Study on hybrid biorack constructed wetland

Decentralized Wastewater Treatment Systems (DWTS) based on natural mechanisms of purification are appropriate for Indian conditions. Biorack constructed wetland are recent developments in the domestic wastewater treatment. In the present study the concept of biorack wetland is extended to Hybrid Biorack Constructed Wetland (HBCW) in which bioracks are supplemented by brickbat as support medium for wetland vegetation. Three separate HBCW reactors were developed with Typha angustifolia, Canna indica and dual-species (Typha angustifolia and Canna indica). Batch studies were carried out on these reactors for secondary treatment of domestic wastewater. COD removal was determined for feed wastewater strength of 100 to 200 mg COD/L by these developed reactors. The growth of vegetation was also monitored. Typha angustifolia and Canna indica were found to be an appropriate combination as dual-species. The COD removal by dual-species is 5 to 10% greater than mono-species under similar conditions of feed and support medium. HBCW is efficient to an extent of 65 to 75% for COD removal. This is preliminary study conducted on HBCW. Further studies on pilot/field scale will provide better insight to assess its suitability as an alternative biological treatment.