| Title |
A Moving Media Complete Mixing Activated Sludge System |
| Authors |
김홍태 ; 민경석 ( Hong Tae Kim ; Kyung Sok Min ) |
| Abstract |
This study was carried out to obtain the basic design and operating parameters of Moving Media Complete Mixing Activated Sludge (MMCMAS) system for the wastewater treatment. A laboratory MMCMAS reactor was operated at the hydraulic loading of 17∼340ℓ/㎡/d, and the rpms of the moving media were varied with the operational hydraulic loading. Following conclusions from this study were drawn ; (1) The laboratory MMCMAS reactor demonstrated that SBOD removal efficiencies of more than 90% were achieved at the hydraulic retention time(HRT) of 1.5 hours that was relatively shorter HRT than conventional activated sludge process. The nitrification rates of MMCMAS reactor varied in the range of 6 to 90%, depending on the hydraulic loading rates. (2) The optimum rotational speed of moving media were 5∼15rpm and 25rpm at the hydraulic loading rates of 17∼122ℓ/㎡/d and 169∼340ℓ/㎡/d, respectively. The organic removal efficiencies were little affected by the variation of rpms of the moving media at the lower hydraulic loading rates, whereas the organic removal efficiencies were reduced at higher hydraulic loading rates. It is therefore concluded that the rpm of the moving media would be an important operating parameter at higher organic loading. (3) The attached biomass on the moving media varied in the range of 32 to 94% of total biomass in the system depending on the hydraulic loading rates. The ratio of attached biomass to total biomass was increased with the increment of hydraulic loading rate. In addition, it was noticed that the concentration of suspended biomass in the system was strongly correlated with the rpms of the moving media. The finding indicates that the shear forces due to the rotational speed of moving media govern the suspended biomass concentration in the system. The biofilm thickness on the moving media was increased with the increment of hydraulic loading rates. It was also found that the density of biofilm was consistently 50±10㎎/c㎥ at the various hydraulic loading rates as well as rpms of the moving media. |