US EPA

2951599 

Journal Article 

Understanding the contribution of biofilm in an integrated fixed-film-activated sludge system (IFAS) designed for nitrogen removal 

Moretti, P; Choubert, JM; Canler, JP; Petrimaux, O; Buffiere, P; Lessard, P 

2015 

1 

Water Science and Technology
ISSN: 0273-1223
EISSN: 1996-9732 

71 

10 

1500-1506 

English 

26442492 

10.2166/wst.2015.127 

WOS:000354728000011 

The objective of this study is to improve knowledge on the integrated fixed-film-activated sludge (IFAS) system designed for nitrogen removal. Biofilm growth and its contribution to nitrification were monitored under various operating conditions in a semi-industrial pilot-scale plant. Nitrification rates were observed in biofilms developed on free-floating media and in activated sludge operated under a low sludge retention time (4 days) and at an ammonia loading rate of 45-70 gNH(4)-N/kgMLVSS/d. Operational conditions, i.e. oxygen concentration, redox potential, suspended solids concentration, ammonium and nitrates, were monitored continuously in the reactors. High removal efficiencies were observed for carbon and ammonium at high-loading rate. The contribution of biofilm to nitrification was determined as 40-70% of total NOx-N production under the operating conditions tested. Optimal conditions to optimize process compacity were determined. The tested configuration responds especially well to winter and summer nitrification conditions. These results help provide a deeper understanding of how autotrophic biomass evolves through environmental and operational conditions in IFAS systems. 

biofilm; IFAS; kinetics; municipal wastewater treatment; nitrification; nitrogen