• 유기물자원화
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• 제15권2호
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• pp.118-127
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• 2007

본 연구에서는 음식물류 폐기물의 탈리액을 이용하여 TS 농도를 변화시켜가면서 그 영향에 대하여 검토하였다. 산발효조와 메탄발효조가 연계되어진 $35^{\circ}C$의 중온소화조인 2상법 소화조(Dual digestion)에 의하여 TS 농도를 5%~10%까지 변화시켜 가면서 실험을 실시하였으며, 그 결과 원수의 투입 TS 농도가 7~8%일 때, 평균적인 제거효율 및 안정화를 나타냈으며 TS 농도 8%이후에는 대부분의 처리수 제거효율이 현저하게 감소하는 추세를 보였다. 반응조가 안정화한 단계에서 $0.3m^3/kg{\cdot}vs$이상의 가스발생량을 보였으며, 염분축적, pH상승의 등의 현상은 관찰되지 않았다. 본 연구를 통해서 음식물류 폐기물 탈리액의 혐기성소화에 있어서 TS 농도의 증가시 공정상에 처리 및 안정화에 미치는 영향이 있으나, TS 농도가 8%이상에서 그 영향이 큰 것으로 분석되었으며, 최종적으로 TS 농도를 8%이내에서 제어하면서 운전하는 것이 가장 효과적인 방법인 것으로 판단된다.

• 한국환경농학회지
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• 제30권1호
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• pp.31-36
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• 2011

축산농가에서 발생되는 돈분 슬러리의 처리 능력을 평가하기 위하여 Full-scale의 단상 혐기성 소화조에서 중온소화와 고형물 체류시간을 20일로 하여 연속식으로 운전하면서 성능평가 및 특성연구를 실시하였다. 운전기간 중 알칼리도는 약 4,000 mg/L(3,500~9,000 mg/L as $CaCO_3$)이였고, 소화조내의 pH는 7.5~8.0 범위로 약간 높은 경향이었으나 pH는 안정적이었다. 바이오가스의 발생량은 OLR 1.2 $g{\cdot}COD/L{\cdot}day$에서 0.69 L/L/day의 바이오가스를 생산하였고, 제거된 COD를 바탕으로 계산된 메탄가스 발생량은 63% 수준이였다. 생산된 바이오가스 중 메탄가스 함량은 65~70%이었고, CO2는 약 30% 전후였으며, 열병합 발전을 실시하였을 때 총전력요구량의 50~75% 수준을 공급하였다. 또한 발전기 부하가 5~9 kW시 평균 1 kWh의 전력을 생산하기 위한 바이오가스 소모량은 약 1.8 $m^3$이였다. 따라서 실제 규모의 plant에서 약 500일간 운전한 결과 유입되는 돈분 슬러리의 TS 농도에 상관없이 소화조 내에 일정 농도의 유기물을 확보할 수 있었고, 바이오가스의 발생량은 일반적인 축산분뇨 가스 발생량 보다 높게 나타나 단상 혐기성 소화공정으로 고효율 처리가 가능한 것으로 나타났다.

• 분석과학
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• 제11권4호
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• pp.281-291
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• 1998

혈액과 소변중의 미량 Cu, Sn 및 Bi를 유도결합 플라스마 질량분석법으로 동시 분석하였다. 혈액시료 1 mL를 closed-vessel digestion system에 넣고 질산과 과산화수소수를 가한 후 microwave oven에서 8분 동안 전처리하였다. Amberlite IRC-718 수지를 정지상으로 사용한, 고체-액체추출법으로 Na, S, P 및 polyatomic species에 의한 매트릭스 방해를 제거하였다. 위 방법에 대한 검출한계를 구한 결과 Cu는 0.000375 ng/mL, Sn 은 0.000297 ng/mL, Bi는 0.000174 ng/mL 이었다. NIST SRM 955a 혈액시료에 표준용액을 첨가하여 구한 회수율은 Cu의 경우 99.1%, Sn은 102.5%, Bi는 98.4%이었다. 아울러 본 연구에서 조사한 최적기기 및 분석조건에서 실제 혈액과 소변시료의 분석을 시도하였다.

• 한국폐기물자원순환학회지
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• 제35권7호
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• pp.616-626
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• 2018

The quality standards of solid refuse fuel (SRF) define the values for 12 physico-chemical properties, including moisture, lower heating value, and metal compounds, according to Article 20 of the Enforcement Rules of the Act on Resource Saving and Recycling Promotion. These parameters are evaluated via various SRF Quality Test Methods, but problems related to the heavy metal content have been observed in the microwave acid digestion method. Therefore, these methods and their applicability need improvement. In this study, the appropriate testing conditions were derived by varying the parameters of microwave acid digestion, such as microwave power and pre-treatment time. The pre-treatment of SRF as a function of the microwave power revealed an incomplete decomposition of the sample at 600 W, and the heavy metal content analysis was difficult to perform under 9 mL of nitric acid and 3 mL of hydrochloric acid. The experiments with the reference materials under nitric acid at 600 W lasted 30 minutes, and 1,000 W for 20 or 30 minutes were considered optimal conditions. The results confirmed that a mixture of SRF and an acid would take about 20 minutes to reach $180^{\circ}C$, requiring at least 30 minutes of pre-treatment. The accuracy was within 30% of the standard deviation, with a precision of 70 ~ 130% of the heavy metal recovery rate. By applying these conditions to SRF, the results for each condition were not significantly different and the heavy metal standards for As, Pb, Cd, and Cr were satisfied.

• 한국토양비료학회지
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• 제47권3호
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• pp.155-164
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• 2014

Recently interest on production of biogas from biomass resources has increased because of climate change in worldwide. In this study, anaerobic digestion efficiency of 17 different types of agricultural waste was evaluated using biochemical methane production potential estimated from the International biochemical methane potential standard method (Germany VDI4630). As a result, theoretical biochemical methane potential ($B_{th}$) of agricultural waste biomass ranged from 0.266 to $0.488Nm^3kg^{-1}$-Volatile Solid $(VS)_{added}$. Ultimate biochemical methane potential ($B_u$) of agricultural waste biomass ranged between 0.176 and $0.417Nm^3kg^{-1}-VS_{added}$. The agricultural waste biomass anaerobic biodegradability with $B_u/B_{th}$ and VDI4630 determined by VS contents was 36.0~95.9% and 30.8~91.1%, respectively. Ultimate methane potential and anaerobic biodegradability given by the VS term showed more reasonable results.

• 한국환경보건학회지
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• 제28권5호
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• pp.77-85
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• 2002

중온과 고온의 혐기성 연속회분식 공정(anaerobic sequencing batch reactor ; ASBR)에서 소화슬러지의 고액분리특성이 처리효율에 미치는 영향을 규명하고자 하였다. 연구결과 침전가능 고형물농도가 높은 도시하수슬러지 처리시 고액분리특성 및 고액분리형태가 전체처리의 안정성 및 처리효율에 상당한 영향을 미쳤다. 중온ASBR에서는 부상농축현상이 일어났으나, 고온ASBR에서는 중력농축에 의한 고액분리가 일어났으며, 상대적으로 고온 ASBR의 처리효율이 우수하였다. 그리고 수리학적 체류시간, cycle period 및 고액분리형태는 소화슬러지의 농축 특성과 임계 고형물농축을 지배하는 중요한 인자였다. 중온ASBR에서 고액분리 후 농축슬러지베드용적(thickened sludge bed volume)은 매우 중요한 운전 요소이며, 소화슬러지의 중력농축특성은 배출시 농축고형물의 유실현상과 침전시 계속적으로 발생하는 소화가스에 의한 슬러지계면의 파괴현상 및 슬러지베드의 불안전성을 야기시켜 처리효율을 감소시켰다. 중력농축의 경우 소화가스와 슬러지농축용적간의 상호작용(cyclic mutual effect)이 주기적으로 일어났으나, 부상농축에서는 이러한 현상이 일어나지 않았다.

• 한국지하수토양환경학회지:지하수토양환경
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• 제18권1호
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• pp.112-122
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• 2013

Current status of soil contamination with fluorine and its source were investigated. The basic principles and procedures of various techniques for the analysis of fluorine contents in soil and solid phase samples were summarized in this review. Analysis of fluorine in solid matrices can be achieved by two types of techniques: (i) UV/Vis spectrophotometer or ion selective electrode (ISE) analysis after performing appropriate extraction steps and (ii) direct solid analysis. As the former cases, the standard method of Korean ministry of environment, alkali fusion-ISE method, pyrohydrolysis, oxygen bomb combustion, aqua regia digestion-automatic analysis, and sequential extraction-ISE method were introduced. In addition, direct analysis methods (i.e., X-ray fluorescence spectrometry and proton induced gamma-ray emission spectrometry) and atomic spectrometry combining with the equipment for introducing solid phase sample were also reviewed. Fluorine analysis techniques can be reasonably selected through site-specific information such as matrix condition, contamination level, the amount of samples and the principles of various methods for the analysis of fluorine presented in this review.

• 상하수도학회지
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• 제8권1호
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• pp.1-8
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• 1994

Laboratory experiments were conducted to investigate the effect of digestion temperature on the settleability and dewaterability of anaerobically digested sludge. The digesters were operated at a hydraulic retention time of 20 days with a loading rate of 0.63~0.66kg volatile solids per cubic meter per day at the temperature of $35^{\circ}C$ and $55^{\circ}C$. A mixed primary and secondary municipal sludge was used as a feed. The interface height of the sludge during settling test was recorded to identify settleability. As a measure of dewaterability of the sludge, specific resistance and capillary suction time were also measured with and without chemical conditioning. Higher digestion efficiency was obtained at $55^{\circ}C$ than $35^{\circ}C$. However, the settleability and dewaterability of the sludge at $35^{\circ}C$ were quite higher than those of the sludge digested at $55^{\circ}C$. The optimum dosages of ferric chloride for sludge conditioning were 0.4% and 0.6% at $35^{\circ}C$ and $55^{\circ}C$, respectively. The filtrate COD of the sludge digested at $55^{\circ}C$ was higher than at $35^{\circ}C$, which means that poor dewaterability of the sludge result in high filtrate COD.

• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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• 제10권S_1호
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• pp.35-40
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• 2001

Effect of the addition of an enzyme/microbial additive(EMA) to enhance anaerobic digestion of the primary sludge was investigated. Two laboratory scale anaerobic digester were operated with primary sludge taken from a municipal wastewater treatment plant. The digester receiving EMA with the sludge feed performed better than the control digester, when both were operated at 10-days and 15-days Solid Retention Time(SRT). Addition of EMA to the experimental digester provided 7%(10-days SRT) and 16%(15-days SRT) higher gas production compared to the control digester when both were fed with the same amount of volatile solids. The reduction in volatile solids was 24% better in the experimental digester compared to the control ar 10-days SRT, and the improvement 10% at 15-day SRT. Improvement in COD reduction, and fecal coliform density reduction were also seen in the experimental digester due to EMA addition compared to the control both ar 10-days SRT and 15-day SRT operation. Preliminary cost benefit analysis for a wastewater treatment plant showed that approximately $115/day in gas production improvements can be realized upon addition of EMA to primary sludge anaerobic digesters operating at 10-day SRT. The value of increased gas production was $172/day if the same digesters are operated with EMA addition at 15-day SRT.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2004년도 임시총회 및 추계학술발표회
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• pp.207-210
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• 2004

Effect of electron accepters on anaerobic degradation of petroleum hydrocarbons by an anaerobic sludge taken from a sludge digestion tank in a soil artificially contaminated with 10,000 mg/kg soil of diesel fuel was tested. Treatments of soil with 30 mL of the digestion sludge (2,000 mg/L of vss (volatile suspended solids)) were incubated under several anaerobic conditions including nitrate reducing, sulfate reducing, methanogenic, and mixed electron accepters conditions for 120 days. Treatments with the digested sludge showed significant degradation of diesel fuel under all anaerobic conditions compare to control treatments with an autoclaved sludge and without the sludge. The amount of TPH degradation after 120days incubation was the largest in the treatment with the sludge and mixed electron accepters (75% removal of TPH) followed in order by sulfate reducing, nitrate reducing, methanegenic condition as 67%, 53％, 43%, respectively. However, the rate of TPH degradation in the nitrate- and sulfate reducing condition within 105 days were comparable with that of the mixed electron accepters condition. Microorganisms in each electron acceptor condition were plated on solid mediums containing nitrate or sulfate as sole electron acceptor and several nitrate- and sulfate reducing bacteria showed effective degradation of diesel fuel within 30 days incubations. These results suggest that anaerobic degradation of diesel fuel in soil with digested sludge is effective for practical remediation of soil contaminated with petroleum hydrocarbons.