• 한국물환경학회지
• /
• 제31권4호
• /
• pp.418-427
• /
• 2015

This study was carried out to evaluate the performance of a lab-scale novel septic tank system for improving the conventional septic tank in the developing countries of water shortages. The lab-scale novel septic tank system consists of sepetic tank, aeration tank with HBC-ring, and sand filter. Optimum HRT was reguired about 1.5days to get a total COD removal efficiency of 90%, COD, BOD and SS removal efficiency was about 70%, 60%, and 85% in sepetic tank only. The structure of sepetic tank with two stages results in the high removal efficiency of organic matter. When sepetic tank, aeration tank, and sand filter were more than HRT 1.5days, 18hrs, and 12hrs, respectively, final effluent was less than 20 mg/L of BOD, 14 mg/L of SS, so that there is a high potential of its use for reusing water in flush toilet. There is no significant effect of HRT change on nutrient removal. Total nitrogen removal efficiency was about 40%, final effluent was 30~40 mg/L of TN, total phosphorus removal efficiency was about 11~25%, final effluent was 9~12 mg/L of TP. Because there is very small amounts of organic nitrogen and phosphorus in effluent, it was possible to reuse water for agricultural use.

• 상하수도학회지
• /
• 제24권1호
• /
• pp.5-14
• /
• 2010

A pilot-scale biological aerated filter (BAF) was operated with an anaerobic, anoxic and oxic zone at $23{\pm}1^{\circ}C$. The influent sCOD and total nitrogen concentrations in the feedwater were approximately 250 mg/L and 35 mg N/L, respectively. sCOD removal at optimum hydraulic retention time (HRT) of 3 hours with recirculation rates of 100, 200 and 300% in the column was more than 96%. Total nitrogen removal was consistently above 80% for 4 and 6 hours HRT at 300% recirculation. For 3 hours HRT and 300% recirculation, total nitrogen removal was approximately 79%. Based on fitting results, the kinetic parameter values on nitrification and denitrification show that as recirculation rates increased, the rate of ammonia and nitrate transformation increased. The ammonium loading rates for maximum ammonium removed were 0.15 and 0.19 kg $NH_3$-N/$m^3$-day for 100% and 200% recirculation, respectively. The experimental results demonstrated that the BAF can be operated at an HRT of 3 hours with 200 - 300% recirculation rates with more than 96 % removal of sCOD and ammonium, and at least 75% removal of total nitrogen.

• 대한환경공학회지
• /
• 제31권12호
• /
• pp.1075-1080
• /
• 2009

혐기성 소화 시 산발효 단계에서 지질 성분이 부분적으로 분해되고 지질 내 이중 결합이 포화됨을 통해 후단의 메탄발효 효율이 향상됨이 보고된 바 있다. 본 연구에서는 혐기성 연속 회분식 반응조(anaerobic sequencing batch reactor, 이하 ASBR) 및 연속 흐름 교반 반응조(continuously stirred tank reactor, 이하 CSTR) 형태의 산생성조를 각각 운전하여 지질 분해 및 독성 저감 효율을 살펴보았다. 기질로는 두 가지 불포화(oleate and linoleate), 두 가지 포화(palmitate and stearate) 지방산(long-chain fatty acids, 이하 LCFA)로 구성된 LCFA 혼합물을 사용하였다. 반응조 내의 높은 미생물 보유량에 의해 ASBR이 수리학적 체류시간(hydraulic retention time, 이하 HRT) 12 hr 이하에서 우월한 성능을 보였다. HRT 9시간에서 ASBR은 36.7%의 LCFA 분해, 14.3%의 이중결합 포화, 43.8%의 산생성 효율을 보였으며, 이는 HRT 15시간의 CSTR 보다 각각 19%, 10%, 21% 높은 수치였다. 지질 함유 폐수의 혐기성 소화 시 ASBR을 이용한 산발효가 효과적일 것으로 판단된다.

• Environmental Engineering Research
• /
• 제11권2호
• /
• pp.77-83
• /
• 2006

The hot spring water of the north Jeonla province such as Wanggung, Jookrim, Seokjung, and Hwasim, has fluoride concentration of 3.9 mg/L, 12.7 mg/L, 1.9 mg/L, and 6.3 mg/L, respectively. These figures fairly exceed the Korean and WHO standard for potable water, which is 1.5 mg/L. Therefore, in this study, research on elimination of fluoride in a hot spring water of Jookrim region, which has the highest level of fluoride concentration level in the north Jeonla province, was carried out. In analysis of Jookrim hot spring water according to the water quality standard for potable water, pH was very high at 9.25 and the concentration of fluoride was 10 times higher than the standard at 18.2 mg/L. Other measurements were within the standard or not detected. After injecting 10g of activated carbon for elimination of fluoride, the fluoride concentration was measured at 13.5 mg/L, and when 70mL or more of alum 10 g/L solution was injected, the concentration was measured at 2.8 mg/L, and injecting 3g of lime was measured at 9 mg/L. Alum showed the best elimination performance among all individual injections. Injection of 25 mL of activated carbon and 100 mL of alum solution together reduced the fluoride concentration down to 1.3 mg/L, which is under the potable standard. Injection of lime 1g and 75 mL of alum 10 g/L solution together reduced fluoride concentration to 4.1 mg/L. From the modifying HRT, by using ion exchange resin column, the pH was stabilized when HRT was Imin and showed range of $6.7{\sim}7.8$. The fluoride concentration reduced gradually as the HRT increased, and satisfied the potable standard when HRT passed 6 min, and after 30 min HRT, the concentration of fluoride was 0.05 mg/L: almost eliminated.

• Journal of Ginseng Research
• /
• 제23권2호
• /
• pp.99-104
• /
• 1999

인삼과 계피 추출물의 인체 직장암 세포(HT-29), 인체 간암 세포(HepG2)및 인체 결장암 세포(HRT-18)의 증식에 미치는 영향을 in vitro에서 확인하였다. 암세포의 배양액에서 인삼 추출물 또는 계피 추출물의 효과는 농도에 비례하여 암세포의 증식을 억제하였다. 세포증식의 억제 정도는 인삼과 계피 추출물을 단독으로 첨가한 것보다 병용하여 첨가한 경우 현저한 상승 효과를 나타내어, 낮은 인삼 농도에서도 HT-29, HepG2및 HRT-18암세포의 증식을 효과적으로 억제하였으며 심지어는 사멸시켰다. 인삼과 계피의 혼합물은 세포주기 중 G1 단계에서 S단계로의 진행을 지체시킴으로써 암세포의 증식을 억제하는 것으로 나타났다.

• 한국환경과학회지
• /
• 제21권12호
• /
• pp.1455-1462
• /
• 2012

The vertical distributions of nitrifying bacteria in aerobic fixed biofilm were investigated to evaluate the relationship between nitrification performance and microbial community at different HRT. Fluorescent in situ hybridization (FISH) and portable ion selective microelectrode system were adopted to analyze microbial communities and ions profiles according to the biofilm depth. Cilia media packed MLE (Modified Ludzack-Ettinger) like reactor composed of anoxic, aerobic I/II was operated with synthetic wastewater having COD 200 mg/L and $NH_4{^+}$-N mg/L at HRT of 6 hrs and 4 hrs. Total biofilm thickness of aerobic I, II reactor at 4 hrs condition was over two times than that of 6 hrs condition due to the sufficient substrate supply at 4 hrs condition (6 hrs; aerobic I 380 ${\mu}m$ and II 400 ${\mu}m$, 4 hrs; aerobic I 830 ${\mu}m$ and II 1040 ${\mu}m$). As deepen the biofilm detection point, the ratio of ammonia oxidizing bacteria (AOB) was decreased while the ratio of nitrite oxidizing bacteria (NOB) was maintained similar distribution at both HRT condition. The ratio of AOB was higher at 4 hrs than 6 hrs condition and $NH_4{^+}$-N removal efficiency was also higher at 4 hrs with 89.2% than 65.4% of 6 hrs. However, the ratio of NOB was decreased when HRT was reduced from 6 hrs to 4 hrs and $NO_2{^-}$-N accumulation was observed at 4 hrs condition. Therefore, it is considered that insufficient HRT condition could supply sufficient substrate and enrichment of AOB in all depth of fixed biofilm but cause decrease of NOB and nitrite accumulation.

• 대한토목학회논문집
• /
• 제7권3호
• /
• pp.1-11
• /
• 1987

중온소화(中溫消化)와 고온소화(高溫消化)의 차이점을 보다 명확히 규명하기 위하여 소화(消化)의 정지(停止)를 포함하는 폭넓은 실험을 행하였다. 연구결과, 정상소화(正常消化)와 소화조해(消化阻害)를 구분짓는 한계체류시간(限界滯留時間)이 존재하여, 중온(中溫)에서는 10일(日), 고온(高溫)에서는 5일(日)부근이었고 그 이하(以下)의 체류시간(滯留時間)에서는 소화(消化)의 조해(阻害)가 급격하게 발생하였는데 고온(高溫)에 비하여 중온(中溫)에서의 조해(阻害)정도가 매우 컸다. 중온소화(中溫消化)의 한계체류시간이상(限界滯留時間以上)에서는 소화(消化)상태가 거의 유사하였으나, 그이하(以下)의 체류시간(滯留時間)에서는 고온소화(高溫消化)가 월등히 양호(良好)하였으며, 고온(高溫)에서는 중온(中溫)에 비하여 소화(消化)슬러지발생량(發生量)이 감소하는 동시에 소화(消化)슬러지의 침강속도(沈降速度)가 크게 증가하고 여과비저항(濾過比抵抗)은 감소하였다. 한편 반응속도(反應速度)는 소화(消化)에 마치는 온도(溫度)와 체류시간(滯留時間)의 영향을 나타내는 데 유효하였다. 또한 온도(溫度)에 관계없이 반응속도(反應速度)가 증가함에 따라 가스발생속도(發生速度)가 선형적(線形的)으로 증가하였고 그 상관관계(相關關係)는 중온(中溫)과 고온(高溫)에서 거의 일치하였다.

• 상하수도학회지
• /
• 제14권1호
• /
• pp.62-75
• /
• 2000

Most of biological treatment to remove contaminants in municipal wastewater have been conducted by activated sludge process. But, the process have several probIems such as enormous site needed for construction of treatment facilities, unstable treatment due to limited ability to control load fluctuation, frequent sludge bulking and appearance of lots of surplus sludge. In this study, the experiments were performed through submerging biofilm of PEPP media in existing aeration tank with raw water from municipal wastewater treatment plant and then submerging PVDC and PEPP media, different from shape and chemical peculiarity in anoxic reactor. Throughout the experience, nutrient removal efficiency according to HRT, nitrogen phosphorous removal efficiency, behavior of nitrogen and dewatering efficiency have been compared and analysed with those of activated sludge process. As the results, BOD removal efficiency according to BOD volumetric load and F/M ratio was not found any differency in two processes, but was decreased below 90% as going along the condition of high load in activated sludge process. Kinetic coefficient was $K_{max}=1.162day^{-1}$, $K_s=53.77mg/L$, $Y=0.166mgVSS/mgBOD_{rem}$. and $K_d=0.019day^{-1}$. It was found that the removal efficiency, even though in aerobic condition, in biofilm process equipped anoxic reactor was higher than the one in activated sludge process within the range of 70~80%, and became better as HRT increased. Phosphorous removal efficiency was not found any differency in two processes. In biofilm process, treament efficiency even in conditions of high load was not decreased, because the biomass concentration could be maintained in high condition compared with activated sludge process. As HRT increased, suspended and attached biomass was increased and the other hand, F/M ratio was decreased as biomass' increasing. Biomass thickness was increased. from $10.43{\mu}m$ to $10.55{\mu}m$ as HRT increased and density of biomass within $40.79{\sim}41.16mg/cm^2$. The results also present that the dewatering efficiency of sludge generated in biofilm process was higher than in activated sludge process, and became better as HRT increased.

• KSBB Journal
• /
• 제20권6호
• /
• pp.443-446
• /
• 2005

음식물 쓰레기로부터의 연속 수소 생성 실험을 다양한 수리학적 체류시간(HRT; 18, 21, 24, 30, 36, 42 h)에서 수행하였다. 음식물쓰레기는 분쇄와 알칼리 처리를 거쳐 27.0 g COD/L(average VS 4.4%)의 농도로 fed-batch 형태로 주입되었으며, 반응조 내의 pH는 $5.3{\pm}0.1$ 이상으로 유지되었다. 126일 간의 운전을 통해 유기성 폐기물로부터의 연속 수소 생성이 안정적으로 진행될 수 있음을 확인하였다. 수소 생성 효율은 HRT에 따라 변하였으며, 30 h에서 가장 높은 수치를(25.8 mL $H_2/g\;VS_{added}$, 0.36 mol $H_2/mol\;hexose_{added}$, 0.91 L $H_2/L/d$) 보였다. 대부분의 조건에서 가장 양이 많은 부산물은 노말부티르산이었으며, 수소생성이 증가함에 따라 노말부티르산의 생성이 증가하였다. 이소프로판을 역시 수소 생성과 관련이 있는 나타났다. 반면, 아세트산의 생성량은 수소생성과 반대되는 경향을 보여 수소 소모 아세트산 생성 경로로 발생되는 양이 많았다고 사료된다. 한편 산발효 효율은 $53.3{\sim}65.7%$인 것으로 나타나 기존 산 발효를 수소발효가 대체할 수 있음을 확인하였다.

• 한국환경농학회지
• /
• 제21권2호
• /
• pp.144-148
• /
• 2002

본 연구에서는 농어촌취락배수의 효율적 처리를 위해 수생식물인 부레옥잠과, 미나리를 이용한 연속식 실험에서 유기물부하(COD)와 Total N, Total P 등을 HRT와 농도를 달리하여 제거효율을 측정하였다. 유기물(COD)의 제거효율은 HRT가 2 day인 부레옥잠조에서는 평균 50%의 제거율을 보였으며, 미나리조에서는 HRT 1.2$\sim$2 day 동안 30$\sim$50%의 제거율을 보였다. 영양염류의 제거효율은 총 질소의 경우 부레옥잠조는 약 329 kg $N/ha{\cdot}day$의 부하에서 HRT 2$\sim$3 day인 경우 40$\sim$53%가 제거되었으며, $NH_4^+-N$의 제거효율은 평균 52%로 Total N의 제거효율보다 다소 높았으며, 인은 8.2 kg $P/ha{\cdot\}day$의 부하에서 HRT 2$\sim$3 day인 경우 31$\sim$40%로 조사되었다. N 및 P 흡수율은 미나리보다 부레옥잠이 높게 나타났으며, 인의 흡수율은 질소의 흡수에 비해 낫게 조사되었다.