Surface Water Treatment with Carica papaya-Based Coagulants: A Natural and Sustainable Solution

Access to clean water remains a global challenge, particularly in areas where populations rely on surface water. These water sources must be treated. Coagulation with chemicals causes environmental problems and adverse effects on human health. Natural coagulants obtained from papaya (Carica papaya) waste are presented as an alternative that is safe for human health, non-polluting, and biodegradable. The effectiveness of these natural coagulants is compared to that of aluminum sulfate using jar tests and synthetic and natural surface water, with statistical tools to model treatment processes. All coagulants have competitive results, reaching turbidity remotion levels above 90%. However, in equivalent tested ranges, natural coagulants require lower dosages and perform better with high initial water turbidity due to their polymeric bridging mechanisms and adsorption processes through the action of their functional groups, as detected by FTIR analysis. Additional testing with contaminated water from the Valsequillo dam confirms the use of these coagulants to treat water, with papaya seed coagulant yielding the best results and requiring lower doses, making it a competitive alternative. It can be concluded that papaya-based coagulants obtained from waste can be used as an eco-friendly alternative to aluminum sulfate in physicochemical treatments to purify surface water for human consumption.