THE DEVELOPMENT AND APPLICATION OF AN ACTIVE COAGULANT FROM TERNARY MATERIAL – SNAIL SHELL, PERIWINKLE SHELL AND COW BONE.

ABSTRACT The rising cost and environmental concerns associated with conventional chemical coagulants such as alum and ferric chloride have necessitated the search for sustainable, low-cost, and eco-friendly alternatives. This project focuses on the development, characterization, and application of a novel active ternary coagulant formulated from snail shell, periwinkle shell, and cow bone — all abundant bio-wastes in Nigeria. The raw materials were collected, washed, dried, pulverized, and calcined at optimized temperatures (700–900 °C) to convert their calcium carbonate and hydroxyapatite content into highly reactive calcium oxide and calcium phosphate compounds. The individual powders were physio-chemically characterized using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and Energy-dispersive X-ray fluorescence analysis. A ternary composite coagulant was then prepared by blending the calcined powders in varying ratios optimized through Response Surface Methodology (RSM). Coagulation–flocculation performance was evaluated using standard jar test procedure on synthetic turbid water and real industrial wastewater (textile effluent and palm oil mill effluent). Key parameters investigated include dosage (0.5-3.0g/L), pH (8.3), settling time, and mixing intensity. Results showed that the optimum ternary blend 15 % snail shell : 70 % periwinkle shell : 15 % cow bone) at 0.82 g/L dosage achieved 97.8 % turbidity removal, 89.2 % COD reduction, and 98.4 % TDS removal at pH 8.3. These values significantly outperformed individual components and were comparable to or better than commercial alum while producing 67% less sludge volume and eliminating aluminium residual in treated water. The ternary coagulant exhibited dual coagulation–adsorption mechanisms, combining charge neutralization, sweep flocculation, and phosphate-based precipitation. Kinetic studies followed second-order models, and adsorption data fitted the Freundlich isotherm. The developed coagulant is non-toxic, biodegradable, and extremely low-cost (virtually zero raw material cost), making it highly suitable for small- and medium-scale water and wastewater treatment plants in developing countries. This research successfully demonstrates the valorization of three common biological wastes into a high-performance natural coagulant, thereby contributing to sustainable waste management and affordable clean water technology.