The nuclear facilities at Korea Atomic Energy Research Institute (KAERI) have generated a variety of organic liquid radwaste and radiation levels are also varied. At KAERI, the organic liquid radwaste has been stored at Radioactive Waste Treatment Facility (RWTF) temporarily due to the absence of the recognized treatment technique while inorganic liquid radwaste can be treated by evaporation, bituminization, and solar evaporation process. The organic liquid radioactive waste such as spent oil, cutting oil, acetone, ethanol, etc. was generated from the nuclear facilities at KAERI. Among the organic liquid radioactive wastes, spent oil is particularly significant. According to the nuclear safety act, radioactive waste can be cleared by incineration and landfilling if it meets the criteria of less than 10 μSv/h for individual dose and 1 person – Sv/y for collective dose. Dose assessment was performed on some organic liquid radioactive waste with a very low possibility of radioactive contamination stored in RWTF at KAERI. As a result, it was confirmed that some wastes met the regulatory clearance standards. Based on this, it was approved by the regulatory body, and this became the first case in Korea and KAERI for permission for regulatory clearance of organic liquid radioactive waste by landfill after incineration.

수도권에 위치한 S매립장 내 3개의 매립장을 대상으로 매립가스 배출 및 주요 경로별 표면 발산과 관련된 분석을 하였다. 전체 매립가스 발생비율 10.9%인 LS1이 총 표면발산 비중은 49.4%를 차지하고 있었다. 3개 매립장에서의 메탄의 총 표면발산은 13.6 Nm3/min로서, LS1 8.4 Nm3/min (61.7%), LS2 4.0 Nm3/min(29.4%), LS3 1.2 Nm3/min(8.9%)이고, 발산경로별로는 상부 7.3 Nm3/min (53.2%), 사면 6.4 Nm3/min(46.7%), 다이크 0.02 Nm3/min(0.1%)이었다. 3개 매립장의 주요 배출경로 별 산화율은 다이크가 87.5%로 가장 크고, 상부 72.3%, 사면 71.8% 순이었다. 메탄을 기준으로 표면발 산 기여율은 매립장 별로 LS1이 전체의 61.7%로 가장 컸다. 주요 배출경로별로는 LS1의 사면이 전체의 41.7%, LS2의 상부 24.4%, LS1의 상부 20.0%로서 S매립장의 전체 메탄 표면발산량의 86.1%를 차지함 에 따라 향후 집중적인 관리가 필요할 것으로 판단되었다.

The present study focuses on the adsorption of organic matter mainly COD from pretreated landfill leachate of Lamdeng Khunou Solid Waste Management Plant, Manipur, India through the employment of H3PO4 treated activated carbon derived from Parkia speciosa (Petai) pods (PPAC). The adsorbent was analyzed for morphological and surface characterization by various methods including, Field emission scanning electron microscopy (FESEM), Energy Dispersive X-Ray Analysis (EDAX), Brunauer–Emmett–Teller (BET) surface area and pH at zero point charges ( pHZPC). The impacts of adsorption processes such as initial pH, temperature, equilibrium time and dose of adsorbent were considered to evaluate the performance of PPAC. At 20 °C, PPAC showed maximum COD removal of 93% within 90 min contact time, at optimum pH 2. Adsorption kinetic was able to explain by Lagergren’s pseudo-second-order equation and intraparticular diffusion models suggesting the combined behavior of both the physical and chemical adsorption of COD on PPAC. Through thermodynamics and isotherm studies, the adsorption of COD on PPAC is revealed to be exothermic with maximum monolayer coverage of 200 mg COD/g PPAC. The performance of the PPAC adsorbent is also compared with other existing reported adsorbents for treating leachate.

Decommissioning of a nuclear power plant (NPP) generate large amounts of various types of wastes. In accordance with the Nuclear Safety and Security Commission Notice of Korea (No. 2020- 6), they are classified as High Level Waste (HLW), Intermediate Level Waste (ILW), Low Level Waste (LLW), Very Low Level Waste (VLLW) and Exempt Waste (EW) according to specific activities. More than 90% of the wastes are at exempt level, mostly metal and concrete wastes with low radioactivity, of which the concentrations of nuclides is less than the allowable concentration of self-disposal. The self-disposal or recycling of these wastes is widely used worldwide. More than 10,000 drums, based on 200 L drum, are expected to be produced in the decommissioning process of a unit of nuclear power plant. Due to the limited storage capacity of the intermediate & low level waste disposal facility in Gyeongju, recycling and self-disposal of EW are actively recommended in Korea. A variety of scenarios were proposed for recycling and self-disposal of decommissioning metal/ concrete wastes, and a computational program called REDISA was developed to perform the dose evaluation for each recycling and self-disposal scenario. The REDISA computer program can calculate external and internal exposure doses by simulating the exposure pathways from waste generation, thru transport, processing, manufacture, to the final destination of recycling or self-disposal. In this study, the self-disposal scenario was only considered for the dose evaluation. Many studies have been conducted to evaluate the exposure doses of the radioactive waste disposal sites. However, there have been few researches on dose evaluation for self-disposal landfills. In particular, the dose evaluation is important not only during the operation period, but also for a long period after the facility is closed. To this end, we developed a conceptual model for dose evaluation for post-closure scenarios of the self-disposal landfill of decommissioning metal/concrete wastes with reference to the methodology of IAEA-TECDOC-1380. The model incorporates three exposure pathways, including external exposure from contaminated soil, internal exposure by inhalation, and internal exposure by ingestion of water and food grown in contaminated soil. The duration of the dose evaluation is set to 100,000 years after the closure of landfill facility. Co-60 was selected as dominant nuclide, and dose evaluation was performed based on unit specific activity of 1 Bq/g. Exposure doses shall be verified for their application in accordance with the annual dose limit of 10 Sv/yr for self-disposal. As a result, the post-closure scenario of selfdisposal landfills have shown negligible effects on public health, which means that the exposures doses from transportation and operational processes should be considered more carefully for selfdisposal of decommissioning metal/concrete wastes.

The decommissioning of a nuclear power plant generates large amounts of radioactive waste, which is of several types. Radioactive concrete powder is classified as low-level waste, which can be disposed of in a landfill. However, its safe disposal in a landfill requires that it be immobilized by solidification using cement. Herein, a safety assessment on the disposal of solidified radioactive concrete powder waste in a conceptual landfill site is performed using RESRAD. Furthermore, sensitivity analyses of certain selected input parameters are conducted to investigate their impact on exposure doses. The exposure doses are estimated, and the relative impact of each pathway on them during the disposal of this waste is assessed. The results of this study can be used to obtain information for designing a landfill site for the safe disposal of low-level radioactive waste generated from the decommissioning of a nuclear power plant.

국내 3단계 매립형 처분시설은 2018년도 한국원자력환경공단의 중^저준위 방폐물관리시행계획에 의하면 주로 원전 해체 현장에서 발생하는 극저준위방폐물을 수용하기 위해 2019년 4월부터 2026년 2월까지 총 104,000드럼(2개 트렌치)을 수용 하기 위해 건설이 계획 중이다(총 2,246억원 투입). 이후 총 5개 트렌치에 260,000드럼이 총 34,076 m2의 면적에 단계적으로 수용되며 따라서 현재 한국원자력환경공단은 관련 인수기준을 마련 중에 있다. 극저준위방폐물 처분시설 인수기준의 경우 프랑스, 스페인 등이 전용 처분시설을 운영하면서 자국의 인수기준을 합리적으로 잘 준용하고 있으나 본 논문에서는 해체방 폐물의 처분에 가장 경험이 많은 미국의 처분시설을 고려하여 국내 매립형 처분시설에 우선적으로 반영되어야 할 사항이 있는지 분석하였고 이를 통하여 경주내 3단계 매립형 처분시설의 인수기준 마련에 도움이 되고자 하였다.

A pilot-scale biocover was installed at a sanitary landfill for municipal waste, and the removal of volatile organic compounds (VOCs) by the biocover was evaluated for a long period of 550 days. The biocover (2.5 m W × 5 m L × 1 m H) was constructed with the mixture of soil, perlite, earthworm cast and compost (6:2:1:1, v/v). The total VOCs concentration of the inlet gas into the biocover was 820.3 ppb~7,217.9 ppb, and the total VOCs concentration of the outlet gas from the surface of the biocover was 12.6 ppb~1,270.1 ppb. The average removal efficiency of total VOCs was 87.6 ± 11.0% (60.5% for minimum and 98.5% for maximum). Toluene concentration was the highest among the inlet VOCs, followed by ethylbenzene, m, p-xylene and o-xylene. These aromatic VOCs accounted for more than 50% of the total VOCs concentration. Other than these aromatic VOCs, hexane, cyclohexane, heptane, benzene, and acetone were major VOCs among the inlet VOCs. Compared with the VOC profiles in the inlet gas, the relative contribution of dichloromethane to the outlet VOCs emitted from the biocover layer increased from 0.1% to 15.3%. The average removal efficiencies of BTEX in the biocover were over 84% during the operation period of 550 days. The average removal efficiencies of hexane, cyclohexane and heptane in the biocover were 86.0 ± 18.9%, 85.4 ± 20.4% and 97.1 ± 4.0%, respectively. The removal efficiency of VOCs in the biocover decreased not only when the ambient temperature had fallen below 5oC, but also when the ambient temperature had risen above 23oC. Information on the VOCs removal characteristics of the biocover installed in the landfill field can be useful for commercializing the biocover technology for the treatment of VOCs.

Seasonal emission characteristics of odors and methane were investigated throughout the period of 17 months in which the emission status of odors and methane from soil cover layers in a sanitary landfill was measured. Complex odor emitted from soil cover layers fluctuated largely at the range of 7~20,800 OU (Odor Unit) in odor dilution ratio, and the median and average values were 2,080 and 4,203 OU, respectively. The intensity of complex odor showed higher values in the spring (5,663 ± 4,033 OU) and winter (6,056 ± 8,372 OU) than in the summer (1,698 ± 3,676 OU) and fall (1,761 ± 451 OU). Based on average concentrations, the compounds with high contribution values for the sum of the odor quotient (SOQ) were hydrogen sulfide (46.1%), methyl mercaptan (26.4%), and dimethyl sulfide (16.8%). This result shows that sulfur compounds were the main odor-causing compounds in the target landfill. The flux of complex odor was 0.17~70.36 OU·m−2·min−1 (Median 0.47, Average 5.40), and the flux of hydrogen sulfide was 0~114.70 μg·m−2·min−1 (Median 0.13, Average 5.91). The methane flux was 0.59~312.70 mg-CH4·m−2·min−1 (Median 25.61, Average 47.99). The methane concentrations emitted at the soil cover layers showed the highest values of 1.0~62.5% (Median 33.0, Average 21.1) in the spring, and the lowest values of 0.1~11.7% (Median 2.3, Average 3.7) in the winter. The methane concentrations in the summer and fall were similar with the average of 17.9% (range of 0.2-44.2%) and 12.5% (range of 2.2-42.5%), respectively. The emission data of odors and methane from soil cover layers can be utilized to establish management policy and apply mitigation technologies for the control of odor and greenhouse gases emitted in landfills.

This study is carried out to compare ingredients and antioxidant activity of Bokryeong, Poria cocos wolf, cultivated in the landfill and facility. Comparisons of the composition of the landfill and facility Bokryeong were conducted in the first and second year. As a result, there was no statistically significant difference in all four components (oxygen, carbon, hydrogen, nitrogen). In the second year, GC-MS analysis was carried out using the extracts containing ginseng epidermis, using the samples taken from the Gangwon-do area in the first year and the second year. As a result, 1,3-Dihydroxyacetone dimer, 2-Furancarboxaldehyde, and Acetaldehyde were detected in the landfill Bokryeong. 2-Furancarboxaldehyde and Acetaldehyde contents were higher in facility Bokryeng. In biological activity assay, The anti-inflammatory of the landfill Bokryeng and facility Bokryeng were compared by using Raw 267.4 cell lines. As a result, it was confirmed that both of them had anti-inflammatory, but no difference was found.

In order to reduce odor and methane emission from the landfill, open biocovers and a closed biofilter were applied to the landfill site. Three biocovers and the biofilter are suitable for relatively small-sized landfills with facilities that cannot resource methane into recovery due to small volumes of methane emission. Biocover-1 consists only of the soil of the landfill site while biocover-2 is mixed with the earthworm casts and artificial soil (perlite). The biofilter formed a bio-layer by adding mixed food waste compost as packing material of biocover-2. The removal efficiency decreased over time on biocover-1. However, biocover-2 and the biofilter showed stable odor removal efficiency. The rates of methane removal efficiency were in order of biofilter (94.9%)>, biocover-1(42.3%)>, and biocover-2 (37.0%). The methane removal efficiency over time in biocover-1 was gradually decreased. However, drastic efficiency decline was observed in biocover-2 due to the hardening process. As a result of overturning the surface soil where the hardening process was observed, methane removal efficiency increased again. The biofilter showed stable methane removal efficiency without degradation. The estimate methane oxidation rate in biocover- 1 was an average of 10.4%. Biocover-2 showed an efficiency of 46.3% after 25 days of forming biocover. However, due to hardening process efficiency dropped to 4.6%. After overturn of the surface soil, the rate subsequently increased to 17.9%, with an evaluated average of 12.5%.

In this study, we investigated influent and effluent water pollutants in 53 Public Sewage Treatment Works (PSTWs) where industrial wastewater or landfill leachate is combined four times for two years from 2014 to 2015. Also, we analyzed the characteristics of heavy metals and volatile organic carbons at influent and effluent of these PSTWs caused by sewage treatment combined with industrial wastewater or landfill leachate. As a result, six heavy metals such as barium, copper, iron, manganese, nickel and zinc, and four volatile organic carbons (VOCs) including phenols, di(2-)ethylhexyl phthalate (DEHP), formaldehyde and toluene were observed above detection limits in most of PSTWs. Also, it was revealed that six heavy metals such as hexavalent chromium, mercury, cadmium, chromium, nickel and selenium, and four VOCs including 1,1-dichloroethylene, vinyl chloride, naphthalene, and epichlorohydrin were observed more frequently according to precipitation. As a result of reviewing the monitoring data on “Water Quality Monitoring Networks” in lower watersheds of PSTWs, both heavy metals and VOCs were below detection limits, indicating that the effluent water had little influence on the watershed. Nevertheless for the better management of influent and effluent pollutants in PSTWs, it is necessary to establish the advanced management plans for water pollutants in PSTWs, which include a list of priority substances management, monitoring plans, and guidelines for industrial wastewater and landfill leachate combined in PSTWs.

The validity of landfill gas models is an important problem considering that they are frequently used for landfill-site-related policy making and energy recovery planning. In this study, the Monte Carlo method was applied to an landfill gas generation model in order to enhance conformity. Results show that the relative mean deviation between measured data and modeled results (MD) decreased from 19.8% to 11.7% after applying the uncertainty range of Intergovernmental Panel on Climate Change (IPCC) to the methane-generation potential and reaction constants. Additionally, when let reaction constant adjust derived errors from all other modeling components, such as model logic, gauging waste, and measured methane data, MD decreased to 6.6% and the disparity in total methane generation quantity to 2.1%.

본 연구는 수도권매립지에서 매립이 완료된 제 1매립장 사면에 식재된 수목과 토양환경 간의 상관관계를 규명하고자 수행하였다. 제 1매립장 사면에 식재된 주요 수목 26종을 대상으로 69개의 식생 조사구조사구(7~20m×5~20m) 를 설치하여 2007년부터 2009년에 걸쳐 조사하였으며, 토양분석은 2007년부터 2008년까지의 수목 생육불량률 기준으로 수목 생육불량 지표종을 선정하고 지표종의 생육정도에 따라 7개의 조사구를 선정하여 토양을 채취하고 분석하였다. 수도권매립지 환경 적응양호 종은 총 10종으로 침엽수는 곰솔(묘목), 향나무로 2종이었으며, 활엽수는 갈참나무, 능수버들, 밤나무(묘목), 살구나무, 상수리나무, 이팝나무, 튤립나무(묘목), 팽나무로 8종이었다. 적응불량인 수종은 총 8종으로 침엽수 2종, 활엽수 6종이었다. 판단보류는 총 8종으로 침엽수 1종, 활엽수 7종이었다. 수목 생육불량 지표종은 불량률이 25% 이상인 종을 중심으로, 개오동나무, 회화나무, 자귀나무, 단풍나무를 선정하여 식재지의 토양환경을 분석하였다. 토양분석결과, 토양산도는 염기성토양이었으며, 토양 삼상은 고상률 60% 이상이거나 55% 이하이지만 기상이 10% 이하인 지역이 대부분이었고, 유기물 함량은 0.14~2.52%이었다.

매립지, 하수처리장 등 혐기성 공정에서 발생하는 바이오가스의 CO2를 제거하고 CH4를 연료로 사용하는 분리 정제 기술이 주목을 받고 있다. 매립지가스에는 35~55%의 CH4, 20~45%의 CO2 및 미량의 암모니아, 황화수소, 실록산 등 포함되어 있다. 본 연구에서는 제습, 탈황, 탈실록산 등의 전처리 과정을 통해 얻어진 가스를 PES(polyethersulfone) 중공사막을 이용하여 CO2/CH4 혼합가스의 투과특성을 관찰하였고 순도 95%의 CH4와 90%의 높은 회수율을 얻을 수 있는 분리막 공정을 설계하였다.

수도권매립지에서는 황량하고 척박한 폐기물매립장을 세계 최대의 환경명소로 탄생시키기 위하여 매립이 완 료된 지역을 중심으로 나무심기 사업을 지속적으로 추 진 중에 있다. 그간 추진된 수목식재 현황을 바탕으로 방문객의 인식을 통해 생태경관 개선효과를 조사하여 수도권매립지의 독창적인 경관 조성에 기여하기 위하여 본 연구가 추진되었다. 2002년부터 2014년까지 교목 239,203주, 묘목 2,125,408주, 관목 2,930,294주로 총 5,294,905주를 수 도권매립지에 식재한 것으로 집계되었다. 년도별로는 사 업초기년도인 2002∼2003년과 2009∼2010년에 각각 2,028,451주(38%), 1,574,172주(30%)로 식재가 집중되 었다. 위치별 식재량은 제1매립장 1,943,713주(37%), 제 2매립장 1,659,743주(31%), 외곽경계지역 1,067,455주 (20%), 녹색바이오단지 623,994주(12%) 순이며, 수목의 성상별로는 관목 2,930,294주(55%), 묘목 2,125,408주 (40%), 교목 239,203주(5%) 순으로 나타났다. 이는 식 재지반이 얕고 환경이 척박한 매립지임을 고려, 관목과 묘목이 주로 식재되었음을 보여준다. 수도권매립지 조경수림대(제 1,2매립장 사면, 차폐수림 대, 도로변, 구 시설지 등)에 식재된 수목을 2013년 기준 전수조사 한 결과 교목 302,481주(104종), 묘목 108,051주 (55종), 관목 143,447㎡(25종)으로 집계되었다. 성상별 주 요 수종으로 교목은 곰솔(21.4%), 상수리나무(11.4%), 이 팝나무(8.7%), 산벚나무(6.5%), 측백나무(6.5%) 순이며, 묘 목은 소나무(42.8%), 곰솔(15.6%), 왕벚나무(6.9%), 대왕 참나무(5.9%), 산벚나무(5.6%) 순, 관목은 개나리(37.9%), 철쭉(17.5%), 수수꽃다리(6.5%), 박태기나무(5.5%), 무궁 화(3.8%) 순으로 나타났다. 위치별로 세분화하여 살펴보면 제1매립장 사면에 식재된 교목은 곰솔, 산벚나무, 상수리 순, 관목은 개나리, 철쭉 순이며, 제2매립장 사면에 식재된 교목은 소나무, 곰솔, 상수리 순, 관목은 개나리, 땅비싸리 순이다. 차폐수림대에 식재된 교목은 느티나무, 곰솔, 산벚 나무 순, 관목은 철쭉, 수수꽃다리 순이며, 도로변에 식재된 교목은 소나무, 느티나무, 리기다소나무 순, 관목은 박태기, 무궁화 순이다. 이를 통해 그간 식재한 묘목이 교목으로 성장하였으며, 수도권매립지에 위치별로 다양한 수종의 수 목이 도입되었음을 알 수 있다. 수도권매립지 방문객을 대상으로 2014년 9월 22일부터 10월 12일까지 3주간 수도권매립지 환경개선 인식조사와 조경수림대 가치추정을 실시하였다. 방문객, 직원, 경력자 등을 대상으로 매립지 문답식 조사지에 의해 진행하였으며 일대일 면접조사와 인터넷(SNS) 설문을 병행하였다. 조사 결과 수도권매립지 주변 환경여건 중 경관생태, 쾌적도, 소 음은 양호하나 토양, 수질, 대기, 악취는 보통 수준으로 조사 되었다. 또한 최근에 방문할수록 매립지 환경이 양호한 것 으로 인식하는 경향을 보였다. 수목 선호기능은 환경개선, 생태적합, 녹음제공, 유지관리용이, 관상기능 순이었으며, 선호수종은 소나무, 느티나무, 벚나무, 참나무류, 단풍나무 순으로 나타났다. 2002년부터 식재된 수목의 누적식재량과 설문조사로 나 타난 환경인식의 상관관계를 분석해 보면, 누적식재량과 경 관생태는 식재량이 누적될수록 방문객의 인식이 심각(2.0) 에서 보통(3.5)으로 개선되어, 현재는 양호한 상태로 파악되 고 있다. 또한 식재량 누적에 따라 경관생태 인식이 단계적 으로 상승되고 있는데, 1단계 상승기인 2003년에서 2008년 은 누적식재량 200만~300만주 구간이며, 2단계 상승기인 2011년에서 2014년은 누적식재량 500만~530만주 구간으 로 파악되었다. 경관생태 인식이 개선되는 시기는 공사가 대대적인 식재사업을 추진한 시기인 2002년에서 2003년, 2009년에서 2010년과 유사하게 나타남을 알 수 있다. 누적 식재량과 전반적인 쾌적도는 경관생태와 유사한 패턴을 보이며, 식재량이 누적될수록 방문객 쾌적도 인식이 심각(1.5) 에서 보통(3.5)으로 상향되고 있으며, 현재 양호한 상태로 파악된다. 쾌적도도 식재량 누적에 방문객 쾌적도가 단계적 으로 상승하고 있으며, 2차에 걸쳐 인식이 개선되었다. 매립지 수목 식재 필요성과 관련해 필요하다(81%), 필요 없다(9%)로 나타났으며, 식재가 필요한 지역으로 매립지 전체 외곽경계(36%), 외부 주거지 인근(24%), 각 매립장 외곽경계(17%), 각 매립장 토양윗층(11%), 기타(12%) 순 으로 나타났다. 수도권매립지 조경수림대 가치추정을 위해 조건부가치 측정법(CVM)을 실시하였으며, 지불의사유도를 위해 이중 양분석택법(초기제시금액 : 1,000원, 2,000원, 3,000원)을 사용하였다. 응답한 236명의 설문조사 결과 매립지 조경수 림대의 주된 생태계서비스는 조절서비스(43%), 서식지서 비스(25%), 문화서비스(21%), 공급서비스(11%) 순으로 나 타났으며, 조경수림대 보전을 위한 가구당 지불의사는 평균 2,377원/월, 지불사유는 유산가치(41%), 존재가치(27%), 사용가치(20%), 선택가치(12%) 순으로 나타났다. 수도권 지역 가구수(1,011만)과 소득 200만원 이상 가구비중 (0.838)을 반영하여 산출한 결과 수도권매립지 조경수림대 의 가치는 연간 2,418억원으로 추산된다.