Nitrogen removal of rural domestic sewage in subsurface constructed wetlands
1.School of Energy and Environment/Key Laboratory of Environment Medical Engineering of Ministry of Education, Southeast University, Nanjing, Jiangsu 210096, China; 2.Jiangsu Provincial Construction Department of Housing and Urban, Nanjing, Jiangsu 210036, China)
Abstract： Rural sewage was treated by two constructed wetlands with different substrates, and nitrogen removal efficiency and factors were studied. The results indicate that the combined substrate constructed wetland shows high nitrogen removal efficiency at hydraulic loading of 10 cm·d-1, and the average removal efficiency of ammonia nitrogen and total nitrogen are 83.2％ and 76.2％, respectively. The optimal hydraulic loading for cinder constructed wetland is 15 cm·d-1, and the average removal efficiency of ammonia nitrogen and total nitrogen are 73.9％ and 71.1％, respectively. Nitrogen removal efficiency is significantly influenced by dissolved oxygen level, organic carbon sources and nitrogen forms in constructed wetland. The shortage of dissolved oxygen and organic carbon sources in the middle and later of constructed wetlands is the key reason for the decrease of nitrogen removal. Nitrogen removal efficiency is significantly influenced by nitrogen form, and total nitrogen removal efficiency is high for the sewage with high proportion of nitrate nitrogen.
2011, Vol. 32 
