Evaluation of Rice Husk Ash and Coconut Shell Ash as Natural Bio-Coagulants for Dairy Wastewater Treatment

The dairy industry generates large volumes of wastewater containing high concentrations of organic matter, fats, proteins, and suspended solids. If discharged without adequate treatment, this wastewater can lead to serious environmental pollution and degradation of water bodies. Conventional treatment methods commonly employ chemical coagulants such as alum and ferric chloride; however, these chemicals are expensive and may lead to secondary environmental contamination. This study investigates the effectiveness of Rice Husk Ash (RHA) and Coconut Shell Ash (CSA) as natural bio-coagulants for the treatment of dairy wastewater. The materials were prepared from agricultural by-products and applied to wastewater samples in different dosages. Important water quality parameters such as pH, turbidity, Biological Oxygen Demand (BOD), Chemical Oxygen Demand (COD), Total Dissolved Solids (TDS), and chloride were analyzed before and after treatment. The experimental results indicate that both RHA and CSA significantly improved the quality of dairy wastewater by reducing turbidity and organic pollution levels. Among the two materials, Rice Husk Ash demonstrated slightly higher removal efficiency due to its high silica content and greater adsorption capacity. The findings suggest that these natural materials can serve as eco-friendly, low-cost, and sustainable alternatives to conventional chemical coagulants in wastewater treatment processes.