title: Performance of permeable media rotating reactors used for pretreatment of wastewaters.
abstract: The impact of organic loading rate (OLR) on carbonaceous materials and ammonia removal was assessed in bench scale rotating media biofilm reactors treating real wastewater. Media composition influences biofilm structure and therefore performance. Here, plastic mesh, reticulated coarse foam and fine foam media were operated concurrently at OLRs of 15, 35 and 60 g sCOD m(-2)d(-1) in three bench scale shaft mounted advanced reactor technology (SMART) reactors. The sCOD removal rate increased with loading from 6 to 25 g sCOD m(-2)d(-1) (P < 0.001). At 35 g BOD5m(-2)d(-1), more than double the arbitrary OLR limit of normal nitrifying conditions (15 g BOD5m(-2)d(-1)); the removal efficiency of NH(4)-N was 82 ± 5, 27 ± 19 and 39 ± 8% for the mesh, coarse foam and fine foam media, respectively. Increasing the OLR to 35 gm(-2)d(-1) decreased NH(4)-N removal efficiency to 38 ± 6, 21 ± 4 and 21 ± 6%, respectively. The mesh media achieved the highest stable NH(4)(+)-N removal rate of 6.5 ± 1.6 gm(-2)d(-1) at a sCOD loading of 35 g sCOD m(-2)d(-1). Viable bacterial numbers decreased with increasing OLR from 2 × 10(10)-4 × 10(9) cells per ml of biofilm from the low to high loading, suggesting an accumulation of inert non-viable biomass with higher OLR. Increasing the OLR in permeable media is of practical benefit for high rate carbonaceous materials and ammonia removal in the pretreatment of wastewater.
authors.affiliation: Cranfield University, Cranfield, MK43 0AL, UK E-mail: t.stephenson@cranfield.ac.uk.
authors.forename: F
authors.initials: F
authors.lastname: Hassard
authors.affiliation: Cranfield University, Cranfield, MK43 0AL, UK E-mail: t.stephenson@cranfield.ac.uk.
authors.forename: E
authors.initials: E
authors.lastname: Cartmell
authors.affiliation: Bluewater Bio, Compass House, 22 Redan Place, London, W2 4SA, UK.
authors.forename: J
authors.initials: J
authors.lastname: Biddle
authors.affiliation: Cranfield University, Cranfield, MK43 0AL, UK E-mail: t.stephenson@cranfield.ac.uk.
authors.forename: T
authors.initials: T
authors.lastname: Stephenson
mesh_terms: D001419:Bacteria / Q000378:metabolism; D018441:Biofilms; D019149:Bioreactors; D009584:Nitrogen / Q000378:metabolism; D010084:Oxidation-Reduction; D014865:Waste Disposal, Fluid / Q000379:methods*
chemical_list: D009584:Nitrogen