Modeling fermentative hydrogen production from sucrose supplemented with dairy manure

Our previous studies had shown that fermentative hydrogen production from sucrose could be improved with dairy manure as a supplement. In addition to contributing to nearly 10% more hydrogen yield at ambient temperature, dairy manure was shown to be capable of providing the required nutritional needs, buffering capacity, and hydrogen-producing organisms, improving the practical viability of fermentative hydrogen production. In this report, we present a kinetic model for fermentative hydrogen production from sucrose supplemented with dairy manure. This model includes hydrogen production from sucrose as well as from the soluble products hydrolyzed from particulate manure. The integrated model was calibrated using experimental data from one batch reactor and validated with dissolved COD, hydrogen, and volatile fatty acid data from four other reactors. Predictions by this model agreed well with the temporal trends in the experimental data, with r2 averaging 0.85 for dissolved COD; 0.94 for total COD; 0.84 for hydrogen; 0.84 for acetic acid; and 0.89 for butyric acid; quality of fit in the case of propionic acid was lower with r2 averaging 0.57.