A Comparative Study of Natural and Chemical Coagulants for Turbidity Removal from Synthesized Turbid Surface Water

Abstract

Effective removal of suspended solids, colloidal turbidity, and organic fractions from surface water matrices is a foundational requirement for potable water production. Conventional water treatment schemes heavily rely on sedimentation processes augmented by synthetic chemical coagulants, predominantly Aluminum Sulfate (Alum), due to its established efficiency in large-scale utilities. However, escalating concerns regarding the environmental footprint of chemical sludge, the economic burden of sludge disposal, and potential neurotoxic health risks associated with residual aluminum have catalyzed research into sustainable biopolymer alternatives. This study systematically evaluates the coagulation performance of four plant-based extracts—Banana Peel (Musa acuminata), Okra (Abelmoschus esculentus), Orange Peel (Citrus sinensis), and Neem Leaves (Azadirachta indica)—and contrasts their efficacy against commercial Alum. Utilizing standard Jar Test apparatus, controlled experiments were conducted on synthetic turbid water stabilized at an initial turbidity of 24 NTU.
The empirical results demonstrated that among the natural alternatives, Azadirachta indica (Neem) leaves achieved the highest clarification efficiency at 62.50% (residual turbidity of 9 NTU), followed closely by Abelmoschus esculentus (Okra) at 58.33% (10 NTU). Conversely, Musa acuminata and Citrus sinensis extracts exhibited moderate and identical efficiencies of 45.84% (13 NTU). While commercial Alum maintained superior performance by achieving a 95.83% turbidity reduction down to a baseline of 1 NTU, the findings validate that natural coagulants hold significant promise as eco-friendly, non-toxic, and economically viable alternatives for decentralized, small-scale, and rural water purification systems.