Performance and microbial community structure of aerobic granular bioreactors at different operational temperature. (February 2020) - Muñoz-Palazon, Barbara
Graphical abstract: Highlights: Granulation was stable for long-term operation, despite not adapted activated sludge. Dense and regular shape surface of granules, without presence of filamentous. Optimal nitrification at mid and high temperature after 60 days. The faster startup was achieved in mid bioreactor due to inoculum proceed. Relevance of ciliate and fungi microorganisms in granules in steady-stable stage. Abstract: Three lab-scale sequential batch reactors were operated under aerobic granular sludge technology for 150 days. The reactors were inoculated with mild temperature-adapted activated sludge from Granada wastewater treatment plant (WWTP) in order to evaluate the microbial dynamics, the granulation process and the performance of the systems under low, mid and high temperature. The faster start-up was achieved at mid temperature at operational day 6, followed by warm temperature at day 10, with nitrogen and organic matter removal ratio higher than 90%. Conversely, the reactor under cold temperature produced granular biomass but the nitrogen and carbon removal ratios did not achieve good performance, close to 80%. The dynamics of Prokarya communities showed that Corynebacterium phylotype was present in all bioreactor despite temperature, although the microbial diversity at mid and warm temperature was higher than at cold temperature. The Eukarya communities in mature granules were represented by Pezizomycotina fungi and Oligohymenophorea ciliate.