• 상하수도학회지
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• 제28권2호
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• pp.249-255
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• 2014

So many drinking water treatment plants are under various difficulties by new reinforced effluent standards. Since the target turbidity, much higher than annual average, for designing sludge thickener have to be set to confront high turbidity season, the sludge at thickener should be put up for a long time during usual days. So the soluble manganese and chloroform may be formed under the anaerobic environment in the sludge thickener when the sludge retention time is longer with low turbidity. This phenomenon results in difficulties to keep regulatory level of the discharged effluent. For an effort to overcome the problems, a sludge aeration was successfully implemented into the thickening process. As a result, the final effluent quality and sludge volume were much improved; 41 % of manganese, 62 % of chloroform and 35 % of sludge volume. Additionally, effluent quality was improved ; 61 % of Manganese on aeration with pH control and we could make sure of stability effluent quality despite a long sludge retention time. We recommended the standard of installation sludge aeration equipment to nationally supply water treatment plant under effluent water quality problem ; Manganese, Chloroform, etc.

• 한국환경보건학회지
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• 제26권3호
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• pp.61-68
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• 2000

The use of photo-catalytic processes in pollution abatement and resource has a significant economic importance. Therefore, the applications of photochemical oxidation of secondary effluent driven by UV, TiO2, TiO2/UV, H2O2/UV and TiO2/H2O2/UV, have been investigated in order to treat the secondary effluent from municipal sewage. Various experimental parameters such as BOD, CODcr, Nurbidity, total P, and SPC were examined in each photo-catalytic reaction system. The results showed that the application of single oxidant such as UV, TiO2 only has a minor effect on parameters reduction (CODcr, BOD, etc) to treat the secondary effluent, whereas the combinations of oxidants increase the removal efficiency. The best removal efficiency in every parameters was achieved by the combination of TiO2, H2O2 and UV. It was also found that the optimum amount of TiO2 for the treatment was 1g/ι to achieve water reuse standard. From the results, the photocatalytic reaction system can be an alternative as a post-treatment to treat the secondary effluent from municipal sewage.

• 상하수도학회지
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• 제30권3호
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• pp.241-251
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• 2016

As the Enforcement Ordinance of Environmental Policy Act was revised in 2013, total organic carbon(TOC) was added as an indicative parameter for organic matter in Water and Aquatic Ecosystem Environmental Criteria. Under these imminent circumstances, a regulatory standard is needed to achieve the proposed TOC limitation control water quality from the public sewage treatment plants(PSTWs). This study purposes to present the determination method for TOC effluent limitation at the PSTWs. Therefore we investigate the TOC effluent limitation of foreign countries such as EU, Germany and USA, and analyse the effluent water qualities of PSTWs. In using these TOC data, we review apprehensively the statistics-based, the technology-based, and the region(water quality)-based determination method of TOC effluent limitation for PSTWs.

• 한국농공학회:학술대회논문집
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• 한국농공학회 2001년도 학술발표회 발표논문집
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• pp.470-474
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• 2001

A pilot study was performed at the experimental field of Konkuk University in Seoul, to examine the waste water treatment using constructed wetland and pond system. The effluent of the wetland system in winter often exceeded effluent water quality standards for sewage treatment plant, therefore, pond system could be applied to additional system. As a result, removal rate of $BOD_{5}$, SS was 84.4%, 81.5% and effluent concentration was 4.6mg/L and 5.0mg/L respectively, when surface water of pond system was discharged in March. So we concluded that pond system stored wetland effluent in winter and discharged surface water of pond system in March, so met water quality standard.

• 한국물환경학회지
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• 제28권6호
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• pp.804-812
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• 2012

This study contemplated domestic and other country's effluent limitation standards and suggested a methodology to establish technology-base limitation value. Current effluent limitation regulates industrial point sources discriminated by discharge flow rate and by regional distinction in Korea. Discharged $BOD_5$ load from large-scale plants(flow rate above $2,000\;m^3/day)$ exceeds 50% of overall industrial wastewater, which present rationale for discrimination based on plant size. However, regional distinction and pollutant- specific regulation might be insufficient to meet practical effectiveness of wastewater management policy, due to the nearly same limitation. Water quality data and treatment methods were investigated in hospital industry. And their distribution of effluent $BOD_5$ concentrations was statistically analyzed to suggest limitation value. Effluent $BOD_5$ concentrations showed lognormal distribution and $95^{th}$ percentile was corresponded to 87.9 mg/L, which could be suggested as tentative effluent limitation in hospital industry. The $95^{th}$ percentile of log-transformed distribution showed similar value of 86.5 mg/L. This study demonstrated reasonable methodology for establishing effluent limitation reflecting wastewater characteristic and treatment technology in separately categorized industry.

• 한국농공학회:학술대회논문집
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• 한국농공학회 1999년도 Proceedings of the 1999 Annual Conference The Korean Society of Agricutural Engineers
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• pp.663-669
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• 1999

The objective of this study are to examine the feasbility of reuse treated sewage effluent ofr agricultural water, and to obtain basic data for estabilishment of rational agricultural water quality standard. From this study, it appears that reuse of treated sewage as a supplemental irrigation water could be feasible and practical alternative for ultimate sewage disposal which often causes water quality problem to the receiving water body. For full scale applicatiion, further study is recommended on the secific guidelines of major water quality components and publc health.

• 한국환경보건학회지
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• 제36권2호
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• pp.141-147
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• 2010

Indicator bacteria of fecal pollution were enumerated and compared by various detection methods for influent and final effluent of a sewage treatment plant. Total coliforms were enumerated by four methods including most probable numbers, chromogenic enzyme substrate test, membrane filtration, and plate counts and were about $10^4$ for influent and $10^2{\sim}10^3\;CFU/ml$ for final effluent. Fecal coliforms ranged between $10^3$ and $10^4$ for influent and $10^2\;CFU/ml$ for effluent by chromogenic enzyme substrate test and membrane filtration. Fecal streptococci counts were 1-log less than fecal coliforms counts, $10^2{\sim}10^3$ for influent and $10^1\;CFU/ml$ for effluent. Total coliforms numbers by plate count both in influent and in effluent showed 1-log higher than by the other three methods. Statistical analysis revealed that numbers of total coliforms by plate count in final effluent had the highest average of correlation (r=0.778, p<0.01) compared with those by the other three methods. In addition, total coliforms numbers by plate count showed most significant correlation (r=0.835, p<0.01) with those by chromogenic test which is well-known as its highest recovery efficiency. These results suggest that the plate count would be the optimum detection method for total coliforms in wastewater treatment plants which are the only microbiological standard of final effluent from wastewater treatment plants in the Republic of Korea, considering economic aspects and difficulties in laboratories.

• 상하수도학회지
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• 제28권6호
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• pp.657-668
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• 2014

Under Korea's Enforcement Decree of the Framework Act on Environmental Policy amended in 2013, total organic carbon (TOC) is newly added as water quality parameter to assess organic pollution in water and aquatic ecosystem. To meet the TOC requirement and improve quality of effluent discharged into public watershed, it is also necessary to develop standards for TOC in effluent from public sewage treatment works (PSTWs). In this study, we reviewed the characteristics and removal efficiency of TOC in influent and effluent of PSTWs. The study found that phosphorus treatment process removed not only soluble phosphorus but also a portion of TOC remaining after the secondary treatment process. TOC concentration in effluent from PSTWs operated in tandem with industrial wastewater treatment work was higher due to influx of insoluble substances from the industrial wastewater treatment work. In order to lay a foundation for the management of TOC from PSTWs, it is necessary to carry out research on TOC from different perspectives. For example, studies on the generation mechanism of TOC and the impact of TOC on drinking water resources, assessment of effluent qualities through monitoring, and development of measures to control TOC for the preservation of aquatic ecosystem are needed.

• 환경영향평가
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• 제22권3호
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• pp.203-217
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• 2013

This study looked at how to establish effluent limitation standards for formaldehyde, a toxic chemical widely used in industries. To this end, we reviewed Water Quality Based Effluent Limitation (WQBEL), Technology Based Effluent Limitation (TBEL), and water quality criteria for protection of human health and aquatic organism. Based on the results, we estimated formaldehyde effluent limitation standards appropriate to control water quality of industrial wastewater in Korea. However, this study has limits due to the lack of some data necessary in estimating formaldehyde effluent limitation. For example, although water quality criteria based on non-carcinogenic properties of formaldehyde were calculated, those based on carcinogenic properties were not be able to estimate because of the absence of applicable cancer potency factor q1. Without applicable factor, we calculated water quality standards for formaldehyde based on water quality criteria of advanced countries including the United States, while with no water quality standard we referred to applicable drinking water quality standards of other countries. For eco-toxicity based on water quality criteria, proper figures could not be calculated since there have been few reliable data.

• 한국환경보건학회지
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• 제28권2호
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• pp.11-22
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• 2002

This study analyzes the river system and water quality conditions of Bukchun in order to establish a basic plan for Preparing a natural learning and experimental area of environmental ecosystem in Bukchun, Gyeongju. It also tries to establish an integrated plan for water management of Bukchun stream based on water contaminants. In addition, after analysing the water quality at 13 points during the non-rainy season, the effluent of municipal wastewater was of relatively better quality with I ~ II grade, below the water quality standard of the river, except in points near Samsung apartments. However, analysing the Hyeongsangang and the effluent of Bomunho and Duckdongdam in rainy season, the water quality was II ~ III grade according to environmental standard. The water Quality of those samples was strongly dependent of non-point source.