• 대한환경공학회지
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• 제29권2호
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• pp.229-234
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• 2007

본 연구에서는 고형물 체류시간, 수리학적 체류시간, 생흡착시간 및 온도 변화가 이단슬러지 유형의 연속회분식반응기 공정 운영에 어떻게 영향을 주는지를 조사함으로서 본 공정을 최적화 하고자 하였다. T-N 제거에 있어서 고형물 체류시간이 증가할수록 T-N 제거효율이 증가하는 경향을 관찰할 수 있었는데 이는 SRT가 증가할수록 SCOD 생흡착효율의 증가와 관련이 있을 것으로 판단된다. HRT 영향에 있어서 HRT 8시간, 10시간 및 15시간에서 암모니아성 제거효율 및 T-N 제거효율은 각각 HRT 영향에 관계없이 거의 같았다. 생흡착시간을 20분 이상 증가시켜도 T-N 제거효율 향상에는 도움이 되지 않는 것으로 관찰되었다. 서로 다른 온도 조건에서 공정 제거 효율 비교에 관해 조사한 결과 온도의 감소가 공정 성능에 영향을 주지는 않았으나 인 제거 효율에 있어서 높은 온도에서보다 낮은 온도에서 인 제거효율이 다소 높게 관찰되었다. 결과적으로 본 연구에서 개발된 공정은 낮은 온도 조건 및 높은 유입 부하를 가진 폐수처리에 적합한 것으로 나타났다.

• 한국수산과학회지
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• 제50권3호
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• pp.250-256
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• 2017

This study investigated the removal efficiency of organic matter and nitrogen from fish farm effluent by hydraulic retention time (HRT) using an upflow biological filter (ANR system) reactor. The recycling time and influent flow in the reactor were controlled to 14.8, 7.4, 5.5 and 3.2 h to evaluate HRT. In addition, each reactor was coupled to a fixed bed upflow filter charged with media. The results showed that removal efficiency was ${\geq}95%%$ with an HRT of 5.5 h, and nitrification efficiency was reduced to 81% with an HRT of 3.2 h, although nitrification efficiency temporarily decreased due to the shock load as HRT decreased. Total nitrogen removal rate was also reduced to about 65% with an HRT of 3.2 h, which was considered a washout effect of nitrifying and denitrifying microorganisms by increasing the shearing force to the filter media, which decreased organic matter and nitrogen removal efficiency.

• 환경위생공학
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• 제11권3호
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• pp.63-68
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• 1996

This study was to discuss limiting factors influenced on the removal efficiencies of nitrogenous compounds investigated using the polypropyrene media which was to attach microorganism in order to apply the fixed-biofilm process. The main limiting factors are the hydraulic retention time (HRT), C/N ratio, $COD/NO_{3}-N$ ratio and temperature. The hydraulic retention time HRT were 6, 8, 10, 12 hrs and the C/N ratio range was 2.5-9.5. The $COD/NO_{3}-N$ ratio range was 3.2-21.9 and the temperature were 15, 20, 25, 30, $35^{\circ}C$, respectively. The results of this study are summerized as follows. 1. Hydraulic retention time (HRT) to obtain removal efficiencies of T-N higher than 85% had to be 10 hrs above. 2. The removal efficiencies of T-N decreased at C/N ratio from 6.2 to 4.8 in this anoxic-contact aeration system. 3. Denitrification rate decreased at $COD/NO$_{3}$-N$ ratio from 8.0 to 5.0 4. As temperature increased, removal efficiencies of T-N increased.

• 환경위생공학
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• 제8권1호
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• pp.107-116
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• 1993

This study is conducted to investigate treatability by activated sludge process for wastewater from acetaldehyde manufacturing plant. The optimum hydraulic retention time in aeration tank for removal of high strength substrate were measured. The removal efficiency were checked out by hydraulic retention time : 35hr., 40hr. and 45hr., respectively. $COD_{Cr}$, like substances were removed in all hydraulic retention time zone directed for efficiency, but non-biodegradable substances were remained. $COD_{Cr}$ biomass loading was 0.81kg $COD_{Cr}/kgMLVSS$ . day at 35hr. of retention time, 0.34 kg$COD_{Cr}$/kg MLVSS . day at 40hr., and O.l9kg$COD_Cr$/kgMLVSS . day at 45hr. And the mean $COD_{Cr}$, removal efficiency was 65.5%, 81.6% and 83.0%, respectively. And also $COD_{Cr}$, volume loading was 1.01kg$COD_{Cr}/m^3$ day, 0.87kg$COD_{Cr}/m^3$ - day, and 0.79kg$COD_{Cr}/m^3{\cdot }$day, respectively. The basic design parameter obtained is as fallows. The value of Specific substrate removal rate coefficient (k), Yield coefficient(Y) and Decay coefficient($k_d$) was $0.0013day^{-1}$, $0.505kgMLVSS/kgCOD_{Cr}$ and $0.040day^{-1}$, respectively.

• 대한환경공학회지
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• 제22권6호
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• pp.1011-1019
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• 2000

본 연구는 유입수의 농도, 수리학적 체류시간 및 F/M비와 슬러지 첨전성과의 상관관계를 새롭게 명확히 밝혀 기존에 제시된 각 처리법 즉 장기포기법, 재래식 활성슬러지법, 고율 활성슬러지법 및 수정포기법의 설계조건이 도출된 원인을 밝히고 동시에 이들 기 제시된 설계조건에 관계없이 설계가 가능함을 확인하기 위한 연구이다. 본 실험은 특히 체류시간과 미생물의 침강성을 중심으로 고찰되었는데, 이는 슬러지의 침강성이 기존 각 처리법의 운전조건을 결정하는 주인자$^{1)}$이기 때문이다. 따라서 각각의 처리법에 대해 제시된 설계범위를 벗어날 경우 슬러지는 팽화하는 것으로 알려져 있으며, 설계의 기초를 제공한 Lesperance$^{1)}$의 실험결과에서도 침강성이 확보되지 않는 부하범위가 발생하는 것으로 나타냈다. 위와 같이 일정 조건에서 슬러지가 팽화하는 원인은 Lesperance가 이전 다년간의 실패와 시도로 밝혀진 연속운전이 가능한 것으로 밝혀진 몇몇의 운전조건을 실험조건으로 채용함에 따라 각각의 체류시간에 해당하는 최적의 부하가 적용되지 않았기 때문이다. 하지만 본 실험결과 부하를 적절히 유지할 경우, F/M비 $6.3kg-BOD/kg-MLSS{\cdot}day$ 이하, HRT 0.67hr 이하의 조건에서 슬러지의 침강성이 SVI치 120 이하로 확보될 수 있음을 확인하였다. 따라서 본 연구에서는 체류시간과 그에 해당하는 최적 부하를 제시하였으며, 체류시간이 미생물의 침강성에 결정적 영향인자임을 밝히고, 아울러 본 실험결과를 근거로 이제까지 알려진 처리법에서는 적용된 바 없는 1시간 이하의 체류시간에서 고율 활성슬러지법의 적용 부하치를 수 배 능가하는 새로운 운전법 (UHR : Ultra high rate)도 가능함을 제시하였다.

• 한국환경농학회지
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• 제21권2호
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• pp.144-148
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• 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.

• 환경위생공학
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• 제9권1호
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• pp.29-37
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• 1994

Anaerobic treatment of wastewater of the red- bean processing industry was carried out and discussed an anaerobic sludge bed reactor( ASBR) as a preliminary study to evaluate applicability of given processes. The dimension of reactor were same as 0.09m- ID$\times $1.5m- height. The type of substrate and the hydraulic retention time( HRT) were considered as experimental variables. The synthetic wastewater with glucose in the laboratory, the wastewater from the red bean processing industry mixed with synthetic wastewater with variation of mixing percent were fed as substrate. The hydraulic retention time was changed from one day to five days. The gas production, the methane content in produced gas, efficiencies of COD removal and 55 removal were evaluated as principal characteristics. With synthetic wastewater as a substrate and at a hydraulic retention time of one day, characteristics of ASBR was the gas production(12$\ell$/day ), the methane content of produced gas(60%), the efficiency of COD removal(92%) and 55 removal(30%). With the real wastewater and at a hydraulic retention time of one day, the gas production and the efficiency of COD removal of the ASBR decreased with the proportion of real wastewater. The gas production and the efficiency of COD removal with real wastewater only was decreased to 70% and 87% of those with synthetic wastewater only, respectively. However, the methane content in produced gas and the efficiency of 55 removal with real wastewater only was increased significantly by 1.25 times and two times of those with synthetic wastewater only, respectively. However, the methane content in produced gas and the efficiency of 55 removal with real wastewater only was increased significantly by 1.25 times and two times of those with synthetic wastewater only, respectively. With real wastewater only as a substrate in the ASBR, the gas production was decreased with an increase of HRT, but the efficiency of COD removal increased with HRTI like the usual trend reported. As a conclusion, the wastewater of the red- bean Processing industry could be treated by anaerobic digestion successfully in the ASBR.Anaerobic treatment of wastewater of the red- bean processing industry was carried out and discussed an anaerobic sludge bed reactor( ASBR) as a preliminary study to evaluate applicability of given processes. The dimension of reactor were same as 0.09m- ID$\times $1.5m- height. The type of substrate and the hydraulic retention time( HRT) were considered as experimental variables. The synthetic wastewater with glucose in the laboratory, the wastewater from the red bean processing industry mixed with synthetic wastewater with variation of mixing percent were fed as substrate. The hydraulic retention time was changed from one day to five days. The gas production, the methane content in produced gas, efficiencies of COD removal and 55 removal were evaluated as principal characteristics. With synthetic wastewater as a substrate and at a hydraulic retention time of one day, characteristics of ASBR was the gas production(12$\ell$/day ), the methane content of produced gas(60%), the efficiency of COD removal(92%) and 55 removal(30%). With the real wastewater and at a hydraulic retention time of one day, the gas production and the efficiency of COD removal of the ASBR decreased with the proportion of real wastewater. The gas production and the efficiency of COD removal with real wastewater only was decreased to 70% and 87% of those with synthetic wastewater only, respectively. However, the methane content in produced gas and the efficiency of 55 removal with real wastewater only was increased significantly by 1.25 times and two times of those with synthetic wastewater only, respectively. However, the methane content in produced gas and the efficiency of 55 removal with real wastewater only was increased significantly by 1.25 times and two times of those with synthetic wastewater only, respectively. With real wastewater only as a substrate in the ASBR, the gas production was decreased with an increase of HRT, but the efficiency of COD removal increased with HRTI like the usual trend reported. As a conclusion, the wastewater of the red- bean Processing industry could be treated by anaerobic digestion successfully in the ASBR.

• Membrane and Water Treatment
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• 제5권4호
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• pp.281-293
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• 2014

The present work aimed to study the decolorization kinetics and characteristics of a selected azo dye under the influence of two key operational parameters including hydraulic retention time (HRT) and solid retention time (SRT). The decolorization efficiency and the two important criteria of k and normalized k (k/MLSS) were evaluated in lab-scale membrane sequencing batch reactors (MSBRs) at various HRTs of 48, 24 and 16 h (with constant SRT) and in addition, at various SRTs of infinity, 40 and 10 d (with constant HRT). According to the obtained results, both zero and first-order kinetics were properly fitted the decolorization profiles of the selected azo dye in all of the applied HRTs and SRTs. Increase of both HRT and SRT positively affected the decolorization efficiency. More MLSS concentrations corresponded to the lower HRTs and the higher SRTs resulted in higher decolorization rate constants (k). However, the effect of reducing the HRT was not compensated by increase of the MLSS concentration in order to reach higher decolorization efficiency. In addition, increase of the decolorization efficiency, as a consequence of the higher MLSS concentrations at longer SRTs, was restrained by decrease of the time-limited decolorization capability of biomass (represented by normalized k). Evaluation of both k and normalized k is suggested in order to have a more precise study on the decolorization kinetics and characteristics.

• 한국미생물·생명공학회지
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• 제25권4호
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• pp.427-433
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• 1997

Sludge Returned CMAS process was applied to treat the wastewater from electric accessory manufacturing company while this type of wastewater was usually treated by chemical process. This result show that the removal rate of TCOD was about 70-80% regardless of hydraulic retention time, On the contrary, the removal rate of BOD was abtained in a range of 77-92% depending on hydraulic retention time. In order to remove more than 80% of organic materials with the proposed process, the F/M ratio should be maintained below 0.17. In this case, the calculated value of organic removal rate, Km, was calculated to be 1.26 hr$^{-1}$, and the ratio of cell synthesis/total energy was 0.32 and 0.26 for COD and BOD base, respectively. The yield coefficient was calculated to be 0.242 and the half velocity coefficient was 0.3 hr$^{-1}$. The value of endogenous respiration coefficient was 0.02 hr$^{-1}$. The measured effluent BOD concentration, MLSS concentration in aeration tank, oxygen uptake rate, and sludge production were matched relatively well with the calculated values using above coefficients, In order to optimize the dewatering of sludge, the hydraulic retention time was recommended to be 15. 6 hrs. These results indicate that the wastewater from an eletric accessory manufacturing company can be treated safely with a biological process.

• KSBB Journal
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• 제6권2호
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• pp.135-141
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• 1991

This study thus looks into two treatment processess : i) Anaerobic digester coupled with hollow fibre membrane unit. Treatment of starch waste with anaerobic digester-membrane system was studied. $0.17\m^2$ area of hollow fibre membrane unit of known pore size was immersed into laboratory-scale anaerobic digestion system. The pore size of membrane was varied from 0.03 to $\0.15mu$m. The hydraulic retention time of anaerobic digester was varied from 1.5 to 10 days. The effect of hydraulic retention time on treatment efficiency was significant while effect of membrane size was not significant. The gas production was about 0.74㎥/kg COD treated. The COD removal efficient was about 80-95% depending on the hydraulic retention time. ii ) Crossflow ultrafiltration as post treatment to anaerobic filter. The effluent from anaerobic filter, which had a total COD in the range of 4,500-5,200 mg/L was treated by crossflow ultrafiltration units. The study conducted with different membrane pore size indicated that membrace with 1,000,000 molecular weight cut-off size gave a higher COD removal efficiency in the range of 83-87% while giving a study flux of $120-130 L/\m^2$.h. A study was conducted to see the long term clogging effect of membrane also.