Abstract
The objective of this study is to evaluate the constructed reed bed treatment system to remove nutrients from secondary effluent. The packed media, the removal characteristics and the optimum water surface loading were discussed.
The results indicated that the growing of the reeds was better and the nutrients removal rates were higher in constructed reed bed treatment systems packed with sand or gravel than in the system packed with net material. The maximum removal rates of DTN and DTP in the system packed with sand were 5.5 g · m-2 · day-1 and 0.5 g · m-2 · day-1 respectively when the water surface loading rate was set at a maximum of 0.38 m3 · m-2 · day-1, and those in the system packed with gravel were 6.6 g · m-2 · day-1 and 1.1 g · m-2 · day-1 respectively when the water surface loading rate was set at 0.60 m3 · m-2 · day-1. It is clear that the low nutrients concentration of effluent can be obtained in the system packed with sand and the volume of treated effluent can be ensured in the system packed with gravel, revealing importance to choose the packed media according to treatment objectives.
