Evaluation of laundry wastewater treatment efficiency using coagulant-flocculation method at laboratory scale

Abstract

This study evaluates the use of ferric chloride (FeCl3) for treating laundry wastewater via Jartest experiments. Under optimal conditions (pH = 6.5, dosage = 80 mg/L), FeCl3 achieved high removal efficiencies: 93% for TSS, 91.67% for turbidity, and 89.7% for phosphorus. Additionally, the concentration of total surfactants in the treated water met the B standards of QCVN 14:2008/BTNMT, and the BOD5/COD ratio improved from 0.33 to 0.46, demonstrating the effectiveness of FeCl3 in reducing biodegradable refractory organic matter. From the research findings, laundry wastewater should be classified as industrial (QCVN 40:2011/BTNMT) and treated according to more stringent standards.

Keywords: Ferric chloride; laudry wastewater; Coagulation-Flocculation; optimal pH; optimal dosage