• Advances in environmental research
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• v.2 no.1
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• pp.51-60
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• 2013

The paper aims to characterise the waste generated in municipality of Varanasi, the most populated city in the state of Uttar Pradesh, India. MSW is a heterogeneous waste and composition of the waste varied from season to season. The generation, collection and management of waste have become a major environmental problem in most of the developing cities. MSW was collected from open dumping grounds for 2 consecutive years. Each year was classified into 3 seasons of 4 months. On analysis it was found that the biodegradable fraction is always more than other fractions with a minimum of 48.25% in rainy season. With such a high fraction of biodegradable wastes, options such as composting and biomethanation could be tried to convert waste into energy. The average weight of waste generation at present is 0.460 kg per capita per day. The study showed that waste generation and collection were increasing every year, which may be attributed to increase in population.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.8 no.3
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• pp.113-118
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• 1988

Laboratory aerobic and anaerobic digesters were operated to determine the nonbiodegradable fractions in PS (Primary Sludge) and WAS (Waste Activated Sludge)from a municipal wastewater treatment plant in Seoul. Nonbiodegradable fractions were determined to be 45 to 47% in PS and 58 to 68% in WAS. Ultimate $CH_4$ gas production rates were estimated to be 0.76 for PS and $0.54m^3/kg$ VS removed for WAS. $CH_4$ contents were respectively 63% for PS and 65% for WAS.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.22 no.12
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• pp.1755-1762
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• 1998

In order to minimize emission of polychlorinated dibenzo dioxins and polychlorinated dibenzo furans (PCDD/PCDFs) from municipal solid waste incinerators, it is important to maintain optimized operating conditions along with the system modification/improvement. Operating conditions of MSW incinerator make very complicated influence on formation of PCDD/PCDFs in each unit apparatus. For revealing these influences, concentrations of PCDD/PCDFs are measured from the stack and from the fly ash, while monitoring the plant operating conditions. The effects are grouped into 3 main categories, combustion conditions, de Novo synthesis effects, and adsorption/destruction effects in the flue gas treatment system. Interpretation of the results showed that de Novo synthesis effect, reformation by metalic catalyst, especially Cu in fly ash in the temperature range of $250{\sim}500^{\circ}C$, is found to influence most dominantly on the concentration of PCDD/PCDFs. A plausible mathmatical model for predicting concentration of PCDD/PCDFs is proposed, and discussed.

• Analytical Science and Technology
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• v.13 no.2
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• pp.215-221
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• 2000

Analysis of fly ashes from the MSW incinerators was carried out using XRF, ICP-MS and ICP-AES. It was found that the major elements of fly ash were Ca, K, Na, Si, Al, S, Cl and O by the XRF analysis. The XRD spectra showed that the fly ashes were mainly consisted with the chlorides, hydroxides, carbonates and also oxides of former elements. For the determination of minor elements such as Zn, Pb, Cu, Cr, and Cd, we used ICP-AES and ICP-MS after microwave digestion and the results were compared with the result of XRF.

• Journal of the Korea Organic Resources Recycling Association
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• v.17 no.4
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• pp.81-90
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• 2009

About 35 domestic incinerators are being operated currently. There is waste management policy to reuse waste efficiently and reduce waste through incineration which include reuse, recycling and energy recovery. However, there is a critical social issue that some heavy metals(Cu, Pb) were found in bottom ash from incineration of waste. After incineration, bottom ash is treated with chemicals to prevent second pollution of heavy metals from bottom ash and increase efficiency of heavy metal stabilization.

• Journal of Korean Society for Atmospheric Environment
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• v.23 no.6
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• pp.666-674
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• 2007

In this study, sampling and analysis was carried out for 13 compounds, in order to investigate the odorous compound emissions from landfill stacks and surrounding ambient air. These results revealed that concentration of hydrogen sulfide was $0.13{\sim}0.66\;ppb$ in the ambient air. Also, concentrations of hydrogen sulfide ($151{\sim}358\;ppm$) were the highest value in odorous sulfur compounds from landfill stacks. In case of VOC, toluene was obtained the highest out of volatile organic compounds. It was found that the concentrations of hydrogen sulfide near the landfill was higher than that inside city such as Seoul although it was located in a rural area. The result was due to the effect of hydrogen sulfide emitted from landfill stacks.

• Journal of the Korean GEO-environmental Society
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• v.2 no.1
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• pp.15-22
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• 2001

The key part in risk assessments for disposal sites of solidified/stabilized (S/S) wastes is to predict the contaminant transport from the S/S wastes to the environment under dynamically changing field conditions after characterizing chemical leaching properties of the ash, to evaluate the risk from the predictions, and finally to decide the risk is acceptable. In this paper, a risk assessment framework for disposal and reuse of S/S wastes was developed considering two limiting cases of contaminant leaching. Two types of waste characterization procedures that can determine waste-specific variables for the two limiting cases were developed and verified by applying them to a landfill site of the Municipal Solid Waste incinerator ash solidified/stabilized by cement.

• Environmental Analysis Health and Toxicology
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• v.26
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• pp.2.1-2.7
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• 2011

Objectives: N-Nitrosodimethylamine (NDMA) is classified as a probable human carcinogen by the United States Environmental Protection Agency (US EPA) and is formed during the chlorination of municipal drinking water. In this study, selected nitrosamines were measured in chlorinated drinking water collected from Chuncheon, Kangwon-do, Republic of Korea, and a risk assessment for NDMA was conducted. Methods: Twelve water samples were collected from 2 treatment plants and 10 household taps. Samples were analyzed for 6 nitrosamines via solid-phase extraction cleanup followed by conversion to dansyl derivatives and high-performance liquid chromatography-fluorescence detection (HPLC-FLD). Considering the dietary patterns of Korean people and the concentration change of NDMA by boiling, a carcinogenic risk assessment from ingestion exposure was conducted following the US EPA guidelines. Results: NDMA concentrations ranged between 26.1 and 112.0 ng/L. NDMA in water was found to be thermally stable, and thus its concentration at the end of boiling was greater than before thermal treatment owing to the decrease in water volume. The estimated excess lifetime carcinogenic risk exceeded the regulatory baseline risk of $10^{-5}$. Conclusions: This result suggests that more extensive studies need to be conducted on nitrosamine concentration distributions over the country and the source of relatively high nitrosamine concentrations.

• Proceedings of the Korean Institute of Resources Recycling Conference
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• 2005.05a
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• pp.33-36
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• 2005

생활폐기물을 소각한 후 발생되는 바닥재는 토목, 건설 분야에서 골재로서 활용 가치가 높으나, Cu, Pb 등 일부 중금속의 용출량이 환경기준치를 초과하여 바닥재의 재활용을 저해시키는 주요 요인으로 작용하고 있다. 본 연구에서는 바닥재의 중금속 용출을 저감시키기 위한 방법으로서 인위적인 탄산화에 의한 생활폐기물 소각 바닥재의 중금속 안정화 특성을 조사하였다. 4mesh를 기준으로 각 입단에 대해 고액비, 온도, $CO_2(g)$ 주입량에 따라 중금속 용출농도를 조사하였다. 중금속용출시험 결과 Pb, Cr, Cd, As는 미량 또는 불검출되었으며, Cu는 4mesh 이상에서 2.21mg/L, 4mesh이하에서 5.12mg/L로 4mesh이하에서 환경기준치를 초과하였다. 4mesh이하에 대해 탄산화 반응을 수행한 결과 $CO_2(g)$ 주입됨에 따라 pH는 초기 12.5에서 8까지 감소하였으며, Cu의 용출 농도는 pH 10에서 1.34mg/L까지 감소되었으며, pH 9-8에서는 불검출되어 탄산화 반응에 의해 바닥재의 환경적 안정성을 증진시킬 수 있음을 확인할 수 있었다.

• Journal of the Korean Wood Science and Technology
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• v.41 no.2
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• pp.87-99
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• 2013

Waste paper stands for the major biodegradable organic fraction of most of municipal solid waste. The potential of waste paper for glucose production was investigated in this current work. The pretreatment was accomplished by first subjecting waste paper to disintegration time (30 s), followed by ink removal of disintegrated waste paper using an deinking agent. Concentrated acid hydrolysis of waste paper with sulfuric acid was optimized to maximize glucose conversion. The concentrated acid hydrolysis conditions for waste paper (disintegrated time: 30 s, deinking agent loading : 15 ml) were optimized by using central composite design and response surface methodology. The optimization process employed a central composite design, where the investigated variables were acid concentration (60~80%), loading sulfuric acid (1~5 ml) and reaction time (1~5 h). All the tested variables were identified to have significant effects (p < 0.05) on glucose conversion. The optimum concentrated acid hydrolysis conditions were acid concentration of 70.8%, loading sulfuric acid of 3.2 ml and a reaction time of 3.6 h. This research of concentrated acid hydrolysis was a promising method to improve glucose conversion for waste paper.