Changes in Microbial Community and Biogas Production due to Ozone Pre-Treatment in Two-Stage Anaerobic Digesters

Sludge treatment is commonly done by anaerobic digestion process which leads to sludge stabilization by converting its organic matter into biogas with high proportion of methane. Therefore, significant efforts have been given to find ways to improve the performance of anaerobic digestion process in recent years. Anaerobic digestion takes place through four consecutive stages as hydrolysis, acidogenesis, acetogenesis and methanogenesis. In single-stage anaerobic digesters, process failures often occur due to accumulation of  volatile fatty acid. To overcome these problems, physical separation of acidogenesis and methanogenesis phases has led to the emergence of two-stage anaerobic digesters. Since the rate-limiting step in anaerobic digestion is the hydrolysis of organic matter, the biogas production mainly depends on the biodegradability of organics in this step. In order to solve this problem, pre-treatment methods are developed. Ozone is one of the strongest and cost-effective oxidative pre-treatment agents. This brings the idea of combining ozone pre-treatment with anaerobic digestion to accelerate the hydrolysis step. In this way, sludge biodegradability and biogas production can also be enhanced. Therefore, this study aims at evaluating the impact of ozone pre-treatment on two-stage anaerobic digester in terms of biogas production and microbial population dynamics. For that purpose, optimum ozone concentration determined for single-stage anaerobic digestion will be used for the pre-treatment of two-stage anaerobic digestion to investigate the changes in biogas production. During two-stage digestion processes the dynamics of microbial consortiums will also be monitored through Flouresence in situ Hybridization (FISH). 

By: Merve AKÇAKAYA

Date & Time: November 6th, 2019 at 15:40 in CZ-14