Fundamental nonlinearities of the reactor-settler interaction in the activated sludge process
Author
Summary, in English
The activated sludge process can be modelled by ordinary and partial differential equations for the biological reactors and secondary settlers, respectively. Because of the complexity of such a system, simulation models are most often used to investigate them. However, simulation models cannot give general rules on how to control a complex nonlinear process. For a reduced-order model with only two components, soluble substrate and particulate biomass, general results on steady-state solutions have recently been obtained, such as existence, uniqueness and stability of solutions. The aim of the present paper is to utilize those results to formulate some implications of practical importance. In particular, strategies are described for the manual control of the effluent substrate concentration subject to the constraint that the settler is maintained in normal operation (with a sludge blanket in the thickening zone) in steady state. Such strategies contain how the two control parameters, the recycle and waste volumetric flow ratios, should be chosen for any (steady-state) values of the input variables.
Department/s
- Mathematics (Faculty of Engineering)
- Partial differential equations
Publishing year
2012
Language
English
Pages
28-35
Publication/Series
Water Science and Technology
Volume
66
Issue
1
Document type
Journal article
Publisher
IWA Publishing
Topic
- Chemical Engineering
- Mathematics
- Water Engineering
- Water Treatment
Keywords
- Clarifier
- Continuous sedimentation
- Modelling
- Partial differential equation
- Thickener
Status
Published
Research group
- Partial differential equations
ISBN/ISSN/Other
- ISSN: 0273-1223