Efficiency of Constructed Wetland (CW) Established with Common Reed aimed at Greywater Treatment in Akure, Nigeria

Abstract

The growing scarcity of freshwater resources is becoming a significant concern in dry and semi-dry areas globally, underscoring importance of household greywater treatment to mitigate this issue. This study focused on evaluating the efficiency of a Constructed Wetland (CW) established with Phragmites australis for the treatment of greywater in Akure, Nigeria. Raw greywater was obtained from the Jadesola female hostel at the Federal University of Technology, Akure (FUTA), and then underwent initial treatment in a 500-liter filtration reservoir that contained multiple layers of pebbles and fine sand. Following this initial treatment, greywater was transferred to a Vertical Flow Sub-Surface Constructed Wetland (CW) established with Phragmites australis for the main treatment phase. Both raw and treated greywater samples were analyzed for Chemical Oxygen Demand (COD), Biochemical Oxygen Demand (BOD), pH, Total Dissolved Solids (TDS), Electrical Conductivity (EC), and heavy metals. The results demonstrated that the CW effectively lowered all measured chemical factors, rendering the treated greywater suitable for irrigation by meeting local wastewater reuse standards. Notably, the CW achieved impressive reductions, with BOD decreasing by 91.4%, COD by 91.5%, and TDS by 38.7%, thereby proving its effectiveness in pollutants removal. The treated greywater complied with local standards for wastewater reuse, making it appropriate for irrigation and other outdoor applications. These outcomes are particularly beneficial for farmers who rely on irrigation during the dry season. Hence, additional studies should be carried out to explore the potential use of treated greywater effluents for irrigating certain types of vegetable crops.