• 유기물자원화
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• 제31권2호
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• pp.19-38
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• 2023

하수처리장에서 생물학적 질소 제거를 위한 질산화, 탈질 과정 중 6대 온실가스 중 하나인 아산화질소가 발생한다. 이번 연구에서는 온실가스 발생량을 정량할 수 있는 컴퓨터 시뮬레이션 프로그램인 EQPS를 이용해 합류식 하수를 처리하는 MLE 공법 하수처리장의 내부반송유량, 수온 그리고 유입수의 일차침전지 by-pass %에 따라 아산화질소가 가장 적게 발생하는 운전 조건을 찾았다. 내부반송 유량은 유입 유량의 200 %이고, 생물반응조 수온이 20 ℃이고 일차침전지에서 생물반응조로 by-pass 되는 유입수가 15 %일 때 아산화질소 배출 계수가 가장 적은 조건임을 확인했다. 또한 깊은 수심에서 공기를 주입하는 심층폭기는 상대적으로 적은 공기공급을 필요로 하기 때문에 일반적인 폭기조에 비해 적은량의 아산화질소가 발생함을 확인하였다.

• 한국환경과학회지
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• 제8권1호
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• pp.107-113
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• 1999

A new biological nutrient removal system combining $A^2/O$ process with fixed film was developed in this work and the characteristics of denitrification were especially investigated in the combined fixed film reactor(CFFR). Media was added in the anaerobic, anoxic and aerobic reactors, respectively. Tests were made to establish the effluent level of $NO_x-N$, COD, DO and nitrite effects on $NO_x-N$ removal in the CFFR by decreasing hydraulic retention time (HRT) from 10.0 to 3.5 hours and by increasing internal recycle ratio form 0% to 200%. The influent was synthesized to levels similar to the average influent of municipal wastewater treatment plants in Korea. SARAN media with a porosity of 96.3% was packed 40% / 130% / 25% based on its reactor volume, respectively. It was found that COD rarely limited dentrification in the anoxic reactor because of high $C/NO_x/-N$ ratio in the anoxic reactor, while DO concentration in the anoxic reactor and $NO_2-N/NO_x/-N$ from the aerobic effluent inhibited denitrification in the anoxic reactor. It was proved that the critical points of DO concentration in the anoxic reactor and $NO_2-N/NO_x/-N$ from the aerobic effluent were 0.15mg/L and 10%, respectively. As the internal recycle ratio increased, DO concentration in the anoxic reactor and $NO_2-N/NO_x/-N$ from the aerobic effluent increased. Especially, at the condition of internal recycle ratio, 200%, DO concentration in the anoxic reactor and $NO_2-N/NO_x/-N$ from the aerobic effluent exceeded the critical points of 0.15mg/L and 10%, respectively. Then, denitrification efficiency considerably decreased. Consequently, it was represented that the control of DO concentration in the anoxic reactor and $NO_2-N/NO_x/-N$ from the aerobic effluent can assure effective denitrification.

• 한국토양비료학회지
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• 제44권2호
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• pp.278-284
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• 2011

축산농가에서 소규모로 발생하는 축산폐수를 인공습지에서 효율적으로 처리하기 위한 최적 조합방법 및 부하량을 조사하기 위해 호기성조, 혐기성조 및 무산소조를 구분하여 9개 시스템의 소형 축산폐수처리장치를 설계 및 제작한 다음 조합방법별 및 부하량별에 따른 수처리 효율을 조사하였다. 축산폐수처리장치의 조합방법에 따른 처리효율을 조사한 결과 COD 처리효율은 호기-호기 조합형과 호기-혐기 조합형이 다른 조합방법에 비해 높았으며, T-N 처리효율은 호기성조-혐기성조 조합형이 다른 조합방법에 비해 높은 처리효율을 보였다. 또한 조합방법에 따른 SS 및 T-P 처리효율은 큰 차이가 없었다. 소형 축산폐수 처리장치에서 부하량에 따른 처리효율을 조사한 결과 SS를 제외한 COD, T-N 및 T-P 처리효율은 축산폐수 부하량 $100L\;m^{-2}\;day^{-1}$까지 안정적이었으나, $100L\;m^{-2}\;day^{-1}$ 이상의 부하량에서는 처리효율이 약간 감소하였다. 소형 축산페수처리장치에서 SS처리의 경우 부하량 $200L\;m^{-2}\;day^{-1}$까지 안정적인 처리효율을 보였으며, 그 이상의 부하량도 처리가 가능할 것으로 판단된다. 이상의 결과 미루어 볼 때, 축산폐수를 처리하기 위한 소형 축산폐수처리장치의 최적조합방법은 호기-혐기 조합이었으며, 부하량은 $100L\;m^{-2}\;day^{-1}$이었다.

• 대한환경공학회지
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• 제28권4호
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• pp.414-420
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• 2006

세정단계를 거치는 혐기성 소화시스템(ADEPT, Anaeorbic Digestion Elutriated Phase Treatment)에서 돈사폐수를 처리한 유출수를 혐기성 암모늄 산화공정(ANAMMOX)에 적용하기 위하여 부분질산화 반응조의 기질로 사용하였다. 중온($35^{\circ}C$)에서 아질산성 질소를 축적하는 조절인자는 용존산소보다는 오히려 HRT, pH, 유리 암모니아(FA)였다. 중탄산의 스트립핑과 완충에 사용된 양을 포함한 중탄산알칼리도의 소모량은 전환된 $NH_4-N$ g당 8.78 g이었다. HRT 1일, DO 농도가 $2.7{\sim}4.4mg/L$의 안정상태에서 부분질산화 반응 유출수의 $NO_2-N/NH_4-N$ 비는 약 $1{\sim}$으로서, 부분질산화-혐기성 암모늄산화 결합공정의 ANAMMOX 반응조의 유입수로서 적합하였다.

• 한국물환경학회지
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• 제30권4호
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• pp.386-393
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• 2014

The aim of this study was to investigate the nutrient removal and biomass productivity in the wastewater using MMBR (Microalgae Membrane Bioreactor). MMBR process was combined OPPBR (Optical Panel Photobioreactor) and MBR (Membrane bioreactor). The OPPBR and MBR were operated 3 days and 9h HRT (Hydraulic retention time), respectively, using microalgae as Chlorella vulgaris. The obtained result indicated that the biomass productivity of 0.498 g/L/d with light transmittance of 92% at a 305 mm depth in the OPPBR was achieved. The total consumption of BOD (Biochemical Oxygen Demand) and COD (Chemical Oxygen Demand) in the MMBR were found to be 97.56% and 96.06%, respectively. Additionally, the removal of TN, $NO_3-N$, TP and $PO_4-P$ were 94.94%, 91.04%, 99.54% and 93.06% in MMBR, respectively. These results indicated that the MMBR process was highly effective for COD, BOD and nutrient removal when compared to the separate OPPBR or MBR process. The MMBR process was effective for nutrient removal and biomass productivity and can be applied to treat wastewater in sewage treatment plant.

• Environmental Engineering Research
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• 제24권2호
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• pp.181-190
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• 2019

Constructed wetlands are improvised man-made systems, designed for adopting the principle of natural wetlands for purifying wastewater - the elixir of life. They are used widely as a cost-effective and energy-efficient solution for treating greywater generated from different tertiary treatment sources. It provides an elaborate platform for research activities in an attempt to recycle earth's natural resources. Among the several organic impurities removal mechanisms existing in constructed wetland systems, the earth's active microbial population plays a vital role. This review deals with the recent advancements in constructed wetland systems from a microbiological perspective to (effect/ devise/ formulate) chemical and physical treatment for water impurities. It focuses on microbial diversity studies in constructed wetlands, influence of wetland media on microbial diversity and wetland performance, role of specific microbes in water reuse, removal of trace elements, some heavy metals and antibiotics in constructed wetlands. The impurities removal processes in constructed wetlands is achieved by combined interactive systems such as selected plant species, nature of substrate used for microbial diversity and several biogeochemical effected reaction cycles in wetland systems. Therefore, the correlation studies that have been conducted by earlier researchers in microbial diversity in wetlands are addressed herewith.

• 상하수도학회지
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• 제32권3호
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• pp.211-220
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• 2018

The water containing soluble manganese may cause problems such as discolored water, unpleasant taste, fouling or scaling of pipes in water distribution system, and so on. Conventional water treatment processes using sand filtration or sedimentation after oxidation, however, cannot often meet manganese standard for drinking water. Two types of oxidants, potassium permanganate ($KMnO_4$) and sodium hypochlorite (NaOCl), were utilized at the same time for manganese oxidation, and then the precipitated manganese oxides were removed by low pressure membrane filtration in this study. In batch experiments, the multiple injection of both oxidants showed more effective manganese removal than did the single injection using either of them. Moreover, the deterioration of manganese removal at low temperature was less serious for the multiple injection than that for the single injection. Manganese removal by the continuous system of oxidation by multiple injection combined with membrane filtration was higher than those by batch experiments at the same oxidation conditions. In addition, less membrane fouling was observed for membrane filtration with oxidation during continuous membrane filtration than membrane filtration without oxidation. These results indicate that the oxidation by multiple injection coupled with membrane filtration was efficient and applicable to actual water treatment for manganese removal.

• 상하수도학회지
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• 제26권6호
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• pp.897-905
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• 2012

Based on the activated sludge model, a simple aerobic digestion model which represents the aerobic sludge digestion by sequencing batch reactor(SBR) equipped with ultrasonicator was composed and performed in this study. The results are as follows. Aerobic digestion efficiency can be increased by adopting ultrasonic pretreatment. For the 5 days of SRT, 24 % of particulate component is predicted to be removed by ultrasonic pretreatment and aerobic digestion. This is 7 %p higher than that of conventional aerobic digestion. A Hybrid SBR aerobic digestion combined with ultrasonication shows higher digestion efficiency than aerobic digestion and ultrasonic pretreatment system. In case of this hybrid system, the digestion efficiency was predicted up to 49 % when the ultrasonication was performed every 2 hours, repeatedly. However, excessive treatment like every hours of ultrasonication in an aerobic digestion process results in adverse effect on TCOD removal because biomass disintegrated completely and the solubilized COD can not be used for the biomass synthesis again.

• 상하수도학회지
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• 제24권4호
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• pp.463-474
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• 2010

In this study, chemical coagulation conditions for treating combined sewer overflow(CSO) occurred during rainy season were evaluated by jar tests with aluminum sulfate[$Al_2(SO_4)_3{\cdot}17H_2O$] and ferric chloride[$FeCl_3{\cdot}6H_2O$]. The raw domestic sewage sampled from the primary sedimentation tank at a local sewage treatment plant was filtered through $150{\mu}m$ sieve before using. Point of zero charge(PZC) for various dose of aluminum sulfate occurred at pH 5.8-6.5, while for ferric chloride occurred at pH 5.3-6.0 in term of streaming current(SC) values. Charge neutralization ability of aluminum sulfate was bigger than that of ferric chloride. Optimum pH and dose of aluminum sulfate and ferric chloride were 6.2, 0.438mM and 5.8, 0.925mM, respectively. Removal efficiencies of TCOD, turbidity, SS and TP were 75, 97, 95, 96% with aluminum sulfate and 74, 96, 98, 99% with ferric chloride at their optimum coagulation conditions. More efficient removal of SS, TP and small particles was possible with ferric chloride at optimum coagulation conditions. Both SC values and COD removal started to increase where soluble phosphorus was completely removed.

• 상하수도학회지
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• 제13권3호
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• pp.61-72
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• 1999

To obtain the experimental data for design and operation of actual filtration processes, a sand filter and three kinds of dual media filters in pilot-plant scale were operated in this study. We analyzed the effect of filter medium composition on the filter performance and the effects of backwash water flow rates, length of stream line and air flow rate on the filter backwash efficiency. We also compared the efficiencies of the combined air-water backwashing and the water backwashing in dual media filters. As the backwash water flow rates or the length of stream line increased, the final turbidity of backwash water was decreased and the filtration duration time after backwash was increased. In the case of the combined air-water backwashing, the backwash water quantity needed for backwashing the dual media filters could be decreased. The total volume of filtered water for the dual media filters during filter run was over three times larger than that for the sand filter. The dual media filters could be operated at a high filtration rate of 360 m/day.