Chemical/synthetic coagulants are widely used to remove suspended solids and organic loads from water, but they pose several environmental and public health issues due to their chronic toxicity. The study evaluated the performance of these natural coagulants individually and in blended combinations with a synthetic coagulant, Alum, in terms of the percentage removal of turbidity, TSS, BOD, and COD after water treatment at optimum dosages. The blended use of all three coagulants in equal proportion showed the best performance (turbidity removal = 91.91%; TSS removal = 51.18%; BOD removal = 41.67%; and COD removal = 55.56%), but increased the pH of treated water from 7.10 to 7.95. The treatment cost analysis showed that Alum had the lowest treatment cost (Rs. 0.78 per 1,000 L); while the blended use of Moringa oleifera and Okra (Abelmoschus esculentus) at the optimum dosage of 120 mg/L had the lowest cost (Rs. 31.20 per 1,000 L) among the natural coagulants. Despite higher cost of treatment, the use of natural coagulants in water and wastewater treatment provide sustainable solutions while reducing the negative impact of synthetic coagulants on the environment and public health
