Nitrogen removal by three types of bioretention columns under wetting and drying regimes  

作　　者：唐宁远 李田 

机构地区：[1]State Key Labortory of Pollution Control and Resource Reuse(Tongji University),Shanghai 200092,China

出　　处：《Journal of Central South University》2016年第2期324-332,共9页中南大学学报（英文版）

基　　金：Project(2011ZX07303-002)supported by National Water Pollution Control and Management Technology Major Program,China

摘　　要：The behaviors of inorganic nitrogen species in three types of bioretention columns under an intermittently wetting regime were investigated. The mean NH+4—N, NO-3—N and total N(TN) removal efficiencies for the conventional bioretention column(Col. T1) are 71%, 1% and 41%, for layered bioretention column with less permeable soil layer(Col. T2) the efficiencies are 83%, 84% and 82%, and for the bioretention column with submerged zone(Col. T3) the values are 63%, 31% and 53%, respectively. The best nitrogen removal is obtained using Col. T2 with relatively low infiltration rate. Adsorption during runoff dosing and nitrification during the drying period are the primary NH+4—N removal pathways. Less permeable soil and the elevated outlet promote the formation of anoxic conditions. 30%–70% of NO-3—N applied to columns in a single repetition is denitrified during the draining period, suggesting that the draining period is an important timeframe for the removal of NO-3—N. Infiltration rate controls the contact time with media during the draining periods, greatly influencing the NO-3—N removal effects. Bioretention systems with infiltration rate ranging from 3 to 7 cm/h have a great potential to remove NO-3—N.The behaviors of inorganic nitrogen species in three types of bioretention columns under an intermittently wetting regime were investigated. The mean NH＋4-N, NO-3-N and total N（TN） removal efficiencies for the conventional bioretention column（Col. T1） are 71%, 1% and 41%, for layered bioretention column with less permeable soil layer（Col. T2） the efficiencies are 83%, 84% and 82%, and for the bioretention column with submerged zone（Col. T3） the values are 63%, 31% and 53%, respectively. The best nitrogen removal is obtained using Col. T2 with relatively low infiltration rate. Adsorption during runoff dosing and nitrification during the drying period are the primary NH＋4-N removal pathways. Less permeable soil and the elevated outlet promote the formation of anoxic conditions. 30%-70% of NO-3-N applied to columns in a single repetition is denitrified during the draining period, suggesting that the draining period is an important timeframe for the removal of NO-3-N. Infiltration rate controls the contact time with media during the draining periods, greatly influencing the NO-3-N removal effects. Bioretention systems with infiltration rate ranging from 3 to 7 cm/h have a great potential to remove NO-3-N.

关 键 词：RUNOFF NH4＋--N NO3 --N BIORETENTION infiltration rate 

分 类 号：X52[环境科学与工程—环境工程]