호기 처리한 침출수 순환에 의한 혐기성 조건에서의 리그노셀룰로스 분해

김석구 ( Seogku Kim ) 한국수처리학회(구 한국수처리기술연구회) 2020 한국수처리학회지 Vol.28 No.6

The objective of this study was to steer the competition between methane producing bacteria and sulfate reducing bacteria towards optimal sulfate reduction and thus promotion of the anaerobic degradation of lignocellulosic material in phase V. In addition to the degradation promoting effect of lignocelluloscic material, sulfate reduction will enhance the suppression of methane production. In the reactors with sulfidogenic condition, the presence of higher concentration of hydrolysis products of cellulose (i.e., glucose) and lignin (i.e., aromatic lignin derivatives) along with higher chemical oxygen demand and total organic carbon in the leachates as compared to those from methanogenic reactors, indicated faster rate of degradation of lignocellulosic material loaded in the reactors. The gas production was higher in the partially saturated methanogenic reactor. The gas production in the reactor with no leachate circulation was delayed, but was higher than the gas production in sulfidogenic reactors. The lower methane production in partially and fully saturated sulfidogenic reactors can be attributed to the degradation of lignocellulosic material to carbon dioxide and sulfide. At end of the experiment, the percentage of lignocellulosic carbon release in sulfidogenic reactors was higher than that in methanogenic reactors. The amount of carbon which is recovered from the gas produced in the partially saturated sulfidogenic reactor by day 700 was 1.4 times larger than carbon release from leachate and aeration tank, while the carbon release from leachate and aeration tank in the fully saturated sulfidogenic reactor by day 700 was 1.3 times larger than carbon which is recovered from the gas produced.

최종 하수처리장 슬러지의 추가감량을 위한 슬러지 전처리 연구

김석구(Seogku Kim),김자현(Jahyun Kim),임준혁(Junhyuk Lim),이제근(Jeakun Lee),이태윤(Taeyoon Lee) 한국지반환경공학회 2014 한국지반환경공학회논문집 Vol.15 No.10

본 연구는 부산시 남부하수처리장의 탈수슬러지를 이용하여 전처리에 따른 분해 및 혐기성 상태에서의 최종 메탄 및 이산화탄소 발생량을 평가하기 위해 Biochemical Methane Potential(BMP) 실험을 실시하였다. 초기 1 % TS 농도의 탈수슬러지를 각각 30분 동안 5M NaOH를 이용하여 알칼리 전처리를 실시하였고 초음파 전처리는 30분 동안 조사밀도를 1.5 W/mL로 조절하여 실시하였으며 알칼리와 초음파 전처리를 병합한 동시 전처리를 시행하였다. 그에 따라 SCOD 값이 초기 33.1 ㎎/L에서 최대 494 ㎎/L로 증가하였다. 또한 BMP 실험을 실시한 결과 31.2∼84.2 mL CH₄/g VS, 9.2∼13.5 mL CO₂/g VS로 나타났다. 영양배지와 상등액 슬러지를 주입여부에 따른 BMP 실험을 실시한 결과 각각 73.1, 73.8 mL CH₄/g VS, 11.2, 13.6 mL CO₂/g VS으로 나타났으며 모델값과는 큰 차이를 보이지 않았다. BMP 실험을 종료 후 VS를 분석한 결과 초기 62 %에서 33.8∼45.4 %로 감소하였다. 알칼리, 초음파 전처리보다는 동시 전처리가 메탄발생량과 SCOD 값을 증가시켰으며 VS 감소율이 증가하여 혐기성 소화율이 향상되었다. In this study, biochemical methane potential test was conducted to estimate ultimate methane and carbon dioxide yield for anaerobic digestion and pretreatment with sewage sludge cake. Two of 0.2 % TS of sewage sludge cakes were treated with 5M NaOH or sonication of 0.51 W/mL during 30 min respectively. Another sample was treated simultaneously with NaOH and sonication in same condition. Then, initial soluble COD increased from 33.1 ㎎/L to 494 ㎎/L. After BMP test, methane production ranged from 3.12 and 84.2 mL CH₄ per g of Volatile Solid (VS) and 9.2 and 13.5 mL CO₂ per g of Volatile Solid (VS) for carbon dioxide. In other tests, injection of nutrient media or sludge supernatant produced 73.1 and 73.8 mL CH₄ per g of Volatile Solid (VS) and 11.2 and 13.6 mL CO₂ per g of Volatile Solid (VS) respectively. When BMP test finished, 62 % of initial volatile solids decreased to 33.8~45.4 %. Simultaneous pretreatment increased soluble COD, reduction rate of volatile solids and digestion efficiency than those for alkaline and ultrasonic pretreatment.

방사능오염수 처리, 환경공학기술의 기회와 도전

김석구(Seogku Kim),안재환(Jae-Hwan Ahn),오혜철(Hye-Cheol Oh) 대한환경공학회 2022 대한환경공학회 학술발표논문집 Vol.2022 No.11

인 제거를 위한 코팅 발포질석 적용 가능성 연구

김석구(Seogku Kim),이태윤(Taeyoon Lee) 한국지반환경공학회 2014 한국지반환경공학회논문집 Vol.15 No.12

본 연구에서는 발포질석을 글리세롤로 코팅하여 인에 대한 흡착력을 높인 발포질석 흡착제 제조 및 인 제거능력을 평가하였다. 발포질석과 4 mol%의 황산을 포함한 글리세롤을 1:4 비율로 혼합 후 380, 580, 780 ℃로 가열하여 다공성 탄소층을 발포질석표면에 부착하였다. 380 ℃로 가열한 질석의 경우 비표면적인 53.1 m2/g을 나타내었으며, TGA 분석을 통해 탄소성분의 산화로 인한 질량손실이 가장 큰 것으로 분석되었다. 380 ℃로 제조된 코팅 발포질석을 이용한 수용액 속의 인 제거를 흡착모델에 적용해보니 Langmuir 모델에 더 적합하며 여기로부터 구한 최대제거량은 710.3 mg/kg으로 기존 점토광물을 이용한 인 흡착연구결과보다 더 흡착용량이 뛰어난 것을 알 수 있었다. In this study, exfoliated vermiculite (EV) coated with glycerol was tested for its abiility to remove phosphorus in aqueous solution. The glycerol modified vermiculite (GS) was prepared with EV/glycerol ratio of 1/4 where glycerol contained 4 mol% H2SO4 and heated until designated temperature. GS heated at 380 ℃ showed that the specific surface area was 53.1 m2/g and mass loss due to oxidation of carbon was maximum from TGA analysis. Removal of phosphorus using GS heated at 380 ℃ was well explained by Langmuir isotherm model and maximum sorption capacity of 710.3 mg/kg is comparable or greater than those of other clay orignated sorbents for phosphorus.

리그노셀룰로오스의 혐기성 분해에 의한 탄수화물과 방향족 화합물의 축적속도 평가

김석구 ( Seogku Kim ) 한국수처리학회 2022 한국수처리학회지 Vol.30 No.5

This study evaluated the degradation properties of lignocellulose in methanogenic and sulfate-reducing environment. Carbohydrates and aromatic compounds, which are lignocellulosic degradation products, were analyzed and the accumulation rates were calculated. Seeding microorganisms, as well as leachate from a model landfill reactor composed of a methanogenic and sulfate-reducing environment that hadbeen operatingfor more than three years wereused. To calculate the accumulation rates of carbohydrates and aromatic compounds, serum vials cultured for 12 days were subjected to 3% (volume ratio) toluene. Toluene was used to selectively inhibit the activity of microorganisms while maintaining the activity of the extracellular degrading enzyme. Galactose, glucose, xylose and mannose produced from holocellulose such as office paper and newspaper in the presence of 3% toluene showed a linear increase in carbohydrate accumulation with time in a sulfate-reducing environment. The accumulation rates of glucose and xylose in the sulfate-reducing environment were faster than in the methanogenic environment, indicating that holocellulose decomposition was faster in the sulfate-reducing environment than in the methanogenic environment. For the lignin-derived aromatic compounds produced in newspapers in the presence of 3% toluene, 7 aromatic compounds were identified in the sulfate-reducing environment, compared to 3 aromatic compounds identified in the methanogenic environment. Accumulation rates of benzoic acid and vanillin were faster in the sulfate-reducing environment than in the methanogenic environment, indicating that lignin degradation was faster in the sulfate-reducing environment than in the methanogenic environment.

도시 하수 및 공장 폐수 슬러지의 바이오가스화에 관한 연구

김자현(Jahyun Kim),김석구(Seogku Kim),황인주(Injoo Hwang),안재환(Jaehwan Ahn),강성원(Sungwon Kang),이원태(Wontae Lee),임준혁(Junhyuk Lim),이제근(Jeakun Lee),이태윤(Taeyoon Lee) 한국지반환경공학회 2014 한국지반환경공학회논문집 Vol.15 No.9

슬러지의 안정화, 휘발성 고형물 감소, 바이오가스 생산을 위해 혐기성 소화공정이 슬러지의 처리 방안으로 연구됐다. 본 연구에서는 하?폐수 슬러지(MWS, IWS), 혼합슬러지(Mix), 탈수슬러지(MWSC)를 대상으로 바이오가스 생산 가능성을 살펴보기 위해 Total solids, Volatile solids, 원소분석, BMP 실험을 하였다. Total solids 함량은 11.2∼20.6 %의 값을 가지며 Volatile solids의 함량은 TS의 62.1∼83.1 %의 값을 가지고 있다. C/N비는 4.96∼8.33의 값을 나타났다. BMP test를 한 결과 혼합슬러지의 경우 약 20일, 하?폐수 슬러지의 경우 약 16∼17일에 메탄발생이 종료되었다. 탈수케이크는 약 10일까지 메탄이 발생하였으며 가장 빨리 메탄발생이 종료되었다. 누적 메탄발생량의 경우 혼합슬러지가 395.50 mL CH₄/g VS으로 가장 높은 누적 메탄 발생량을 가진다. 누적 이산화탄소 발생량은 탈수케이크를 제외하고 비슷한 값을 보이고 있다. Anaerobic digestion was investigated for the stabilization of sludge, decrease of volatile solids, production of biogas for wastewater sludge. In this study, total solids and volatile solids, elemental analysis were conducted to determine characteristics of various types of sludges and investigate the feasibility of biogas production of Municipal Wastewater Sludge (MWS), Industrial Wastewater Sludge (IWS), mixed sludge (Mix), and Municipal Wastewater Sludg Cake (MWSC). Total solids, volatile solids, and C/N ratio were determined in the range of 11.2∼20.6 %, 62.1∼83.1 % of TS and 4.96∼8.33 %. Using the biochemical methane potential (BMP test), mixed sludge and wastewater sludge finished the methane production within approximately 20 day and 16∼17 day. Sludge cake finished within 10 day. Mixed sludge produced 395.5 mL CH4 per g of Volatile Solid (VS) and resulted in the highest methane production. For carbon dioxide production, five sludges had similar value of accumulated carbon dioxide production except for sludge cake.

부산시 도심하천 퇴적물의 유기물 및 중금속 오염도 평가

이준기(Lee Junki),김석구(Kim Seogku),송재홍(Song Jaehong),이태윤(Lee Taeyoon) 한국지반환경공학회 2010 한국지반환경공학회논문집 Vol.11 No.1

본 연구는 부산시에 위치한 하천들에 대한 기본적인 퇴적물 데이터와 현재의 오염상태에 대한 정보를 제공하기 위한 목적으로 수행되었다. 먼저 부산시 하천 중 14곳을 선정하고 대상하천의 퇴적물을 채집하였다. 그리고 pH, 공업분석, 원소분석, COD, 유기탄소함량, 강열감량, 중금속 등을 분석하여 채집한 시료에 대해 분석을 실시하였다. 그 결과 퇴적물의 COD, 유기탄소함량, 강열감량, 중금속 함량이 각각 1.20~75.07㎎ L?¹, 0.19~11.54%, 0.23~34.21%, 0.4~732.6㎎ ㎏?¹로 나타났다. 최종적으로 퇴적물의 분석 데이터를 각각 USEPA 퇴적물 환경기준과 캐나다 온타리오 퇴적물 환경기준과 비교 하였으며, 먼저 USEPA 퇴적물 환경기준과 비교했을 때, 총 9개 시료가 심한오염상태인 것으로 분류되었고 3개 시료가 중간오염상태인 것으로 나타난 반면, 캐나다 온타리오 퇴적물 환경기준과 비교한 경우, 총 3개 시료가 SEL(Severe Effect Level), 총 10개 시료가 LEL(Lowest Effect Level)인 것으로 평가 되었다. The main purpose of this study is to offer informations about the current conditions and basic data of sediments for the urban streams in the Busan city. Total 14 urban streams were selected and sediment samples were collected. Then, It was investigated the sediment qualities though the measurement of pH, proximate analysis, elemental analysis, COD, organic carbon content, volatile solid content and heavy metal concentration. Results show that COD, organic carbon content, volatile solid content and heavy metal concentration of sediment are determined in the range of 1.20~75.07 ㎎ L?¹, 0.19~11.54%, 0.23~34.21% and 0.4~732.6 ㎎ ㎏?¹, respectively. Finally, Analysis data of sediments were compared with USEPA sediment quality standards and ontario sediment quality guidelines. As a result, when compared with USEPA sediment quality standards, total 9 samples were evaluated as heavily polluted and total 3 samples were evaluated as moderately polluted. But, when compared with ontario sediment quality guidelines, total 3 samples were evaluated as Severe effect level and total 10 samples were evaluated as lowest effect level.

BMP(Biochemical Methane Potential) test를 통한 도심하천 퇴적물의 최종메탄발생수율 및 생분해도 산정

송재홍(Song Jaehong),김석구(Kim Seogku),이준기(Lee Junki),고태훈(Koh Taehoon),이태윤(Lee Taeyoon) 한국지반환경공학회 2010 한국지반환경공학회논문집 Vol.11 No.2

본 연구는 부산시에 위치한 하천퇴적물에 대한 현재의 오염상태와 혐기성 상태에서의 잠재메탄발생량을 평가하기 위해 실시하였다. 먼저 부산시 하천중 총 5곳을 선정하였고 대상하천의 퇴적물을 채집하였다. 그리고 퇴적물특성을 알아보기 위해 퇴적물의 화학적산소요구량, 강열감량, 총 유기탄소에 대해서 분석을 실시하였고 그 결과 각각 15.20∼75.07㎎ g<SUP>-1</SUP>, 2.34∼11.54%, 1.28∼34.21%로 나타났다. 또한 실험실규모의 BMP Test를 실시하였고 그 결과 pH가 약간 증가하다가 약 7.11∼7.35에서 평형을 이루었으며, C/N, 최종메탄 및 이산화탄소수율 그리고 생분해도는 각각 1.05∼10.27, 10.1∼179.4, 10.3∼34.4, 4.0∼30.1을 나타내었다. 그리고 최종메탄수율과 C/N비, 최종이산화탄소수율, COD, 강열감량, 총유기탄소와의 상관관계를 알아보기 위해 선형모델에 최소자승법을 적용해 평가하였고 그 결과, COD(r²=0.7586)와 강열감량(r²=0.7876)을 제외한 나머지 모든 항목에서 최종메탄수율과 높은 상관관계를 띔을 알 수 있었다(r²=0.9795∼0.9858). 따라서 C/N 또는 TOC 분석결과를 통해 메탄발생수율을 예측 가능할 것으로 판단된다. The main objective of this study was to offer informations about the current conditions of stream sediments and to evaluate biochemical methane potentials of stream sediments from the urban streams in Busan city using conventional BMP tests. First we select total 5 urban streams and collect sediment samples. Then, COD, proximate analysis, volatile solid, organic carbon content and elemental analysis were conducted to determine characteristics of the sediments. Results show that COD, volatile solid and organic carbon content are determined in the range of 15.20∼75.07 ㎎ g<SUP>-1</SUP>, 2.34∼11.54% and 1.28∼34.21%, respectively. Also, several biochemical methane potential tests were performed in a laboratory. As a result, pH values of the reactors generally increased and then stabilized at 7.11∼7.35. In addition, C/N ratio, ultimate methane and carbon dioxide yield (mL/g VS) and biodegradability (%) were determined to 1.05∼10.27, 10.1∼179.4, 10.3∼34.4 and 4.0∼30.1, respectively. For the determination of the correlations between ultimate methane yield and ultimate carbon dioxide yield, C/N ratio, COD, volatile solid and organic carbon content, a linear model was fitted to the data using a least-squares algorithm. As a result, except for COD (r²=0.7586) and volatile solid (r²=0.7876), Linear model was well fitted to each data with good values of the correlation coefficient (r²=0.9795∼0.9858). Finally, we propose empirical equations, which contain C/N ratio or TOC, for the prediction of ultimate methane yield for the urban streams in Busan city.

수중 방사성물질 선택적 흡착처리기술 개발

오혜철(Hye-Cheol Oh),김석구(Seogku Kim),안재환(Jae-Hwan Ahn) 대한환경공학회 2022 대한환경공학회 학술발표논문집 Vol.2022 No.11

팽창질석에 의한 수용액내의 구리 제거능 평가

송재홍(Song Jaehong),이준기(Lee Junki),김석구(Kim Seogku),이태윤(Lee Taeyoon) 한국지반환경공학회 2009 한국지반환경공학회논문집 Vol.10 No.7

본 연구는 팽창질석을 사용하여 수용액 상의 구리이온 흡착 제거능을 평가 하고자 하였다. 질석의 화학적 조성분석은 XRF, 구리이온 농도분석은 UV-VIS를 각각 사용하여 이루어졌다. 수용액 상의 구리이온의 제거양상을 살펴보기 위해 batch kinetic test와 batch sorption test가 실시되었고, 그 결과 구리의 제거속도(Kobs, 1/hr)는 초기pH 3일때 0.73, pH 4일때 1.52, pH 5일때 1.71였고 초기농도가 1㎎ L<SUP>-1</SUP> 일때 3.19, 5일때 1.90, 10일때 0.73으로 초기구리농도와 반비례하고 초기 pH와는 비례하여 증가하는 양상을 보였다. 하지만 초기용액의 농도차이보다 초기pH의 영향이 지배적일 것이라는 예상하에 동일한 농도에 pH만 달리하여 실험해본 결과 역시 예상대로 pH에 따라 제거속도가 크게 차이남을 알 수 있었다. 최종적으로 batch sorption test를 통해 얻은 결과를 각각 Freundlich와 Langmuir 등온흡착식에 대입한 결과 두 식 모두 양호한 fitting 결과를 얻을 수 있었으나 Freundlich 식의 결정계수가 0.965로 Langmuir 식의 결정계수 0.936보다 좀 더 높게 나타나 좀 더 정확한 fitting 결과를 보여주었다. Langmuir 모델로부터 얻은 최대흡착용량(Qmax), Freundlich 모델의 분배계수, n 값은 각각 1,250㎎ ㎏<SUP>-1</SUP>, 635.1L ㎏<SUP>-1</SUP>, 1.69였다. 이러한 결과는 팽창질석이 다양한 형태의 수용액 상에 존재하는 구리이온을 효과적으로 제거할 수 있음을 보여준다. The main objective of this study was to examine the removal properties of Cu from water by inflated vermiculites. The component of vermiculites was analyzed by XRF and the concentration of Copper ion was measured by UV-VIS. Serial batch Kinetic tests and batch sorption tests were conducted to determine the removal characteristics for Cu in aqueous solutions. The result shows that removal rate, Kobs, of Cu are 0.73, 1.52, and 1.71 for initial pH 3, pH 4, pH 5, respectively, and are 3.19, 1.90, and 0.73 for the initial concentration of 1 ㎎ L<SUP>-1</SUP>, 5 ㎎ L<SUP>-1</SUP>, 10 ㎎ L<SUP>-1</SUP>, respectively. It leads to the conclusion that the removal rates are inversely proportional to the initial Cu concentration and are increased proportionally to the initial pHs. Finally, Sorption data were correlated with both Langmuir and Freundlich isotherms. As a result, Langmuir and Freundlich models were well fitted to batch isotherm data with good values of the determination coefficient. but the determination coefficient value for the Freundlich model fit was slightly higher than that of Langmuir model (0.965 for the Freundlich model and 0.936 for the Langmuir model). Using the Langmuir model, the maximum sorption capacity (Qmax), Freundlich partition coefficient, and the numerical value of n wrer estimated as 1,250 ㎎ ㎏<SUP>-1</SUP>, 635.1 L ㎏<SUP>-1</SUP> and 1.69, respectively. These results show that the inflated vermiculites could be used as an excellent adsorbent for copper contained in various types of aqueous solutions.