• Journal of Korean Society of Water and Wastewater
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• v.21 no.5
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• pp.551-558
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• 2007

From the view point of biological wastewater treatment, C/N ratio is one of the most important factor in biological nutrient removal process. However, municipal sewage in Korea is characterized by extremely low content of carbon source and relatively higher portion of N source. Accordingly, it is necessary to dose external carbon source in order to obtain higher degree of carbon source within the process. In this study, the effects of pH pretreatment as an alternative plan for increasing carbon source on the cell disruption and COD solubility of waste activated sludge were conducted under well defined experimental conditions. During 5 hours, the value of COD solubilization rate ($S_R$) at pH 11.5 is approximately 4.4 times higher than the value of $S_R$ at pH 9.5. It is expected that the level of SCOD increased due to the result from cell disruption. However, VSS/TSS ratio was not significantly changed after 5 hours. As Alkalinity changes gradually from less than 15, 30 and 60 meq NaOH/L, average RBCOD/SCOD fraction showed 34, 36 and 45%,respectively.

• Journal of the Korean Society for Marine Environment & Energy
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• v.9 no.1
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• pp.14-20
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• 2006

In this study, the feasibility of simultaneous removal of organic materials and nitrogen in the waste-water from fisheries processing plant was evaluated using entrapped mixed microbial cell technique(EMMC) process. The experiment was performed using activated sludge from municipal sewage treatment plant which was immobilized with gel matrix by cellulose triacetate. It was found that the stable operation at the treatment system which is composed of anoxic and oxic tank, was possible when the organic and nitrogen loading rates were increased stepwise. The organic and nitrogen loading rates were applied from 0.65 to $1.72kgCOD/m^3/d$ and from 0.119 to $0.317kgT-N/m^3$ with four steps, respectively. The maximum nitrogen loading rate which could satisfy the regulated effluent standard of nitrogen concentration, was $0.3kgT-N/m^3/d$. The removal efficiency of total nitrogen was decreased apparently as increasing nitrogen loading rates, whereas the removal efficiency of ammonium nitrogen was effective at the all tested nitrogen loading rates. Therefore, it was concluded that nitrification was efficient at the system. Nitrate removal efficiency ranged from 98.62% to 99.51%, whereas the nitrification efficiency at the oxic tank ranged 94.0% to 96.9% at the tested loading rates. The removal efficiencies of chemical oxygen demand(COD) and those of total nitrogen at the entire system ranged from 94.2% to 96.6% and 73.4% to 83.4%, respectively.