Polishing of Secondary Effluent by a Two-Stage Vertical-Flow Constructed Wetland
Chunhui Zhang, Shuhui Tan, Juan Li, Chen Peng
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School of Chemical and Environmental Engineering, China University of Mining and Technology (Beijing),
Beijing 100083, P.R. China
Submission date: 2014-01-20
Final revision date: 2014-03-06
Acceptance date: 2014-03-28
Publication date: 2015-04-02
Pol. J. Environ. Stud. 2015;24(2):923–928
A two-stage vertical-flow constructed wetland (VFCW) was built to advanced treatment of secondary effluent containing organic and inorganic nutrients (nitrogen and phosphorus) from a municipal sewage treatment plant in Beijing, China. The results showed that the VFCW effluent achieved 66-83% and 81-90% removal for COD and TP, respectively. Meanwhile, NH4+-N and TN were almost completely removed during stable operation of the wetland system. The VFCW effluent concentrations of COD, TN, and TP were less than 30 mg·L-1, 1.5 mg·L-1, and 0.3 mg·L-1, respectively, which can meet the environmental quality standards for surface water in China. Because of the special design, the better performance of the VFCW was that it allowed the treatment of wastewater under multiple aerobic, anoxic, and anaerobic conditions sequentially in different heights of the CW unit. New media materials, rice husks, and steel slag were the key to the efficient removal of TN and TP. This technology could be adopted to improve the secondary effluent quality.