• Clean Technology
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• v.19 no.4
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• pp.401-409
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• 2013

BBiodegradable polymers have attracted great attention because of the increased environmental pollution by waste plastics. In this study, PLA (polylactic acid)/Clay-20 (Cloisite 20) and PLA (polylactic acid)/PBS (poly(butylene succinate)/Clay-20 (Cloisite 20) nanocomposites were manufactured in a twin-screw extruder. Specimens for mechanical properties of PLA/Clay-20 and PLA/PBS (90/10)/Clay-20 nanocomposites were prepared by injection molding. Thermal, mechanical, morphological and raman spectral properties of two nanocomposites were investigated by differential scanning calorimetry (DSC), tensile tester, scanning electron microscopy (SEM) and raman-microscope spectrophotometer, respectively. In addition, hydrolytic degradation properties of two nanocomposites were investigated by hydrolytic degradation test. It was confirmed that the crystallinity of PLA/Clay-20 and PLA/PBS/Clay-20 nanocomposite was increased with increasing Clay-20 content and the Clay-20 is miscible with PLA and PLA/PBS resin from DSC and SEM results. Tensile strength of two nanocomposites was decreased, but thier elongation, impact strength, tensile modulus and flexural modulus were increased with an increase of Clay-20 content. The impact strength of PLA/Clay-20 and PLA/PBS/Clay-20 nanocomposites with 5 wt% of Clay-20 content was increased above twice than that of pure PLA and PLA/PBS (90/10). The hydrolytic degradation rate of PLA/Clay-20 nanocomposite with 3 wt% of Clay-20 content was accelerated about twice than that of pure PLA. The reason is that degradation may occur in the PLA and Clay-20 interface easily because of hydrophilic property of organic Clay-20. It was confirmed that a proper amount of Clay-20 can improve the mechanical properties of PLA and can control biodegradable property of PLA.

• Journal of the Korea Organic Resources Recycling Association
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• v.11 no.1
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• pp.130-130
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• 2003

본 연구는 음식물찌꺼기의 재활용 방법의 일환으로 음식물 퇴비와 돈분 퇴비를 혼합, 고추 작물에 적용하여 생육 및 품질면에서 합리적인 시용량을 검증하고 토양 이화학적 특성변화 및 고추 생육과 수량에 미치는 영향을 평가하기 위해 실시하였다. 퇴비의 처리는 관행구(2ton/10a의 돈분 퇴비)와 음식물 퇴비 및 돈분 퇴비의 혼합구인 0.5t:1.5t, 1.0t:1.0t, 1.5t:0.5t, 2.0t:0ton/10a의 4개 처리구등 총 5개 처리구를 난괴법 3반복으로 수행하였다. 돈분 퇴비와 음식물 퇴비의 이화학적 특성을 분석한 결과 음식물 퇴비는 유기물이 기준량에 2배정도 높았으며, NaCl은 공정규격인 1%를 약 2.5배정도 초과하였다. 음식물 퇴비의 시용량 증가에 따라 토양 pH는 처리구별 특별한 변화는 없었으며, EC는 전체적으로 증가하였다. 생육기간 중 대조구와 음식물 퇴비의 처리구간 생육차이가 약간 나타났으며, 그로 인해 고추의 수량에 영향을 미친 것으로 판단된다. 음식물 퇴비 처리구에서 1ton/10a이상 일 때 시용량이 증가할수록 수확량 및 고추 개수에 있어서 감소 경향을 보였지만 수량 차이는 크지 않았다. 또한 capsaicin 함량에서도 음식물 퇴비 처리구간에 큰 차이는 보이지 않았다. 음식물 퇴비의 시용량에 따라 고추에 흡수되는 양분 흡수량은 큰 차이를 보이지 않았다. 결론적으로 음식물 퇴비를 시용한 고추 재배 시험에서 토양의 유기물 함량 증가, 물리성 개량, 토양 pH 완충력 증대 등의 효과를 보였다. 그러나 음식물 퇴비를 50%이상 돈분 퇴비와 혼합 시용시 고추의 수량이나 품질의 저하 및 토양의 염류집적의 우려가 나타났으나, 50%이하로 혼합 시용시 큰 무리는 없었다. 현재 적정 혼합비율을 구명하기 위한 연구가 진행중이다.

• KSBB Journal
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• v.18 no.4
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• pp.318-323
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• 2003

This study was carried out to investigate the possibility of reusing newspaper or paperbox waste by methane fermentation. When 15 g of newspaper and box wastes were digested separately for 24 days by batch fermentation, the amount of total organic acids produced were 2461 and 4978 mg/L, respectively. The tCOD removal rates were found to be 60.9 and 62.4%, respectively. In addition, the removal efficiencies of total solid were 34.8 and 33.4%, and those of volatile solid were 40.0 and 39.2%, respectively. During this period, the amounts of biogas produced were 6.95 and 6.43 L. In a semicontinuous reaction, tCOD removal efficiencies for newspaper and box wastes were 64.7 and 65.0%, respectively, after 14 days of digestion. After 25 days, which were needed to stabilize the methane fermentation, the amounts of biogas produced daily were 0.31 and 0.30 L/g.dry wt, respectively. Methane contents were 57.3 and 56.2%, respectively, and the pHs in the anaerobic acidogenic and methanogenic fermenters were 5.0 and 7.5, respectively.

• Korean Journal of Soil Science and Fertilizer
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• v.30 no.1
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• pp.72-83
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• 1997

Forty six natural habitats of Korean lespedeza(Leapedeza stipulacea Maxim.) were investigated for the growth characteristics, mineral contents of plant and the physico-chemical properties of natural habitat's soil compared with the upland soil nearby the habitat. The results obtained were summarized as follows. Plant height and dry matter yield were higher in the samples taken in late than early August showing large variation within the sampling date and location. Korean lespedeza showed higher contents of Fe and Mn, but lower contents of K, Ca, Mg and Cu than Alfalfa. The contents of P and Zn were about the same. The natural habitat showed higher soil pH and Ca content but lower contents of $P_2O_5$, K, and organic matter than the vicinity of natural habitats and the average soil of Korea. The contents of Mg were about the same. The soil texture of natural habitats showed much higher portion of sand and extremely low portions of silt and clay than both area. Korean lespedeza is so well adapted to the soil with low fertilizer and organic matter that other crops and most weeds fail. It also appears to thrive on the sandy loams, loamy sands of the piedmont region such as waste land and on the similar soils with variously physico-chemical properties.

• Journal of the Korea Organic Resources Recycling Association
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• v.31 no.1
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• pp.5-14
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• 2023

In this study, LiDAR-reflective black hollow-structured silica/titania(B-HST) materials are successfully synthesized by employing the NaBH₄ reduction and etching method on silica/titania core/shell(STCS) materials, which also effectively enhance near-infrared(NIR) reflectance. Moreover, core-etched supernatant solutions are collected and recycled for the synthesis of extracted silica(e-SiO₂) process, which successfully applies as filler materials for semiconductor epoxy molding compound(EMC). In detail, B-HST materials, fabricated by the sequential experimental steps of sol-gel, reduction, and sonication-mediated etching method, manifest blackness(L^*) of 13.2 similar to black paint and excellent NIR reflectance(31.1%). Consequently, B-HST materials are successfully prepared as LiDAR-reflective black materials. Additionally, core-etched supernatant solution with silanol precursors are employed for synthesis of homogeneous silica filler materials via sol-gel method. As-synthesized silica fillers are incorporated with epoxy resin and carbon black for the preparation of semiconductor EMC. Experimentally synthesized EMC exhibits comparable mechanical-chemical properties to commercial EMC. Conclusively, this study successfully proposes designing procedure and practical experimental method for simultaneously synthesizing the NIR-reflective black materials for self-driving vehicles and EMC materials for semiconductors, which are materials suitable for the industrial 4.0 era, and presented their applicability in future industries.

• Journal of the Korea Organic Resources Recycling Association
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• v.18 no.1
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• pp.98-103
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• 2010

This study was carried out on the composting of the most part of the plant waste materials inflowed-drifting into the dam during the localized heavy rain and the rainy season, due to the abnormal climate change, and for the sewage sludge banned to dispose legally into the ocean from the year of 2012. It was analysed the distinctive physicochemical qualities of the compost with treatment S-1(dam suspended particle sawdust : oak tree bark : sewage sludge : chicken manure = 30 : 20 : 40 : 10) and treatment S-2(dam suspended particle sawdust : oak tree bark : sewage sludge : chicken manure = 30 : 30 : 30 : 10). Both S-1 and S-2 maintained for 10 days at above $65^{\circ}C$ of the compost pile temperature, and the most of its pathogen were destroyed. In case of pH, until the 90th day into composting, S-1 with the pH value of 7.78 was slightly higher than S-2. The C/N value of S-1 was 15.3 and that of S-2 was 16.9. The quality of its final product was satisfied to the manufacture-standards. The GI value of S-1 was 91 higher than that of S-2, which was 84. In conclusion, it is highly recommendable to manufacture S-1 for its frequent usage of dam suspended particle sawdust and sewage sludge, and for its excellent quality and safety.

• Journal of the Korea Organic Resources Recycling Association
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• v.18 no.4
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• pp.77-85
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• 2010

Pig slurry has been considered as environmental waste to be treated in an appropriate manner. Recently, there has been the movement toward reusing the pig slurry as an alternative fertilizer sources for agricultural lands. For instance, SCB(Slurry Composting & Biofiltration) liquid fertilizer has been developed and widely used in Korea. However, the impacts of swine slurry liquid fertilizers on both agricultural environment and crop yield have not been investigated yet. Therefore, the current study was conducted to accumulate the basic data which can be subsequently used to determine appropriate application amount of swine slurry liquid fertilizers (SCB liquid fertilizer and storage liquid fertilizer) as well as the application method for each liquid fertilizer. For this, growth of rice was cultivated under the treatment of SCB liquid fertilizer, storage liquid fertilizer, and chemical fertilizer. Also, control treatment (no fertilizer) was included for comparison and all treatments were conducted in five replication. Rice growth was good with the treatment in the order of chemical fertilizer>storage liquid fertilizer>SCB liquid fertilizer>control and likewise, the yield amount of rice straw was in the same order of rice growth. The rice yield amount appeared to be no difference among the treatment except control which showed the least yield amount. Also there was no difference in nitrogen and phosphorus concentrations in rice among the treatment except control which showed the least concentration.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2000.11a
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• pp.44-63
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• 2000

Situated close to Heathrow Airport, and adjacent to the M4 and M25 Motorways, the site at Axis Park is considered a prime location for business in the UK. In consequnce two of the UK's major property development companies, MEPC and Redrew Homes sought the expertise of Intergeo to remediate the contaminated former industrial site prior to its development. Industrial use of the twenty-six hectare site, started in 1936, when Hawker Aircraft commence aircraft manufacture. In 1963 the Firestone Tyre and Rubber Company purchased part of the site. Ford commenced vehicle production at the site in the mid-1970's and production was continued by Iveco Ford from 1986 to the plant's decommissioning in 1997. Geologically the site is underlain by sand and gravel, deposited in prehistory by the River Thames, with London Clay at around 6m depth. The level of groundwater fluctuates seasonally at around 2.5m depth, moving slowly southwest towards local streams and watercourses. A phased investigation of the site was undertaken, which culminated in the extensive site investigation undertaken by Intergeo in 1998. In total 50 boreholes, 90 probeholes and 60 trial pits were used to investigate the site and around 4000 solid and 1300 liquid samples were tested in the laboratory for chemical substances. The investigations identified total petroleum hydrocarbons in the soil up to 25, 000mg/kg. Diesel oil, with some lubricating oil were the main components. Volatile organic compounds were identified in the groundwater in excess of 10mg/l. Specific substances included trichloromethane, trichloromethane and tetrachloroethene. Both the oil and volatile compounds were widely spread across the site, The specific substances identified could be traced back to industrial processes used at one or other dates in the sites history Slightly elevated levels of toxic metals and polycyclic aromatic hydrocarbons were also identified locally. Prior to remediation of the site and throughout its progress, extensive liaison with the regulatory authorities and the client's professional representatives was required. In addition to meetings, numerous technical documents detailing methods and health and safety issues were required in order to comply with UK environmental and safety legislation. After initially considering a range of options to undertake remediation, the following three main techniques were selected: ex-situ bioremediation of hydrocarbon contaminated soils, skimming of free floating hydrocarbon product from the water surface at wells and excavations and air stripping of volatile organic compounds from groundwater recovered from wells. The achievements were as follows: 1) 350, 000m3 of soil was excavated and 112, 000m3 of sand and gravel was processed to remove gravel and cobble sized particles; 2) 53, 000m3 of hydrocarbon contaminated soil was bioremediated in windrows ; 3) 7000m3 of groundwater was processed by skimming to remove free floating Product; 4) 196, 000m3 of groundwater was Processed by air stripping to remove volatile organic compounds. Only 1000m3 of soil left the site for disposal in licensed waste facilities Given the costs of disposal in the UK, the selected methods represented a considerable cost saving to the Clients. All other soil was engineered back into the ground to a precise geotechnical specification. The following objective levels were achieved across the site 1) By a Risk Based Corrective Action (RBCA) methodology it was demonstrated that soil with less that 1000mg/kg total petroleum hydrocarbons did not pose a hazard to health or water resources and therefore, could remain insitu; 2) Soils destined for the residential areas of the site were remediated to 250mg/kg total petroleum hydrocarbons; in the industrial areas 500mg/kg was proven acceptable. 3) Hydrocarbons in groundwater were remediated to below the Dutch Intervegtion Level of 0.6mg/1; 4) Volatile organic compounds/BTEX group substances were reduced to below the Dutch Intervention Levels; 5) Polycyclic aromatic hydrocarbons and metals were below Inter-departmental Committee for the Redevelopment of Contaminated Land guideline levels for intended enduse. In order to verify the qualify of the work 1500 chemical test results were submitted for the purpose of validation. Quality assurance checks were undertaken by independent consultants and at an independent laboratory selected by Intergeo. Long term monitoring of water quality was undertaken for a period of one year after remediation work had been completed. Both the regulatory authorities and Clients representatives endorsed the quality of remediation now completed at the site. Subsequent to completion of the remediation work Redrew Homes constructed a prestige housing development. The properties at "Belvedere Place" retailed at premium prices. On the MEPC site the Post Office, amongst others, has located a major sorting office for the London area. Exceptionally high standards of remediation, control and documentation were a requirement for the work undertaken here.aken here.

• Journal of the Korean Society for Marine Environment & Energy
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• v.9 no.1
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• pp.14-20
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• 2006

In this study, the feasibility of simultaneous removal of organic materials and nitrogen in the waste-water from fisheries processing plant was evaluated using entrapped mixed microbial cell technique(EMMC) process. The experiment was performed using activated sludge from municipal sewage treatment plant which was immobilized with gel matrix by cellulose triacetate. It was found that the stable operation at the treatment system which is composed of anoxic and oxic tank, was possible when the organic and nitrogen loading rates were increased stepwise. The organic and nitrogen loading rates were applied from 0.65 to $1.72kgCOD/m^3/d$ and from 0.119 to $0.317kgT-N/m^3$ with four steps, respectively. The maximum nitrogen loading rate which could satisfy the regulated effluent standard of nitrogen concentration, was $0.3kgT-N/m^3/d$. The removal efficiency of total nitrogen was decreased apparently as increasing nitrogen loading rates, whereas the removal efficiency of ammonium nitrogen was effective at the all tested nitrogen loading rates. Therefore, it was concluded that nitrification was efficient at the system. Nitrate removal efficiency ranged from 98.62% to 99.51%, whereas the nitrification efficiency at the oxic tank ranged 94.0% to 96.9% at the tested loading rates. The removal efficiencies of chemical oxygen demand(COD) and those of total nitrogen at the entire system ranged from 94.2% to 96.6% and 73.4% to 83.4%, respectively.

• Journal of Korean Society for Atmospheric Environment
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• v.22 no.E2
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• pp.49-56
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• 2006

This pilot study focuses on emissions characterization of air pollutants produced from incineration of some municipal solid wastes (MSWs). The MSWs incinerated by an electric furnace maintained up to $600^{\circ}C$ included food, paper, and plastic wastes. The pollutants analyzed in this study included concentrations of volatile organic compounds (VOCs), bottom ash contents, and heavy metals extracted from the bottom ash of each waste. The VOCs identified were classified based on their chemical structure. The total emissions of VOCs produced from incineration of the papers were identified as the highest followed by those from the plastics and the food wastes. Aliphatic alkenes were major VOC compounds produced from incineration of plastic or food wastes, while furans were major VOCs produced from incineration of papers. The second major VOCs produced from incineration of food, plastics, and papers were aromatics. In particular, hazardous air pollutants such as benzene were produced with considerable amount of emission concentration. The bottom ash contents of papers were usually much higher than those of food or plastic wastes. The bottom ash contents produced from incineration of food and plastics were much lower than those of other MSWs. In analysis of heavy metals extracted by an ultrasonic method from the bottom ashes of the papers, high concentrations of heavy metals were identified from incineration of newspapers and box (cardboard). In addition, it was identified that the general public might be exposed to considerable amounts of lead concentrations during incineration processes and uses of paper cup and from ashes.