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Cultivated lands within the river district are likely non-point sources of pollution that could be directly discharged into rivers and lakes, as well as identified as significantly risky areas for pollutant run-off during floods. In this study, major non-point sources in surface run-offs, from cultivated lands within the river districts, and their effects on the bodies of water in North Han River Basin were examined. It was found that pollutant concentrations in the run-offs from farms appeared to be generally higher than in the run-offs from paddies. Initial concentrations of pollutants during rainy seasons were usually higher than the medians of their concentration ranges, though not necessarily the highest. The unit loads of BOD from cultivated lands within river districts, which were proposed in this study for the first time in Korea, were 4.56, 3.35, and 10.26 kg/km2/year for paddies, farms, and greenhouses, respectively. Likewise the unit loads of total nitrogen (TN) were proposed as 1.54, 8...

We evaluated the settling ability and dewaterability of granulated methane-oxidizing bacteria (GMOB) after granulation using a continuous-flow reactor. A comparative analysis on the settling and dewatering characteristics due to changes in the sludge retention time (SRT) during cultivation of the GMOB was also conducted for SRTs of 10, 15 and 20 days. In assessing dewaterability, the specific resistance to filtration (SRF) of the activated sludge and GMOB was found to be 8.21×10 13 --2.38×10 14 and 4.88×10 12 --1.98×10 13 m/kg, respectively. It was also confirmed that as the SRT decreased, the SRF of the GMOB increased. In the case of the bound EPS, the activated sludge registered 147.5 mg/g-VSS while the GMOB exhibited 171--177.2 mg/g-VSS. In the case of the soluble EPS in effluent, the activated sludge measured 62 mg/L and the GMOB had 17.4--21.4 mg/L. The particle size analysis showed that the mean particle diameters of the GMOB were 402, 369, and 350 µm, respectively, at the SRTs of 20, 15 and 10 days. In addition, it was found that the GMOB had a larger mean particle diameter and exhibited much better settleability and dewaterability than the activated sludge did.