Performance Evaluation of Orange Seeds and Peels as Natural Coagulants for Surface Water Treatment

The increasing demand for alternative water treatment methods has led to growing interest in natural coagulants for purifying surface water particularly in low-resource communities. In this study, the coagulation performance of orange (Citrus sinensis) seeds and peels as natural alternatives to alum for surface water treatment was investigated. Coagulant dosages ranging from 2–10 g/L were evaluated for their effectiveness in reducing turbidity, total suspended solids (TSS), total dissolved solids (TDS), chemical oxygen demand (COD) and biological oxygen demand (BOD). The results showed that orange seeds achieved maximum reductions of 73.6% turbidity, 61.7% TSS, 36.2% TDS, 65.5% COD and 48.3% BOD at an optimal dosage of 8 g/L, outperforming orange peels across all parameters. In comparison, alum at 2 g/L demonstrated higher treatment efficiency, with turbidity, COD and BOD reductions of 81.5%, 69.7%, and 55.6%, respectively. While reductions in turbidity and organic matter were substantial, TDS removal was limited thus suggesting the need for additional treatment stages to meet WHO drinking water standards. These findings suggest that orange seeds and peels are promising alternatives to conventional coagulants for surface water treatment and supports the application of natural and biodegradable alternatives for water treatment practices.