Optimization of conditions for hydrogen production from complex dairy wastewater by anaerobic sludge using desirability function approach

Present study deals with the multiple-response optimization for biohydrogen production using anaerobic sludge and outstanding approach to overcome the drawbacks of conventional response surface methodology (RSM). Dairy wastewater was used as source in batch fermentation was followed for this study. Response surface methodology (RSM), based on a three level, four variable Box-Behnken design, was employed to obtain the best possible combination of substrate concentration, pH, COD/N ratio and COD/P ratio for maximum H-2 yield (HY) and specific hydrogen production rate (SHPR). Experimental data were evaluated by applying RSM integrating a desirability function approach. The optimum H-2 yield and SHPR conditions were: substrate concentration 15.3 g COD/L, pH 5.5, COD/N ratio 100.5 and COD/P ratio 120 with maximum overall desirability D of 0.94. The confirmation experiment under these optimal condition showed a HY and SHPR of 13.54 mmol H-2/g COD and 29.91 mmol H-2/g-VSS.d, respectively. This was only 0.22% and 0.20%, respectively, different from the predicted values, suggesting that the desirability function approach with RSM was a useful technique to get the maximum H-2 yield and SHPR simultaneously. Copyright 2013, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.