄⁺-N去除率占整个时期NH₄⁺-N去除率的61%～88%.3种植物系统中NH₄⁺-N的去除率(45%～56%)普遍高于泡沫板系统(38%)与空白系统(38%),而TN和COD去除效果差异则与植物类型有关;随着水体中起始COD浓度的升高,系统中DO逐渐由好氧状态降至0,该结果对NO₃^--N去除率影响最大(去除率由67%上升至95%),而对其它水质指标(COD,TN,NH₄⁺-N)的影响相对较小.

Purification of ammonia-type eutrophic waterbody in surface flow constructed wetland at a low temperature

Denitrification in three floating-plant systems, including two subspecies of hyacinth and duckweed, and foamy board system were investigated by batch cultivation at a low water temperature of 6.8 degrees C to 7.2 deggres C. Effect of initial COD on the system at a water temperature of 6.4 degrees C to 11.2 degrees C was also discussed. The results were obtained as follows: DO was one of the important factors, NH4+ -N removals in aerobic condition were 61%-88% in overall period. NH4 -N removal in plant systems was higher than that in the foamy board and control systems while differences of TN and COD removals among plant system, foamy board system and control system were determined by the floating-plant type. The increase of initial COD concentration, followed by the decrease of DO from >4 mg/L to 0 mg/L, resulted in an obvious improvement of NO; -N removal. However, it had a less effect on other water quality norms such as COD, TN and NH4+ -N.