Effects of Over-liming on Wastewater Detoxification for Enhancement of Biogas Production

Abstract

Detoxification by overliming was applied to enhance biogas production from an industrial baker’s yeast production wastewater. Various operational parameters affecting the detoxification, i.e., temperature, duration time, and pH, were studied for improvement of biogas production. Overliming was carried out at different pH levels (9 to 12) and temperatures (20 to 60°C) for different periods of time (0 to 12 h). Then, the detoxified wastewaters were subjected to anaerobic digestion. The maximum biogas production of 425 ml CH₄/g COD, and the maximum yield of methane production of 3.06 l CH₄/l wastewater were achieved under optimum conditions for overliming of wastewater.

Keywords:

• anaerobic digestion
• baker’s yeast wastewater
• biogas
• inhibitors
• overliming

ACKNOWLEDGMENTS

The authors gratefully acknowledge Ilona Sarvari Horvath at the University of Borås for the scientific support, Mr. Harati and Mr. Gholami at Isfahan Municipal Wastewater Treatment for providing the inoculum, and Mr. Safi at Shahrekord Baker’s Yeast factory for providing the baker’s yeast wastewater.