Performance of Common Reed (Phragmites australis) in a Constructed Wetland for Greywater Treatment in Akure, Nigeria

Abstract

Shortage of freshwater is becoming a growing problem in both dry and semi-dry regions of the world, hence the need to make use of other source of water for agricultural production. The study was conducted to examine the performance of common reed in a constructed wetland for greywater treatment in Akure, Nigeria. Raw greywater was collected from Jadesola Hostel, Federal University of Technology, Akure, and pretreated through a combination of gravel of diameters < 32 mm, 24 mm and 16 mm with fine sand of diameter 0.2 mm arranged accordingly. The filtered water was thereafter released to a plastic constructed wetland (CW) which also consisted of same combination of layers of gravel and sand with common reed planted on it for complete treatment. The raw and treated greywater were analyzed for Biochemical Oxygen Demand (BOD), Chemical Oxygen Demand (COD), Total Dissolved Solid (TDS), and heavy metals. It was discovered that CW planted with common reed was effective in the treatment of greywater with reduction in BOD by 91.4%, COD by 91.5% and TDS by 38.7%. CW had appreciable removal effect on heavy metals with reduction in: manganese (Mn) from 0.100 ppm to 0.012 ppm, iron (Fe) from 0.014 ppm to 0.002 ppm, lead (Pb) from 0.05 ppm to 0.001 ppm and zinc (Zn) from 0.154 ppm to 0.148 ppm. Therefore, the use of common reed in constructed wetland for greywater treatment is recommended for farmers involved in irrigation with greywater, especially during dry seasons, and most importantly under the rising global water scarcity due to climate change.