• 한국지하수토양환경학회:학술대회논문집
• /
• 한국지하수토양환경학회 2003년도 추계학술발표회
• /
• pp.467-470
• /
• 2003

Leaking underground storage tanks are a major source of groundwater contamination by petroleum hydrocarbons. Aerobic bioremediation has been highly effective in the remediation of many fuel releases. However, Bioremediation of aromatic hydrocarbons in groundwater and sediments is ofen limited by the inability to provide sufficient oxygen to the contaminated zones due to the low water solubility of oxygen. Nitrate can also serve as an electron acceptor and results in anaerobic biodegradation of organic compounds via the processes of nitrate reduction and denitrification. Because nitrate is less expensive and more soluble than oxygen. it may be more economical to restore fuel-contaminated aquifers using nitrate rather than oxygen. And denitrifying bacteria are commonly found in the subsurface and in association with contaminated aquifer materials. These studies have shown that BTEX and MTBE can be degraded by the nitrate-amended microcosms under aerobic and anaerobic conditons. Biodegradation of the toluene and ethylbenzne compounds occurred very quickly under denitrifying conditions. MTBE, benzene and p-xylene were recalcitrant under denitrifying conditions in this study, But finally Biodegradaton was observed for all of the test compounds.

• 한국지하수토양환경학회:학술대회논문집
• /
• 한국지하수토양환경학회 1999년도 추계학술발표회
• /
• pp.28-31
• /
• 1999

The purpose of this study is to see the effect of microbial population and dynamics of the indigeonous microorganisms on hydrocarbon contaminated areas. The microbial structures and activities to determine the microbial capabilities of the contaminated sites are very important for the remedial action technology selection. Throughout microbial studies on different conditions by ETS(Electron Transport System) and microbial activity analysis, it was found that aeration and water contents are the most important factors in this site remediation. According to test results, Burkholderia spp. was dominant species, and acclimation is also an important factor for the accerelated biodegradation.

• 한국지반공학회:학술대회논문집
• /
• 한국지반공학회 2002년도 가을 학술발표회 논문집
• /
• pp.681-688
• /
• 2002

Study was peformed to develop the‘environmental double pile’for the remediation of low-permeable contaminated soil. This technique is similar in function to‘sand drain pile’But this applies recyclable oyster shell treated as waste materials to a drain material and the pile is consisted of two layers. Inner metal pile is located in center and oyster shells are filled around it. By this technology, contaminated ground water is pumped out through the oyster shell and purified by drainage, adsorption, and reaction processes. Afterwards, the grout material is injected through the inner pile for the effect of the solidification / stabilization. As a result, the concept of this technique is a development of one-step process technology. Through the test, a consolidation characteristic by radial drain is going to be evaluated and the optimum standard of this technology will be calculated.

• 대한전기학회논문지:전기물성ㆍ응용부문C
• /
• 제53권7호
• /
• pp.364-369
• /
• 2004

In this Paper, a flashover prediction method using the leakage current in the contaminated EPDM distribution polymer insulator is proposed. The leakage currents on the insulator were measured simultaneously with the different salt fog application such as 25g, 50g, and 75g per liter of deionized water. Then, the measured leakage currents were enveloped and transformed as the CDFS using the Hilbert transform and the level crossing rate, respectively. The obtained CDFS having different gradients(angles) were used as a important factor for the flashover prediction of the contaminated polymer insulator. Thus, the average angle change with an identical salt fog concentration was within a range of 20 degrees, and the average angle change among the different salt fog concentrations was 5 degrees. However, it is hard to be distinguished each other because the gradient differences among the CDFS were very small. So, the new weighting value was defined and used to solve this problem. Through simulation, it Is verified that the proposed method has the capability of the flashover prediction.

• 한국환경보건학회지
• /
• 제1권1호
• /
• pp.1-4
• /
• 1974

A study was carried out to find out the biological contamination of beaches in Korea from May 16, to June 2, 1972. Turbidity was measured and coliform groups were examined by membrane filter method as well as general sanitary condition of beaches. Main findings were as follows: 1. The average coliform group count was 5.0 per 100 ml of tested water, and the range of coliform. group count was 0~120 out of 8 beaches, Chungmun beach was found to be the least contaminated while Daechun was the most contaminated (23. 3/100 ml), however, those beaches surveyed. were satisfactory as far as bacteriological contaminations were concerned. 2. The average coliform group count of water samples from rising tides was 2.8/100 ml. The range of coliform count from rising tide was 0~26/100 ml, and those from receding were 1~120/100 ml. 3. The average turbidity of the water in Korean western beaches was 5.0 ppm, while that of Chejudo was 2.0 ppm. of 8 beaches surveyed, the turbidity of Daechon beach was the highest (7.0 ppm). 4. Out of 8 beaches surveyed shower facilities existed at only 4 beaches (50%), however the drainages of showers and bath rooms were not sanitarily adequate.

• 한국환경복원기술학회지
• /
• 제8권5호
• /
• pp.1-9
• /
• 2005

This study was conducted to investigate the effect of aquatic plant as a botanical air purification on the indoor air pollution by formaldehyde. Three aquatic plants such as Eichhornia crassipes, Cyperus alternifolius, Echinodorus cordifolius, were selected for this study and they were placed in the artificially contaminated chamber under laboratory condition. The results showed that all three plants could remove the formaldehyde from the contaminated air system effectively. Reduction in the formaldehyde levels by Eichhornia crassipes, which is the floating plant, might be associated with the factors of plant and water. Reduction in the formaldehyde levels by Cyperus helferi and Echinodorus cordifolius, which were emergent plant, was due to the complex effect of plant, soil medium and water. In aquatic plant system, dissolution, microbial degradation in rhizosphere, uptake through root and shoot, sorption to soil and shoot, hydrolysis are known as the main mechanisms of water soluble pollutants in the given system. The advantages of indoor air quality control system using aquatic plants can be; 1) various purifying mechanisms than foliage plants, 2) effective for decontamination of water soluble pollutants; 3) easy for maintenance; 4) diverse application potential. Therefore it was suggested from the results that indoor air control system of aquatic plants should be more effective for reduction of indoor air pollutants.

• 한국지하수토양환경학회지:지하수토양환경
• /
• 제18권1호
• /
• pp.67-77
• /
• 2013

To improve the energy efficiency of conventional thermal treatment, soil remediation with microwave has been studied. In this study, the remediation efficiency of contaminated soil with semi-volatile organic contaminants were evaluated with microwave oven and several additives such as water, formic acid, iron powder, sodium hydroxide (NaOH) solution, and activated carbon. For the experiment, loamy sand and sandy loam collected from Imjin river flood plain were intentionally contaminated with hexachlorobenzene and phenanthrene, respectively. The contaminated soils were treated with microwave facility and the mass removals of organic contaminants from soils were evaluated. Among additives that were added to increase the remediation efficiency, activated carbon and NaOH solution were more effective than water, iron powder, and formic acid. When 10 g of hexachlorobenzene (142.4 mg/kg-soil) or phenanthrene (2,138.8 mg/kg-soil) contaminated soil that mixed with 0.5 g iron powder, 0.5 g activated carbon and 1 ml 6.25 M NaOH solution were treated with microwave for 3 minutes, more than 95% of contaminants were removed. The degradation of hexachlorobenzene during microwave treatments with additives was confirmed by the detection of pentachlorobenzene and tetrachlorobenzene. Naphthalene and phenol were also detected as degradation products of phenanthrene during microwave treatment with additives. The results showed that adding a suitable amount of additives for microwave treatments fairly increased the efficiency of removing semi-volatile soil organic contaminants.

• 한국토양환경학회지
• /
• 제4권1호
• /
• pp.49-55
• /
• 1999

본 연구에서는 고농도의 디젤로 오염된 토양을 효율적으로 정화하기 위해, 알칼리제와 과산화수소를 이용하는 새로운 방식의 토양세척기법에 대하여 일련의 회분식 실험을 통하여 최적의 운전조건을 검토하고자 하였다. 알칼리제인 NaOH를 이용하여 세척수의 pH를 상승시켜, 강 알칼리 상태에서 과산화수소를 주입하면 미세기포가 발생되며, 이 미세기포에 의해 토양에 흡착되어 있는 유류 오염물질이 효과적으로 탈착·부상된다. #60(0.25mm) 이하의 자연토양을 6,500mg TPH/kg dry soil로 오염시켜 사용하였으며, 세척수의 pH, 진탕비(토양중량 : 세척용액의 부피), 과산화수소 주입량, 세척시간에 의한 영향을 살펴보았다. 세척수의 pH는 12, 진탕비는 1 : 5, 과산화수소의 주입량은 1%, 세척시간은 1시간으로 적용한 결과 최대효율(60%)을 얻을 수 있었다.

• 한국물환경학회지
• /
• 제22권4호
• /
• pp.590-598
• /
• 2006

In-situ Air sparging (IAS) is a groundwater remediation technique, in which organic contaminants volatilize into air form the saturated to vadose zone. This study was carried out to evaluate the effect of sludge and soil microbial community structure on air sparging of Total Petroleum Hydrocarbons (TPH) contaminated groundwater soils. In the laboratory, diesel (10,000 mg TPH/kg) contaminated saturated soil. The Air was injected in intermittent (Q=1500 mL/min, 10 minute injection and 10 minute idle) modes. For Terminal-Restriction Fragment Length Polymorphism (T-RFLP) analysis of eubacterial communities in sludge of wastewater treatment plants and soil of experiment site, the 16S rDNA was amplified by Polymerase Chain Reaction (PCR) from the sludge and the soil. The obtained 16S rDNA fragments were digested with Msp I and separated by electrophoresis gel. We found various sequence types for experiment with sludge soil samples that were closely related to Agrococcus, Flavobacterium, Thermoanaerobacter, Flexibacter and Shewanella, etc, in the clone library. The results of the present study suggests that T-RFLP method may be applied as a useful tool for the monitoring in the TPH contaminated soil the fate of microorganisms in natural microbial community.

• 치위생과학회지
• /
• 제15권4호
• /
• pp.383-392
• /
• 2015

치과치료를 위해 다양한 용도로 DCU에서 배출되는 물이 사용된다. 이 DCU 물의 질에 관한 계속되는 논란으로 인한 환자들의 불안감을 줄이고 양질의 치과 치료를 제공하기 위해서는 DCU 물이 음용수만큼 깨끗하게 유지되어야 한다. 따라서 본 논문은 DCU 물의 세균 오염 수준과 오염된 DCU 물의 임상적 위험성에 대하여 설명하고, 세균 오염을 방지하기 위한 여러 가지 관리 방법들을 검토하였다. 여러 국가에서 DCU 물을 대상으로 오염도를 확인하는 연구가 많이 진행되어 DCU 물이 높은 수준으로 오염되어있다는 것이 입증되었다. 오염된 DCU 물로 인해 감염된 일부 사례도 보고되었고 이는 DCU 물이 감염의 잠재적인 원인일 수 있음을 보여주었다. DCU 물로 인한 잠재적 감염의 위험성을 줄이기 위해서는 효율적인 소독방법을 사용하고 자체적인 모니터링 또한 시행되어야 한다. 하지만 제안되고 있는 여러 가지 수관관리 소독방법으로 인해 치과종사자들의 혼란이 야기되고 있으며, 효율적인 소독방법을 보편화하기 위해서는 관련 연구가 더 진행되어야 할 것으로 생각된다. 치과치료를 받는 환자들을 안심시킬 수 있는 좋은 치과서비스를 제공하기 위해서는 정책적인 개선과 국내 치과 상황에 맞는 수관 관리 지침이 빠른 시일 내에 시행되어야 할 것으로 생각된다.