• Journal of Soil and Groundwater Environment
• /
• 제9권2호
• /
• pp.48-53
• /
• 2004

This study is objected to estimate the variation of the coefficient of leachate according to designs in landfill cover systems. Design (a) is the unsanitary landfill cover system with 50 cm soil. But Design (b), (c) are sanitary cover systems which are composed of soil top layer, drainage layer, barrier liner(Design (b): Geomembrane(1.5 mm) and compacted clay liner(30 cm), Design (c) compacted clay liner(45 cm)), gas venting layer. Quantity of leachate estimates Rational Method generally and depend on the coefficient of leachate, on one of the factors in Rational Method largely. The coefficient of leachate is defined as the leachate production ratio result from incident precipitation. To estimate the variation of the coefficient of leachate, the authors use HELP(Hydrologic Evaluation of Landfill Performance) Simulation and Pilot Test. As a result of HELP Simulation, the coefficient of leachate is 0.36∼0.42 in Design (a) and 0.03∼0.15 in Design (b), (c) according to designs in landfill cover systems and quality of barrier liner placement. These numerical values are similar to 0.13 with the coefficient of leachate in Pilot Test.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• 제14권8호
• /
• pp.4033-4038
• /
• 2013

Sedimentary rocks from construction waste are discarded through open storage and landfilling, which causes an increase in construction cost and inefficient of execution of works. Some sandstone are selected and utilized as aggregates, but shale is buried as industrial waste. Therefore, in this research, we evaluated weathering properties of shale aggregate that is widely distributed throughout Daegu-Kyeongbuk region and freeze-thaw characteristics of concrete according to the replacement ratio of shale aggregate, in an effort to stabilize aggregate supply-demand in Daegu-Kyeongbuk region and develop alternative aggregates. We used red shale and black shale in the experiment, which were exported from a construction site in Deagu. We verified the usage of shale as a concrete aggregate by comparing andesite, which is broadly used as a thick aggregate for concrete, to hornfels, which is a metamorphic sedimentary rock. As a result of the experiment, we observed no degradation phenomenon for andesite and hornfels. However, a part of country rock containing black shale was found to be exfoliated. Red shale started having cracks in the direction of stratification after 1.5 months of direct exposure, and it broke into smaller pieces after approximately 4 months. After 300 cycles of freeze-thaw process on the concrete manufactured according to the replacement ratio of shale aggregate, the modulus of elasticity was 97% for plain and 95% for hornfels. In the case of RS_100, it was 57% after 210 cycles, and for BS_100, it was 54% after 240 cycles. Therefore, we established that, as the number of repetition increases, the freeze-thaw resistance decreases dramatically.

• Journal of Korean Society of Environmental Engineers
• /
• 제32권7호
• /
• pp.665-675
• /
• 2010

The effects of chemical binders (ladle slag, ordinary portland cement (OPC), hydroxyapatite and calcium hydroxide) on the solidification/stabilization of heavy metals (Cd, Cu, Ni, Pb, Zn) in sewage sludge were evaluated by chemical leaching tests such as EDTA extraction, TCLP and sequential extraction. The results of EDTA extraction showed that heavy metal concentrations in sewage sludge were highly reduced after solidification/stabilization with slag, cement or calcium hydroxide. However, EDTA interrupted solidification/stabilization of heavy metals by hydroxyapatite. The TCLP-extracted heavy metal concentrations in sewage sludge after solidification/stabilization with chemical amendments were highly reduced. However, Cu concentration in the sewage sludge solidified/stabilized with slag, cement or calcium hydroxide increased because the pH of TCLP solution was higher than 7. Mixtures of sludge 1 : slag 0.2 : calcium hydroxide 0.1 (wt ratio) showed the least leachability in batch TCLP and EDTA extraction. The results of sequential extraction (SM&T, formaly BCR) indicated that the distribution of heavy metals changed from exchangable and carbonate fractions to strongly bound organic fraction. It was found that maximum leachate concentrations of Ba, Cd, Cr and Pb from sewage sludge amended with slag and calcium hydroxide were far below US EPA TCLP regulations.

• Journal of the Korean GEO-environmental Society
• /
• 제10권7호
• /
• pp.125-133
• /
• 2009

Wastewater sludge had normally filled up in land before revising the law of waste material management in 2003, which does not permit landfill of organic sludge in Korea. After the law, most sludge has been littered in the ocean up to now. However, due to the London Convention 96 Protocol, littering sludge in the ocean will also be prohibited after 2011. This Protocol makes countries find out new methods to treat wastewater sludge. There is no exception in Korea too. Many researchers have urgently try to find out better ways to treat sludge. One of ways is to make sludge recycle energy and the success of it depends on drying method. Specifically, it really depends how to make sludge dry ecologic friendly and economic efficiently. Therefore, wastewater sludge produced in Youngdong was analyzed to make it energy resources in this study. The sludge was tested to analyze the drying and chemical characteristics of it by irradiating microwave. In the result, it is sure that the sludge has little heavy metals as like as others in country side. High calories, 3370 Kcal, shows that it has good potential to be recycle energy. Moreover, weight deduction of the sludge vs. time shows long S-curve and has same deduction ratio. Specifically, S-curve can be divided by three sections based on the curvature points. There are steady state reduction ratio of weight and approximately 80% of weight duction in the second section. This results can be used to estimate the amount of sludge reduction in the full-scale microwave dryer. Drying capacity of microwave shows approximately 1.0 kg/kw/hr. It makes sure that sludge recycle energy has the potential of economic efficiency too.

• Journal of Environmental Impact Assessment
• /
• 제26권6호
• /
• pp.563-573
• /
• 2017

Coal ash is generated from coal-fired thermal power plants every year. The remaining quantity of coal ash ends up in the landfills except for the recycled portion, and the existing ash pond capacity is limited almost. Currently, the difficulties are faced in building a new ash treatment plant because of the concerns about the environmental impacts of landfills at individual plant facilities. In terms of minimizing the environmental impact, the recycling and effective uses of coal ash are recognized as urgent issues to be challenged. Accordingly, this study examines the obstacles in expanding the recycling of the coal ash in South Korea and proposes solutions based on the case study analysis. The analysis results are as follows: 1) specific recycling guidelines and standards are required to be established in accordance with the contact medium (soil, ground water, surface water and sea water) and the chemical. 2) by providing the recognition environmentally safe in recycling the coal ash, transparency in establishing the planning stages and active communication with the community through promotion and research are essentially needed. 3) practical support system is required to encourage the power plant companies to use the coal ash as beneficial use.

• Applied Chemistry for Engineering
• /
• 제23권3호
• /
• pp.259-265
• /
• 2012

Differently from fly ash, the bottom ash produced from thermal power generation has been treated as an industrial waste matter, and almost reclaimed or was applied with the additive of the part concrete. Bottom ash has various problems to use with the aggregate. Bottom ash is lighter than typically the sand or the gravel and it's physical properties (compressive strength etc.) is somewhat low because of high absorptance. In order to manufacture the ash concrete, we used a bottom ash as a main material and a pure sulfur as a binder. In this study, fundamental research methods that vary the grain-size of bottom ash and the ratio of sulfur vs ash were investigated to improve the quality of ash concrete such as compressive strength. Bottom ash in this research which occurs from domestic 4 place power plants, was checked physical and chemical properties. The compressive strength seems the result which simultaneously undergoes an influence in content of the sulfur and Bottom ash grain-size. We got the result of the maximum 92 MPa. The compressive strength was high result for grain size below 1.2 mm and high sulfur content.

• Journal of the Korean Institute of Landscape Architecture
• /
• 제29권1호
• /
• pp.131-139
• /
• 2001

This paper aims at surveying through case studies the planting possibility on the interval artificial ground between the bank and the core landfill of the first section of works in the SUDOKWON Landfill area landfill area which was completed, followed by the layer-on-layer landfill process involving the latch or sealing layer against emitting landfill gas from the reclaimed waste. The survey results are as follows; 1. The layers of the artificial planting ground on the landfill were established on the basis of top-on-top procedure for a waste layer, a topping soil layer (T=50cm), a gas blocking layer (broken stones T=30cm), a filter layer (non-woven fabric 700g), a sheet protecting soil layer (T=20cm), and a blocking layer (HDPE SHEET 2.0mm), an irrigation layer (SAND T=30cm), a filter layer (non-woven fabric 700g), a sheet protecting soil layer (T=20cm), and a blocking layer (HDPE SHEET 2.0mm), an irrigation layer (SAND T=30cm), a filter layer (non-woven fabric 700g), a planting layer (T=90cm+), a top mound (T=2m). 2. Since no direct damage on the planting layer affected by the landfill gas was detected, planting is found to be still possible and successful except the severely unequal subsidence portion. 3. The mortality rate is discovered different on different trees: Pinus thunbergii (H3.0$\times$W1.0m) 11.25%, Pinus thunbergii (H2.5$\times$W0.8m) 4.73%, Koelreuteira paniculata 8.67%, Hibiscus syriacus 5.68%, Deutzia parviflora 6.50%, Forsythia koreana 8.17%, Rho. yedoense v. poukhanese 32.22%, and Spiraea pru v. symplicifolia 18.89%; although the last two of which are generally considered to have a strong generic growing character, they are subject to be weakened when exposed to the contaminated microclimate of the site like landfill gas. 4. The damage rates, on Pinus thunbergii, Koelreuteria paniculata, Hibiscus syracus, Forsythia koreana, Deutzia parviflora, Rho. yedoense v. poukhanense were shown to decrease to 7.31-17.69% in the second check (June 2000) lower than 5.77-46.92% in the first examination (June 1999), whereas the damage on Spiraea pru v. symplicifolia relatively increased. It is believed that preparatory method of the air pollution, change of temperature, odor by emitting landfill gas, and minute dust from vehicles should be made, and a research on this matter will be conducted in the near future.

• Journal of the Korean Society of Environmental Restoration Technology
• /
• 제5권5호
• /
• pp.58-66
• /
• 2002

We present a planting plan of the buffer-forest belts created at the boundary area of the waste landfill site which is located in the coastal area of Kyubg-Gi province. In order to form a proper section of ground soil excavated from the sea and a forest which shows a distinction of the vegetation stratification, the planting plan with trees, sub-trees, shrubs, and seedlings (produced at a sprout cultivation place) is devised with an adjustment of planting density. 1. The preparation of mounding is required for planting at a waste landfill site. We first estimate an economical and efficient banking height together with the quantity of soil, and prepare a planting ground with excavated ground soil for the consideration of soil recycling. On the planting ground a banking with a height of 1.5-2m is produced by self-supported soil, playing a role in a salt blocking and an irritation layer of planting. Finally, an additional banking with a height of 2m is produced by qualified vegetation soil, forming a vegetation section with a total height of 6m. 2. Since the planning site is located in the border, the planting area is composed of two regions : one is an inclined face (slope 1 : 3) toward the inside of the landfill site and the other is an inclined face (slope 1 : 4) toward the inland. The buffer planting in the former (latter) region consists of wind break forest (mixed-landscape forest) within a width of less than 35m. 3. Based on the data obtained from the literatures and the investigation of local plants, we choose the 21 plant species (such as Pinus thunbergii, Pinus densiflora, Sorbus alnifolia, Albizzia julibrissin and etc.) and the additinal 7 species which are grown at a sprout cultivation palce of the SUDOKWON landfill site (Rosa rugosa, Quercus acutissima, Prunus armeniaca var. ansu., and etc.). Sub-trees with a height of above 2.5m and seedlings are planted with an interval of $1.5{\times}1.5m$ ($0.45roots/m^2$) and $0.5{\times}0.5m$ ($4roots/m^2$), respectively. Here, both trees exhibit communities planting with more than three rows. Shrubs are planted with $9-16roots/m^2$, depending on their size. Since this case study provides a reference of the planting beds as well as a planting plan at the SUDOKWON landfill site, it is not sufficient for the present plan to be utilized for the formation of buffer-forest belts which are used for the analysis of environmental factor and the reduction of environmental pollutants in the sea waste landfill site. Thus, further studies with the ecological basis are demanded for the environment planting restoration in the sea waste landfill site.

• Resources Recycling
• /
• 제13권2호
• /
• pp.39-46
• /
• 2004

The amount of electric furnace dust has been steadily increasing due to the increase of iron scraps which are usually recycled by electric furnace melting process. To date, this electric furnace dust has usually been treated by landfilling, however, because of shortage of landfill sites and heavy metal leaching more desirable treatment schemes are urgently needed. Among several possible schemes for the proper treatment of electric furnace dust, its recycling can be said to be most desirable. In present study, the triboelectrostatic separation of zinc and zinc-containing components from electric furnace dust was attempted based on its physicochemical properties such as particle shape, size distribution, and chemical assay. The dust was found to be mixed with spherical and non-spherical shaped particles and its major component materials were $ZnFe_2$$O_4$, ZnO, Fe, Zn, and FeO. The content of zinc-containing components in the entire dust was observed to be in the range of 15～30 wt%, which reasonably justified that zinc is recyclable. The triboelectrostatic characteristic of each component material was found to be different each other since their work functions were different, and based on this characteristic zinc and zinc-containing component could be flirty separated from the dust. After selecting a proper tribo-elec-trification material, the separation features of zinc and zinc-containing component were examined by taking the distance of electrodes, electric field strength, and scavenging as the experimental variables. The highest zinc-content obtained under the optimal separating condition was found to be up to 50wt%.

• Economic and Environmental Geology
• /
• 제51권5호
• /
• pp.429-438
• /
• 2018

Since concrete is a hardened aggregates of various materials, it needs to be crushed for chemical analyses. However, the effect of sample crushing on the analytical results has not been precisely assessed till today. In this study, we prepared concrete test pieces using Portand cements and fly ashes as binding materials, and ponded ashes and sands as aggregates and analyzed the heavy metals of the test pieces using Standards for Fair Testing of Soil Contamination (SFTSC) and Wastes (SFTW). For this, each test piece was partially crushed at first and sieved for separation of grains of <0.15 mm, 0.15-0.5 mm, and 0.5-5 mm from the same crushed samples (Crushing Method I). Results of those samples using SFTSC showed a clear trend that analyzed heavy metal concentrations are higher in the finer fractions. Particularly, fractions with <0.15 mm indicated much higher concentrations than the theoretical ones, which were calculated based on the concentrations of individual materials and their mixing fractions. In contrast, the analytical results were generally comparable with the theoretical ones when the test pieces were totally pulverized such that all the crushed grains were <0.15 mm in size (Crushing Method II). These results are associated with the fact that cement materials and fly ashes, which are high in heavy metals relative to other materials, are enriched in the fine fractions. The analytical results using the SFTW derived very low concentrations in most of parameters and did not indicate the dependence of concentrations on the crushing methods due to using distilled water as leaching agent.