Monday, April 29, 2013
Exhibit Hall
The crude glycerol, a byproduct of the biodiesel industry, can be used as substrate for biological hydrogen production. However, only a few genera of microorganisms are able to play this role. Based on this, the objective of this study was to investigate the influence of different pre-treatments on different types of inocula to identify the best source of microorganism for producing hydrogen from crude glycerol. Four different inocula were tested: goat rumen liquid; sludge from an UASB reactor treating municipal wastewater; sludge from an UASB reactor treating food industry wastewater, and a mixture of the last three. Three pretreatments were tested: thermal (the inocula was heated to 90°C during 15min), chemical (addition of 740mg/L of chloroform) and acid (the pH of the inocula was set to 3 using HCl during 24h). A control, with no treatment, was also tested. The batch tests were performed in 0.2L bottles with 16.0gCOD/L, 4.5gVS/L, temperature of 37°C and shaking conditions of 120rpm. The results showed that the sludge from an UASB reactor treating municipal wastewater without pretreatment achieved the highest molar hydrogen yield (0.46molH2/molglycerol). However the highest specific hydrogenogenic activity was achieved using goat rumen liquid pretreated also without pretreatment (563mLH2/gVS.d), which is an indication that this inoculum can be fed at a high organic loading rate. The results also indicate that the use of an adequate inocula and the control of pH and OLR suffices leads to a high H2 production, and no pretreatment is necessary.