Date of Award


Degree Type


Degree Name

Master of Engineering Science


Civil and Environmental Engineering


Dr. George Nakhla

Second Advisor

Dr. Jesse Zhu


The performance of a Liquid-Solid Circulating Fluidized Bed (LSCFB) Bioreactor for treatment of wastewater with anoxic and aerobic beds and lava rock as biofilm carrier media was used to investigate the impact of the carbon to nitrogen (COD∕N) ratio on the process performance, with particular focus on total nitrogen removal. Three different municipal wastewaters with COD/N ratios of 10:1, 6:1 and 4:1 were tested at an empty bed contact time of 0.82 h. It was found that 90% of influent organic matter was removed throughout the study with 58% removal in the anoxic column at COD/N ratio of 4:1. Total nitrogen removal efficiencies at COD/N ratios of 10:1 to 4:1 were 91%, 82% and 71% and simultaneous nitrification-denitrification (SND) occurred in the aerobic downer. Furthermore, the achievability of sewer discharge criteria during the treatment of rendering wastewater, characterized by COD of 29,509± 438 mg L^1, BODs of 20,161 ± 673 mg L', TKN of 1,087± 21 mg L^1 and NH4-N of 605 ± 6.2 mg L^1, was carried out. More than 90% of influent organic matter, 79-96% nitrogen was removed during treatment of rendering wastewater. Biofilm thicknesses were monitored throughout the study period. Average biofilm thickness of <100 and 750 μm were observed in the downer and riser, respectively.



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