Simultaneous effects of pH and substrate concentration on hydrogen production by acidogenic fermentation
Financial support: Fondecyt 1060220 project from the Chilean Council for Research in Science and Technology (CONICYT). 1060220 and 1090482 projects from Fondecyt and ALEGAS from PUCV, Chile.
Keywords: acidogenic, Gompertz modified, heat treatment, hydrogen, surface response.
The present research examined the effects of initial substrate concentration and pH on the yield and productivity of hydrogen production by acidogenic fermentation. Assays were carried out at three different initial pH levels (5.5, 6.5 and 7.5) and three initial substrate concentrations (3, 5 and 10 g COD/L). Glucose was used as carbon source and the experiments were conducted at 37°C in batch tests, after a thermal pretreatment to eliminate methanogenic microorganisms. Conversions of glucose into hydrogen were between 16.75 and 27.25% of theoretical maximum, and high values of hydrogen productivity were obtained. An optimum value for the yield of glucose between initial pH of 6.3 and 3.7 g COD/L and productivity of the 5.95 H2/gVSS h and initial pH of 6.7 and 10 g COD/L were obtained from the response surface.