Investigating the effectiveness of aquatic plants (Echinocloa L and Cyperus L ) in removing nutrients from wastewater: The case of Chemelil constructed wetland- Kenya

Abstract

This study focused on the effectiveness of wetland plants: Echinocloa pyramidalis (L) andCyperus papyrus (L) in purifying wastewater from sugar factory stabilization pond effluent. This study was performed in a pilot-scale Free Water Surface Constructed Wetland (FWSCW) system in Chemelil sugar factory, Kenya. Four of the eight constructed wetlands (CWs) were planted with C. papyrus and the other half with E. pyramidalis.Water samples and plant specimen were taken fortnightly at inlets and outlets of the cells and analysed for total phosphates and total nitrates. The data was analysed by use of Microsoft excel and SPSS computer packages. Water analysis recorded a reduction in the nutrient levels between the inlet pond nine and the final outlet channel to River Nyando. The plants grown in the wetland experienced a reduction in the level of total foliar nitrogen and phosphorous, indicating that though the nutrients were being removed from the wetland, the same were not those assimilated by the plants either. The control plants had higher folia phosphorous and nitrogen, an indication that the system of the constructed wetland was able to eliminate the nutrients effectively from the plants. Key words: Wastewater, eutrophication, assimilation, Echinocloa pyramidalis, Cyperus papyrus, sugar factory. wastewater.