Review on use of lignocellulosic biomass-derived carbon sources for biological wastewater treatment: Scale-up challenges and pretreatment strategies

Carbon sources play a pivotal role in biological wastewater treatment, providing the primary energy and carbon supply for microbial growth and activity. These microorganisms, including both heterotrophic and autotrophic communities, drive the reduction and removal of harmful oxyanions, such as sulfate and nitrate, which often originate from industrial effluents, agricultural runoff, and other human activities. The selection, availability, and biodegradability of carbon sources significantly influence treatment efficiency, operational feasibility, and overall process economics. This review provides a comprehensive synthesis of current knowledge on a wide spectrum of carbon sources, ranging from commercially supplied carbon sources to sustainable lignocellulosic biomass-derived carbon sources. It examines their comparative performance under different environmental and operational conditions, highlights key limitations, and discusses effective pretreatment strategies aimed at enhancing carbon release and microbial accessibility. Special emphasis is placed on the environmental and practical advantages of utilizing these sustainable lignocellulosic biomass-derived carbon sources for large-scale oxyanion removal. Furthermore, the review outlines existing research gaps and future directions, focusing on carbon source optimization, microbial adaptation mechanisms, and the scaling of pretreatment technologies. By addressing these challenges, the study provides a roadmap for advancing sustainable and economically viable biological treatment processes for oxyanion removal from wastewater. • Lignocellulosic wastes as sustainable carbon sources for sulfate/nitrate removal. • Techno-economic framework predicts carbon source requirements for oxyanion removal. • Carbon source selection and pretreatment strategies with techno-economic insights. • Quantitative roadmap for scaling lignocellulosic carbon in wastewater treatment.