Chen, B., Zeng, H., Yang, F. et al. Functional biochar as sustainable precursors to boost the anaerobic digestion of waste activated sludge from a circular economy perspective: a review.Biochar6, 60 (2024). https://doi.org/10.1007/s42773-024-00345-y

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Waste activated sludge (WAS), a byproduct of wastewater treatment, holds significant potential for energy and resource recovery. Anaerobic digestion (AD) is a key technology in this process, breaking down organic matter to produce methane while stabilizing pollutants. However, raw biochar used in AD often faces limitations due to its small pore structure and low abundance of functional groups. Functional biochar, with enhanced properties through various modifications, addresses these issues effectively.

Functional biochar enhances AD by facilitating electron transfer, providing buffering effects, and immobilizing microorganisms, thereby increasing methane production and overall AD efficiency. It also helps alleviate the inhibitory effects of substances present in WAS, such as heavy metals and toxic organic matter. The review by Bi Chen and colleagues systematically explores methods to prepare and modify functional biochar, discussing its multiple roles in improving the AD of WAS.

The modified biochar not only improves methane yield but also supports circular economy goals by promoting resource utilization and carbon neutrality. It is especially significant in creating a sustainable model where waste is transformed into valuable resources, thereby supporting environmental and economic sustainability. Future research directions are suggested to further optimize functional biochar applications, ensuring its effectiveness in diverse environmental conditions and expanding its role in sustainable waste management and energy production.