RESUMO
The role of the hydrolytic stage in high solids temperature phased anaerobic digestion was investigated with a mixture of cattle slurry and maize silage with variable ratios (100, 70 and 30% volatile solids coming from cattle slurry). It was incubated for 48â¯h at 37, 55, 65 and 72⯰C. Soluble chemical oxygen demand and biochemical methane potential were measured at 0, 24 and 48â¯h. Higher temperatures improved the amount of solubilized COD, which confirmed previously reported results. Nevertheless, solubilization mostly took place during the first 24â¯h. The rate of methane production in post-hydrolysis BMPs increased after 48â¯h hydrolysis time, but not after 24â¯h. The first order kinetic constant rose by 40% on average. No correlation was observed between soluble COD and downstream methane production rate, indicating a possible modification of the physical structure of the particulate solids during the hydrolytic stage.