• Journal of the Korea Organic Resources Recycling Association
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• v.12 no.3
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• pp.76-85
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• 2004

Anaerobic decomposition of municipal solid waste (MSW) had potential adverse impacts such as the production of methane and long-term post closure on human health and the environment. It was demonstrated that aerobic degradation of MSW resulted in the reduction of a methane yield and the enhancement of stabilization of MSW. Excavated solid wastes were both aerobically and anaerobically treated in order to evaluate the effects of air injection on the stabilization of landfill site. The municipal solid waste (MSW) samples were excavated from a 10-year old landfill (operation period: 1991. 11~1994. 11), Jeonju, Korea. Excavated municipal solid wastes are primarily composed of soils and vinyl/plastics. For the two aerobic simulated lysimeters, the levels of $O_2$ ranged 1.6~23.1% and the levels of $CO_2$ ranged 1.5~15.1%, which confirmed the aerobic decomposition. Aeration did prevent methane formation. For the anaerobic simulated lysimeter, the $CO_2$ rose as $O_2$ was consumed and low levels of CH4 were produced. The pH levels ranged from 7.7 to 8.9 for anaerobic lysimeter and from 7.3 to 8.5 for aerobic lysimeters. As expected, aerobic treatment proved to enhance the removal of biodegradable materials in the excavated solid wastes when monitoring the concentration of BOD, COD, $NH_4-N$, and $NO_3-N$ in the leachate.

• Journal of the Korea Organic Resources Recycling Association
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• v.14 no.1
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• pp.139-150
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• 2006

Landfilling is one of the most widely used methods for the final disposal of solid wastes. Landfilled wastes are degraded by residing microorganisms and the microbial degradation is affected by many factors such as moisture, oxygen, pH, alkalinity, sulphate, nutrient, temperature, and so on. Especially among these factor, oxygen and moisture within aerobic landfill play a major role in microbial degradation. In this study, 1) the effects of oxygen on the velocity of waste degradation and 2) the effect of moisture on the degradation of municipal solids waste (MSW) in aerobic condition were investigated. It was found that the BOD and CODcr concentration from the leachate of aerobic lysimeters dropped faster by 80 days after the start of the test compared to those from the anaerobic lysimeters. To see the effect of moisture, four aerobic lysimeters filled with MSW and four different levels of moisture (20, 30, 40, and 50%) were installed. From this test, higher moisture in MSW produced higher $CO_2$ concentration, meaning moisture was effective for the microbial degradation. thus, we concluded that higher moisture level in the aerobic landfill might help early-stabilization microbial degradation.

• Journal of the Korean GEO-environmental Society
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• v.7 no.4
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• pp.63-71
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• 2006

This study was conducted to evaluate air injection mode on stabilization of landfill gas and to predict the time for landfill mining. It took 8 times longer for pulse aeration to get to aerobic condition, compared to continuous aeration. It was evaluated that continuous aeration mode is more preferable than pulse mode for rapid air exchange in landfill mining. High correlation ($r^2$ = 0.95) was found between continuous aeration time and time to maintain aerobic condition when $0.2m^3/min$ of air was continuously injected and stopped. The aerobic condition ($CH_4$ < 5%) was maintained for 1.5 times longer than aeration time.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2003.11a
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• pp.325-326
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• 2003

매립지 내부에서 진행되는 혐기성 분해로 인한 폐기물의 부패현상은 일반적으로 악취와 관련한 직접적인 대기오염문제에서부터 메탄과 이산화탄소와 같은 온실기체의 발생 등과 같이 기후환경변화와 관련된 문제에 이르기까지 매우 심각한 오염원으로 인식되고 있다. 특히 매립지 내부의 가스상 오염물질들의 누적을 억제하기 위하여 설치하는 배출공에서는 이산화탄소나 메탄과 같은 온실기체 이외에도 약 80여 종에 이르는 다양한 휘발성유기화합물질 (Volatile Organic Compound, 이하 VOC) 성분들이 검출되기도 하였다 (Young and Parker, 1983). (중략)

• Journal of the Korea Organic Resources Recycling Association
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• v.8 no.1
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• pp.90-96
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• 2000

The composition of leachates varies depending on the waste characteristics, landfill age and landfilling method. Generally, leachates contain high dissolved organic substance and ammonia nitrogen whereas phosphorus concentration was very low. Leachate A produced from young landfill is characterized by high BOD5/COD ratio (0.8) whereas leachate C produced from old landfill has lower BOD5/COD ratio (0.1). Maximum biochemical methane potential of leachate A, B (from medium landfill) and C were 271,106 and 4 ml CH4/g-COD, respectively. On the other hand, the maximum biodegradability of leachate A, B, and C were 75,30, and 1%, respectively. These results indicated that anaerobic treatment of leachate from young landfill was effective in removing organic pollutants. In case of leachate C, carbon might reside in the form of large molecular weight organic compounds such as lignins, humic acids and other polymerized compounds of soils, which are resistant to biodegradation. The lag-phase period increased with the increasing organic concentration in leachate. In case of leachate A of concentration greater than 25%, the lag-phase period increased sharply. This implied that the start-up period of anaerobic process using an unacclimated inoculum could be extended due to the higher concentration of leachate. This relatively long lag-phase is probably related to the fact that most of the inhibitory compounds have been diluted beyond their inhibitory concentrations of less than 50%. Furthermore, the ultimate methane yield and methane production rate decreased as leachate concentration increased. It was anticipated the potential inhibition was related with the steady-state inhibition as well as the initial shock load.

• Journal of the Korea Organic Resources Recycling Association
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• v.15 no.2
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• pp.136-146
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• 2007

Landfill leachate was successfully treated in upflow anaerobic sludge blanket (UASB) reactors regardless of the addition of granular sludge. Initial operating period was significantly reduced by the addition of granular sludge. At hydraulic retention time (HRT) of one day, chemical oxygen demand (COD) removal rates in Control and Granule reactor were maintained over 90%, respectively with organic loading rate (OLR) of $4-8kgCOD/m^3.d$. During the experiment, the inorganic precipitates were accumulated in and around the sludge, and in the wall of the reactors were formed in both reactors regardless of addition of granular sludge. Specific methanogenic activity (SMA) increased as adaptation of microorganism to the substrate and OLR were increased. The maximum SMA value of the sludge for Granule reactor was about $0.57gCOD/g{\cdot}VSS{\cdot}.d$. The SMA value was not decreased because of excessive inorganic accumulation, however, it was needed to have pre-treatment process of influent to remove the inorganic metals.

• Journal of the Korea Organic Resources Recycling Association
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• v.14 no.4
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• pp.151-160
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• 2006

Anaerobic treatment of landfill leachate was studied to investigate the behaviors of pollutant and the characteristics of microorganism for 10 months. The upflow anaerobic sludge blanket (UASB) reactor achieved about 90% chemical oxygen demand (COD) removal at organic loading rates(OLR) up to $20kgCOD/m^3.d$. At higher OLR ($8-20kgCOD/m^3.d$), the propionate concentration increased, indicating that converting propionate to acetate was the rate-limiting step. Nevertheless, increase in the precipitate inside and on the surface of granules as well as on the wall of the reactor resulted in operational problems. The main inorganic precipitate in the granule was calcium compound. Although specific methanogenic activity (SMA) was not affected seriously in this study, metals had to be removed prior to anaerobic treatment so as to be free from the excessive inorganic accumulation that resulted in operational problems.

• Journal of the Korea Organic Resources Recycling Association
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• v.23 no.4
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• pp.40-51
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• 2015

This study is to estimate the viability of aerobic stabilization technology for reducing greenhouse gas (GHG) emissions from landfills in Korea. In this study, methane emissions were estimated by applying Landfill gas estimation model (LandGEM) to Y landfill in Korea. By comparison of an anaerobic condition (baseline) and an aerobic condition, the amount of $CO_2eq$ savings was calculated. The $CO_2eq$ savings take place inside the landfilled waste during aeration due to the conversion of previously anaerobic biodegradation to aerobic processes, releasing mainly $CO_2$. It was demonstrated that 86.6% of the total GHG emissions occurring under anaerobic conditions could be reduced by aerobic stabilization technology. This means the aerobic stabilization technology could reduce environmental contamination through early stabilization and GHG emissions considerably at the same time. Therefore, the aerobic stabilization technology is one of the optimal technologies that could be employed to domestic landfill sites to achieve sustainable landfill.

• Journal of the Korea Organic Resources Recycling Association
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• v.12 no.1
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• pp.104-109
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• 2004

In this study, we stabilized the screened soil from landfills by using aerobic bioreactor and evaluated aerobic decomposition of it. Four lab-scale bioreactors (anaerobic and 1 PV/day aeration, 5 PV/day aeration, 10 PV/day aeration) filled with screened soil were operated to investigate the effect of air injection quantity on stabilization of screened soil. In case of aerobic bioreactors, the decomposition of organics in screened soil was higher than anaerobic bioreactor. According to the results of landfill gas and soil respiration test, the air injection quantity of 5 PV/day was most efficient in stabilization of screened soil.

• Journal of the Korea Organic Resources Recycling Association
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• v.13 no.1
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• pp.124-130
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• 2005

Landfilling is most widely used as the final disposal tool of solid wastes. Solid wastes landfilled are stabilized by microbial degradation which is affected by several factors such as moisture, oxygen, pH, alkalinity, sulphate, nutrient, inhibitor, hydrogen, and temperature. Especially moisture plays a major role in microbial degradation. In this study, the effects of moisture on the degradation of municipal solids waste (MSW) were investigated. Four lysimeters with four different levels of moisture content i.e., 20, 30, 40, and 50% were operated; lysimeters were packed with MSW, and anaerobically operated. Anaerobic lysimeters with higher moisture content produced more $CO_2$ and landfill gases (LFG). It means that the moisture has a positive effect on the microbial degradation.