• Proceedings of the Korean Geotechical Society Conference
• /
• 2009.09a
• /
• pp.186-193
• /
• 2009

Since its opening in 1992, Sudokwon Landfill has become a landfill in which wastes generated from more than 22 million people are treated and disposed of. Its first phase landfill was closed in 2000 and the second phase landfill is in operation since then. The Korean environmental policies on refuse have drastically evolved for the last decade or so. From merely safe containment of wastes, the utilization of them as a source for energy generation and the minimization of waste volume to be filled in landfills are in the mainstream. Keeping in pace with the new trends, several challenging projects are in their way to blossom in Sudokwon Landfill. This paper briefs some important activities in the landfill. They are (1) geotechnical issues related to the construction and maintenance of the $1^{st}$ and $2^{nd}$ Landfills and (2) landfill gas and bioreactor which are recently emerging in the market.

• Structural Engineering and Mechanics
• /
• v.47 no.4
• /
• pp.545-557
• /
• 2013

Disposal of construction wastes poses major challenge to the municipal administration in the developing countries. At the same time new developments in these countries are unscrupulously exploiting the natural resources. The sustainable development requires judicious and careful utilization of natural resources. In this context, reuse of construction and demolition waste can save the global natural resources to greater extent. In this work the bricks and concrete waste from construction sites were crushed to the desired sizes and mixed in various proportions to study its properties in the concrete both in fresh and hardened states. Six mixes of natural and recycled aggregates were used to make the coarse aggregates for the concrete. From each mix nine cylinders were cast, which were tested at 7,14 and 28 days. The properties of concrete with recycled aggregates were compared with the control mix having natural aggregates. The nominal ratio of cement sand and coarse aggregates were kept at 1:2:4 by weight for all mixes. The tests have shown that concrete with recycled aggregates made from old concrete and brick bats provide greater opportunities for reuse of construction wastes in concrete.

• Biotechnology and Bioprocess Engineering:BBE
• /
• v.11 no.6
• /
• pp.538-543
• /
• 2006

A packed bed reactor (PBR) was fed with nitrate containing synthetic wastewater or effluent from a sequencing batch reactor used for nitrification. The C source introduced into the PBR consisted of volatile fatty acids (VFAs) produced from anaerobic acidogenesis of food wastes. When nitrate loading rates ranged from $0.50\;to\;1.01\;kg\;N/m^{3}{\cdot}d$, the PBR exhibited $100{\sim}98.8%\;NO_{3}^{-}-N$ removal efficiencies and nitrite concentrations in the effluent ranged from $0\;to\;0.6\;NO_{2}^{-}-N\;mg/L$. When the PBR was further investigated to determine nitrate removal activity along the bed height using a nitrate loading rate less than $1.01\;kg\;N/m^{3}{\cdot}d$, 100% nitrate removal efficiency was observed. Approximately 83.2% nitrate removal efficiency was observed in the lower 50% of the packed-bed height. When reactor performance at a C/N ratio of 4 and a C/N ratio of 5 was compared, the PBR showed better removal efficiency (96.5%) of nitrate and less nitrite concentration in the effluent at the C/N ratio of 5. VFAs were found to be a good alternative to methanol as a carbon source for denitrification of a municipal wastewater containing 40 mg-N/L.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
• /
• 2003.05a
• /
• pp.617-620
• /
• 2003

열분해를 이용한 폐기물의 처리가 여러 유해물질을 저감시킬 수 있다는 기대감으로 국내에서도 열분해를 이용한 폐기물 처리 관련 연구가 많이 진행되고 있다. 아울러 폐기물을 열분해 한 후에 산소를 공급하여 가스화와 동시에 잔재를 용융시키는 열분해 가스화 용융이나 예열공기와 혼합하여 고온으로 연소시키면서 잔재를 용융하는 열분해 연소 용융 등의 방식이 개발되면서 다이옥신과 소각재의 발생을 차단하는, 환경적으로는 제로 에미션(zero-emission)에 근접하는 기술에 대한 관심도 높아지고 있다.(중략)

• Journal of the Korea Concrete Institute
• /
• v.18 no.5 s.95
• /
• pp.589-594
• /
• 2006

The recycling of industrial wastes in the concrete manufacturing is of increasing interest worldwide, due to the high environmental impact of the cement and concrete industries and to the rising demand of infrastructures, both in industrialized and developing countries. The production of municipal wastes in the South Korea is estimated at about 49,902 ton per day and only 14.5% of these are incinerated and principally disposed of in landfill. These quantities will increase considerably with the growth of municipal waste production, the progressive closing of landfill, so the disposal of municipal solid waste incinerator(MSWI) ashes has become a continuous and significant issue facing society, both environmentally and economically. MSWI ash is the residue from waste combustion processes at temperature between $850^{\circ}C\;and\;1,000^{\circ}C$. And the main components of MSWI ash are $SiO_2,\;CaO\;and\;Al_2O_3$. The aim of this study is to find a way to useful application of MSWI ash(after treatment) as a structural material and to investigates the hydraulic activity, compressive strength development composition variation of such alkali-activated MSWI ashes concrete. And it was found that early cement hydration, followed by the breakdown and dissolving of the MSWI-ashes, enhanced the formation of calcium silicate hydrates(C-S-H). The XRD and SEM-EDS results indicate that, both the hydration degree and strength development are closely connected with a curing condition and a alkali-activator. Compressive strengths with values in the 40.5 MPa were obtained after curing the activated MSWI ashes with NaOH+water glass at $90^{\circ}C$.

• Journal of the Korea Organic Resources Recycling Association
• /
• v.13 no.1
• /
• pp.90-99
• /
• 2005

This study was conducted to survey the attitude of Chuncheon citizens on food waste generation. About 50% of the citizens were generating $5{\sim}10{\ell}$ of MSW (municipal solid wastes) a week. These answers were almost from below 35 years old. And the citizens answered that the ratio of FW (food waste) to MSW were 10-30%. They were generating FW enveloped in a standardized vinyl bag after dewatering. About 10% of the answers were generating FW with MSW without any dewatering. The reason for FW generation in large quantities was to cook and buy much more food materials than needed. They thought that malodor and harmful insect were the most severe problems from FW storage. The systematic management was the most needed in individual restaurants. They answered that an individual citizen should make an effort to reduce FW generation. However, in fact, they did not do their best to try to reduce FW generation. They agreed that an individual citizen should try to reform 'present food culture' and to think FW as resources.

• Journal of Korean Society of Environmental Engineers
• /
• v.22 no.5
• /
• pp.907-918
• /
• 2000

The pyrolysis characteristics of celluloses and plastics, which are the principal materials contributing to the municipal solid wastes(MSWs), was investigated with a thermal gravimetric analysis reaction system. The experiments were carried out in a nitrogen atmosphere in the temperature range of 400~900K at various experimental conditions. Also, a modified pyrolysis model for compressed MSWs has been proposed. Varing the heating rate to 20, 30, 40K/min, reaction orders of MSWs' main component were around 1.1~1.9, activation energies were 117~166kJ/mol for celluloses and 187~239kJ/mol for plastics. Char yield was proportional to the heating rate, particle size, and compressed ratio. The model proposed in this study, which is applying Arrhenius equation and thermodynamics, is closer to the experimental results than the conventional model.

• Journal of the Korea Organic Resources Recycling Association
• /
• v.14 no.3
• /
• pp.138-147
• /
• 2006

In this study, the composition and physico-chemical characteristics of municipal solid waste (MWS) which was treated in national park area kyungnam-do landfill were investigated. It is necessary to measure the characteristics of MSW and sludge to build a waste treatment facility, the data-base and total managing of the landfill. This MSW was composed of 34.62% of food wastes, 36.05% of papers, 15.37% of plastics & vinyls, 2.28% of textiles, 3.33% of wood, 0.49% of rubber & leathers and others, respectively. Most of MSW are composed of food, paper and plastic waste and more than 90% was combustible waste. For three components, moisture is 29.84%, combustible component is 62.30% and ash is 7.86%. The chemical element has the high order of carbon, oxygen, hydrogen on the dry basis of wastes. Also, the low heating value of the MSW which is measured by calorimeter is calculated as 2377.8kcal/kg. low heating value of the sludge is calculated as 338.06kcal/kg.

• Journal of Korean Society of Environmental Engineers
• /
• v.32 no.11
• /
• pp.1046-1053
• /
• 2010

The objective of this study was to investigate the pyrolytic reaction characteristics of a mixed fuel of municipal solid wastes and low-grade anthracite. The reaction variables are pyrolysis condition of mixing ratio, reaction temperature, temperature increase rate. As a result, the optimum mixing ratio was 20 wt.% low-grade anthracite in MSW, which maintains for the low heating value over 3,500 kcal/kg on pyrolysis. The most high reaction velocity constant was shown at $700^{\circ}C$. Also, under the all experimental condition, the reaction velocity constant increased linearly as temperature rate increase, but pyrolysis has to be considered electric power cost and yield of char at lower temperature rate.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.11 no.2
• /
• pp.99-105
• /
• 1991

This study was carried out to provide basic data to be necessary for the selection of an energy recovery process based on the characteristics of municipal solid wastes(MSW). The samples were collected at Kangdong-Ku in Seoul and conducted ultimate and proximate analyses. Laboratory scale anaerobic digesters were operated to determine the non biodegradable fractions of the wastes. The results indicated that carbon and hydrogen contents, and lower heating values could be calculated from the volatile contents of MSW by the following equations : C = 0.57 VS, H =0.084 VS, and HL=49.5 VS-(6-0.045VS) W. Nonbiodegradable fractions were respectively 58.9% of volatile matters and 77.7% of MSW. Incineration and refuse derived fuel(RDF) processes appeared to be the most efficient processes in terms of weight reduction and energy recovery, But determining the energy recovery processes, the fluctuations of heating values of MSW throughout a year and available landfill site and secondary pollution should be considered.