• 한국물환경학회지
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• 제27권4호
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• pp.461-466
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• 2011

The feasibility of utilizing food waste leachate as an external carbon source was tested to enhance biological nutrient removal from an industrial wastewater with an average flow rate of $164,800m^3/d$ and a low carbon/nitrogen ratio of 2.8. A considerable improvement in the removal of nitrogen and phosphorus was observed when a certain amount of the leachate, ranging from 70 to $142m^3/d$, was supplemented to the biological industrial wastewater treatment process. The addition of the leachate led to an increase in the BOD/N ratio (4.5) and the removal efficiency of nutritents from 29.7% to 71.7% for nitrogen and from 34.8% to 65.6% for phosphorus. However, an excessive dose of the leachate that significantly exceeded $120m^3/d$ caused serious operational problems, like oil-layer formation in the grit chamber and scum layer in the primary clarifier. Thus, an supplement of food waste leachate at a dose acceptable to an existing facilities can be a practical and effective means to enhance the nutrient removal from industrial wastewater and to dispose of the food waste leachate.

• 청정기술
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• 제23권1호
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• pp.34-41
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• 2017

스크러버는 적정한 처리효율을 유지하기 위하여 세정수를 지속적으로 교체해 주어야 한다. 하지만 화학업종 대부분은 폐수 처리시설이 없어 스크러버 세정수를 위탁 처리하고 있으며, 처리비용 때문에 자주 교체해 주지 못하는 실정이다. 이로 인해 악취배출허용기준을 초과하거나 배출구 농도가 더 높아지는 역전현상을 유발하기도 한다. 이에 세정수를 자체 정화 하여 사용할 수 있도록 여과와 흡착 공정으로 구성된 세정수 처리시스템을 개발하였다. 세정수 처리 시스템은 화학업종 두 개 스크러버를 대상으로 적용하였으며, 세정수 수질 상태와 악취저감 효과를 평가하였다. 세정수 처리 시스템 적용 결과 50% 이상의 수질개선 효과와 20% 이상의 악취개선 효과를 확인 하였으며, 기존 운영대비 40%의 비용절감 효과도 기대할 수 있었다.

• 상하수도학회지
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• 제21권3호
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• pp.359-366
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• 2007

Slow sand filtrations have been widely used for water treatment in small communities, however their capacity is often limited by high turbidity in the raw water. For this reason, several pre-treatment facilities were required for a slow sand filter. Turbidity removal from the highly turbid raw water was investigated in roughing filters as a pre-treatment process. The roughing filters followed by rapid mixing tank were operated in the form of a contact filtration. In several jar tests, the predetermined optimum aluminium sulfate (alum) doses for turbid water of 30 and 120NTU were 30 and 50mg/L, respectively. At the optimum alum dose, physically optimum parameters including G value of $220sec^{-1}$ and rapid mixing time of 3 minutes were applied to the contact filtration system. Without addition of alum, the filtrate turbidity from the roughing filters, packed respectively with different media such as sand, porous diatomite ball and gravel, was in the range of 5~30NTU at filtration velocities of 30 and 50m/day. However, the application of a contact filtration to roughing filters showed stably lower filtrate turbidity below 1.0NTU at filtration velocity of 30 m/day. Although the filtration velocity increased to 50m/day, filtrate turbidity was still below 1.0NTU in both single and double layer roughing filters. At influent turbidity of 120NTU, the filtrate turbidity was over 5 NTU in the triple layer roughing filter, which shortened the filter run time. The flocs larger than $10{\mu}m$, formed in the rapid mixing tank, were almost captured through the roughing filter bed, while the almost flocs smaller than $10{\mu}m$ remained in filtrate.

• 한국방재안전학회논문집
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• 제12권3호
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• pp.35-49
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• 2019

현재 한국 내 공공하수처리시설은 2018년 현재 600개 이상 운영 되고 있으며 하수종말처리시설은 법적으로 유입수량이 일일 500톤 이상 설계되어 운영되는 처리시설을 말한다. 마을 하수도는 50톤 이상 500톤 미만 유입되는 소규모 하수처리시설을 의미한다. 그러나 설계유입수량과 수질이 유사한 처리시설은 거의 없다. 이러한 현실은 하수관로의 노후화로 인한 빗물의 유입, 지하수의 침입과 하수관로에 폐수의 무단 투입 등으로 설계유입수량과 수질이 실제 현실과 많이 다른 것은 어쩔 수 없는 현실이다. 본 연구에서는 국내 많은 지역 하수관로 기술진단을 실시한 것 중 대표적 사례 2개소의 하수관로를 선정하여 청천시와 강우시 시간대별 유량 및 BOD 수질분석, 침입수 유량 및 비율 산정을 통해 하수처리시설의 적절한 운영과 하수관로와 그 부속 시설의 노후화 진단평가를 위한 기초자료로 활용하고자 하며, 일일 500톤 이상 공공하수처리시설 유입수 분석을 청천시 주1회 24시간 동안 시간대별 채수 및 분석, 우천시 강우영향일 고려하여 동일시간대 채수 및 분석을 주기적으로 실시하는 것을 제안한다.

• 한국산학기술학회논문지
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• 제20권2호
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• pp.378-384
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• 2019

식품 폐수 처리 설비중 폐수처리장 폭기조 송풍 설비 개선을 통한 수질개선 효과 및 전기사용량 변화에 따른 온실가스 발생량을 평가 하였으며, 식품 폐수처리장에서 발생되는 슬러지를 탈수, 보관, 이송하는 설비의 효율적인 개선을 통한 전기사용량 개선전과 개선후 변화에 따른 온실가스 발생량도 함께 평가하였다. 폐수처리장 설비 개선에 따른 온실가스 배출량 평가는 폐수처리 공정으로 부터의 직접배출과 전력사용으로부터의 간접배출량으로 구분 된다. 폐수처리장 수질 개선 효과는 BOD 제거율이 63.3%, COD 제거율 42.0%, SS 제거율 71.0%, T-N제거율이 39.6%로 나타났으며, 폐수처리에 의한 온실가스 직접배출량(Scope 1)과 전력소비량 변화에 대한 온실가스 간접배출량(Scope 2)을 적용하여 온실가스 배출량을 산정한 결과 설비 개선전 3,668.8tCO2eq./yr 에서 설비 개선후 3,392.8tCO2eq./yr 으로 감소 하여 총 276.0tCO2eq./yr (8.0%)의 온실가스 감축 효과가 있는 것으로 평가 되었다. 이상의 결과는 배출원의 수질 개선 효과로 인한 것이 아니라 전기사용량 감소로 인해 온실가스 배출량이 감소하였기 때문이다.

• Membrane and Water Treatment
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• 제11권5호
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• pp.345-351
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• 2020

Eutrophication of surface waters is commonly caused by excessive inputs of nutrients such as nitrogen and phosphorus. Nakdong River basin was chosen as the study area to investigate the effect of point and non-point source pollution of nitrogen on eutrophication in water body. Non-point source inputs of nitrogen accounted for approximately 84% in the total nitrogen input of the upper Nakdong river watershed, which mainly consists of agricultural land and forests. However, point source inputs of nitrogen accounted for 58~85% in the total nitrogen input of the middle and lower watersheds, including urban area. Therefore, for watershed near urban area, control of point source inputs of nitrogen may be an optimal method to control eutrophication. In this respect, the enforcing reduction of nitrogen in the final effluent of wastewater treatment facilities is needed. On the other hand, to enact more stringent nitrogen regulations, the LOT (limit of technology) and environmental impact should be considered. In this study nitrogen data were analyzed to propose new nitrogen regulations.

• 환경위생공학
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• 제7권2호
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• pp.83-94
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• 1992

Recently water demand is increasing as the industry prospers. The increase of water demand is followed by the increase of wastewater discharge which pollutes rivers and ground water extensively. These rivers, reservoirs and ground water are sources for drinking water and their contamination affects the quality of water supply and other potable water. In Korea there are 776 water treatment plants which supply drinking water from main rivers or reservoirs. Rivers are the biggest water source for drinking water is being contaminated, the innovation of treatment process is needed. The construction and operation of water supply facilities is under the control of the Ministry of Construction and the water supply offices of cities and provinces. However, drinking water quality is under the control of the bureau of sanitation in the Ministry of Health and Social Affairs. There are 33 items in drinking water quality standards of Korea. Trihalomethanes, Selenium, Diazinone and other three of pesticides have been included lately, The Ministry of Health and Social Affairs is planning to enhance. the level of $VOC_S$(Vola-tile Organic Compounds) standard. Drinking water quality standard is the goal to protect the quality of supply water and ground water. In order to protect the source water from domestic or industrial water, technological improvement and adequate investment should be urgently made. The ultimate goal of drinking water quality is safety and health of consumers. The more stringent the standard are, the better the water quality will be. As the drinking water quality standards become more stringent this year, various and positive solutions by the authorities concerned must be prepared.

• 상하수도학회지
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• 제32권5호
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• pp.453-460
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• 2018

The impact of sodium hydroxide, which is one of chemicals of clean in place (CIP) for removing membrane fouling, on the PVDF membrane is reviewed with respect to physical/chemical structural change, the permeability affected therefrom. Based on the cleaning concentration applied in membrane water treatment facilities, 10% of accumulated defluorination was confirmed up to 166g.hr/L which reflects the exposure time. However, membrane resistance was confirmed to be reduced by about 10%. Through FT-IR and EDS analysis, reduction of F and change of are confirmed as factors that affect the permeability of membrane. Membrane resistance, which affects permeability, is affected by loss of additives for hydrophilicity, rather than defluorination of PVDF material. Therefore, in order to check membrane degradation degree, an accelerated test by NaOH was carried out, loss of additives was confirmed, and then PVDF inherent characteristic was observed.

• 상하수도학회지
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• 제33권3호
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• pp.177-190
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• 2019

The purpose of this study was to analyze the effects of sewerage facilities through I/I analysis by rainfall by selecting areas where storm overflow diverging chamber is remained due to the non-maintenance drainage equipment when the sewerage system was reconstructed as a separate sewer system. Research has shown that wet weather flow(WWF) increased from 106.2% to 154.8% compared to dry weather flow(DWF) in intercepting sewers, and that the WWF increased from 122.4% to 257.6% in comparison to DWF in storm overflow diverging chamber. As a result, owing to storm overflow diverging chamber of partially separate sewer system with untreated tributary of sewage treatment plant, rainfall-derived infiltration/inflow(RDII) has been analyzed 2.7 times higher than the areas without storm overflow diverging chamber. Meanwhile, infiltration quantity of this study area was relatively higher than that of other study areas. Therefore, it is necessary to reduce infiltration quantity through sewer pipe maintenance nearby river. Drainage equipment maintenance should be performed not to operate storm overflow diverging chamber in order to handle the appropriate sewage treatment plant capacity for rainfall because it is also expected that RDII due to rain will occur after maintenance. In conclusion, it is necessary to recognize aRDII(allowance of rainfall-derived infiltration/inflow) and to be reflected it on sewage treatment plant capacity because aRDII can occur even after maintenance to the complete separate sewer system.

• 상하수도학회지
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• 제31권6호
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• pp.539-549
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• 2017

In water treatment process using microfiltration membranes, manganese is a substance that causes inorganic membrane fouling. As a result of analysis on the operation data taken from I WTP(Water Treatment Plant), it was confirmed that the increase of TMP was very severe during the period of manganese inflow. The membrane fouling fastened the increase of TMP and shortened the service time of filtration or the cleaning cycle. The TMP of the membrane increased to the maximum of $2.13kgf/cm^2$, but it was recovered to the initial level ($0.17kgf/cm^2$) by the 1st acid cleaning step. It was obvious that the main membrane fouling contaminants are due to inorganic substances. As a result of the analysis on the chemical waste, the concentrations of aluminum(146-164 mg/L) and manganese(110-126 mg/L) were very high. It is considered that aluminum was due to the residual unreacted during coagulation step as a pretreatment process. And manganese is thought to be due to the adsorption on the membrane surface as an adsorbate in feed water component during filtration step. For the efficient maintenance of the membrane filtration facilities, optimization of chemical concentration and CIP conditions is very important when finding the abnormal level of influent including foulants such as manganese.