• Journal of Korean Society on Water Environment
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• v.22 no.1
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• pp.91-96
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• 2006

Many small scale Sewage Treatment Plants (STPs) are currently being constructed at many rural areas. The STPs in rural area suffer from low concentration and large inflow quantity fluctuation during wet weather mainly due to illicit combined sewer system. Sequencing Batch Reactor (SBR) is a process effectively coping with these obstacles. The main objective of this study was to evaluate SBR with high hydraulic loading and low inflow concentration. The operating conditions tested were: organic loading rate = $0.17-0.42KgBOD/m^3/d$, hydraulic loadings = $12.1-61.5m^3/m^2/d$, average MLSS concentration = 2500 mg/L, F/M ratio = 0.026-0.17 KgBOD/Kg MLSS, HRT = 9-12 hr HRT, and SRT = 5.6-33.6 days. Organic loading rate on SBR did not impact significantly on BOD and SS removal efficiencies. To increase treatment efficiencies, low hydraulic loading rate with low concentration was required. The results suggested that low influent concentration with high inflow rates during wet weather requires extended time for settling.

• Journal of Environmental Science International
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• v.23 no.5
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• pp.985-993
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• 2014

For the field application of dielectric barrier discharge plasma reactor, a multi-plasma reactor was investigated for the inactivation of microorganisms in sewage. We also considered the possibility of degradation of non-biodegradable matter ($UV_{254}$) and total organic carbon (TOC) in sewage. The multi-plasma reactor in this study was divided into high voltage neon transformers, gas supply unit and three plasma modules (consist of discharge, ground electrode and quartz dielectric tube). The experimental results showed that the inactivation of microorganisms with treated water type ranked in the following order: distilled water > synthetic sewage effluent >> real sewage effluent. The dissolved various components in the real sewage effluent highly influenced the performance of the inactivation of microorganisms. After continuous plasma treatment for 10 min at 180 V, residual microorganisms appeared below 2 log and $UV_{254}$ absorbance (showing a non-biodegradable substance in water) and TOC removal rate were 27.5% and 8.5%, respectively. Therefore, when the sewage effluent is treated with plasma, it can be expected the inactivation of microorganisms and additional improvement of water quality. It was observed that the $NH_4{^+}$-N and $PO{_4}^{3-}$-P concentrations of sewage was kept at the constant plasma discharging for 30 min. On the other hand, $NO_3{^-}$-N concentration was increased with proceeding of the plasma discharge.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2002.09a
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• pp.327-330
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• 2002

In this study, analyses of contaminant transport are peformed to evaluate the diffusion effect of A sewage tunnel. First, Crank's analytical method is used to measure the concentration change of contaminant with time and space. Two dimensional numerical analysis is performed to measure concentration distribution of contaminant. Both methods show that the diffusion effect is little even after 500 years. This means that when flow converges into the tunnel, the environmental effect of contaminant in tunnel is not serious because there is no advection occurs.

• Journal of Environmental Science International
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• v.16 no.2
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• pp.211-218
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• 2007

The objectives of this study have been carried out to investigate the solubilization of municipal sewage sludge by single and dual frequency ultrasonic pretreatment, and the methane production characteristics of pretreated sewage sludge by specific methanogenic activity test for sewage sludge reduction. The waste activated sludge was collected from thickened tank of Suyoung sewage treatment plant in Busan city, and its concentration was adjusted to 1.0% total solids. Ultrasonic frequency was varied 15, 20, 15+20 kHz, and acoustic density was used a maximum 176W/L. The dual frequency ultrasonic pretreatment was found to be more effective than single frequency ultrasonic in the solubilization rate and methane production. The $SCOD_{Cr}/TCOD_{Cr}$, rate were 15.2%, 13.9%, 17.0% with single frequency of 15 kH2, 20 kHz, dual frequency of 15+20 kHz, respectively. The application of dual frequency ultrasound for sewage sludge pretreatment can be interest for sewage treatment plants having problems in sludge treatment and disposal.

• Journal of Korean Society of Water and Wastewater
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• v.27 no.5
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• pp.603-610
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• 2013

According to industrialization, increased toxic chemicals discharge has been causing water pollution. Especially domestic sewage is a major source of water pollution. Sixty percent of the total wastewater discharged is domestic sewage. Self-purification capacity of rivers and streams is drastically reduced by the emission of domestic sewage, industrial wastewater and livestock wastewater. Although domestic sewage is managed by implementing standards and regulations, toxicity effect of domestic sewage to humans and the environment is not yet clearly understood. In this study, by using daphnia magna, the ecotoxicity of domestic swage was assessed. Cl, Cu, Pb, COD, T-N, DO, pH and residual chlorine were investigated as background concentrations. The experiments were conducted with water samples obtained from three local sewage treatment plants. The experiment results indicated that higher level of toxicity corresponds to the higher pollution concentrations. The higher level of combinations of background concentrations such as heavy metals leads to the worse ecotoxicity. Especially, the Cu concentration affects the TU value.

• Journal of the Korea Organic Resources Recycling Association
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• v.27 no.3
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• pp.27-39
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• 2019

In this study, thermal-alkali pre-treatment (THAP) optimal condition and co-digestion efficiency with THAP of the mixture food waste and sewage sludge were evaluated for improving the performances of co-digestion for mixed food waste and sewage sludge. The optimal condition of THAP was evaluated for solubilization COD, CST(Capillary Suction Time), TTF(Time to Filter), and volatile fatty acids (VFAs) with THAP temperature and NaOH concentration. In addition, the co-digestion of mixed food waste and sewage sludge were evaluated using biochemical methane potential (BMP) test. The optimal THAP reaction temperature and NaOH concentration of food waste and sewage sludge were $140^{\circ}C$ and 60 meq/L to solubilization COD over 20%, CST and TTF under 60sec and VFAs concentration over 12,000 mg-COD/L, respectively. The optimal condition of co-digestion of mixed food waste and sewage sludge equal to THAP condition. Therefore, it was determined that the optimal condition of THAP reaction temperature and NaOH concentration for co-digestion of mixed food waste and sewage sludge were $140^{\circ}C$ and 60 meq/L, respectively.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 1993.10a
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• pp.1405-1414
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• 1993

The purification of sewage deriving from agricultural and food industries is today a serious problem mainly in areas characterized by intensive production plants. The solution examined in this work, involves a system of natural evaporation which employs special panels with a large evaporating surface constituted by an internal cellular structure in polyethilene. Using renewable energy they allow to speed up the natural evaporating effect thus eliminating some drawbacks such as swamps and obtaining sewage concentration with relatively low costs. The institute of agricultural engineering has carried out tests on the disposal of sewage deriving from two very important production sectors; pig-breeding and olive oil production . at a were gathered in order to verify the operating capacity of plants and their variables . On the remaining concentrated part tests were also carried out in order to know its chemical and chemical-physical features and to study the possibility for its us .

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2000.10a
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• pp.611-616
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• 2000

Effect of reclaimed sewage on the paddy rice culture was examined by field experiment for two consecutive years. The domestic sewage was treated by the comstructed wetland, and the effluent of the treatment wetland was used for irrigation water. Growth components and yields were compared against the CONTROL plot where conventional fertilization was applied. In general, addition of the reclaimed sewage irrigation which contained high nutrient concentration didn＇t affect paddy rice culture adversely, and even better growth and more yields were observed. Overall, reclaimed sewage irrigation was thought to be one of practical alternatives for irrigation water.

• Journal of environmental and Sanitary engineering
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• v.17 no.3
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• pp.83-88
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• 2002

This study was performed to determine the possibility of sludge treatment by ozone for reducing the sludge production in sewage treatment. To evaluate the characteristics of the release of organic matters and nutrient from sludge degradation by ozone, SCOD, SBOD/TCOD, T-N and T-P were analyzed. From the results, we concluded that the concentration of soluble organic matters(SCOD) was increased with reaction time. Also, The concentration of T-N and T-P were increased with time like as organic matters. Quantities of released SCOD, SBOD, T-N and T-P by ozonization were 0.038g, 0.058 g, 0.011 g, 0.012 g per g MLSS, respectively.

• Journal of Korean Society on Water Environment
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• v.23 no.4
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• pp.512-517
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• 2007

The limiting nutrient of eutrophication in freshwater bodies in Korea was examined and the phosphorus concentration standard for sewage treatment effluent was discussed. The weight ratio of N/P in 13 major reservoirs showed the range of 18 to 163, which implies phosphorus is more limited than nitrogen for algal growth. In the correlation analysis phosphorus showed higher correlation with chlorophyll-a concentration than with nitrogen. In the algal bioassay phosphorus spike test enhanced algal growth in all 25 samples of five reservoirs, while nitrogen was found to co-limit only in four samples. It confirms that phosphorus is the only limiting nutrient for eutrophication in Korean reservoirs. As many reservoirs are eutrophic in Korea, phosphorus control is critical for the management of water quality. The phosphorus standard of sewage treatment effluent in Korea was compared with other countries, and it can be concluded that phosphorus standard is too high to be effective in eutrophication control and a lower phosphorus standard is essential for the water quality improvement.