Treatment of waste water containing ethylene glycol (EG) by implementing a sequence of two Moving Bed Biofilm Reactors (MBBR) were studied. Reactors were operated at different hydraulic retention times (HRT) of 48, 24, 18, and10 hours while EG concentration was in the range of 10 mg/l to 1,150 mg/l. Throughout the experiments the ratio of EG Chemical Oxygen Demand (COD) to total COD was changed from 0.0 to1.0. The maximum removal efficiency of EG was achieved at HRT of 18 hours during the tests and COD removal efficiency varied from 71.7% to 96.7%.
To describe the kinetics of biodegradation in biofilm processes, models based on Monod’s equations as well as models suggested by other researchers including Grau and Stover- Kincannon were used. As an outcome of this study, both Grau and Kincannon-Stover models were determined to be the most appropriate models for this reactor. These models gave high correlation coefficients and appeared to be able to predict the reactor performance under different conditions. The kinetic studies showed that biofilm diffusion is the most important parameter in controlling the mass transfer phenomena compared to hydraulic factors in the system.
Published on: Jul 31, 2015 Pages: 2-7