• Title/Summary/Keyword: aerobic digestion

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The Comparision of the Characteristics of Water Quality in Alternative Aerobic-Anoxic and Aerobic Sludge Digestion (선택적인 Aerobic-Anoxic과 Aerobic 슬러지소화에서의 수질특성 비교)

  • Lim, Bong-Su
    • Journal of Korean Society of Water and Wastewater
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    • v.11 no.1
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    • pp.74-80
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    • 1997
  • The objectives of this study were to compare the characteristics of water quality in alternative Aerobic-Anoxic(A/A) and Aerobic(Control) sludge digestion. The A/A process control parameter as the pH signal(dpH/dt) was used. Comparison of the result of A/A digestion with those of Aerobic digestion indicated a 54% saving in aeration compared to Aerobic digestion. TN removal efficiency rates of A/A and Aerobic digestion were 45% and 4%, respectively. The concentration of COD(64 mg/l and 268 mg/l for the A/A and Aerobic digestion, respectively) and Ortho-P in the supernatant were also less with A/A digestion. MLVSS and Coliform destructions were noticed similar for both digestion, but better dewatering charateristics were noted for the A/A digestion.

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Performance Evaluation of Hybrid SBR Aerobic Digestion combined with Ultrasonication by using a Mathematical Model (초음파 결합형 SBR 호기성 소화 모델과 영향 예측)

  • Kim, Sung Hong;Lee, Dong Woo;Kim, Dong Han
    • Journal of Korean Society of Water and Wastewater
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    • v.26 no.6
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    • pp.897-905
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    • 2012
  • Based on the activated sludge model, a simple aerobic digestion model which represents the aerobic sludge digestion by sequencing batch reactor(SBR) equipped with ultrasonicator was composed and performed in this study. The results are as follows. Aerobic digestion efficiency can be increased by adopting ultrasonic pretreatment. For the 5 days of SRT, 24 % of particulate component is predicted to be removed by ultrasonic pretreatment and aerobic digestion. This is 7 %p higher than that of conventional aerobic digestion. A Hybrid SBR aerobic digestion combined with ultrasonication shows higher digestion efficiency than aerobic digestion and ultrasonic pretreatment system. In case of this hybrid system, the digestion efficiency was predicted up to 49 % when the ultrasonication was performed every 2 hours, repeatedly. However, excessive treatment like every hours of ultrasonication in an aerobic digestion process results in adverse effect on TCOD removal because biomass disintegrated completely and the solubilized COD can not be used for the biomass synthesis again.

A Study on the Conditioning with Polymer and the Particle Size Distribution of Intermittent Aerobic Digestion Sludge (간헐포기 소화 슬러지의 고분자 응집제에 의한 개량과 입도 분포 변화에 관한 연구)

  • Kim, Hee-Jun;Kim, Seong-Hong;Choi, Jae-Seong
    • 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.

Ultrasonic Pretreatment for Thermophilic Aerobic Digestion in Industrial Waste Activated Sludge Treatment

  • Kim, Young-Kee;Kwak, Myung-Shin;Lee, Won-Hong;Park, Jeong-Woo
    • Biotechnology and Bioprocess Engineering:BBE
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    • v.5 no.6
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    • pp.469-474
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    • 2000
  • In order to enhance the degradation efficiency of waste activated sludge (WAS) by thermophilic aerobic digestion, an ultrasonic pretreatment was examined. It was observed that ultrasonic pretreatment increased the solubilization of organic matter in the WAS and that the solubilization ratio of the organics increased during the first 30 min but did not extensively increase thereafter. Therefore, a pretreatment time of 30 min was determined to be the economical pretreatment time from the experimental results. From the digestion experiments, which was conducted using the WAS collected from an oil refinery plant in Inchon, Korea, investigating the effects of an ultrasonic pretreatment on thermophilic aerobic digestion, it was confirmed that the proposed ultrasonic pretreatment was effective at enhancing the release of the cellular components in WAS and the degradation of released components in the thermophilic aerobic digestion.

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Aerobic and Anaerobic Digestion of Swine Manure (好氣性 및 嫌氣性 消化에 의한 豚糞處理)

  • Kim, Nam Cheon;Min,, Dal Ki
    • Journal of Environmental Health Sciences
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    • v.14 no.2
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    • pp.43-49
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    • 1988
  • This study was conducted to evaluate the organic removal efficiencies and sludge production in aerobic and anaerobic digestion of swine manure. A laboratory single-stage, high-rate, anaerobic digester was operated at 5, 10, 25 and 30 day's HRT at the temperature of 35$\circ$C, and also aerobic digester operated at 10, 20 and 28.6 day's HRT at the temperature of 20$\circ$C. The conclusions from this study are as follows: 1. While the BOD removal efficiency by anaerobic digestion was 30 to 75%, it was 99% over by aerobic digestion. 2. The sludge production was similar in both aerobic and anaerobic digestion. 3. The gas production was 0.21 to 0.55 m$^3$/kg VS fed by anaerobic digestion.

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Performance Estimation of SBR Aerobic Digestion Combined with Ultrasonication by Numerical Experiment (수치실험을 통한 초음파 결합형 SBR 호기성 소화의 거동 예측)

  • Kim, Sunghong;Kim, Donghan;Lee, Dongwoo
    • Journal of Korean Society of Water and Wastewater
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    • v.27 no.6
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    • pp.815-826
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    • 2013
  • Using a developed mathematical model and calibrated kinetic constants, numerical experiments for a aerobic digestion of wastewater sludge by SBR aerobic digestion process combined with ultrasonication (USSBR) were performed in this study. It simulated well the phenomena of the decomposition of particulate organics and the release of organic nitrogen and transformation. To achieve 40 % of particulate organics removal, USSBR process requires only 6 days of SRT and 14 W/L of ultrasonic power whereas SBR aerobic digestion process requires 12 days of SRT. Based on the model simulation results, an empirical equation was presented here. This equation will be used to predict digestion efficiency for the given variables of SRT and ultrasonic power dose. USSBR aerobic digestion process can reduce the nitrogen concentration. The optimal operation strategy for the simultaneous removal of solids and soluble nitrogen in this process is estimated to 7 days of SRT with 14 W/L of ultrasonic power dose while anoxic period was 6 hours out of 24 hours of cycle time. In this condition, 40 % of particulate organics as well as 36 % of total nitrogen will be removed and the soluble nitrogen concentration of the centrate will be lower less then 40 mg/L.

Cost Estimation of Intermittent Aerobic Digestion (간헐포기소화의 비용 평가)

  • Kim, Woon Joong;Kim, Seong Hong;Kim, Hee Jun
    • 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.

Numerical Model for SBR Aerobic Digestion Combined with Ultrasonication and Parameter Calibration (초음파 결합형 SBR 호기성 소화의 모델과 매개변수의 보정)

  • Kim, Sunghong;Lee, Inho;Yun, Jeongwon;Lee, Dongwoo
    • Journal of Korean Society of Water and Wastewater
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    • v.27 no.4
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    • pp.457-468
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    • 2013
  • Based on the activated sludge model(ASM), a mathematical model which represents the aerobic sludge digestion by sequencing batch reactor(SBR) combined with ultrasonic treatment was composed and performed in this study. Aerobic digestion using sequencing batch reactor(SBR) equipped with ultrasound treatment was also experimented for the purpose of parameter calibration. Most of the presented kinetic parameters in ASM or ASM2 could be used for the aerobic digestion of sludge but the parameters related in hydrolysis and decay rate needed modification. Hydrolysis rate constant of organic matter in aerobic condition was estimated at $0.3day^{-1}$ and the maximum growth rate for autotrophs in aerobic condition was $0.618day^{-1}$. Solubilization reactions of particulate organics and nitrogen by ultrasonication was added in this kinetic model. The solubilization rate is considered to be proportional to the specific energy which is defined by specific ultrasound power and sonication time. The solubilization rate constant by ultrasonication was estimated at $0.202(W/L)^{-1}day^{-1}$ in this study. Autotrophs as well as heterotrophs also decomposed by ultrasonic treatment and the nitrification reaction was limited by the lack of autotrophs accumulation in the digester.

Digestion of settleable solids from recirculating fish tank as nutrients source for the microalga Scenedesmus sp. cultivation

  • Rotthong, Maneechotiros;Chiemchaisri, Wilai;Tapaneeyaworawong, Paveena;Powtongsook, Sorawit
    • Environmental Engineering Research
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    • v.20 no.4
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    • pp.377-382
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    • 2015
  • The high concentration of nitrogen and phosphorus in wastewater incorporated with the ability to use carbon dioxide as the carbon source make the microalgae become more attractive in wastewater treatment process. This study evaluates the optimal conditions for the digestion of settelable solids from the recirculating aquaculture system to produce the biomass of the green microalga Scenedesmus sp. After solids separation, aerobic digestion of settleable solids under disperse condition produced nitrate as the final product of consequently ammonification and nitrification processes. With the optimal digestion procedure, nitrate concentration during aerobic digestion in 2000 mL vessel increased from $9.63{\pm}0.65mg\;N/L$ to $58.66{\pm}0.06mg\;N/L$ in 10 days. Thereafter, cultivation of Scenedesmus sp. was performed in 1000 mL Duran bottle with air bubbling. The highest Scenedesmus sp. specific growth rate of $0.321{\pm}0.01/d$ was obtained in treatment using liquid fraction after aerobic digestion as the whole culture medium for Scenedesmus sp. cultivation. With this study, digestion of $8,800{\pm}128.12mg\;dry\;weight/L$ of settleable solids from fish pond finally produced $1,235{\pm}21mg\;dry\;weight/L$ of Scenedesmus sp. biomass.

A Study on Usage of Results from Batch Reactor for Design of Aerobic Digestion (호기성 소화조 설계시 회분식 반응조에서 획득된 결과의 이용방안에 관한 연구)

  • Choung, Youn-Kyoo;Ko, Kwang-Baik;Park, Joon-hong
    • Journal of Korean Society of Water and Wastewater
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    • v.8 no.3
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    • pp.1-8
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    • 1994
  • In the general process of design for aerobic digestion, the design for field plant of which inflow pattern is continuous inflow is performed using the results from lab scale batch reactor. However, the recent researchers reported that the general designs were performed as over-estimated, Therefore, in this study, laboratory batch experiments were carried out at $20^{\circ}C$ and pH 7.5 on the aerobic digestion of waste activated sludge at different solid levels. This treatise could consider the negligence about effective digestion periods the usage of VSS as solid concentration, and the effect of initial solid concentration of solid degration rate coefficient($k_d$) as reasons of the overestimated design, and showed the scheme of how to design for aerobic digestion from batch experiment.

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