• Korean Journal of Fisheries and Aquatic Sciences
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• v.20 no.1
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• pp.69-78
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• 1987

Human wastes are rich in organic matter and therefore affect the dissolved oxygen when they are discharged into the sea. The breakdown of this organic matter liberates nutrients. The purpose of this study is to evaluate the self-purification capacity in the southern waters of the East Sea during the three cruises in June, July and August, 1986. Streeter and Phelps' model has been used in this study. Factors in this model, deoxygenation constant and reaeration coefficient, have been determined by applying oxygen consumption method and a closed system model. Deoxygenation constant and reaeretion coefficient are 0.177-0.313/day and 0.025-0.364/day respectively. The self-purification capacity to the DO value of 5mg/l is found to be $42.29\~434.25g\;BOD/m^2$, and to a great extent depends on the vertical mixing.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.24 no.1
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• pp.21-30
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• 1991

In Summer, oxygen-deficient water masses were developed extensively in the closed eutrophic bays such as Chinhae Bay which results in mass mortality of marine organisms and severe decrease the production of the bay every year. Under the circumstances, this study was performed to investigate the oxygen depletion relating to eutrophication, and also to evaluate self-purfication capacity of Buk Bay by dissolved oxygen mass balance in 1988. The mean concentration of total inorganic nitrogen, phosphate phosphorus and chlorophyll-a were $11.06{\mu}g-at/l,\;0.80{\mu}g-at/l\;and\;1.11mg/m^3$ respectively, which were over eutrophication criteria. Oxygen-deficient water mass was formed in July with the minimum concentration of 2.08ml/l(mean) at the bottom of all stations and recovered slowly in August. The decay and reaeration coefficient calculated from dissloved oxygen sag curve were 0.222/day and 0.018ml/l/day, respectively. To maintain above 4ml/l of oxygen to prevent oxygen-deficient water mass, it is recommendable to supply as much as 0.856ml/l/day of dissolved oxygen or should be reduced the same mass loading of BOD from watershed by the construction of wastewater treatment plant.