title: Effect of nitrogen limitation on performance of toluene degrading biofilters.
abstract: The literature reports conflicting observations regarding the need for nutrient addition to biofilters treating contaminated gases. Such conflicts are often based on quasi-steady-state performance data collected on biofilters operated under continuous loading conditions. In the studies described herein, the impact of nitrogen limitations on two toluene-fed biofilters was assessed over a 97-day period. The biofilters were packed with polyurethane foam medium and contained different initial levels of nitrate-nitrogen. Toluene and CO2 concentration profiles were monitored during both normal steady loading conditions and short-term, unsteady-state transient loading conditions (e.g., shock loads). Packing medium samples were periodically removed and analyzed to quantify changes in nitrate-nitrogen content over time. Data are presented which show that over long-time periods (several months), nutrient-induced kinetic limitations diminished biofilter performance during transient, unsteady-state conditions even when performance during normal steady loading was not adversely affected. Elemental analysis of biomass removed from the biofilters support nitrate-nitrogen and CO2 concentration profile data and clearly illustrate how kinetically limited biofilters fail during shock loads even when there is an overall stoichiometric excess of nutrients.
authors.affiliation: Department of Civil and Environmental Engineering, Louisiana State University, Baton Rouge, LA 70803-6405, USA. moemwil@lsu.esu
authors.forename: W M
authors.initials: WM
authors.lastname: Moe
authors.forename: R L
authors.initials: RL
authors.lastname: Irvine
mesh_terms: D001673:Biodegradation, Environmental; D018441:Biofilms; D009584:Nitrogen / Q000378:metabolism*; D014050:Toluene / Q000378:metabolism*
chemical_list: D014050:Toluene; D009584:Nitrogen