[Relationships between loading rates and nitrogen removal effectiveness in subsurface constructed wetlands].
About forty kinds of nitrogen loading removal rate were studied in field in 15 months, inflow and outflow loading rules of reeds/Zizania caduciflora/mixing and no-plant bed were discussed in different inflow loading. The four kinds SFS inflow loading changed from 400 mg x (m2 x d)(-1) to 8 000 mg x (m2d)(-1), while outflow loading is less than 7,000 mg (m2 d)(-1). Results show that outflow loading increase with the increase of inflow loading, linear relation is obvious. Total nitrogen removal rate has the same trend at low inflow loading. But in high inflow loading TN removal rate has much variation. The system had better run between 2,000 mg x (m2 x d)(-1) and 4,000 mg x (m2 x d)( -1) inflow loading. Average removal rate in between 1062 mg x (m2 x d)(-1) and 2 007 mg x (m2 x d)(-1). Plant SFS removal rate is better than no-plant SFS. TN removal rate of reed and zizania caduciflora bed is 63 % and 27 % higher than no-plant bed. Plant harvesting is unimportant and contributes less than 5% of TN removal loading, plant can improve system microenviroment and hydrology condition which could increase TN removal rate. The results provided deep insight to SFS nitrogen removal and reference to SFS design.
Zhang
Rong-she
RS
Department of Environmental Science and Engineering, Tsinghua University, Beijing 100084, China.
Li
Guang-he
GH
Zhou
Qi
Q
Zhang
Xu
X