Rate constants for the removal of pollutants in wetlands: A mini review

The constructed wetlands (CWs) possess tremendous significant potential for the treatment, reuse and recycle of wastewater. As compared with conventional wastewater treatment methods, CW has great significance in terms of resource enhancement at lower cost. The enhanced applications of CWs for the treatment purposes have led to the development of better design of CW systems. To describe the treatment processes in CWs, the various numerical models have been proposed in the literature. Considering the large applicability of CWs all over the world, the researchers have derived values of the rate constants. Based on kinetic data from the pilot-scale or laboratory observations, few studies have been reported for the estimation of rate constants. Most of the researchers have used the first-order kinetics for estimation of rate constants for removal of several pollutants including biochemical oxygen demand (BOD),chemical oxygen demand (COD), total nitrogen (TN) and total phosphorus (TP) in various types of wetlands comprising CWs as well as free water surface wetlands. The present study delivers a comprehensive review on the rate constants for the removal of numerous pollutants such as BOD, COD, TN and TP in different wetlands around the world