• Journal of Korean Society of Environmental Engineers
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• v.38 no.11
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• pp.589-595
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• 2016

This study evaluated the environmental impacts for landfill treatment of the wastewater treatment sludge (WTS) from petrochemical firms by life cycle assessment (LCA) and reviewed the impact reduction by landfill gas (LFG) utilization. The functional unit was 'landfill of 1 ton of WTS', and the system boundary included the process of input and treatment for WTS in landfill site. The impacts were high at landfill process (LP) and leachate treatment process (LTP). Global warming (GWP) and photochemical oxidants creation (POCP) were high at LP, while abiotic depletion (ADP), acidification (AP), eutrophication (EP), ozone depletion (ODP) were high at LTP. The major substances of various impact categories were crude oil (ADP), $NO_X$ (AP, EP), $CH_4$ (GWP, POCP), $Cl_2$ (ODP), respectively. The major factor of ADP, AP, EP was attributed from the generation of electricity used in LTP, and the methane within uncollected LFG was main factor of GWP and POCP. Therefore, electricity consumption reduction is identified to be an impact improvement option, and the flaring system installation or enhanced LFG recovery could be an alternative to reduce impacts. Among the various categories, GWP accounted the highest impact (${\geq}90%$) followed by ADP, POCP. In the avoidance impact resulted from the utilization of LFG, to substitute B-C oil or LNG showed the impact reduction of 32.7% and 12.0%, respectively.

• Journal of Korean Society of Environmental Engineers
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• v.29 no.8
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• pp.915-921
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• 2007

As a preliminary measurement of siloxanes in landfill gas(LFG), this study was conducted to determine the best suitable solvent applicable to the extraction of siloxanes in the domestic landfill using liquid-absorption method. Three solvents of n-hexane, acetone, and methanol were tested and the results obtained from GC analysis for each solvent were compared to their properties. Results showed that the resolution in the GC spectrum was the best from methanol due to the lack of overlapping of the peaks between silane and solvent. The detected siloxanes concentration were varied at maximum 2.6 times depending on the types of solvent as well as extraction velocity and impinger steps. In total, the highest concentration of siloxanes was obtained from methanol, which showed ideal pattern in the absorption of each impinger step and the least relative standard deviation. Accordingly, it is concluded that methanol is the most suitable solvent for the extraction of siloxanes in the domestic landfill. However, it is considered that solvent suitability can vary depending on the waste components and landfill record in landfills.

• Journal of Energy Engineering
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• v.20 no.1
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• pp.13-20
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• 2011

The high fuel flexibility of Micro Gas Turbine(MGT) has boosted their use in a wide variety of applications. Recently, the demand for biogas generated from the digestion of organic wastes and landfill as a fuel for gas turbines has increased. We researched the influence of firing landfill gas(LFG) on the performance and operating characteristics of a micro gas turbine combined heat and power system. $CH_4$ and $CO_2$ simultaneous recovery process has been developed for field plant scale to provide an isothermal, low operating cost method for carrying out the contaminants removal in Land Fill Gas(LFG) by liquid phase catalyst for introduce into the green house for the purpose of $CO_2$ rich cultivation of the plants. Methane purification and carbon dioxide stripping by muti panel autocirculation bubble lift column reactor utilizing Fe-EDTA was conducted for evaluate optimum conditions for land fill gas. Based on inflow rate of LFG as 0.207 $m^3$/min, 5.5 kg/$cm^2$, we designed reactor system for 70% $CH_4$ and 27% $CO_2$ gas introduce into MGT system with $H_2S$ 99% removal efficiency. A green house designed for four different carbon dioxide concentration from ambient air to 1500 ppm by utilizing the exhaust gas and hot water from MGT system.

• Journal of Energy Engineering
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• v.25 no.3
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• pp.104-113
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• 2016

This study analyzes correlation between methane gas production and injection of food waste water to motivate to expand renewable energy as a way of GHG (Green House Gas) mitigation to achieve the national GHG target proposed for the climate agreement in Paris last year. Pretreatment of food waste water was processed with pH 6 at $35^{\circ}C$ and used the fixed-bed upflow type reactor with the porous media. As a result of operation of pilot-scaled bioreactor with food waste water, the methane gas production was 6 times higher than the methane gas production of control group with rain water. The average production of methane was $56{\ell}/day/m^3$ which is possible to produce $20m^3$ of methane in $1m^3$ of landfill. As a way of energy source, when it is applied to the landfill over $250,000m^3$, it is also able to achieve financial feasibility along with GHG reduction effect. GHG reductions of $250,000m^3$ scale landfill were assessed by registered CDM project and the annual amount of reductions was 40,000~50,000 $tCO_2e$.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.219.2-219.2
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• 2010

가스하이드레이트(gas hydrate)는 고압과 저온 조건에서 물분자간의 수소결합으로 형성되는 3차원 격자구조에 동공(cavity)이라는 빈 공간이 생기고 이 동공에 가스가 물리적으로 포획되어 생성되는 것으로, 수소결합을 하는 물의 격자(Host) 내에 메탄등의 저분자가스(Guest)가 포획된 결정체이다. 가스 하이드레이트는 미량의 물을 첨가, 가압하면 부피비로 약 200배의 가스를 고상의 형태로 저장할 수 있으며, 열역학적으로 안정된 결정체이기 때문에 하이드레이트로 존재하기 위한 최소한의 온도, 압력조건이 충족되면 고상으로 항구적인 존재가 가능할 수 있어 가스의 수송 및 저장에 높은 경제성을 가지는 방법이다. 현재 운영중인 전국의 242개소 매립지 중에서 발전 및 연료로 활용가능한 조건을 같춘 자원화 대상 매립지는 약 14곳에 불과한 형편이고 이들 중 대부분 시설은 자원화 시설을 운영하고 있으나. 중소규모 매립지에서 발생하는 LFG에 대하여 효율적인 이용 및 처리 방안이 없어 태워 없어지거나 방치하는 등 매립가스를 활용하는 기술은 미흡한 실정이다. 이러한 LFG는 많은 환경적인 문제를 야기하지만, 50vol% 이상의 고농도 메탄이 함유되어 있어 이를 대체에너지원으로 이용할 경우 환경적인 문제를 해결함과 동시에 신재생에너지원으로 활용 가능하다. 본 연구에서는 중소규모 매립지에서 발생하는 LFG를 활용하기 위하여 하이드레이트 형성/해리 Pilot plant의 제작을 통하여 $CH_4$와 $CO_2$(단일, 복합가스의 실험)의 하이드레이트화 연구를 진행 중이다.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 1996.12a
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• pp.87-95
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• 1996

The stabilization and reclamation of old disposal sites is becoming more important as significant numbers of disposal sites are closed and abandoned. This technical paper covers an overview of the key issues and methodologies for stabilizing and constructing facilities on old landfills. The slide portion of this presentation also include photographs showing actual construction activities. The key issues that are prevalent in remediating and closing old landfills are : correcting the stormwater flow, leachate breakout, constructing cover caps, controlling landfill gas migration and odors, cleanup groundwater and stabilizing side slopes. Some key techniques for constructing facilities on old landfills include： use of piling, installation of active landfill gas systems, providing LFG barriers under buildings, using utilidors and flexible utility interfaces and designing for site settlement. This Paper provides proven conceptual methods for solving these problems.

• Journal of the Korean Society of Mineral and Energy Resources Engineers
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• v.55 no.6
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• pp.649-659
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• 2018

In this study, after operational data for a landfill gas power plant were collected, the methane gas concentration was predicted using a deep learning method. Concentrations of methane gas, carbon dioxide, hydrogen sulfide, oxygen concentration, as well as data related to the valve opening degree, air temperature and humidity were collected from 23 pipeline bases for 88 matches from January to November 2017. After the deep learning model learned the collected data, methane gas concentration was estimated by applying other data. Our study yielded extremely accurate estimation results for all of the 23 pipeline bases.

• Journal of the Korea Organic Resources Recycling Association
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• v.8 no.4
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• pp.121-128
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• 2000

Landfill and lysimeter experiments were conducted to estimate the optimum air injection method for the degradation of waste in landfill and the pre-stabilization. Continuous injection with low pressure and quantity can be effective for pre-stabilization of old landfill due to the lower contents of volatile solids in landfill. Air injection and landfill gas (LFG)extraction showed that the SVE (Soil Vapor Extraction) effect by air ventilation was more significant than the biodegradation of organics. Theses results suggested that they could accelerate the biological stabilization of organic waste in landfills. It is also expected that they would reduce the problems including gas emission during the landfill mining, separation and/or transportation to such levels that might be discharged directly to the atmosphere or with minimal treatment, if required.

• New & Renewable Energy
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• v.6 no.2
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• pp.27-32
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• 2010

Low Calorific Gas Turbine (LCGT) has been developed as a next generation power system using landfill gas (LFG) and biogas made from various organic wastes, food Waste, waste water and Livestock biogas. Low calorific fuel purification by pretreatment system and carbon dioxide fixation by green house system are very important design target for the optimum applications of LCGT. Main troubles of Low Calorific Gas Turbine system was derived from the impurities such as hydro sulfide, siloxane, water contained in biogas. Even if the quality of the bio fuel is not better than natural gas, LCGT may take low quality gas fuel and environmental friendly power system. The mechanical characterisitics of LCGT system is a high energy efficiency (>70%), wide range of output power (30 kW - 30 MW class) and very clean emission from power system (low NOx). A green house has been designed for four different carbon dioxide concentration from ambient air to 2000 ppm by utilizing the exhaust gas and hot water from LCGT system. LCGT is expected to contribute achieving the target of Renewable Portfolio Standards (RPS).

• New & Renewable Energy
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• v.7 no.3
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• pp.67-73
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• 2011

MGT fuelled by landfill gas was tested to asses feasibility of its exhaust gas application for $CO_2$ enrichment. The exhaust gas was analyzed during start-up and normal operation with different MGT load conditions. Due to the changes of air/fuel ratio and combustion mode, $O_2$, $CO_2$, CO and NOx concentration were varied within wide ranges during the MGT start-up. Especially, NOx emissioin level was increased up to 20.01 ppmv. Different tendencies of $O_2$, $CO_2$, CO and NOx concentrations were observed with MGT output changes. $O_2$ and CO concentrations were shown to be decreased and NOx and $CO_2$ concentrations were shown to have opposite trends. NOx emission level (0.8~1.88 ppmv) was very low compared to other types of combustion based power generation equipment. Unburned hydrocarbon emission level was substantially decreased with MGT load increase. Especially, $C_2H_4$ concentration was below the detection limit(0.2 ppmv) around the nominal load condition. The exhaust gas from landfill gas fuelled MGT system was shown to be feasible for $CO_2$ fertilization. Concentrations of major components were within or below the maximum allowable ranges.