A sustainable paradigm of sewage sludge biochar: Valorization, opportunities, challenges and future prospects

Abstract The generation of sludge during wastewater treatment has drawn the attention of various scientists on its toxicity and safety in lieu of its disposal in the environment. Source of sludge generation in the environment includes sewage and industrial sludge. Indiscriminate usage of sludge generation and its poor disposal management system poses hazardous effects on water quality at a global level. Preparation of biochar from sewage sludge biochar has attained the attention of most of the researchers for their effectiveness in improving soil quality, reduction of uptake of heavy metals and potential benefits in agriculture fields to nourish the soil. In this review, an exhaustive list of sewage sludge biochar (SSBC) production from vast literature has compiled, and their characterization, application, quantification with risk assessment approach, impact on climate change, life cycle and cost analysis have been presented. The high cost of biomass disposal, (transportation, treatment and landfilling), is a serious concern. This paper presents the state of the art review on the applications of SSBC for the adsorption of antibiotics, heavy metals, textile dyes, phenolic compounds as well as minimizing agrochemical pollution. It is evident from the literature that the SSBC has multiple benefits, including revenue generation option.