• Journal of Environmental Science International
• /
• v.29 no.11
• /
• pp.1015-1024
• /
• 2020

Using the waste(sand wastr and boiler ash) in fluidized bed inciverator, lightweight aggregate concrete was produced and a recycling plan was prepated. The first, the result of the leaching test shows that the waste fluid sand and boiler ash did not exceed the effluent standard. This indicates that there is no harmful effect for recycling. The second, in the lightweight aggregate test using waste fluid sand and boiler ash, the sample that combined cement, waste fluid sand, and sand showed the highest compressive strength, and the mix proportion was 10: 7: 3. Lightweight aggregate concrete that combined cement, waste fluid sand, boiler ash, and sand had a low compressive strength by and large. The third, the same results were identified in the relation between the content of SiO₂ and that of Na₂O. As the SiO₂ content is lowered, the overall viscosity and plasticity of the concrete also decrease, which is not a good condition to form concrete. As for Na₂O, as the content increases, the viscosity of the sample and the viscosity of the cement are remarkably lowered, and the strength of the finished concrete is lowered. Therefore, it was concluded that the higher the content of SiO₂ and the lower the content of Na₂O, the more suitable it is to mix with cement to produce concrete. Fourth, from the fluidized bed incinerator currently operated by company A in city B, a total of 14,188 tons/year were discharged as of 2016, including 8,355 tons/year of bottom ash (including waste fluid sand) and 5,853 tons/year of boiler ash. The cost for landfill bottom ash and boiler ash discharged is 51,000 won/ton, and the total annual landfill cost is 723,588,000 won/ year. Assuming that the landfill tax to be applied from the year 2018 is about 10,000 won/ton, and if there is no reduction in waste disposal charge, an additional landfill tax of 141,880,000 won/year will be imposed. Consequently, the sum total of the annual landfill cost will be 865,468,000 won/year. Therefore, if the entire amount is used for recycling, the annual savings of about 8.7 billion won can be expected.

• Journal of Environmental Science International
• /
• v.26 no.4
• /
• pp.509-519
• /
• 2017

The study focuses on 32 environmental facilities in Incheon Metropolitan City, South Korea, categorizes them by sector: sewage treatment, wastewater treatment, incineration, landfill, water purification, and water supply. Their GHG reduction results are analyzed through quantitative and qualitative measures for 2012 to 2015. The study surveys and examines GHG reductions of the environmental facilities for two categories - facility operation and management. The findings are as follows: First, the GHG reduction rate, an emission-to-allocation ratio, from 2012 to 2015 is 89.67%. Second, GHG reductions coming from qualitative measures of facility management are even greater than those from quantitative measures of facility operation. Third, GHG reductions through facility operation are mostly attributable to overhauls, less use of facilities, resources recycling, process improvement rather than the betterment of fuels, facilities and energy efficiency. Fourth, higher reduction can be achieved by effective facility management, qualitative measures.

• Environmental Engineering Research
• /
• v.22 no.4
• /
• pp.339-346
• /
• 2017

The objective of this study is the evaluation of the performance of a large-scale respirometer (LSR) of 17.7 L in the determination of the methane generation rate constant (k) values. To achieve this objective, a comparison between anaerobic (GB21) and LSR tests was conducted. The data were modeled using a linear function, and the resulting correlation coefficient ($R^2$) of the linear regression is 0.91. This result shows that despite the aerobic conditions, the biodegradability values that were obtained from the LSR test produced results that are similar to those from the GB21 test. In this respect, the LSR test can be an indicator of the anaerobic biodegradability for landfill waste. In addition, the results show the high repeatability of the tests with an average coefficient of variance (CV) that is lower than 10%; furthermore, the CV for the LSR is lower than that of the GB21, which indicates that the LSR-test method could provide a better representation of waste samples. Therefore, the LSR method allows for both the prediction of the long-term biodegradation potential in a shorter length of time and the reduction of the sampling errors that are caused by the heterogeneity of waste samples. The k values are $0.156y^{-1}$ and $0.127y^{-1}$ for the cumulative biogas production (GB21) and the cumulative oxygen uptake for the LSR, respectively.

• New & Renewable Energy
• /
• v.5 no.2
• /
• pp.15-24
• /
• 2009

As new small scale LFG (landfill gas) energy project model which can improve economic feasibility limited due to the economy of scale, LFG-Microturbine combined heat and power system with $CO_2$ fertilization into greenhouses was proposed and investigated including basic design process prior to the system installation at Gwang-ju metro sanitary landfill. The system features $CH_4$ enrichment for stable microturbine operation, reduction of compressor power consumption and low CO emission, and $CO_2$ supplement into greenhouse for enhancement plant growth. From many other researches, high $CO_2$ concentration was found to enhance $CO_2$ assimilation (also known as photosynthesis reaction) which converts $CO_2$ and $H_2O$ to sugar using light energy. For small scale landfills which produce LFG under $3\;m^3$/min, among currently available prime movers, microturbine is the most suitable power generation system and its low electric efficiency can be improved with heat recovery. Besides, since its exhaust gas contains very low level of harmful contaminants to plant growth such as NOx, CO and SOx, microturbine exhaust gas is a suitable and economically advantageous $CO_2$ source for $CO_2$ fertilization in greenhouse. The LFG-Microturbine combined heat and power generation system with $CO_2$ fertilization into greenhouse gas to enhance plant growth is technologically and economically feasible and improves economical feasibility compared to other small scale LFG energy project model.

• Journal of Korean Society of Environmental Engineers
• /
• v.22 no.5
• /
• pp.927-938
• /
• 2000

When microorganism is injected into porous medium such as soils along with appropriate substrate and nutrients, biomass retained in the soil pore. Soil pore size and shape are varied from the initial condition as a result of biofilm formation, which make hydraulic conductivity reduced. In this research, hydraulic conductivity reduction was measured after microorganism are inoculated and cultured with synthetic substrates and nutrients. Biomass-soil mixture was evaluated its applicability to the field condition as an alternative liner material in landfill by measuring hydraulic conductivity change after repetitive freeze-thaw cycles. Resistance of biofilm to chemical solution and degree of biodegradation were measured through column test.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
• /
• 2002.04a
• /
• pp.73-76
• /
• 2002

Biofilter performance to reduce C $H_4$ emissions from MSW landfills was tested under a variety of environmental and design conditions. The optimum soil moisture content for C $H_4$ oxidation in a loamy sand was 13% by weight. The addition of N $O_3$-N did not affect the C $H_4$ oxidation rate. Soil depths of 30cm and 60cm were equally efficient in C $H_4$ oxidation. When the C $H_4$ loading rate was decreased, the percentage of C $H_4$ oxidized increased. The maximum C $H_4$ oxidation rate was 27.2 mol $m^{-2}$ $d^{-1}$ under optimum conditions (loamy sand soil, 13% moisture content, 30cm soil depth, and an loading rate of 32.8 mol $m^{-2}$ $d^{-1}$). Based on the above results, the installation of a properly sized and managed biofilter above a landfill cover should be capable of achieving a major reduction in atmospheric methane emissions from MSW landfills built with RCRA covers.

• Journal of the Korean Geotechnical Society
• /
• v.17 no.6
• /
• pp.225-233
• /
• 2001

Field model tests were performed to develop the grid-net landfill leachate leakage detection system using electrical resistance. Electric circuit tests were also carried out to investigate the expected electrical effects of grid-net electric circuit. The resistance of leaking point showed lower value than that of non leaking point. Grid-net leakage detection system was thought to be effective to locate the leachate leaking point. The measured electrical resistance along the wire including the leaking point was slightly reduced following the reduction of electrical resistance at the leaking point, which was explained by electric circuit test results.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2008.03a
• /
• pp.1061-1064
• /
• 2008

A completion of settling process takes a lot of time for dredged materials of high moisture content, such as contaminated sludge, in landfill site. In general, additives (e.g. flocculants) are used for reducing settling time of such colloidal material, which results in the increase of sludge volume, and hence much space is required in landfill site. This study is to suggest alternative method in order to enhance the settling process of cohesive clayey soils. A number of gravitational sedimentation tests as well as electrokinetic experiments were conducted to investigate the variation of initial moisture content on the settling behaviour of clay slurry. Surface settlement, electric current and local voltage gradient were monitored during the experiment, and moisture content and soil pH were measured after the experiment. From the results, the application of electrokinetics was found to be effective in volume reduction (i.e. increase of settling velocity and decrease of final moisture content) by comparison with gravitational settling process.

• Journal of Energy Engineering
• /
• v.26 no.4
• /
• pp.35-44
• /
• 2017

Disposal of municipal solid waste has become a major problem in many countries around the world. As landfill space for the disposal of ash from Municipal Solid Waste Incineration (MSWI) becomes scarce, numerous reports and researches address the various environmental issues about the municipal solid waste incineration waste management and other particulate matters with the range of 10 ~ 2.5. Although in many developing and industrialization countries landfill with the disposal of municipal solid waste, open incineration has become a common practice. Large municipal waste incinerators are major industrial facilities and have the potential to be significant sources of environmental pollution. Despite the significant volume reduction from incineration, waste recycling is important to ensuring the future welfare of mankind. The main goal of the present work is the physical and chemical characterization of the local incineration bottom ash towards its eventual re-utilization. In this paper, we reported the studies on physical and chemical characteristics of municipal solid waste incineration (MSWI) fly ash and bottom ash containing particulate matter whose particulate sizes are lower than $PM_{10}$, $PM_{2.5}$ and heavy metal were investigated.

• Journal of Korean Society on Water Environment
• /
• v.24 no.2
• /
• pp.201-205
• /
• 2008

The korean government started to ban the sanitary landfill of food wastes as of 2005. The radical change of policy is primarily due to the limited landfill site, but aimed to promote not only to reduce the food waste production but also to enhance the reuse and recycle. The performance of elutriated acid fermentation to evaluate the effects of elutriating ratios was investigated. The fermenters were operated with elutriating water to food waste volumetric ratio of 2, 1, 0.5 and 0.25. Initial pH of elutriating water was set for 9 based on the pH effects study. The cumulative amounts of SCOD production rate were $0.34gSCOD/gVS_i$, $0.45gSCOD/gVS_i$, $0.26gSCOD/gVS_i$ and $0.28gSCOD/gVS_i$ with the ratios of 2, 1, 0.5 and 0.25, respectively. The cumulative productions of VFAs were 0.12 gVFAs as $COD/gVS_i$, 0.28 gVFAs as $COD/gVS_i$, 0.21 gVFAs as $COD/gVS_i$ and 0.14 gVFAs as $COD/gVS_i$ with the ratios of 2, 1, 0.5 and 0.25, respectively. The volume reduction were 58%, 52%, 45% and 47% with the ratios of 2, 1, 0.5 and 0.25, respectively.