Customized design of horizontal flowconstructed wetlands employing secondary datasets

Values of areal removal rate constant (k, m/day) were derived by employing a dataset of 74 horizontal flow constructed wetlands (HFCWs) using P-k-C* approach, which showed large variation (0.006–0.40 m/day) as these systems were largely under-loaded. This dataset was classified based on substrate loading rates, temperature, and depth to reduce the SDs of k values among the subsets. Further, the k values for organics removal were optimized by eliminating data of 10%, 20% and 30% of the most underloaded HFCWs, which led to a sharp reduction in observed SDs from 84.74% to 4.85%; 116.48% to 3.42%; and 114.70% to 6.89% respectively for the aforementioned scenarios for organics removal. These stable k values can be adopted for area calculations for optimizing the design of HFCWs and the computations made here will help identify the limiting nutrient that would govern the design under specific requirements. • Analysis of 74 HSSF CWs carried out using plug flow equation. • Areal rate constant (k) values observed to show high variation 0.006–0.40 m/day. • Classification of k values done to narrow down intra class standard deviations. • Area calculated using optimized k values found to be lower than actual CW area. • This approach may serve as excellent design support tool for judicious land use.