Performance of inclined plates settler integrated with constructed wetland for high turbidity water treatment

Abstract

The purpose of this study was to investigate and demonstrate cost-effective treatment technologies for highly turbid waters, used for domestic purposes in rural areas of Tanzania where conventional community water treatment techniques are not available. Pilot-scale inclined plates settler integrated with constructed wetland (IPS-CW) system was investigated on earth dam water with turbidities ranging from 186 to 4,011 NTU. The IPS was used as a physical pretreatment system preceding the CW, meant for the removal of organic matter, nutrients, and pathogens. Major focus of the IPS-CW system was on turbidity and faecal coliform (FC) removal, and at 5 L/min flow rate mean maximum removal efficiencies of 95.9% and 94.3% were achieved, respectively. Total suspended solids, nitrate (NO3−), ammonium, biological oxygen demand (BOD5) and phosphate removal were studied and removal efficiencies of 97.4%, 91.7%, 71.3%, 91.7% and 49.8% were obtained at 5 L/min flow rate, respectively. Although the use of these combinations of technologies in improving drinking water quality is uncommon, results demonstrated that NO3− and BOD5 met WHO and TBS drinking water standards of ≤50 mg/l and ≤6 mg/L respectively. Due to low production cost and simplicity in operation, the system is relevant for application in rural communities. Highlights Provision of feasible treatment units for rural communities lacking access to clean water.; Validating the use of a combination of the IPS and CW for high turbidity water treatment.; Treating surface waters to meet the potable water standards.; Efficient, cost-effective, and easy to operate drinking water treatment unit.;

Keywords

• constructed wetland
• earth dams
• inclined plates settler
• pretreatment of water
• turbidity