• Korean Management Science Review
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• v.33 no.4
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• pp.17-31
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• 2016

Waste sector has been a target of abatement policies by the most governments, even though its greenhouse gas (GHG) emission is not so high, since it is related to almost of other sectors. This study propose new GHG calculation equations which resolves logical contradiction of IPCC GL (Intergovernmental Panel on Climate Change Guideline) equations by including waste-to-energy effects. According to two GHG calculation equations, GHG emission inventory and BAU by the year 2050 have been computed. And GHG abatement potential and marginal cost for the five abatement policies carefully selected from the previous researches have been calculated for the year 2020. The policy that makes solid fuel like RDF from flammable wastes and uses them as combustion fuel of electricity generations has been found to be the most efficient and effective one among five policies. The cumulative abatement amount when five policies not mutually exclusive are applied sequentially has been reckoned.

• Advances in environmental research
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• v.7 no.2
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• pp.73-85
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• 2018

The anaerobically digestion and agricultural application of organic wastes was conducted using food wastes and cow dung. Twenty kilograms each of the feed stocks was added into two 30 liters-capacity batch digesters. The anaerobic digestion was carried out within a temperature range of $25-31^{\circ}C$ for a retention time of 51 days. The results showed a cumulative gas yield of 5.0 bars for food waste and no gas production for cow dung within the retention time. Bacteria such as Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Proteus vulgaris and Clostridium sp were isolated. Fungi isolated included Aspergillus niger, Aspergillus nidulan, Trichophyton rubrum and Epidermophyton flocossum. The non-dispersive infrared (NDIR) analysis of the biogas produced confirmed that the gas consisted of $CH_4$, $CO_2$ and $H_2$. Statistical analysis revealed there was no significant correlation between temperature and biogas produced from the organic wastes (r= 0.177, p = 0.483).The organic wastes from the biogas production process stimulated maize growth when compared to control (soil without organic waste) and indicated maximum height. The study therefore reveals that food waste as potential substrates for biogas production has a moderate bio-fertilizer potential for improving plant growth and yield when added to soil.

• Journal of Korean Society of Water and Wastewater
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• v.26 no.5
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• pp.629-636
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• 2012

This study focuses on the feasibility of bio-gas production using anaerobic digestion by measuring methane generation and biodegradability through the BMP test of industrial organic wastes. Organic wastes consist of entrails of pigs and organic residues of rumen generated from slaughter houses, wastewater sludge from slaughter waste water, fish offal and residues of vegetables from public wholesale markets, and wastewater sludge from the process of wastewater treatment in paper mill. The cumulative methane production by BMP test ranges from 149.3 ml/g-VS to 406.6 ml/g-VS and this is similar to methane generation of the normal wastewater sludge and food waste. As a result of measurement of biodegradability, wastewater sludge (S1 ~ S4) is low, ranging from 27.1% to 58.9 % and organic residues of rumen (G1) is low at 49.6 %. In conclusion, it turned out that raising the hydrolysis by various pre-treatments is necessary in order to produce bio-gas by using industrial organic wastes.

• Environmental Engineering Research
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• v.25 no.3
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• pp.374-383
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• 2020

Landfill gas (LFG) emissions from a given amount of landfill waste depend on the carbon flows in the waste. The objective of this study was to more accurately estimate the first-order decay parameters through methane (CH₄) and carbon flow balances based on the analysis of a full-scale landfill with long-term data and detailed field records on LFG and leachate. The carbon storage factor for the case-study landfill was 0.055 g-degradable organic carbon (DOC) stored per g-wet waste and the amounts of DOC lost with the leachate were less than 1.3%. The appropriate CH₄ generation rate constant (k) for bulk waste was 0.24 y-1. The the CH₄ generation potential (L0) values ranged 33.7-46.7 m3-CH₄ Mg-1, based on the fraction of DOC that can decompose (DOCf) value of 0.40. Results show that CH4 and carbon flow balance methods can be used to estimate model parameters appropriately and to predict long-term carbon emissions from landfills.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.29 no.2
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• pp.57-62
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• 2017

The heat transfer performance of a multi-heat-source fluidized bed heat exchanger was analyzed. The fluidized bed heat exchanger examined in this study can simultaneously recover the waste heat from gas, water vapor, and hot water. The effects of waste water flow rate, gas flow rate, and cooling water flow rate were examined to find their experimental correlations with the heat transfer coefficient. A computer program using the correlations was developed in this study to predict the thermal performance of the fluidized bed heat exchanger. The calculated heat transfer rates of gas, water vapor, waste water, and cooling water were compared with the measured values. It was found that the error of the calculated values was less than 12%.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.23 no.2
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• pp.164-171
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• 2011

The objectives of this study are to propose a suitable treatment facility for waste energy recovery after analyzing the waste generation and disposal situation in Jejudo, to establish the plan to install the solar photovoltaics and wind power plant considering the site conditions and finally to establish the environmental energy town plan in conjunction with the existing facilities. The food waste biogas plant is selected as the treatment capacity of 200 ton/day. It is estimated that the biogas plant will produce the electricity of 7,594 MWh per year, which will reduce the greenhouse gas of 4,177 $tCO_2$ per year. The solar photovoltaics and wind power plant will produce the electricity of 13,410 MWh per year, which will reduce the greenhouse gas of 7,375 $tCO_2$ per year. Environmental energy town will give us the reduction of operating cost by centralized treatment of residues and byproducts, and by efficient utilization of produced energy.

• Journal of the Korean Institute of Gas
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• v.18 no.2
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• pp.28-34
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• 2014

In the natural gas pressure regulation station, high pressure natural gas is decompressing using pressure regulation valves. Waste pressure occurred in the pressure regulation process can be recovered through adopting turbo expanders. However, in the waste pressure recovery process, Joule Thompson effect causes below $0^{\circ}C$ and this low temperature freezes outside land of pipeline or generates methane hydrate in the pipeline which can block the pipeline. Therefore, turbo expander systems are accompanying with a boiler for preheating natural gas. Molten carbonate fuel cell (MCFC), one of the high temperature fuel cell, can use natural gas as a direct fuel and is also exhausting low emission gas and generating electricity. In this paper, a thermodynamic analysis on the hybrid MCFC-turbo expander system is conducted. The fuel cell system is analyzed for the base load of the hybrid system.

• Journal of Korean Society of Water and Wastewater
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• v.14 no.1
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• pp.117-126
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• 2000

Solubilization pretreatments were conducted to enhance the anaerobic digestion of the waste activated sludge. Four pretreatment techniques including heating, sonication freezing and thawing, and enzyme addition were employed to solubilize the waste activated sludge under various conditions. Thermal pretreatment by heating showed the highest efficiency compared with other methods, and freezing and thawing was confirmed as a feasible alternative of solubilization as well as the pretreatment of dewatering. There is a clear correlation between the solubilization efficiency of the waste activated sludge and the gas production. Batch digestion results showed the cumulative gas production as much as four times after thermal pretreatment as compared with that by the control sludge without pretreatment. As a result, hydrolysis or solubilization pretreatment might play a significant role in the high rate digestion of the waste activated sludge.

• Journal of Korean Society for Atmospheric Environment
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• v.22 no.6
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• pp.842-850
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• 2006

The role of chlorination reactions in the formation of polychlorinated dibenzofurans (PCDFs) in a municipal waste incinerator was assessed using a chlorination model for predicting PCDF isomer distributions. Complete distributions of PCDF congeners were obtained from a stoker-type municipal waste incinerator operated under 13 test conditions. Samples were collected from the flue gas prior to the gas cleaning system. While total PCDF yields varied by a factor of five to six, the distributions of congeners were similar. A chlorination model, dependent only on the observed distribution of monochlorinated isomers, was developed to predict the distributions of poly-chlorinated isomers formed by chlorination of dibenzofuran (DF). Agreement between predicted and measured PCDF isomer distributions was high for all homologues, supporting the hypothesis that DF chlorination can play an important role in the formation of PCDF byproducts.

• Journal of the Korean Wood Science and Technology
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• v.17 no.2
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• pp.13-19
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• 1989

Two different quartz types of gasification reactor were used for pyrolysis and gasification of sawdust, ricestraw, ricehusk and municipal wastes which contain only cellulosics., operating at 1 atmospheric and vacuum pressure respectively. Also a stainless steel autoclave gasification reactor was used which is possible to use up to 100 atmospheric pressures and $800^{\circ}C$ of reaction temperature to complete pyrolysis and gasification reaction. The catalysts used in this reaction w- ere $K_2CO_3$, $Na_2CO_3$, Ni and Ni-$K_2CO_3$ as CO-Catalyst. The product gas mixtures were identified to be CO, $CO_2$, $C_3H_3$, $CH_4$ and $CH_3CHO$ etc. by Gas Chromatography and Mass Spectrometry. The pressurized gasification reaction shows significant increase in terms of methane composition and yield of product gases, comparing with those from unpressurized gasification reactions. The total volume of product gas mixtures amounts to 1600-1800ml per1gof waste of waste lignocellulosics or municipal waste, and the metane content of the gas mixtures reached to 40%, when $800^{\circ}C$ of reaction temperature and 100 atmospheric pressures with Ni-$K_2CO_3$ as CO-catalyst in the pressurized gasification reaction were used. This results show that the product gas mixtures containing 40% of methane call be used for alternative enegy source.