Abstract:
Characterization of Submerged Fixed-Film Aerobic Process is described in this thesis. The effectsof organic loading rate and appropriate conditions on the biodegradation of synthetic wastewaterwere determined. Many types of microorganisms were found in the system including paramecium,free swimming ciliates, sessile stalked ciliate, rotifer, nematode and annelid worm which is leadingto a complex food chain and results in a low sludge yield. The effluent suspended solids at steadystate were lower than 30 mg/l. Microorganism were mostly strained within the bed void rather thanattached to the media and its density depended directly on organic loading rate. Increasing of filmthickness caused insufficient oxygen within the film and coupling with film weight leading toperiodical sloughing. At the same organic loading rate, the COD, TKN and Total Phosphorusremoval efficiencies of the systems with HRT variation were slightly better than those of thesystems with COD concentration variation, i.e., 80-95, 50-70 and 50-70 percent as compare to70-85, 50-65 and 50-65 percent, respectively. During film sloughing the treatment efficiencydecreased moderately.