Considering all the R1-R7 stable vessels, an average of 59.4 ± 9.2% of the initial COD of the SDW was converted into VFA ,indicating that SDW has significant acidogenic potential. Indeed, in comparison with previous studies using liquid wastes, only whey wastewater, paper mill wastewater and dairy wastewater have been reported to have DA values in the range observed for SDW [14]. Moreover, most of the acidification occurred during the first few days. For each vessel, the DA values reached after 6 days were between 66% and 100% of the final DA.