Evaluation of Rice Husk and Neem Leaf Powder as Sustainable Biosorbents for Sewage Treatment

Abstract

The uncontrolled discharge of untreated municipal sewage presents significant environmental and public health challenges, highlighting the need for affordable and sustainable wastewater treatment technologies. This study investigates the applicability of rice husk (RH) and neem (Azadirachta indica) leaf powder (NLP) as natural biosorbents for the treatment of municipal sewage. Sewage samples collected from Srirampura, Bengaluru, were treated under controlled laboratory conditions using a standard jar test apparatus with varying biosorbent dosages. Treatment performance was evaluated through the analysis of key physicochemical and biological parameters, including pH, total hardness, calcium, magnesium, chloride, alkalinity, acidity, total dissolved solids (TDS), and biochemical oxygen demand (BOD), following APHA standard analytical protocols. Both Rice husk (RH) and neem leaf powder (NLP) exhibited dosage-dependent improvements in effluent quality, demonstrating substantial pollutant removal efficiencies. Rice husk showed higher removal efficiencies for calcium, chloride, TDS, and BOD, whereas neem leaf powder was more effective in reducing total hardness and acidity and in stabilizing pH. Overall, rice husk demonstrated comparatively higher adsorption capacity across most measured parameters. The results indicate that agricultural and biological waste materials such as rice husk and neem leaf powder can serve as low-cost, environmentally benign biosorbents, offering a promising approach for decentralized and sustainable municipal sewage treatment.