Evaluation of Titanium Dioxide Modified Biochar in a Moving Bed Biofilm Reactor for Wastewater Treatment

Abstract

Wastewater treatment is essential for reducing environmental pollution and improving effluent quality. Conventional biological treatment technologies, including the Moving Bed Biofilm Reactor (MBBR) are widely used for organic pollutant removal; however, their performance depends on wastewater characteristics, biofilm development, and operating conditions. The present study evaluates the potential application of titanium dioxide (TiO₂)-modified rice husk biochar in an MBBR system for wastewater treatment. The proposed approach combines the adsorption properties of biochar with the potential photocatalytic activity of TiO₂ to enhance contaminant removal. A laboratory-scale reactor with a working volume of 15 L was used to investigate treatment performance under controlled operating conditions, with a conventional MBBR serving as the control. Wastewater samples were collected from selected sources including a sewage treatment plant, a milk-processing facility, and industrial sources. Treatment performance was assessed primarily through biochemical oxygen demand (BOD), chemical oxygen demand (COD), and total dissolved solids (TDS). The study also considered the influence of reactor configuration, carrier characteristics, aeration, sunlight exposure, and biofilm development on treatment performance. The principal evaluation outcomes are the comparative removal efficiencies of BOD, COD, and TDS in the conventional and TiO₂-modified biochar systems. This investigation provides a basis for assessing the practical applicability of TiO₂-modified biochar in hybrid biological treatment and for identifying the operational and material-related factors requiring further investigation. Further quantitative validation is necessary to establish the magnitude of performance improvement, material stability and suitability for practical wastewater treatment applications.