STUDY ON DECENTRALIZED DOMESTIC WASTEWATER TREATMENT BY CONSTRUCTED WETLAND VERTICAL - SUBSURFACE FLOW SYSTEM FOR SMALL COMMUNITIES

Abstract

This research investigated the feasibility of using constructed wetland system with vertical - subsurface flow (VF-SFS) for treating the decentralized domestic wastewater for household and small community. The pilot studied on three beds included three macrophytes tested parallel reed, vetiver and bulrush with four different hydraulic application rates (176, 132, 88 and 44 mm/ day).This study was tested with six different parameters such as biochemical oxygen demand (BOD), total suspended solids (TSS), orthophosphate (PO43-), ionized ammonia (NH4+) and nitrate (NO3-) nitrogen and total coliform loadings. The removal rate of characteristic parameters was obtained: BOD5 96%, TSS 96.9%, N-NH4+ 60.5%, PO43- 47.6%, total coliform 97.7%, respectively. In particular, the highest removal efficiency was obtained in the bed with the longer hydraulic retention time. Simultaneously, there was no removal difference among 03 beds constructed wetland with 03 different plant species, significantly. Through the results of research, VF-SFS can be considered an appropriate treatment method for domestic wastewater; however the additional pre-treatments were necessary to remove grit, heavy solids and floating scum.