최근 국제법에 의해 하수처리장에서 발생되는 슬러지의 해양투기가 금지됨에 따라 하수처리 과정 중 발생된 슬러지의 처리방법이 문제가 되고 있다. 일반적으로 하수 및 슬러지는 혐기성조건에서 최종처리되며, 이과정 중 메탄(CH4) 및 아산화질소(N2O)가 배출되어 하수처리장은 지구온난화가스의 배출원으로 알려져 있다. 따라서, 하수처리장에서 발생하는 지구온난화 가스 배출량을 고려할 필요가 있으며, 지구온난화 가스 배출을 최소화할 수 있는 최적의 하수처리 공정 및 슬러지처리에 대한연구 필요성이 증가하고 있다. 따라서 본 연구에서는 주요생물학적 하수처리공정에 따른 온실가스 발생량 및 슬러지 배출량을 계산하며, 이에 따라 온실가스 배출을 최소화하는 하수 및 슬러지처리방법을 제시하고자 한다. 생물학적 하수처리공정으로는 Anaerobic/Anoxic/Oxidation(A2O), Bardenpho, Virginia Initiative Plant_x000D_ (VIP), University of Cape Town(UCT)을 이용하였으며, 동력학적 하수처리모델링 프로그램인 GPS-X를 이용해 본 공정의 모델링을 수행하였다. 이를 바탕으로 하수처리과정에서 발생하는 온실가스 및 슬러지 배출량을 계산하며, 이를 통해 온실가스 배출을 최소화하는 공정을 선택하였다. 온실가스 및 슬러지 배출량은 2006 IPCC 가이드라인에서 제시한 식을 통해 계산되었다. 또한 다양한 슬러지 처리 시나리오(퇴비화, 소각, 매립)에 대한 환경성평가를 수행하였으며, 이를 통해 각 시나리오의 결과를 하나의 지표로써 비교·평가하였다. 본 연구결과, 4가지 하수처리공법 중 Bardenpho 공법에서 환경성이 가장 좋은 것으로 나타났으며, 슬러지 처리 시나리오 중 퇴비화가 온실가스를 가장 적게 배출하였다.

In compliance with an international lawabout the ocean dumping of the sludge, the proper sewage treatment process which occurs from the wastewater treatment process has been becoming problem.Generally the sewage and the sludge are controlled from anaerobic conditionwhen the sewage is treated and landfilled, where the methane(CH4) and the nitrous oxide(N2O) from this process are discharged.Because these gases have been knownas one of the responsible gases for global warming, the wastewater treatment processis become known as emission sources of green house gases(GHG). This study is to suggesta new approach of estimate and environmental assessment of greenhouse gas emissions andsludge emissions_x000D_ from wastewater treatment processes. It was carried out by calculating the total amounts of GHG emitted from biological wastewater treatment process and the amount of the sludgegenerated from the processes. Four major biological wastewater treatment processes which are Anaerobic/Anoxic/Oxidation(A2O), Bardenpho, Virginia Initiative Plant(VIP), University of_x000D_ Cape Town(UCT)are used and GPS-X software is used to model four processes. Based on the modeling result of four processes, the amounts of GHG emissions and the sludge produced fromeach process are calculated by Intergovernmental Panel on Climate Change(IPCC) 2006 guideline report. GHG emissions for water as well as sludge treatment processes are calculated_x000D_ for environmental assessment has been done on the scenario of various sludge treatments, such as composting, incineration and reclamation and each scenario is compared by using a unified index of the economic and environmental assessment.It was found that Bardenpho process among these processes shows a best process that can emit minimum amount of GHG with lowest impact on environment andcomposting emits the minimum amount of GHG for sludge treatment.

Green House Gases(GHG) Emission Environmental Assessment Wastewater Treatment Process Activated Sludge Model(ASMs) Optimal Sludgetreatmentstrategy

Ministry of Education, Science and Technology, TRM of the reduction and treatment technologies of CO2 (2006)
IPCC, IPCC Guidelines for National Greenhouse Gas Inventories (2006)
Margarita P, Scarlette LG, J. Environ. Manage., “Application of Strategies for Sanitation Management in Wastewater Treatment Plants in Order to Control Reduce Greenhouse Gas Emissions.", 88(4), 658 (2007)
Hong J, Hong J, Otaki M, Jolliet O, Waste Management., “Envionmental and Economic Life Cycle Assessment for Sewage Sludge Treatment Processes in Japan.", 29, 696 (2009)
Kim M, Yoo C, Korean Chem. Eng. Res., “Design and Environmental/Economic Performance Evaluation of Wastewater Treatment PlantsUsing Modeling Methodology.", 46(3), 610 (2008)
Mogens H, Willi G, Takashi M, Mark L, Activated Sludge Models ASM1, ASM2, ASM2d, and ASM3., IWA Publishing in its Scientific and Technical Report series (2000)
Henze M, Gujer W, Mino T, Loosdrecht M, Activated Sludge Models ASM1, ASM2, ASM2d and ASM3, IWA Scientific and Technical report No.9, IWA, UK (1999)
Hwang EJ, “Appication of Combined Model of Activated Sludge Model and Anaerobic Digestion Model to Wastewater Treatment Plant,” Ph. D. thesis, the Univ of Pukyong, Korea (2007)
Batstone DJ, Keller J, Angelidaki I, Kalyuzhnyi SV., Pavlostathis SG, Rozzi A, Sanders WTM, Siegrist H, Vavilin VA, Anaerobic Digestion Model No. 1 ADM1, IWA Scientific and Technical report No.13, IWA, UK (2002)
Nowak O, Franz A, Svardal K, Muller VM, Kuhn V, Wat. Sci. Tech., “Parameter Estimation for Activated Sludge Models with the Help of Mass Balances.", 39(4), 113 (1999)
Hydromantis, Inc., GPS-X Tutorial Guide, Hydromantis (2004)
Lee CH, “Determination of the Optimal Design Parameters of Advanced Wastewater Treatment Process with Acid Fermentation using GPS-X Model,” Ph. D. thesis, the Univof Hanyang, Korea (2006)
Copp JB, The COST-simulation benchmark: description and simulator manual, COST ‘Simulation Benchmark’ Manual (2001)