Multivariable control of nutrient-removing activated sludge systems

• Published in: Water research (Oxford) Vol. 33; no. 12; pp. 2864 - 2878
• Main Authors: Steffens, M.A., Lant, P.A.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01-08-1999; Elsevier Science
• Subjects: Applied sciences; Biological and medical sciences; biological nutrient removal; Biological treatment of waters; Biotechnology; control; Environment and pollution; Exact sciences and technology; Fundamental and applied biological sciences. Psychology; General purification processes; Industrial applications and implications. Economical aspects; model based control; Pollution; Wastewaters; Water treatment and pollution; Australia; model based control; control; biological nutrient removal; Activated sludge; Multivariable control; Process control; Elimination; Nutrient; Nitrogen; Waste water purification; Biological purification
• ISSN: 0043-1354; 1879-2448
• DOI: 10.1016/S0043-1354(98)00521-1

The aim of this paper is to evaluate several multivariable model-based control algorithms for controlling nitrogen removal in activated sludge processes. We contend that the control of nutrient removal in activated sludge systems is a multivariable control problem, rather than a multiloop problem. The work is a simulation study of a predenitrification activated sludge plant. Several model-based controllers are evaluated and compared against a base-case and multiloop controller. We introduce a quantitative measure to aid in controller evaluation. Model based control algorithms are shown to be able to provide tight control of N removal, thereby offering significant benefits in terms of deferred capital expenditure. This is in return for increased operating costs.