Operation of the vertical subsurface flow and partly submersed stormwater wetland with an intermittent recycle

ABSTRACT In this study, a vertical subsurface flow (VSF) stormwater wetland having a partially submersed zone in the bottom was operated for 90 d. This wetland is designed to recycle the effluent on the basis of designated antecedent dry days (ADDs). A total of four groups of bench-scale VSF wetlands filled with different media such as woodchip, pot gravel, synthetic fiber and volcanic stone were made. Each group of wetlands having the same media was operated with different recycle scheme. Operational results show that at the beginning of the wetland operation for about 30 d, there was a maturation or acclimation phase as usually observed in a filter and biofilm process. After the acclimation phase, the wetland displayed stable functions. Regardless of the media and operational mode employed, all groups of wetland were found to be able to reduce 70% of TSS in the stormwater. For nutrients removal, different medium showed different performances. Woodchip was most effective for TN removal (more than 25%), w...