• Membrane and Water Treatment
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• 제11권3호
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• pp.173-177
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• 2020

Wastewater treatment plants (WWTPs) have been recognized as one of the significant greenhouse gas (GHG) generators, due to the complex biochemical reaction and huge consumption of energy and materials. Recently, WWTPs have been built underground and they will be confronted with the challenges of mitigating GHG emissions and improving the quality of treated wastewater. Here, we focus on estimating GHG emissions to set up effective management plans for a WWTP built underground. First, we apply the process-based life cycle assessment (LCA) with an inventory database of the underground WWTP for a case study. Then, we identify significant factors affecting GHG emissions during service life using sensitivity analysis and suggest the proper tactics that could properly reduce GHG emissions from the WWTP.

• Journal of Microbiology and Biotechnology
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• 제21권9호
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• pp.988-994
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• 2011

A significant amount of nitrous oxide ($N_2O$), which is one of the serious greenhouse gases, is emitted from nitrification and denitrification of wastewater. Batch wastewater nitrifications with enriched nitrifiers were carried out under oxygen-limited condition with synthetic (without organic carbon) and real wastewater (with organic carbon) in order to find out the effect of ammonium concentration on $N_2O$ emission. Cumulated $N_2O$-N emission reached 3.0, 5.7, 6.2, and 13.5 mg from 0.4 l of the synthetic wastewater with 50, 100, 200, and 500 mg/l ${NH_4}^+$-N, respectively, and 1.0 mg from the real wastewater with 125 mg/l ${NH_4}^+$-N. The results indicate that $N_2O$ emission increased with ammonium concentration and the load. The ammonium removal rate and nitrite concentration also increased $N_2O$ emission. Comparative analysis of $N_2O$ emission from synthetic and real wastewaters revealed that wastewater nitrification under oxygen-limited condition emitted more $N_2O$ than that of heterotrophic denitrification. Summarizing the results, it can be concluded that denitrification by autotrophic nitrifiers contributes significantly to the $N_2O$ emission from wastewater nitrification.

• 한국환경과학회지
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• 제23권11호
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• pp.1881-1888
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• 2014

Greenhouse gas (GHG) emissions from dye wastewater treatment processes were estimated by analysing their mass and energy balances, which were then used as baseline information for environmental assessment. The total GHG emissions from dye wastewater treatment plants were divided into direct emissions from the treatment processes and indirect ones from electricity usage. The amounts of $CO_2$, $CH_4$ and $N_2O$ emissions were calculated according to the Intergovernmental Panel on Clime Change (IPCC) guideline for the GHG target management system. For 3 years between 2011 and 2013, direct and indirect emissions were on average 8,742.7 and 7,892.0 Ton.$CO_2eq/year$, respectively, with the former exhibiting 52.6 %. Also, compared to 2012, in 2013, the eco-efficiency indicator by the GHG emissions was found to be more than 1, suggesting that environmental quality was effectively improved.

• 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.

• 상하수도학회지
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• 제24권3호
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• pp.319-332
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• 2010

In general, wastewater treatment systems consume high-energy consumption depending on operation characteristics of the facilities. Therefore, greenhouse gas(GHG) reduction activities that are application of digestion gas, induction of renewable energy etc. are conducted to reduce energy consumption and to increase energy independence ratio. In this study, GHG reduction in wastewater treatment system identified, searched application of Clean Development mechanism(CDM) approved methodology. If the methodologies apply to GHG reduction activities such as application of digestion gas, heat pump system using the wastewater as heat source, hydropower using the methodology determined CDM applicability, otherwise through several assumptions calculated expectable GHG reduction emissions and determined CDM applicability. As a result, the order of calculated GHG reduction emission showed that collected and energy generation of digestion gas is 66,775 $tCO_2$/yr, gas engine cogeneration system is 8,182 $tCO_2$/yr, heat pump system using the wastewater as a heat source is 72,715 $tCO_2$/yr, and hydropower is 561 $tCO_2$/yr. Consequently, the order of calculated Certified Emission Reductions(CERs) benefit showed that heat pump system using the wastewater, as a heat source is 1,381 million won/yr was estimated as the highest, followed by a collected and energy generation of digestion gas is 1,268 million won/yr.

• 생태와환경
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• 제47권1호
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• pp.13-23
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• 2014

본 연구는 시설하우스에서 비점오염원으로 인해 배출되는 오염된 농업배수를 인공습지에서 효과적으로 처리하기 위한 기초자료를 확보하기 위해 인공습지에서 여재종류, 조합방법 및 부하량에 따른 오염물질 정화효율을 평가하였다. 인공습지의 조합방법은 수직-수평흐름조, 수평-수직흐름조, 수평-수직-수평흐름조 및 수직-수평-수평흐름조로 구분하여 설계 및 시공하였으며, 여재는 왕사, 쇄석, 방해석 및 혼합여재로 구분하여 각 조에 충진하였다. 또한 농업배수 부하량을 150, 300, $600L\;m^{-2}day^{-1}$으로 달리하여 오염물질의 처리효율을 조사하였다. 조합방법별 수처리효율은 HF-VF-HF 조합방법이 다른 조합방법에 비해 높은 처리효율을 보였으며, 최적여재는 COD 처리효율은 왕사가 가장 높았고, T-N은 쇄석, T-P는 방해석이 가장 높았다. 하지만 모든 처리효율과 경제성 부분을 고려하였을 때 최적여재는 혼합여재가 가장 효과적일 것으로 판단된다. 농업배수의 부하량에 따른 처리효율 결과 COD는 농업배수 부하량 $600L\;m^{-2}day^{-1}$까지 안정적인 처리효율을 보였으나, T-N 및 T-P는 $150L\;m^{-2}day^{-1}{\fallingdotseq}300L\;m^{-2}day^{-1}$ > $600L\;m^{-2}day^{-1}$의 순으로 농업배수의 부하량이 증가함에 따라 약간 감소하는 경향이었다. 따라서 시설하우스 농업배수 처리를 위한 인공습지 농업배수처리장의 최적조건은 HF-VH-HF 조합형 인공습지에 왕사, 쇄석 및 방해석이 혼합된 혼합여 재로 충진하고 부하량 $300L\;m^{-2}day^{-1}$ 이하의 농업배수를 주입하는 것이 최적일 것으로 판단된다.

• 한국환경과학회지
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• 제20권10호
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• pp.1233-1241
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• 2011

The main objective of this experimental investigation was $CH_4$ recovery from biogas generated in municipal and wastewater treatment plant. The polysulfone hollow fiber membrane was prepared in order to investigate the permeation properties of $CH_4$ and $CO_2$. Permeability of $CO_2$ in Polysulfone membrane was 11-fold higher than of $CH_4$ gas. A membrane pilot plant for upgrading biogas was constructed and operated at a municipal wastewater treatment plant. The raw biogas contained 66 ~ 68 Vol % $CH_4$, the balance being mainly $CO_2$. The effect of the operating pressure of feed and permeate side and feed flowrate on $CH_4$ recovery concentration and efficiency were investigated with double stage membrane pilot plant. The $CH_4$ concentration in the retentate stream was raised in these tests to 93 Vol % $CH_4$.

• 웰빙융합연구
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• 제6권2호
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• pp.33-37
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• 2023

Purpose: Since 2013, marine dumping of wastewater has been banned, and research on eco-friendly and efficient land treatment has emerged. This study compared and tested changes in biogas production and anaerobic process efficiency depending on whether or not enzyme pretreatment was performed during anaerobic digestion from single-phase and two-phase to medium-temperature. Research design, data and methodology: The total sugar, direct sugar, pH, and acidity before and after fermentation were analyzed by G/C by anaerobic fermentation of the liquor wastewater, food wastewater 1, and food wastewater 2 at 30℃ for 67 hours, and the amount of methane gas generated was analyzed by balloon volume. Results: It was found that stable organic acid concentration and pH were found in the enzyme-treated food wastewater 2, and the amount of methane gas generated was also increased. Conclusions: When anaerobic digestion of the liquor wastewater and the food wastewater together, the performance of enzyme pretreatment resulted in increased digestive efficiency. It will be the basic data that can contribute to carbon neutrality and greenhouse gas reduction by increasing the production of biogas.

• 한국산학기술학회논문지
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• 제19권9호
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• pp.518-525
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• 2018

21세기에 들어서면서 기후변화로 인한 환경변화가 심각해짐에 따라 온실가스 배출에 대한 관심도 높아지고 있다. 우리나라의 기온은 1904년 이후 2000년까지 약 $1.5^{\circ}C$ 상승하였으며, 기후가 아열대 특성을 나타내는 것으로 조사되었다. 이에 따라 홍수 및 가뭄 등의 발생횟수가 증가하여 인간이 활용할 수 있는 용수가 매년 감소하고 있으며, 상수도 사용에 대한 비용은 매년 상승하고 있어 평소 버려지는 폐수의 재이용은 불가피한 상황에 직면해 있다. 본 연구는 반도체 공정에 투입되는 초순수 제조과정에서 발생되는 농축폐수를 재이용시스템을 설치하여 6개월간 운전한 월별 자료를 활용하여 온실가스 발생량 및 절감방안 등에 대하여 조사하였다. 조사결과 상수도 공급량은 월 평균 약 $2,767m^3$의 절감 효과가 있음을 알 수 있었다. 온실가스 발생량은 물재이용시스템의 전기사용량으로 인해 월 평균 약 $1,329.07kg-CO_2$ 추가발생 하였지만, 상수도 사용량 절감에 따른 월 평균 $918.64kg-CO_2$ 감축량을 반영하면, 월 평균 $410.43kg-CO_2$의 온실가스가 증가됨을 알 수 있었다. 물재이용시스템의 일부 공정을 개선한다면 온실가스 발생량은 증가가 아닌 월 평균 $254.41kg-CO_2$로 절감됨을 확인할 수 있었다.

• Advances in environmental research
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• 제3권2호
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• pp.173-183
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• 2014

A comprehensive mathematical model was developed for this study to estimate on-site and off-site GHG emissions from wastewater treatment plants (WWTPs). The model was applied to three different hybrid WWTPs (S-WWTP, J-WWTP, and T-WWTP) including anaerobic, anoxic, and aerobic process, located in Seoul City, South Korea. Overall on-site and off-site GHG emissions from S-WWTP, J-WWTP, and T-WWTP were $305,253kgCO_2e/d$, $282,682kgCO_2e/d$, and $117,942kgCO_2e/d$, respectively. WWTP treating higher amounts of wastewater produced more on-site and off-site GHG emissions. On average, the percentage contribution of on-site and off-site emissions was 3.03% and 96.97%. The highest amount of on-site GHG emissions was generated from anoxic process and the primary on-site GHG was nitrous oxide ($N_2O$). Off-site GHG emissions related to electricity consumption for unit operation was much higher than that related to production of chemicals for on-site usage. Recovery and reuse of biogas significantly reduced the total GHG emissions from WWTPs. The results obtained from this study can provide basic knowledge to understand the source and amount of GHG emissions from WWTPs and strategies to establish lower GHG emitting WWTPs.