Domestic wastewater treatment through constructed wetland in India

Abstract

The paper highlights the use of constructed wetlands for the removal of BOD, nitrogen, phosphorus and pathogens from primary treated wastewater. The constructed wetland consists of emergent macrophytesTypha latifolia and Phragmites carca grown in cement pipes having 0.1256 m2 area and 0.8 meter deep filled with 30% soil and 70% sand. The hydraulic loadings were maintained at the rate of 5 cm per day. The BOD removal in wetlands was observed to be 78-91%. The nitrogen content reduced from 30.8 mgl−1 to 9.5 mgl−1 whereas phosphate in treated wetland effluent was 9.6 mgl−1 as against the mean inflow total phosphate content of 14.9 mgl−1. The country’s first constructed wetland, of 90m × 30m size, was installed at Sainik School, Bhubaneshwar in the State of Orissa. Two types of macrophytes, viz. Typha latifolia and Phragmites carca, were planted. At present 180-200 m3 wastewater is being treated through wetland. BOD and nitrogen removal were 67-90% and 58-63% respectively. The constructed wetland treatment was found to be efficient in removal of BOD and N, and economically viable. The system, being easy to operate and low cost, can provide an economical viable solution for wastewater management.