As water scarcity becomes a global challenge, sustainable wastewater treatment technologies are increasingly essential. A recent study conducted by Ouyang et al, (2025) in Water Research Journal highlights the potential of sludge biocharBiochar is a carbon-rich material created from biomass decomposition in low-oxygen conditions. It has important applications in environmental remediation, soil improvement, agriculture, carbon sequestration, energy storage, and sustainable materials, promoting efficiency and reducing waste in various contexts while addressing climate change challenges. More (SB) as a cost-effective and eco-friendly solution in constructed wetlands coupled with microbial fuel cells (MFC-CWs).

Constructed wetlands are effective for treating wastewater but face limitations in removing nitrogen under low carbon-to-nitrogen (C/N) ratios. This study explores the use of sludge biochar and activated carbonActivated carbon is a form of carbon that has been processed to create a vast network of tiny pores, increasing its surface area significantly. This extensive surface area makes activated carbon exceptionally effective at trapping and holding impurities, like a molecular sponge. It is commonly More as electrode materials in MFC-CWs. The findings show that sludge biochar significantly enhances nitrogen removal efficiency, achieving 95.85%, while also generating power at a maximum density of 9.05 mW/m².

The mechanisms underlying this improvement include the electrochemical properties of sludge biochar, which promote oxygen reduction reactions and microbial activity. By facilitating better electron transfer and enriching beneficial microbes like Geobacter and Thiobacillus, biochar-based systems achieve higher denitrification and energy production. Moreover, sludge biochar provides an affordable and sustainable alternative to traditional electrode materials like activated carbon.

This innovative approach offers dual benefits: improving wastewater treatment efficiency and generating renewable energy. It demonstrates how biochar can transform waste management, reduce environmental pollution, and enhance resource sustainability, paving the way for large-scale applications in reclaimed water treatment

SOURCE: Ouyang, B., Zhang, Z., Chen, F., Li, F., Fu, M. L., Lan, H., & Yuan, B. (2024). Energy production and denitrogenation performance by sludge biochar based constructed wetlands-microbial fuel cells system: Overcoming carbon constraints in water. Water Research, 123024. https://doi.org/10.1016/j.watres.2024.123024