Electronic Thesis and Dissertation Repository


Master of Engineering Science


Chemical and Biochemical Engineering


Zhu, Jingxu

2nd Supervisor

Nakhla, George


In three parallel aerobic inverse fluidized bed bioreactors (AFBBR), the attachment rate and biofilm quantity during the startup stage and the biofilm characteristics and nutrient removal efficiency at steady-state were analyzed to evaluate the characteristics of three different particle carriers, polyethylene (PE), polypropylene (PP) and activated carbon-coated polyethylene (PEC) under various operating conditions. In addition, the effects of other factors, such as hydraulic retention time (HRT) and carbon-nitrogen (C/N) ratio were also tested to optimize the startup method and to accelerate the biofilm attachment process for the particles. The results showed that under a favourable startup condition of 4h HRT and 300 mg/L influent COD, PE had reached the best attachment in 14 days and PEC came in second, using 20 days, whereas PP failed to achieve attachment due to serious shear force. The peak attached biomass were 9.4 mg VSS/g media for PE and 10.7 mg VSS/g media for PEC respectively. Additionally, PEC had the lowest suspended biomass fraction and detachment rate.

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