Application of Lab-Scale MBBR to Treat Industrial Wastewater using K3 Carriers: Effects of HRT, High COD Influent, and Temperature

Abstract

In current study, the efficiency of a lab-scale MBBR was studied using K3 Kaldnes carriers. COD containing contaminant of 1000 to 3500mg/l was used to examine the system performance by measuring BOD and COD at different HRTs, temperature and inlet CODs. It should be noted that K3 Kaldnes carriers was not used in previous studies. To determine optimal HRT, BOD and COD of the effluent were examined at different HRTs of 3, 5, 8, and 12 hours. The optimum HRT was 8 hours with COD removal efficiency more than 80%. Despite of HRT=12 hours with the highest COD removal efficiency ~86%, HRT=8 hours were chosen as the optimal HRT due to the time-consuming refinement process with only a slight difference of 3% in removal efficiencies. Additionally, the effects of temperature in the range of 19 to 32°C were studied at optimal HRT. The results indicate that there is a sharp change in COD removal efficiency slope at a temperature range between 20 to 25°C due to the high activity of microorganisms, leading to an increase in the COD removal efficiency from 70% to ~90%. By increasing the temperature beyond 25°C, the rate of increase in COD removal efficiency is reduced by as much as 94%. According to the results, 27°C may be considered as the optimum temperature. Studying the effects of different inlet CODs up to 3500mg/l reflects a non-monotonic behavior in MBBR’s performance. In general, for all inlet CODs, MBBR system shows more than 80% removal efficiency. Keywords: