Enhanced Biohydrogen Production From Wastewater And The Influence Of Operating Parameters

Abstract

Enhancement of fermentative biohydrogen production was investigated both by treatment of microbial community and optimization of key parameters using the statistical methodology. The effect of temperature, initial pH, and feed to microorganisms (F/M) ratios, individually and interactively, on fermentative hydrogen production by mixed cultures was investigated in batch tests and the optimization of fermentative hydrogen production process was conducted by response surface methodology using a Box–Behnken design. The maximum hydrogen yield of 372.90 mL/g glucose was estimated at the temperature of 30.91°C, the initial pH of 8, and the F/M ratio of 0.25. The maximum hydrogen production rate of 6.55 mL/h was estimated at the temperature of 30.03°C, the initial pH of 7.27, and the F/M ratio of 1.79. The maximum substrate consumption efficiency of 98.8% was estimated at the temperature of 30.35 °C, the initial pH of 7.5, and the F/M ratio of 0.25. Total of volatile fatty acids (VFAs) and ethanol were analyzed at the end of all experiments and their changes with operational parameters were investigated. Modified Gompertz equation could describe the progress of cumulative hydrogen production in the batch tests of this study successfully.

Keywords:

• Biohydrogen
• Fermentation
• Optimization
• Batch flask
• Gompertz model
• Response surface methodology

ACKNOWLEDGMENT

The authors would like to thank Dr. Nasrin Etesami for help with statistical analysis and Dr. Mohammad Seraji for help with GC startup. They also thank the Isfahan Water and Wastewater Treatment Company for help with anaerobic sludge support.