Performance of a Horizontal Subsurface Flow Constructed Wetland in Treating Aquaculture Wastewater

Abstract

The escalating demand for water and the increasing pollution of natural water bodies necessitate innovative solutions for wastewater treatment and reuse. This study investigated the potential of a horizontal subsurface flow (HSSF) constructed wetland to treat aquaculture wastewater for reuse. The system, planted with Taro (Colocasia esculenta) and sugarcane (Saccharum officinarum L.), received effluent from a recirculating aquaculture system (RAS) producing African Catfish (Clarias gariepinus). The study assessed the impact of varying hydraulic retention times (1-3 days) and flow rates (11-108 L/min) on water quality parameters, including dissolved oxygen, electrical conductivity, salinity, total dissolved solids, temperature, and pH. Results showed significant increase in dissolved oxygen (4.25-5.52 mg/L), while electrical conductivity (491-677 µS/cm), salinity (0.23-0.32 ppt), and total dissolved solids (237-332 mg/L) decreased considerably. Temperature (29.28-31.07 °C) and pH (7.57-7.59) remained stable and within acceptable ranges for reuse in African Catfish production. However, retention time and flow rate did not significantly affect treatment efficiency within the tested parameters. Further research is recommended to explore the impact of longer retention times, wider flow rate ranges, different plant species and substrate types, and microbial community analysis to optimize the system's performance and promote sustainable aquaculture practices.

Keywords

• water quality
• constructed wetland
• hydraulic retention time
• flow rate
• aquaculture effluent