An analysis of nitrogen removal and control strategies in an alternating activated sludge process

Abstract An integrated dynamic model and control system are presented for the activated sludge process. The integrated model is comprised of separate models for the influent pump station, air supply and distribution system, biological reactor, and solids-liquid separator. The models for the pump station and for the air supply and distribution system were based on those for a full-scale plant, the Sagemont plant, Houston, Texas, and use standard engineering equations. The models for the biological reactor and solids-liquid separator are more research oriented and were obtained primarily from the literature. Predictions using these models are therefore expected to be more qualitative than quantitative. The integrated model will be used in part II of the paper to explore process control strategies by computer simulation.

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System Identification and Control of the Activated Sludge Process by Use of a Statistical Model

Water Science & Technology ◽

10.2166/wst.1989.0316 ◽

1989 ◽

Vol 21 (10-11) ◽

pp. 1161-1172 ◽

Cited By ~ 8

Author(s):

M. Hiraoka ◽

K. Tsumura

Keyword(s):

Control System ◽

System Identification ◽

Statistical Model ◽

Activated Sludge ◽

Sewage Treatment Plant ◽

Treatment Plant ◽

Ar Model ◽

Diurnal Changes ◽

Activated Sludge Process ◽

And Control

The authors have been developing a hierarchical control system for the activated sludge process which consists of an upper level system controlling long-term seasonal variations, a control system of intermediate level aiming at optimization of the process and a control system of lower level controlling diurnal changes or hourly fluctuations. The control system using the multi-variable statistical model is one of the most appropriate control systems based on the modern control theory, for applying the lower level control of the activated sludge process. This paper introduces our efforts for developing the reliable data acquisition system, the control experiments applying the AR-model, one of the statistical models which were conducted at a pilot plant and present studies on the system identification and control at a field sewage treatment plant.

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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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Multivariable modeling and control of an activated sludge process

Water Science & Technology ◽

10.2166/wst.1998.0527 ◽

1998 ◽

Vol 37 (12) ◽

pp. 149-156 ◽

Cited By ~ 4

Author(s):

Carl-Fredrik Lindberg

Keyword(s):

Activated Sludge ◽

Nitrate Concentration ◽

State Space Model ◽

Activated Sludge Process ◽

Invariant State ◽

Linear Quadratic ◽

Modeling And Control ◽

Space Model ◽

And Control ◽

Time Invariant

This paper contains two contributions. First it is shown, in a simulation study using the IAWQ model, that a linear multivariable time-invariant state-space model can be used to predict the ammonium and nitrate concentration in the last aerated zone in a pre-denitrifying activated sludge process. Secondly, using the estimated linear model, a multivariable linear quadratic (LQ) controller is designed and used to control the ammonium and nitrate concentration.

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