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 Title: Mathematical Models and Optimization Techniques for Use in Analysis and Design of Wastewater Treatment Systems Author(s): Tang, Chi-Chung Department / Program: Civil Engineering Discipline: Environmental Engineering Degree Granting Institution: University of Illinois at Urbana-Champaign Degree: Ph.D. Genre: Dissertation Subject(s): Engineering, Sanitary and Municipal Abstract: The objective of current wastewater treatment plant design practice is to provide a cost effective processing system for a given wastewater. The design of such a system involves many tradeoffs that have to be examined in detail before cost effectiveness can be achieved.In this thesis, a mathematical framework is developed for use in the design of a secondary wastewater treatment system. Mathematical models predicting the performance of various unit processes are used to construct a comprehensive system model. Three efficient optimization approaches to generate cost effective wastewater treatment system designs are studied. The first approach transcribes the comprehensive system model into a nonlinear program that includes 64 variables and 58 constraints. A generalized reduced gradient algorithm is applied to solve this model. The second approach uses an existing algorithm for solving generalized geometric programs. Partitioning of model variables into two sets is necessary. A number of geometric programming subproblems resulting from the partitioning are solved. The third approach decomposes the wastewater system into a liquid and a sludge subsystem. The liquid subsystem is optimally designed, while the sludge subsystem design includes embedded optimization steps. The overall optimal design is obtained from coordination between the two subsystem designs.Design of wastewater treatment systems frequently involves unmodeled issues. Therefore the least cost design of a wastewater treatment system may not be practically useful. However, the comprehensive system model can be used as a tool for the analysis of process performance. Important insights about process design, modeling, and integration can be gained by exercising the system design model. Potentially fruitful areas for future research can also be identified. This is illustrated through the use of an example problem. Issue Date: 1984 Type: Text Description: 273 p.Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1984. URI: http://hdl.handle.net/2142/69940 Other Identifier(s): (UMI)AAI8502313 Date Available in IDEALS: 2014-12-15 Date Deposited: 1984
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