Keywords: domestic wastewater, chemically enhanced primary treatment, CEPT, constructed wetlands, FAC, fly ash coagulant, wastewater treatment, water pollution
Domestic wastewater treatment with CEPT-wetlands process
This study aimed to develop an effective process with less construction and operation cost and with flexibility of meeting different temperature requirements, namely CEPT-construted wetland processes. To reduce the chemical cost for the CEPT process, fly ash was firstly utilised to develop an efficient compound coagulant. The lab-scale experimental results showed that with low Fly Ash Coagulant (FAC) dosage the removals of COD, Total Phosphorus (TP) and Suspended soild (SS) could achieve more than 62%, 91% and 93%, respectively. The coagulation effluent TP and SS had already met the level IB of the Discharge Standard of Pollutants for Municipal Wastewater Treatment Plant (GB18918-2002). When the effluent was further treated by following wetlands system with a HRT 2?4 d, the COD could be removed up to 65-77% with the final effluent COD less than 64 mg/L.