• Proceedings of the Korean Environmental Sciences Society Conference
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• 2006.05a
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• pp.351-354
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• 2006

본 연구에서는 산발효산물과 하수슬러지의 혼합소화를 위한 적정 혼합비를 도출을 위하여 음식물찌꺼기 고온 산발효산물과 하수슬러지의 생분해 특성과 적정혼합비를 도출하고자 수행한 결과 음식물찌꺼기 고온 산발효액과 하수슬러지를 혼합비별로 회분식 혼합소화 실험을 실시 한 결과 혼합비 1:1에서 385ml CH$_4$/g VS$_{added}$로 가장 높은 메탄발생량을 나타내었다. 이러한 결과는 음식물찌꺼기와 하수슬러지를 1:1로 동일하게 혼합하여 비교 소화실험을 실시했을 때 의 293m1 CH$_4$/g VS$_{added}$와 비교하여 상대적으로 높은 메 탄발생량을 나타내었다.

• Economic and Environmental Geology
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• v.38 no.1
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• pp.91-99
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• 2005

Acid Rock Drainage(ARD) is the product formed by the atmospheric(i.e. by water, oxygen and carbon dioxide) oxidation of the relatively common iron-sulphur mineral pyrite($FeS_2$). ARD causes the acidification and heavy metal contamination of water and soil and the reduction of slope stability. In this paper the generation characteristics and the prediction of ARD of various cut slopes were studied. An attempt to classify the rocks into several groups according to their acid generation potentials was made. Acid Base Accounting(ABA) tests, commonly used as a screening tool in ARD predictions, were performed. Fourteen rock samples were classified into PAF(potentially acid forming) group and four rock samples into NAF(non-acid forming) group. The chemical analysis of water samples strongly suggested that ARD with high content of heavy metals and low pH could pollute the ground water and/or stream water.

• Journal of the Korea Organic Resources Recycling Association
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• v.8 no.3
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• pp.112-117
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• 2000

Food waste is the main source of decay, odors and leachate in collection, transportation and landfill due to the high volatile solids (VS) and moisture content. Acidogenic fermentation of food waste is affected by the fermentation constraints including the biodegradability of substrate and the degrading capability of microorganisms. The biodegradability of food waste is mainly related to cellulosic materials, which are hardly degraded and comprise about 50% of food waste. The efficient and economical method of improving hydrolysis is, therefore, to apply microorganisms with increased cellulose-degrading capability. In this experiment, rumen microorganisms were inoculated to improve the low efficiency of acidogenic fermentation, and then compared with that of mesophilic acidogens. The fermentation of food waste in a leaching bed reactor employing rumen microorganisms resulted in the enhanced acidification (71.2% at $3.0d^{-1}$), which was higher than that (59.8% at $4.5d^{-1}$) employing mesophilic acidogens. This indicated that Rumen microorganisms had an enhanced waste-degrading capability.

• Economic and Environmental Geology
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• v.54 no.5
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• pp.561-572
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• 2021

Aggregate collection is taking place in many areas in Korea, resulting in large cut slopes or large amounts of cut rocks. If the development site for such aggregate collection is a stratum accompanied by sulfide minerals, Acid Rock Drainage (ARD) may occur, which may cause environmental pollution in the development site and surrounding areas. As a result of the study on forest aggregate samples, most of the samples were classified as acid-forming potential samples, and among them, some samples from Gwangju, Goyang, and Sokcho were classified as potential acid-generating samples. This can be expected to affect the quality of aggregates when a large amount of aggregate is used in the future. Therefore, it is judged that these forest aggregates need to be managed when they are used. By predicting the occurrence of ARD through the acid-generating ability test, it is expected that economic losses that may occur in the future can be reduced, and it is judged that the problem of surrounding environmental pollution can be further alleviated.

• Journal of the Korean GEO-environmental Society
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• v.13 no.4
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• pp.5-11
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• 2012

Acid mine drainage (AMD) is one of the most severe environmental problem that results from the oxidation of pyrite $(FeS_2)$ and various other metal sulfides. In this study, the influence of microorganism was tested on the process where AMD was released and the method to inhibit AMD generated by microorganisms at abandoned mine area. The activity and growth rate of Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans, common microorganisms affecting AMD occurrence, were measured. Chlorine dioxide $(ClO_2)$, NaCl, or surfactant (ASOR-770) was used as an inhibitor for working on activity and growth of microorganism. Among the three inhibitors, 10ppm of chlorine dioxide was the most effective inhibitor for AMD control due to the reduced the activity and growth of microorganisms by 20%.

• Journal of Korean Society of Environmental Engineers
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• v.30 no.12
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• pp.1231-1238
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• 2008

This study was performed to evaluate the treatability of food waste leachate using lab-scale two-phase anaerobic digestion system. Effects of influent pH, hydraulic retention time (HRT), and recycle of methanogenic reactor effluent to the thermophilic acidogenic reactors were investigated. For methanogenic reactors, effects of internal solids recycle and temperature were studied. Performance of the acidogenic reactors was stable under the conditions of influent pH of 6.0 and HRT of 2 d with the recycle of methanogenic reactor effluent, and acidification and VS removal efficiency were about 30% and 40%, respectively. Up to the organic loading rate (OLR) of 7 g COD/L/d, effluent SCOD values of mesophilic and thermophilic methanogenic reactors either lower or kept the same with the internal solids recycle. Also, decreasing tendency in specific methane production (SMP) due to the organic loading increase became diminished with the internal solids recycle. Mesophilic methanogenic reactors showed higher TCOD removal efficiency and SMP than thermophilic condition under the same OLR as VSS was always higher under mesophilic condition. In sum, thermophilic acidogenesis-mesophilic methanogenesis system was found to be better than thermophilic-thermophilic system in terms of both organic removal and methane production.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.03a
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• pp.491-498
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• 2005

Acid Rock Drainage(ARD) is the product formed by the atmospheric(i.e. by water, oxygen and carbon dioxide) oxidation of the relatively common iron-sulphur minerals pyrite($FeS_2$). ARD causes the acidification and heavy metal contamination of water and soil and the reduction of slope stability. In this study the generation characteristics and the prediction of ARD of various road cut slopes were studied. An attempt to classify the rocks into several groups according to their acid generation potentials was made. Acid Base Accounting(ABA) tests, commonly used as a screening tool in ARD predictions, were performed. Sixteen rock samples were classified into PAF(potentially acid forming) group and four rock samples into NAF(non-acid forming) group. The chemical analysis of water samples strongly suggested that ARD with high content of heavy metals and low pH could pollute the ground water and/or stream water.

• KSBB Journal
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• v.8 no.5
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• pp.438-445
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• 1993

Raw cow manure was treated by a 4-step integrated system with phase separation anaerobic digestion and algal culture. When the first methane fermentation was performed by the effluent from the acid fermenter with retention time of 4 days, the elrerage blogas production rate was 977m1/1 culture/day Gas productivity compared to conventional single-stage anaerobic digestion increased up to 31.4%. As the 2nd methane fermenter was fed by the effluent from the first methane fermenter with 4 days of retention time, average amount of 428m1/1 culture/day of biogas was produced. The reduction rate of COD in the effluent from the acid fermenter, the 1st and the 2nd methane fermenter were 71.8%, 42.6% and 24.0% respectively. Finally, we examined algal treatment process for the effluent from the 2nd methane fermenter. A semi-continuous culture of Chlorella sp. PSH3 was conducted by feeding the effluent with retention time of 10days. In this process, the production rate of algal biomass and COD reduction rate were averaged 1.8g/1 culture/day(2.8$\times$106 cells/ml) and 73%, respectively. Through the 4-setp treatments, the total chemical oxygen demand was reduced from 51,300ppm to 85ppm. Therefore, the reduction rate of total chemical oxygen demand reached about 99.8%. The results indicate that the integrated system could be applicable for treatment of organic wastes, concurrently producing biogas and algal biomass.

• Journal of the Korean Geotechnical Society
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• v.30 no.7
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• pp.5-15
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• 2014

Abandoned mine deposits are exposed to various physico-chemical geo-environmental hazards and disasters, such as acid mine drainage, water contamination, erosion, and landslides. This paper presents the ring shear characteristics of waste materials. The ring shear box with a rotatable O-ring was used in this study. Three tests were performed: (i) Shear stress-time relationship for given normal stress and shear speed, (ii) shear stress as a function of shear speed, and (iii) shear stress as a function of normal stress. For a given normal stress (50 kPa) and speed (0.1 mm/sec), the materials tested exhibit a strain softening behavior, regardless of drainage condition. The peak and residual shear stresses were determined for each normal stress and shear speed. The shear stress was measured when shear speed is equal to 0.01, 0.1, 1, 10, 50, 100 mm/sec or when normal stress is equal to 20, 40, 60, 80, 100, 150 kPa. From the test results, we found that the shear stress increases with increasing shear speed. The shear stress also increases with increasing normal stress. However, different types of shearing mode were observed in drained and undrained conditions. Under drained condition, particle crushing was observed from the shearing zone to the bottom of lower ring. Under undrained condition, particle crushing was observed only at the shearing zone, which has approximately 1 cm thick. It means that a significant high shear speed under undrained condition can result in increased landslide hazard.

• Korean Journal of Veterinary Research
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• v.13 no.2
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• pp.165-170
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• 1973

1972년 여름, 사관생도(士官生徒) 승마교육용(乘馬敎育用)으로 육군사관학교(陸軍士官學校) 군마대(軍馬隊)에서 사육(飼育)하고 있는 승마용(乘馬用) 마필(馬匹)(오스트레일리아 및 일본산(日本産))과, 군용마(軍用馬)로서의 개발시험(改發試驗)에 공시중(供試中)인 제주도산(濟州道産) 재내마필(在來馬匹)에 발생(發生)한 14예(例)의 피부사상균성(皮膚絲狀菌性) 윤선(輪癬)을 대상(對象)으로 그 치료시험(治療試驗)을 실시(實施)하였던 바, 다음과 같은 결론(結論)을 얻었다. 임상증례(臨床症例) 관찰(觀察) (1) 초기증상(初期症狀) 발현(發現)은 군마고유번호(軍馬固有番號) 15번(番), 마명(馬名) 거상(巨象)(원명(原名) Shane)의 이마 및 이근부(耳根部) 견부(肩部)에 직경(直徑) 3cm 정도(程度)의 원형(圓型) 병소(病巢)가 나타났으며, 곧 이어 다른 마필(病巢)에 산발적(散發的)으로 발생(發生)했다. 발생률(發生率)은 31.8%(군마(軍馬) 44%, 조랑말 15.8%)로서 지난해 군부대(軍部隊) 목장(牧場)에서 집단발생(集團發生)했던 Bovine Ringworm의 발생률(發生率)(56.4%)보다 낮았다. (2) 증상(症狀)은 원형발진(圓型發疹) 및 양감(痒感), 가피형성(痂皮形成), 피모탈낙(皮毛脫落), 농포형성(膿疱形成) 및 신모발생등(新毛發生等)의 순(順)으로 진행(進行)했으며 환축(患畜)과 접촉(接觸)하는 사람에게도 감염(感染)하는 인축공통전염병(人畜共通傳染病)의 일종(一種)이었다. (3) 품종(品種) 및 성별(性別), 연령에 따른 유의성(有意性)은 인정(認定)할 수 없었다. 치료시험(治療試驗) 결과(結果) (1) 본병(本病)은 Ichthammol이나 Undecylenic Acid 처리(處理)에 있어서 치료효과(治療效果)를 나타냈다. (2) 상기(上記)한 항사상균제 처리(處理)와 동시(同時)에 Hydrccortisone의 보조요법(補助療法)을 실시(實施)하였을때, 약효(藥效)가 빨리 나타나고 치료기일(治療期日)도 단축(短縮)되었다. (3) 본증(本症)은 조기(早期)에 발견(發見) 치료(治療)해야하며 일반적(一般的)으로 완치(完治)하는데 장기간(長期間)을 요(要)하였다.