Expanded granular sludge bed (EGSB) reactor treating actual domestic wastewater: Temperature influence

Abstract

To demonstrate the feasibility of using expanded granular sludge bed (EGSB) reactor as the single reactor for the treatment of domestic treatment when the temperature fluctuates between 15°C (winter) and 26°C (summer), the effects of operation temperature (15°C, 26°C) on the performance, methanogenic activity and granular size distribution were investigated in this paper. The results indicated that the EGSB reactor could keep very high COD removal efficiencies (80.2%-82.3%) at 0.5h-0.8h HRT when treating actual domestic wastewater at ambient temperature (15°C to 26°C). The COD average removal efficiencies would decrease to only 78.3% and/or 72.3% for 0.4h HRT and/or 1.0-3.0h HRT. Although enhancing Vup could increase COD removal efficiency, the increasing quantity was comparatively limited. When using EGSB reactor to treat actual domestic wastewater at ambient temperature (15°C-26°C), the 15-24L.h-1 influent flow and 3.0m.h -1 Vup was suitable. At 26°C, the SMA was not decreased. But at 15°C, the SMA was distinctly decreased, however which could resume at 35 deg; C. Low temperature would compel the microorganisms to get together as soon as possible. Compared with 26°C, the average size of the granules was increased from 0.9mm to 1.0mm at 15°C. © 2013. The authors.