Assessing constructed wetland treatment performance

Abstract

This chapter presents the assessment of the constructed wetland treatment performance . The assessment was done by partitioning the inflow runoff hydrograph into ten segments and then investigating the treatment performance of each runoff segment within a constructed wetland. Accordingly, the hydrologic and hydraulic factors generated by the conceptual model were also appropriately allocated to the ten segments. The analysis outcomes showed that large and small rainfall events are differently treated in a constructed wetland. The pollutant load reductions for the initial sector of runoff from large rainfall events were relatively low, due to the rapid mixing taking place within the system. This highlights the need to establish an inlet pond prior to the flow entering the constructed wetland, so that the inflow will initially stabilise. This is also supported by the fact that the initial sector of runoff generally carries higher pollutant loads.