Long-term effect of the antibiotic cefalexin on methane production during waste activated sludge anaerobic digestion

- Long-term effect of cefalexin on methane production during sludge fermentation was assessed.
- Cefalexin exhibited a temporary inhibition in methane production, followed by a marked recover.
- The highest methane yield was 450 mL at 1000 mg-CLX/L after 157 days of digestion, rising by 63.8%.
- Extracellular polymeric substances protected microbes for self-growth and fermentation.