ABSTRACT
The responses of a steady-state, continuous-flow, completely-mixed fluidized bed reactor (FBR) to a range of monoethylamine (MEA) impulses are analyzed in terms of its combined carbon oxidation and nitrification efficiencies. Immobilized cells are cultivated at a mean cell residence time (MCRT) that exceeds 75 days. Responses due to bacterial activities and physical flows are separately estimated using a methodology based on mass balance calculations. MEA inhibition becomes evident when respective critical impulse loadings are exceeded, i.e., 0.12 mg TOC/mg VS for carbon oxidation and 0.021 mg TOC/mg VS for nitrification (TOC: total organic carbon, VS: volatile solids). Nitrifying cells are shown to be more susceptible to MEA impulses than their heterotrophic counterparts. However, the presence of nitrification activities under the conditions tested demonstrates the advantages of cell immobilization that offer greater flexibility when challenged with suddenly increased MEA loads over a short period of time. Mass balance calculations on nitrogen species confirms that 0.583 mg NH(4)(+)-N is produced per mg MEA-C removed when the assimilatory nitrogen requirements for cell synthesis are negligible.
