• Journal of Animal Environmental Science
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• v.13 no.3
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• pp.161-170
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• 2007

Ozone from a pilot-scale ozone generator was treated on fermented pig liquid manure stored in a storage tank in order to reduce odor substances during the process of fermented liquid manure production. The group of ozone treatment showed one less than the organic matter compared that of the control. The preferable condition for characteristic changes was when the ratio of BOD to COD was less than 1.5. Ozone treatment showed better oxidizing power than control as it removed more suspended solids and had less methyl isobutyl ketone(P<0.05). Odor reduction measured by olfactory method was higher in ozone treatment than in control.

• Korean Journal of Ecology and Environment
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• v.56 no.2
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• pp.127-139
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• 2023

Daechung Reservoir has been suffering from severe cyanobacterial blooming periodically due to the water pollutants from the watershed, especially nutrients from nonpoint sources. As a countermeasure, an artificial wetland was constructed to mitigate the pollutant load from the watershed by utilizing the vegetation. We investigated the water quality of the influent and outflow of the wetland during years 2014~2020 to evaluate the performance of pollutant removal through the wetland. Major pollutants (e.g. BOD, COD, SS, T-N, and T-P) were largely reduced during the retention in the wetland while nutrients removal was more efficient than that of organic matters. Pollutant removal efficiency for different inflow concentrations was also investigated to estimate the wetland's capability as a way of managing nonpoint sources. The efficiency of water treatment was significantly higher when inflow concentrations were above 75^th percentile for all pollutant, implying the wetland can be applied to the pre-treatment of high pollution load including initial rainfall runoff. Furthermore, the yearly variation of removal efficiency for seven years was analyzed to better understand long-term trends in water treatment of the wetland. The annual treatment efficiency of T-P was very high in the early stages of vegetation growth with high concentration of inflow water. However, it was confirmed that the concentration of inflow water decreased, vegetation stabilized, and the treatment efficiency gradually decreased as the soil was saturated. The findings of the study suggest that artificial wetlands can be an effective method for controlling harmful algal blooms by alleviating pollutant load from the tributaries of Daechung Reservoir.

• Journal of the Korea Organic Resources Recycling Association
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• v.17 no.2
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• pp.93-100
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• 2009

This research was performed to figure out the optimal mixing ratio of food- to livestock wastewater for the best degradation of organic matter in the anaerobic digestion. The presence of various microorganisms, such as Escherichia coli and Staphylococcus aureus, was also investigated in both wastewater in this process. Enteric bacteria were only found in livestock wastewater, whereas pathogenic bacteria like S. aureus were detected in both wastewater. The optimal mixing ratio of food- to livestock wastewater for the best mineralization was found to fifty to fifty, with reduction ratios of $BOD_5$, CODcr SS as 23.2%, 24.7%, 19.7%, respectively. Hygiene of the digested sludge was also analyzed by counting the number of total colonies and various pathogens. Enterobacteriaceae including E. coli were barely detected in 10 days after reaction. Meanwhile, S. aureus was gradually reduced during reaction, even showing 1,000~5,000 CFU/mL in final days.

• Korean Journal of Ecology and Environment
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• v.38 no.3 s.113
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• pp.372-381
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• 2005

This study was conducted to test the efficiency of water quality improvement using the dissolved air flotation (DAF) technique in a shallow eutrophic reservoir. The application of DAF was followed by the addition of a chemical coagulant (poly aluminum chloride; PAC). The experiment was conducted in the mesocosm scale (wide ${\times}$ length ${\times}$ depth: 6 m ${\times}$ 6 m ${\times}$ 3 m). Suspended solids (SS) and volatile SS (VSS) concentration decreased by 54 ${\sim}$ 71% and 57 ${\sim}$ 79% of the initial concentrations, respectively. Total phosphorus and Chl- a concentration also decreased by 74 ${\sim}$ 92% and 54 ${\sim}$ 98%, respectively. BOD decreased by>86% while COD decrease ranged 29 ${\sim}$ 63%. Dissolved inorganic P (DIP) and dissolved total P (DTP) concentration decreased by 34 ${\sim}$ 88% and 62 ${\sim}$ 88%, respectively. After DAF application further onto the sediment, DIP-release rates from the sediment decreased by 17% (0.82 ${\to}$ 0.68 mg $m^{-2}$$day^{-1}$ in the oxic condition and 23% (2.27 ${\to}$ 1.76 mg $m^{-2}$$day^{-1}$) in the anoxic condition, compared to the release rate from the untreated sediment. DTP-release rate from both the oxic and anoxic sediments also decreased by 33% (5.62 ${\to}$ 3.78 mg $m^{-2}$$day^{-1}$) and 20% (6.23 ${\to}$ 4.99 mg $m^{-2}$$day^{-1}$), respectively. These results suggest that the DAF application both to the water column and onto the sediment be effective to improve water quality by removing particulate matters in the water column as well as reducing P-release from the sediment.

• Korean Journal of Agricultural and Forest Meteorology
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• v.9 no.1
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• pp.29-36
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• 2007

This study was carried out to develop a water quality simulation model for the evaluation of an ungauged watershed. For this purpose, the WASP5 model was selected and modified. The model consists of three sub-models, LOAD-M, DYN-M, and EUT-M. LOAD-M, an empirical model, estimates runoff loadings using point and non-point source data of villages. The Geum River Estuary watershed was selected to calibrate and verify the Modified-WASP5. The LOAD-M model was established using field data of water quality and quantity at the gauging stations of the watershed and was applied to the ungauged watersheds, taking the watershed properties into consideration. The result of water quality simulation using Modified-WASP5 shows that the observed average BOD data from Gongju and Ganggyeong were 2.6 mg/L and 2.8 mg/L, and the simulated data were 2.5 mg/L and 2.4 mg/L, respectively. Generally, simulation results were in good agreement with the observed data. This study focused on formulating an integrated model for evaluating ungauged watersheds. Even though simulation results varied slightly due to limited availability of data, the model developed in this study would be a useful tool for the assessment and management of ungauged watersheds.

• Proceedings of the Korea Water Resources Association Conference
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• 2009.05a
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• pp.1817-1821
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• 2009

최근 전자제품 사용의 증가로 인해 버려지는 전자제품의 양도 함께 증가하고 있으며 이렇게 늘어난 전자폐기물이 부적절한 방식으로 처리될 경우 우리에게 악영향을 미치는 위험물질이 될 수 있다. 본 연구에서는 이러한 전자폐기물 중 하나인 폐 LCD 유리를 이용한 수질정화용 여재를 이용하여 전자폐기물에 의한 오염을 줄이고, 동시에 강우시 표면 유출로 인하여 발생되는 비점오염을 제어하고자 하였다. 본 연구에서 이용한 수처리 여재는 기존 수처리 여재의 단점을 보완하는 대체 여재 개발이라는 목적에 적합할 것으로 판단된다. 이에 본 연구에서 발포기술이 적용된 폐 LCD 유리 여재의 비점오염에 의한 수질정화능력평가를 하기 위해 실험 장치를 구성하여 실험하였다. 반응조는 직경 0.10 m, 높이 0.75 m 크기(총용량= 5.89 $\ell$)로 두께 10mm의 투명 아크릴판으로 3조를 제작하였다. 유입수는 미량 펌프를 이용하여 유입하였다. 각 반응조의 체류시간에 의한 수질정화능력을 평가하였다. 연구 결과, 오염물질에 대한 제거효율 범위는 SS $64.1%\sim88.2%$, BOD $29.8\sim52.4%$, COD $56.8\sim66.1%$, T-N $39.4\sim\;52.3%$, T-P $14.1\sim36.8%$로 나타났다. 체류시간이 가장 길었던 반응조의 경우, 대부분의 측정항목에서 높은 처리 효율을 볼 수 있었다. 초기에 처리 효율이 낮은 것은 미생물이 부착되지 않았기 때문이라고 판단되며, 실험의 중반과 후반에서 미생물이 부착이 되는 시점부터 높은 처리효율을 보이는 것으로 나타났다.

• Journal of the Korea Organic Resources Recycling Association
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• v.10 no.4
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• pp.75-80
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• 2002

The sewage sludge with concentrated MLSS, ranging from 5967 to 8400mg/L was degraded by ultrasound. In this study, ultrasound treatment was used to investigate the behavior characterization of SBOD, sludge biodegradation, C/N ratio, TN, turbidity and sludge morphology. From the experimental results of C/N ratio change and TN removal, the optimal irradiation time was found to be 10 minutes. The results showed the relative index of sludge biodegradation(SBOD/TCOD) was enhanced to 0.76 from the initial value of 0.013 at the 5967mg/L MLSS, during the 60minutes treatment. Throughout this research, the results provide useful engineering reference data for reuse of sewage sludge using ultrasound.

• Journal of Korean Society on Water Environment
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• v.23 no.5
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• pp.600-606
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• 2007

Livestock wastewater containing concentrated organic matters and nutrients has been known as one of the major pollutants. It is difficult to apply the conventional activated sludge process to treat livestock wastewater because of high Non-biodegradable (NBD) matter and ammonia. The objectives of this study are to remove NBD matters including aromatic compounds and ammonia in livestock wastewater using Coagulation-Fenton oxidation-Zeolite (CFZ) processes and ascertain applicable feasibility in the field through pilot plant experiment. NBD matters and color remained in the treated water were removed over 92% by Fenton oxidation as the second treatment process. Ammonia was removed by over 99.5% in the zeolite ion exchange process as the last treatment method. From $UV_{254}$, $E_2/E_3$ ratio and GC/MS analyses of treated water at each process, the aromatic compound was converted to aliphatic and aromaticity was decreased. In pilot scale test, organics and ammonia removal efficiencies were not much different from the result of lab-scale test at various operation conditions. Furthermore, reaction time and dosage of Fenton reagent in pilot scale experiment reduced by 40 min and 50% rather than in lab-scale test. $BOD_5$, $COD_{Mn}$, SS, T-N and T-P of treated water in the pilot-scale experiment also met the effluent standards.

• Journal of Animal Environmental Science
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• v.8 no.3
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• pp.153-158
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• 2002

Decolorization system using ozone was developed to reduce the pollutants and dark brown color remained in effluent of activated sludge process for pig wastewater. The results are as follows. 1. Wastewater temperature was increased during the ozone treatment from 31$^{\circ}C$ to 41.9$^{\circ}C$. 2. Oxidation reduction potential(ORP) at the beginning time was 148㎷, but it was increased to 330㎷ according to the ozone treatment. 3. 11mg/l of BO $D_{5}$ in effluent of activated sludge process was decreased to 1mg/l by ozone treatment, CO $D_{MN}$ also decreased from 83mg/l to 1.0mg/l. 4. 442 unit(dark brown color) of color in effluent of activated sludge process was changed to 6 units(colorless), and color removal efficiency was 98.6%.

• Journal of Korean Society of Water and Wastewater
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• v.19 no.6
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• pp.791-799
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• 2005

The phased isolation intra-clarifier ditch system used in this study is a simplified novel process enhancing simultaneous removal of biological nitrogen and phosphorus in municipal wastewater in terms of elimination of additional pre-anaerobic reactor, external clarifier, recycle of sludge, and nitrified effluent recirculation by employing intrachannel clarifier. Laboratory-scale phased isolation ditch system was used to assess the treatability on municipal wastewater. When the system was operated at the HRTs of 6~12hours, SRTs of 9~31days, and cycle times of 2~8hours, the system showed removals of BOD, TN, and TP as high as 88~97%, 70~84%, and 65~90%, respectively. The rainfall in Korea is generally concentrated in summer because of site-specific characteristics. Especially, the wet season has set in on June to August. In combined sewers, seasonal variations are primarily a function of the amount of stormwater that enters the system. In order to investigate the effect of hydraulic shock loading on system performance, the laboratory-scale system was operated at an HRT of 6hours (two times of influent flowrate) during two cycles (8hours). The system performance slightly decreased by increasing of influent flowrate and decreasing of system HRT. Nitrification efficiency and TN removal were slightly decreased by increasing of influent flowrate (decreasing of system HRT), whereas, the denitrification was not affected by hydraulic shock loading. However, the higher system performance could be achieved again after four cycles. Thus, the phased isolation technology for enhanced biological nutrient removal in medium- and small-scale wastewater treatment plants suffering fluctuation of influent quality and flowrate.