Modelling of pollutant removal rates in constructed wetlands under varying hydraulic loading rates

Abstract

A subsurface horizontal flow constructed wetland located at University of Moratuwa was observed from January 2012 to November 2012 in order to derive empirical equations for the treatment efficiencies of BOD, COD, Nitrate-N, Nitrite-N and Total Phosphorous with varying hydraulic loading rates. Source of polluted water was the grey water effluent from the Staff canteen which is located near the constructed wetland. BOD, COD, Nitrate-N, Nitrite-N and Total Phosphorous, turbidity and conductivity were taken to ascertain the water quality. Overall treatment efficiency of the wetland cell is above 75% for all parameters. Regression technique was used to derive the empirical equations. IBM SPSS statistics -20 software was used in analysing the experimental data. The derived equations exhibit a high level of accuracy since predicted data and actual data shared a strong correlation of 79.1% for COD, 93.2% for BOD, 85.1% for Nitrate-N, 84.1% for Nitrite-N and measurements 86.2% for Total Phosphorous. Constructed wetlands in tropic environments capable of using these equations with relevant adjustments to the original.