Hydrothermal pretreatment of sewage sludge a case study on the efficiency of biogas production and anaerobic digestion via metabolites and microbial distribution changes
Hydrolysis phase in anaerobic digestion is widely considered as the most common rate-limiting phase. Recent research had discovered that hydrothermal pre-treatment is a viable way of improving the reaction kinetics of this phase by improving the quantity of volatile fatty acids through the acceleration of digestion of biopolymers to monomers, thereby improving the efficiency of biogas production. In this case study, sewage sludge digestion in the production of biogas via anaerobic digestion has been enhanced by hydrothermal pre-treatment process. There are three separate groups of data to be investigated, with the most ideal condition being reaction temperature of 150oC, reaction time of 90 minutes and reaction gas of air. Current data had verified the increase in quantity of acetic acids produced and consumed together with the identification on the dominant increase in Methanosarcinales which assimilates acetic acid as a carbon source proving the viability of hydrothermal pretreatment on improving anaerobic digestion efficiency. The final increased quantities of biogas, methane and carbon dioxide measured after anaerobic digestion was completed further confirmed on the use of these methods as a good means of increasing anaerobic digestion productivity.