Effect of temperature on the anaerobic thermophilic conversion of volatile fatty acids by dispersed and granular sludge

摘要: Abstract The effect of temperature on the rate volatile fatty acid (VFA) conversion by thermophilic methanogenic sludge, cultivated at 55°C, was studied using both batch activity tests and continuous flow experiments. dependence acetate in range between 37–70°C could be described an Arrhenius derived model when dispersed sludge with a low specific used. For this optimum found 65°C. However, maximum utilization not affected 50°C to 65°C granular high Crushing granules led 2 3 fold increase 60–65°C, indicating that very likely limited diffusion into granules. Similar results were obtained butyrate as substrate. crushed similar less active sludge. In contrast, propionate oxidation highest intact while for sludges. affinity VFA increased decreasing temperature. This phenomenon most pronounced treatment VFA-mixture UASB reactor appeared only slightly moderately loading rates applied, i.e. 20 kg COD·m −3 ·d −1 . had strong applying 40–90 accompanied effluent concentrations. reveal thermostability wastewater process 45–60°C if “high-rate” reactors bed are