[Transformation of inorganic nitrogen in slag-wetland during the start-up period].
Lab-scale subsurface flow slag-wetlands were constructed to study the removal efficiency and transformation processes of low-concentration inorganic N during the start-up period. As for ammonium-dominated wastewater, the removal rates of total nitrogen (TN), ammonium nitrogen (NH4(+)-N), nitrate nitrogen (NO3(-)-N) and nitrite nitrogen (NO2(-)-N) were 0.12 g x (m2 x d)(-1), 0.07 g x (m2 x d)(-1), 0.10 g x (m2 x d)(-1) and 0.04 g x (m2 x d)(-1), respectively. Nitrifying bacteria was not detected by fluorescence in situ hybridization (FISH) on the slag. NH3 volatilization is the main contribution for N removal resulting from high pH (> 10) and surface soil absorbed most of NH3. For nitrate-dominated wastewater, the removal rates of TN and NO3(-)-N were 0.23 g x (m2 x d)(-1) and 0.48 g x (m2 x d)(-1), and NO2(-)-N accumulated by 0.22 g x (m2 x d)(-1) during the process of denitrification. Removal efficiency of inorganic N for nitrate-dominated wastewater was higher than that for ammonium-dominated wastewater during the start-up period of slag-wetlands, so steel slag can be used as a substrate in constructed wetlands for extensive treatment of nitrate pollution.
Sun
Shu-Ming
SM
Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China. smsun06@yahoo.com.cn
Shan
Bao-Qing
BQ
Peng
Wan-Jiang
WJ
D001673:Biodegradation, Environmental; D009566:Nitrates / Q000737:chemistry / Q000302:isolation & purification; D009584:Nitrogen / Q000737:chemistry* / Q000302:isolation & purification*; D000644:Quaternary Ammonium Compounds / Q000737:chemistry / Q000302:isolation & purification; D013232:Steel; D014865:Waste Disposal, Fluid / Q000379:methods*; D053833:Wetlands
D009566:Nitrates; D000644:Quaternary Ammonium Compounds; D013232:Steel; D009584:Nitrogen