摘要
人工湿地是一种高效、低耗的污水处理方法,能有效降低水体生物耗氧量、化学耗氧量、总悬浮物及污染细菌等,而对氮(N)的去除率较低且不稳定。水体中的总氮(TN)可分为颗粒物有机氮(PON)和总可溶性氮(TDN)。目前对TDN的各组分,如可溶性有机氮(DON)、氨氮(NH_4^+-N)和硝氮(NO_3^--N)的去除机理及方法较为关注,而对总体上的PON和TDN的组成比例及去除率了解仍不充分。该研究在北京野生动物救护中心水禽栖息的人工湖及配套人工湿地展开,从2014年4—11月监测了净化前后水体中各种N形态组成和去除率,并分析了藻类爆发与PON和TDN去除率的关系。结果表明,4─7月人工湖中PON质量浓度占TN质量浓度47.83%±9.90%(平均值±标准差,下同),8─10月升至86.93%±7.71%。水体中PON与叶绿素a(Chl a)质量浓度呈显著正相关(n=8,r=0.76,P<0.001),由此推测8─9月藻类急剧增多可能使人工湖中的TDN转变为PON。生长季人工湖水进入表流人工湿地后PON降低60.02%±22.97%,PON去除量占TN去除量90%以上。PON与Chl a的去除率均表现为8─10月低于4─7月,暗示在浮游生物爆发期人工湿地PON的去除能力可能达到了满负荷。另外,生长季表流人工湿地对水体TDN去除效果不明显(-16.40%±27.88%)。该研究获得结论,水禽栖息的污水进入表流人工湿地后TN去除主要以PON为主,且PON去除率与藻类动态相关。针对此类污水,增强人工湿地PON去除能力将能有效提高污水TN去除率,尤其在藻类爆发期除N效果更为显著。
Constructed wetlands are an effective and green method for purifying wastewater. They efficiently remove the biological oxygen demand, chemical oxygen demand, total suspended solids and bacteria contamination. However, the removal of nitrogen by constructed wetland has been found to be less efficient. Information is lacking on the relative proportions of particulate organic nitrogen (PON) and total dissolved nitrogen (TDN) in total nitrogen (TN). Furthermore, their removal efficiency in constructed wetlands is poorly known, although the removal efficiency of TDN components (DON, NH4+-N, NO3-N) has been widely studied. This study was conducted at the Beijing Wildlife Rescue and Rehabilitation Centre, where a constructed lake for the habitation of waterbirds and a constructed wetland for purifying sewage from the lake are located. During April to November 2014, we monitored the efficiency for the wetland to remove different nitrogen forms from the lake sewage, and analyzed the relationship between phytoplankton dynamics and nitrogen removal. The PON accounted for 47.83%±9.90% (mean±SD) of TN in the constructed lake during April-June, compared to 86.93%±7.71% during August-October. The Chla positively correlated with PON (n=8,r=0.76, P<0.001) over the study period, indicating that increases in PON may result from the phytoplankton proliferation in summer and autumn. We speculated that the TDN in the constructed lake might have been transformed to PON by phytoplankton. The PON removal efficiency in the constructed wetland was 60.02%±22.97%, and acted as the primary pathway of N-removal (90% of TN removal) for surface flow constructed wetlands. The removal efficiencies of both PON and Chla were lower during August-October than that during April-July, implying that the PON removal might have achieved the maximum efficiency during phytoplankton blooms. The removal of TDN (-16.40%±27.88%) was insignificant in the surface flow constructed wetland from April to November. In conclusion, the surface flow constructed wet
出处
《生态环境学报》
CSCD
北大核心
2016年第3期503-509,共7页
Ecology and Environmental Sciences
基金
国家自然科学基金项目(31300400)
中央级公益性科研院所基本科研业务费专项(CAFYBB2014QB025)
关键词
人工湿地
颗粒物有机氮
可溶性总氮
叶绿素A
氮去除率
constructed wetland
particulate organic nitrogen
total dissolved nitrogen
chlorophyll a
nitrogen removal efficiency