Performance Efficiency of Common Reed, Sand and Gravel for Greywater Treatment in a Constructed Wetland in Akure, Nigeria

The release of greywater lacking any treatments into drainage channels, land surfaces and normal water bodies will lead to environmental deprivation and health risks. In this study, common reed combined with natural materials of sand and gravel was used in a system of constructed wetland for the treatment of greywater in Akure, Nigeria. Raw greywater (RGW) was collected from Jadesola Hostel, Federal University of Technology, Akure, and pretreated using a combination of gravel with fine sand, arranged accordingly. The filtered water was subsequently released to a plastic constructed wetland (CW) consisting of similar combination of layers of gravel and sand with common reed planted on it to achieve complete treatment. The RGW, filtered greywater (FGW) and treated greywater (TGW) were analyzed for biochemical oxygen demand (BOD), chemical oxygen demand (COD), total suspended solid (TSS), total nitrogen (TN) and fecal coliforms (FC). Results showed reductions in BOD, COD, TSS, TN and FC by 80.20%, 78.35%, 56.07%, 45.93% and 74.71%, respectively, for FGW and by 90.92%, 91.46%, 93.46%, 53.66% and 82.10%, respectively, for TGW. Therefore, it was concluded that the combination of common reed, sand and gravels in constructed wetland offers an effective means of accomplishing physical and biological treatment of greywater, especially for reuse in irrigation. Hence, it was recommended that acceptance of the combined system will help farmers in ensuring sufficient treatment of greywater and satisfies the standard requirements for wastewater reuse and application in both field crop irrigation and other outdoor needs.