Bioaugmentation with a proprietary facultative bioculture in a two-phase anaerobic digestion process of cobia fish wastes from indoor aquaculture system

摘要

For this study, we investigated a BioAugmentation Process (bioagumentation) system for therndegradation of indoor aquaculture fish wastes using a specially designed acid producingrnbioculture in the facultative (FAC) phase of a two-phase anaerobic digestion reactor atrnmesophilic temperature (40℃ ±2℃). This bioagumentation-FAC system was expected tornincrease the rate of the anaerobic digestion through addition of the proprietary FAC bioculturerncontaining microorganisms that are responsible for one or more rate limiting steps in therndigestion process. Additionally, the bioagumentation-FAC was also expected to elevate the endrnpoint of digestion by suppressing undesirable metabolic pathways. With undesirable byproductsrn(e.g. hydrogen sulfide) being largely avoided at the FAC phase and more acid-producingrnmicroorganisms present, more fatty acids would be produced and available for methanernproducing organisms, thereby increasing the rate of methane production. In this study werndemonstrated improved performance of a bioagumentation-FAC compared to nonrnbioagumentation-FAC anaerobic digestion system used to treat an aquaculture waste from thernbottom of fish tanks, which primarily consists of fish feces, excess fish food and other excretoryrnwastes. Fishwaste exhibited high digestibility. In a semi-batch test for 50 days, 95% ofrntheoretical methane production was produced as total biomethane potential for thernbioagumentation-FAC reactor. The bioagumentation-FAC anaerobic system produced 21% to 36%rnmore total methane (ml/g VSadded) in the semi-continuous experiment. bioagumentation hydrogenrnsulfide concentrations were 13% to 22% lower. Finally, applying plastic media in ourrnbioreactors has increased methane production by 83% and 48% for 8 days and 16 days HRT,rnrespectively.