Study on Treatment of Domestic Wastewater by Modified Bio-Rack System

Abstract

Bio-rack system is an innovative approach to treat domestic wastewater by addressing the problems observed in constructed wetlands. It is rack of vertical pipes in which wetland plants are vegetated. In the present study, the modifications to conventional bio-rack system in terms of multi-species vegetation and different flow pattern are incorporated. Racks were made from waste (packaged drinking water) bottles and vegetated with Canna Indica and Typha Angustata. Modified and conventional bio-rack systems were operated in continuous mode for 12 and 24 h of hydraulic retention time (HRT) with organic loading rate of 140–300 gm COD/m2 day. COD removal efficiency for control and modified system for 12 and 24 h HRT was observed to be 55–67% and 65–73%, respectively. Dissolved oxygen level was also higher for modified system than conventional system for both HRTs. The modified system was found to be more efficient than conventional system. The study indicated that modified system showed better performance for COD, BOD and TKN removal and in terms of oxygenation. It can be a low-cost option for the domestic wastewater treatment in decentralized systems.