title: Submerged bed versus unsaturated flow reactor: A pressurized hydrogenotrophic denitrification reactor as a case study.
abstract: The paper compares the main features of a submerged bed reactor (SuBR) with bubbling and recirculation of gas to those of an unsaturated flow reactor (uSFR) with liquid recirculation. A novel pressurized closed-headspace hydrogenotrophic denitrification system characterized by safe and economic utilization of H2 gas was used for the comparison. Under similar conditions, denitrification rates were lower in the SuBR as a result of a lower effective biofilm surface area and overall gas-liquid mass transfer coefficient kLa. Similar values of effluent DOC were achieved for both reactors, although effluent suspended solids concentration of the SuBR were substantially higher. On the other hand, the required cleaning frequency in the SuBR was 2.5 times lower. Moreover, the SuBR is expected to reduce the recirculation energy consumption by 0.35 kWh/m(3) treated.
authors.affiliation: Faculty of Civil and Environmental Engineering, Technion - Israel Institute of Technology, Haifa 32000, Israel. Electronic address: epsztein@tx.technion.ac.il.
authors.forename: Razi
authors.initials: R
authors.lastname: Epsztein
authors.affiliation: Faculty of Civil and Environmental Engineering, Technion - Israel Institute of Technology, Haifa 32000, Israel.
authors.forename: Michael
authors.initials: M
authors.lastname: Beliavski
authors.affiliation: Faculty of Civil and Environmental Engineering, Technion - Israel Institute of Technology, Haifa 32000, Israel.
authors.forename: Sheldon
authors.initials: S
authors.lastname: Tarre
authors.affiliation: Faculty of Civil and Environmental Engineering, Technion - Israel Institute of Technology, Haifa 32000, Israel.
authors.forename: Michal
authors.initials: M
authors.lastname: Green
mesh_terms: D018441:Biofilms; D019149:Bioreactors; D058440:Denitrification
keywords: Closed-headspace reactor; Gas recirculation; Hydrogenotrophic denitrification; Liquid recirculation; Submerged bed; Unsaturated flow