• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.1B
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• pp.113-118
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• 2006

Cost estimation of an intermittent aerobic digestion technology was carried out in this study. Aeration ratio is one of the most important design factors and it affects installation and power consumption cost. For the purpose, digestion efficiency was fixed at 35% of SS reduction and the reactor type was assumed a 2-chamber sequencing batch reactor (SBR). Installation cost and power consumption cost were evaluated and converted in terms of present value that could reflect the rate of discount and the rate of economic growth. The lower aeration ratio needs higher installation cost but lower power consumption cost. From the point of only installation cost, conventional aerobic digestion is cheaper than intermittent aerobic digestion. But intermittent aerobic digestion is better economical for more than 10 years of estimated service life. The optimal aeration ratio was dependent on the service life and it was lower as the estimated service life increased. For the 45 years as the service life, the optimal aeration ratio was estimated 0.3 and the total cost was 64% of the conventional aerobic digestion.

• Journal of Environmental Health Sciences
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• v.26 no.4
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• pp.82-87
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• 2000

생물학적 슬러지를 대상으로 간헐포기 소화와 호기성 소화의 회분실험을 실시하였다. 생물학적 슬러지의 간헐포기 및 호기성 소화 초기단계에서 미생물의 감량은 주로 내생 호흡에 의해 이루어졌다. 이 단계에서 질소는 곧바로 용출되지 않고 슬러지내에 잔존함으로서 슬러지의 질소함량은 일시적으로 증가한다. 그러나 소화후반에서는 최초의 질소함량수준으로 다시 감소하였다. 34일간의 회분식 소화에서 호기성 소화의 총질소 제거효율은 0.1%로서 거의 제거가 안된 반면, 포기 비율 0.25, 05 및 0.75인 간헐포기 소화에서는 각각 42.7%, 42.5% 및 17.6%로 나타나 간헐포기 소화가 호기성 소화보다 질소 제거측면에서 우수하였다. VSS의 감소에 따라 슬러지내의 인도 수중으로 용출하였으나, 인 용출율은 VSS 감소율 보다 훨씬 낮았고 그 결과 소화슬러지의 인 함량은 지속적으로 증가하였다. 호기성 소화와 간헐포기 소화는 소화슬러지의 인 함량이 증가하는 공정이므로 반송수의 인 부하는 상대적으로 낮아지게 되고 이는 하수의 영양염류 제거측면에서 긍정적인 효과를 미칠 것으로 기대된다.

• Journal of Korean Society on Water Environment
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• v.20 no.4
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• pp.370-375
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• 2004

Synthetic organic polyelectrolytes can be used to condition sludges to enhance their dewaterability. When conditioning biological sludges, the charge on the polymer has a significant impact on the effectiveness of the polymer as a conditioner. The objectives of this investigation were to determine the most effective type and dosage of polymer for conditioning digested sludge prior to dewatering, and to investigate the relationship between dewaterability and particle size. 3 types of digested sludge were used under the different digestion processes like anaerobic digestion, aerobic digestion and intermittent aerobic digestion. CST(capillary suction time), TTF(time-to-filter) and SRF(specific resistance to filtration) were tested as a dewaterability index and the number of particle distribution was analyzed using particle size analyzer. The results indicate that cationic polymer appears to be required for effective conditioning of these 3 types digested sludge and the optimal polymer dosage is about 0.6% of SS. CST and TTF are well correlated with mean particle diameter of which the dimension order is 1.7.

• Journal of Environmental Health Sciences
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• v.30 no.3
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• pp.253-258
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• 2004

Synthetic organic polyelectrolytes can be used to condition sludges to enhance their dewaterability. Intermittent aerobic digestion is an useful digestion technology and has many advantages like neutral pH, low installation cost and easiness to operation. The objectives of this study were to investigate the dewaterability of intemittent aerobic digestion sludge and to find the relationship between dewaterability and particle size distribution change under the conditioning of intermittent aerobic digestion sludge by cationic polyelectrolyte. Digested sludge from intermittent aerobic digestion was used and cationic polyacrylamide polymer was added as a conditioner. CST(capillary suction time), TTF(time-to-filtration) were tested as a dewaterability index and the number of particle distribution was analyzed using particle size analyzer. The results indicate that cationic polyelectrolytes is useful to enhance dewaterability of intermittent aerobic digestion sludge. Mean particle diameter was increased as polymer dosage increased and its value was reached up to 100 mm on the condition of optimal cationic polymer dosage. CST and TTF are well correlated with mean particle diameter when the weighting order is 1.7. By the optimal conditioning with cationic polymer, particles in the filtrate are also reduced significantly and this means that conditioning is helpful to main stream by reducing SS loading from return flow.

• Journal of the Korea Organic Resources Recycling Association
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• v.21 no.2
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• pp.63-70
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• 2013

Experiments in a pilot-scale hybrid multi-stage unit system (HMUS) combination of ATAD and EGSB followed by SBR process for pig slurry treatment were conducted to demonstrate the feasibility of using autothermal thermophilic aerobic digestion (ATAD) and expended granular sludge bed (EGSB) followed by sequencing batch reactor (SBR) system. Contaminants in pig slurry with high organic matter, nitrogen (N) and phosphorus (P) content were completely removed in the combined process. The highest removal rate for CODcr among contaminants in the feed pig slurry was attained by about 43.3% in ATAD unit process. Also TS removal rate of 96.5% was attained and the highest in the next coagulation unit process. The highest removal rate of CODcr under operating parameter conditions of OLR(organic loading rate), 3-6Kg $COD/m^3{\cdot}day$ and line velocity, 1.5-4m/h was earned at 3days of HRT. The disinfection of pathogens was effective at 50,000mg/L of TS in ATAD unit process. Biogas production per organic removal was $2.3{\sim}8.5m^3/kgTS{\cdot}d$ (average $5.2m^3/kgTS{\cdot}d$) in EGSB unit process. The average removal rates of CODcr 71.7%, TS 64.1%, TN 45.9%, and TP 50.4% were earned in the intermittent aeration SBR unit process.