• 한국지반환경공학회 논문집
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• 제8권1호
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• pp.13-20
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• 2007

폐기물 매립지에서 발생하는 침출수는 주변 환경오염은 물론 지하수 오염등 2차적 환경오염을 발생시킬 우려가 매우 크다. 따라서, 쓰레기 매립지에서는 차수층을 설치하여 침출수를 차단 정화시켜서 2차적인 환경오염을 막고 있다. 차수층으로 사용되는 재료는 불투수성재료로서 일반적으로 투수계수가 $1{\times}10^{-7}$ cm/sec 이하가 되는 재료를 사용한다. 이러한 저 투수성을 갖는 자연상태의 점성토를 현장 부근에서 대량으로 확보하기는 매우 힘들기 때문에 그에 상응하는 저투수성 재료를 확보하는 방법으로 수밀성이 좋은 혼화재를 현장에 분포하는 현장토에 혼합하여 사용한다. 즉 벤토나이트와 MCG 고화재를 이용한 혼합토는 폐기물매립지에서 차수층으로 널리 이용되는 재료로서 차수효과와 내구성에서 크게 인정받고 있는 재료이다. 본 연구는 배합재료(혼합토)에 따른 폐기물매립지 차수층의 변화를 벤토나이트, MCG 고화재를 이용하여 실험하였다. 이들 재료의 혼합비가 현장에 미치는 영향을 다양한 공학적 실험을 통하여 분석하였다.

• 한국지하수토양환경학회지:지하수토양환경
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• 제22권3호
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• pp.10-17
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• 2017

In this study, the evolution and origin of major dissolved constituents of crystalline bedrock groundwater in a coastal area were evaluated using multivariate statistical and groundwater quality analyses. The groundwater types mostly belonged to the $Na(Ca)-HCO_3$ and $Ca-HCO_3$ types, indicating the effect of cation exchange. Stable isotopes of water showed two areas divided by first and secondary evaporative effects, indicating a pattern of rapid hydrological cycling. Saturation indices of minerals showed undersaturation states. Thus, the degree of evolution of groundwater is suggested as in the low to intermediate stage, based on field and laboratory analytical conditions. According to the principal component analysis (PCA) results, the chemical components of EC, $Ca^{2+}$, $Mg^{2+}$, $K^+$, $HCO_3{^-}$, $SO{_4}^{2-}$ (PCA 1), $F^-$ (PCA 3), $SiO_2$ (PCA 4), and $Fe^{2+}$ (PCA 5) are derived from various water-rock interactions. However, $NO_3{^-}$, $Na^+$, and $Cl^-$ (PCA 2) represented the chemical characteristics of both anthropogenic sources and natural sea spray.

• 대한환경공학회지
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• 제32권7호
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• pp.682-689
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• 2010

본 연구는 화력발전소에서 발생한 바텀애쉬와 폐타이어를 성토재로 사용하기 전 환경에 미치는 영향을 파악하기 위해 수행되었다. 바텀애쉬에 대해서는 3가지 초기 pH 4, 6, and 8 조건에서 실험하였고, 폐타이어와 바컴애쉬 폐타이어 혼합물은 pH 4 조건에서 실험하였다. 7가지 중금속 중 Pb과 Zn이 먹는물 수질기준을 초과하였으나 1 PVE안에 모두 기준을 만족하였다. 5가지 음이온 중 황산염의 농도만 기준치의 최대 10배 정도로 크게 검출이 되었으며 높은 분배계수로 인해 수질기준치 이하로 낮아지는 데 걸리는 시간도 최대 8.21 PVE에 달하였다. 혼합물의 경우 바텀애쉬와 비교 시 중금속 및 음이온의 농도를 낮추었으며 요구되는 PVE도 8.21에서 5.89로 낮추는 효과가 있었다.

• 상하수도학회지
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• 제10권2호
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• pp.104-116
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• 1996

Anaerobic digestion is generally used for the treatment of volatile organic solids such as manure and sludge from waste water treatment plants. However, the reaction rate of anaerobic process is slow, and thus it requires a large reactor volume. To minimize such a disadvantage, physical and chemical pre-treatment is generally considered. Another method to reduce the reactor size is to adopt different reactor system other than CSTR. In this paper, the effects of heat pre-treatment and reactor configurations on the anaerobic treatability of volatile solids was studied. Carrot, kale, primary sludge, and waste activated sludge was chosen as the test materials, and the BMP method was used to evaluate the maximum methane production and first order rate constants from each sample. After the heat treatment at $130^{\circ}C$ for 30min., the measured increase in SCOD per gram VS was up to 394 mg/L for the waste activated sludge. However, the methane production potential per gram VS was increased for only primary and waste activated sludge by 17-23%, remaining the same for carrot and kale. The overall methane production process for the tested solids can be described by first order reactions. The increased in reaction constant after heat pre-treatment was also more significant for the primary and waste activated sludge than that for carrot and kale. therefore, the heat pre-treatment appeared to be effective for the solids with high protein contents rather than for the solids with high carbohydrate contents. Among the four reactor systems studied, CSTR, PFR, CSTR followed by PFR, and PFR with recycle, CSTR followed by PFR appeared to be the best choice considering methane conversion rate and the operational stability.

• 한국폐기물자원순환학회지
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• 제35권8호
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• pp.762-769
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• 2018

This study was carried out to examine the improvement plan by analyzing the characteristics of imported wastes, operation rate, and benefits of energy recovery for incineration facilities with a treatment capacity greater than 50 ton/day. The incineration facility capacity increased by 3,280 tons over 15 years, and the actual incineration rate increased to 2,783 ton/day. The operation rate dropped to 76% in 2010 and then rose again to 81% in 2016. The actual calorific value compared to the design calorific value increased by 33.8% from 94.6% in 2002 to 128.4% in 2016. The recovery efficiency decreased by 29% over 16 years from 110.7% to 81.7% in 2002. Recovery and sales of thermal energy from the incinerator (capacity 200 ton/day) dominated the operation cost, and operating income was generated by energy sales (such as power generation and steam). The treatment capacity increased by 11% to 18% after the recalculation of the incineration capacity and has remained consistently above 90% in most facilities to date. In order to solve the problem of high calorific value waste, wastewater, leachate, and clean water should be mixed and incinerated, and heat recovery should be performed through a water-cooled grate and water cooling wall installation. Twenty-five of the 38 incineration facilities (about 70%) are due for a major repair. After the main repair of the facility, the operation rate is expected to increase and the operating cost is expected to decline due to energy recovery. Inspection and repair should be carried out in a timely manner to increase incineration and heat energy recovery efficiencies.

• 유기물자원화
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• 제18권3호
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• pp.60-67
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• 2010

우리나라의 대형 생활폐기물소각시설의 건설시기를 보면 상당수가 1980년대 후반인 것을 알 수 있다. 대부분의 시설들은 이 시기에 설계되었으며 그 후에 건설된 소각로 역시 변경이나 조정 없이 시설해온 것으로 조사되고 있다. 그러나 소각로에 반입되는 폐기물의 성상은 정부의 폐기물수거 정책에 의해 급격히 변화하고 있다. 이는 생활폐기물의 발열량변화를 조사해 봄으로도 쉽게 알 수 있다. 그 결과 많은 소각시설에서 과열에 의해 내화물과 화격자가 손상되고 있다. 한편 보일러 전열면에 클링커가 생성되어 열전달에 방해를 줌으로 이용열량이 줄어들 뿐만 아니라 연소실의 온도가 상승되는 등 원하지 않는 현상이 연속되고 있다. 이를 개선하기 위해 폐기물저장고에 물을 뿌리거나, 분리수거해 온 음식물류 폐기물을 다시금 혼합하여 혼소하거나 연소실에 물을 분사하는 방법을 동원하고 있다. 이러한 방법은 근본적인 해결책이 되지 않으며, 설계부터 다시 하여 새로 시설하는 것 또한 비용적인 측면에서 효과적이지 못하다. 따라서 본 연구를 통해 위와 같은 문제를 원천적으로 해결 하기위한 방법을 도출해 보았다.

• 대한영양사협회학술지
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• 제3권1호
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• pp.55-62
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• 1997

The waste rates of 98 food items after pre-preparation were surveyed to provide database for good menu planning. The waste rates turned out 0-64.27% in vegetables, 6.38-7.03% in potatoes, 6.25-68.75% in fishes and shellfishes, 16.61% in eggs, and 16.00-56.84% in fruits. Foods with high waste rates were vegetables, fishes and shellfishes. Survey results were compared with other food composition tables. Foods with 30% higher waste rate than other food composition tables were squash leaf, pacific ocean perch, sweet potato stalk, water cress, green peas, alaska pollack, bluefin tuna, beka squid, crown daisy, dodok, amaranth, beef ribs. Food which waste rates turned out to be decreased by about 30% in this study were corb shell, pomfret, sea mussel, warty sea squirt. For the menu planning, reasonaly exact waste rates for each food items are essential. Since survey results show significant deviations, there should be more studies for exact waste rates for each food.

• 한국해양공학회지
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• 제24권3호
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• pp.52-58
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• 2010

This study investigated the engineering properties of waste tire powder-bottom ash added composite soil, which was developed to recycle dredged soil, bottom ash, and waste tire powder. Test specimens were prepared using 5 different percentages of waste tire powder content(0%, 25%, 50%, 75%, and 100% by weight of the dry dredged soil), three different percentages of bottom ash content (0%, 50%, and 100% by weight of the dry dredged soil), and three different particle sizes of waste tire powder (0.1~2 mm, 0.9~5 mm, and 2~10 mm). Several series of unconfined compression tests, direct shear tests, and flow tests were conducted. The experimental results indicated that the waste tire powder content, particle size of waste tire powder, and bottom ash content influenced the strength and stress-strain behavior of the composite soil. The flow value increased with an increase in water content, but decreased with an increase in waste tire powder content.

• 한국세라믹학회지
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• 제43권10호
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• pp.626-634
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• 2006

Ceramics manufacturers in the nation produced more than 5000 tons of ceramics wastes a year increasing industrial waste quantity: However, almost no researches were made to reduce environmental pollution and to recycle waste ware. In this study, white ware scraps that were produced at Icheon, Gyeonggi-do were recycled to make use of them as raw materials of ceramics body and to develop new ceramics body that had economic advantages and good quality. The findings showed that the addition of waste ware had limit of 20 wt% considering molding. The addition of waste ware of 20 wt% to white ware lowered baking temperature of the white ware that was added by waste ware of 20 wt% by 30$^{\circ}C$ than existing white ware, and property values were good, for instance, porosity of 3% in average and water absorptivity of 2% in average, and the bending strength recorded more than 800 kgf/$cm^2$ to be high than that of existing white ware being sold in market. The waste ware could be used to produce new ware body and to recycle resources and to solve environmental problems caused by burial and to improve property of ceramics and to save transportation costs as well as baking costs.

• Nuclear Engineering and Technology
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• 제55권8호
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• pp.2889-2896
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• 2023

The waste acceptance criteria for heavy metals in mixed waste should be developed by reflecting the leaching behaviors that could highly depend on the repository design and environment surrounding the waste. The current standards widely used to evaluate the leaching characteristics of heavy metals would not be appropriate for the silo-type repository since they are developed for landfills, which are more common than a silo-type repository. This research aimed to explore the leaching behaviors of cementitious waste with Pb, Cd, and Sb metallic and oxide powders in an environment simulating a silo-type radioactive waste repository. The Toxicity Characteristic Leaching Procedure (TCLP) and the ANS 16.1 standard were employed with standard and two modified solutions: concrete-saturated deionized and underground water. The compositions and elemental distribution of leachates and specimens were analyzed using an inductively coupled plasma optical emission spectrometer (ICP-OES) and energy-dispersive X-ray spectroscopy combined with scanning electron microscopy (SEM-EDS). Lead and antimony demonstrated high leaching levels in the modified leaching solutions, while cadmium exhibited minimal leaching behavior and remained mainly within the cement matrix. The results emphasize the significance of understanding heavy metals' leaching behavior in the repository's geochemical environment, which could accelerate or mitigate the reaction.