Organic matter removal and nitrification using a woven hollow fiber tube as biological media

Attached growth micro-organisms are known to be beneficial to the removal of low-concentration organic matter because they can have a long retention time due to their very slow growth rate compared with the suspended growth micro-organisms suitable for high-concentration organic substance treatment. In this study, the characteristics of the treatment of organic and nitrogen pollutants in low concentrations were investigated by injecting air into the inside of the tube, using a woven-hollow fiber tube as biological media. According to the changes in the hydraulic retention time, the biochemical oxygen demand (BOD) concentrations of the influent and the treated water were 29.8-37.6 mg/L and 8.6-18.5 mg/L, respectively. The suspended solid (SS) of the influent was 33.9-36.7 mg/L, and that of the treated water was 1.6-3.6 mg/L, showing a high SS removal efficiency of more than 90%. The investigation of the BOD and the NH4+-N removal efficiency according to the surface loading rate revealed that the effects caused by the increase in the surface loading rate are greater in NH4+-N than in BOD. The attached growth micro-organisms decreased by detachment after 20 d, and increased again, securing a constant amount of growth micro-organisms.