Mechanism and design of intermittent aeration activated sludge process for nitrogen removal

The performance of the submerged membrane separation activated sludge process with intermittent aeration was investigated in a laboratory scale experiment by changing organic loading rate and intermittent aeration cycle. A rectangular PVC tank was used as an aeration tank, in which a flat-sheet type Micro-Filtration membrane made of poly-olefin with a pore size of 0.2 mm was submerged. Organic loading rate to the reactor was set at 0.3 and 0.8 g-TOC/L/day. C/N ratio in the feed was set at around 5.0 for every condition. Aeration cycle was changed from 10 min-10 min (aeration - stop) to 120 min-120 min in different organic loading conditions. Flux through the membrane was set at 0.25 m/day. Membrane fouling proceeded rapidly in 0.8 g-TOC/L/day conditions. However, when organic loading rate was 0.3 g-TOC/L/day, bacterial metabolic substances were degraded rapidly compared to the production, thereby decreasing viscosity in mixed liquor. Nitrogen removal rate was between 60% and 80% for 0.8 g-TOC/L/day loading, and between 50% and 65% for 0.3 g-TOC/L/day loading. And the nitrogen removal was highest in 40 min to 60 min aeration cycle conditions. Too short aeration cycle did not result in sufficiently long anoxic periods for denitrification while too long a cycle resulted in unnecessary anaerobic periods after depletion of nitrate. Intermittent aeration was effective also for decreasing viscosity in mixed liquor.

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Optimization of Operating Parameters of Intermittent Aeration-Type Activated Sludge Process for Nitrogen Removal: A Simulation-Based Approach

Water Environment Research ◽

10.2175/106143010x12851009156600 ◽

2011 ◽

Vol 83 (7) ◽

pp. 636-642 ◽

Cited By ~ 3

Author(s):

Ayanangshu Dey ◽

Dennis D. Truax ◽

Benjamin S. Magbanua

Keyword(s):

Activated Sludge ◽

Nitrogen Removal ◽

Operating Parameters ◽

Activated Sludge Process ◽

Intermittent Aeration ◽

Simulation Based

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Nitrogen Removal by Intermittent Aeration Activated Sludge Process with Automatically Controlled Aeration Time

Japanese Journal of Water Treatment Biology ◽

10.2521/jswtb.40.11 ◽

2004 ◽

Vol 40 (1) ◽

pp. 11-21

Author(s):

YOICHI HAMAMOTO

Keyword(s):

Activated Sludge ◽

Nitrogen Removal ◽

Activated Sludge Process ◽

Intermittent Aeration ◽

Aeration Time

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Operational Results of the Wolfsburg Wastewater Treatment Plant

Water Science & Technology ◽

10.2166/wst.1992.0496 ◽

1992 ◽

Vol 25 (4-5) ◽

pp. 203-209 ◽

Cited By ~ 7

Author(s):

R. Kayser ◽

G. Stobbe ◽

M. Werner

Keyword(s):

Wastewater Treatment ◽

Activated Sludge ◽

Nitrogen Content ◽

Total Nitrogen ◽

Nitrogen Removal ◽

Wastewater Treatment Plant ◽

Treatment Plant ◽

Phosphate Removal ◽

Total Nitrogen Content ◽

Activated Sludge Process

At Wolfsburg for a load of 100,000 p.e., the step-feed activated sludge process for nitrogen removal is successfully in operation. Due to the high denitrification potential (BOD:TKN = 5:1) the effluent total nitrogen content can be kept below 10 mg l−1 N; furthermore by some enhanced biological phosphate removal about 80% phosphorus may be removed without any chemicals.

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Specific organic and nutrient loads in stabilized sludge from municipal treatment plants

Water Science & Technology ◽

10.2166/wst.1996.0342 ◽

1996 ◽

Vol 33 (12) ◽

pp. 243-250 ◽

Cited By ~ 1

Author(s):

O. Nowak ◽

A. Franz ◽

K. Svardal ◽

V. Müller

Keyword(s):

Activated Sludge ◽

Nitrogen Removal ◽

Single Stage ◽

Nutrient Loads ◽

Activated Sludge Process ◽

Waste Sludge ◽

Sludge Stabilization ◽

Nitrogen Loads ◽

Theoretical Considerations ◽

P Removal

By means of theoretical considerations and of statistical evaluations, specific organic and nitrogen loads in separately stabilized sludge have been found to be in the range of 16 to 20g VSS/PE/d and of 1.1 to 1.5 g N/PE/d respectively. About 0.6g P/PE/d are removed from the wastewater in activated sludge plants without chemical or enhanced biological P removal. By using the single-stage activated sludge process without primary sedimentation and without separate sludge stabilization, almost complete nitrogen removal can be achieved, but specific organic and nitrogen loads in the waste sludge are up to two times higher than in separately stabilized sludge.

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