Characteristics of distribution and decomposition of organic matters in stream water and sewage effluent

This study was performed to investigate the distribution and decomposition characteristics of organic matter in stream water and sewage effluent located in Gwangju. Average of dissolved organic carbon (DOC) to total organic carbon (TOC) ratio was approximately 73.9% in the Youngsan river system. The concentration of refractory dossolved carbon (RDOC) was 3.7 mg/L corresponding to 80.9% of the DOC. The ratio of recalcitrant organic carbon was relatively higher than that of biodegradable organic carbon in stream. Oxidation efficiencies in the stream were 45.0% for BOD, 63.0% for CODMn and 106.5% for CODcr. In case of sewage effluent was 33.6%, 65.7% and 136.1% respectively. Mean decomposition rate (K-d) of Youngsan river mainstream, its tributary sites and sewage effluent were about 0.042 day(-1), 0.043 day(-1) and 0.028 day(-1), respectively and the difference was not significant between the mainstream and its tributary sites (t-test, p>0.05). Kd of the sewage effluent was lower than that of stream water.