Trihalomethane Species Forecast Using Optimization Methods: Genetic Algorithms and Simulated Annealing

• Published in: Journal of computing in civil engineering Vol. 19; no. 3; pp. 248 - 257
• Main Authors: Lin, Yu-Chung, Yeh, Hund-Der
• Format: Journal Article
• Language: English
• Published: Reston, VA American Society of Civil Engineers 01.07.2005
• Subjects: Applied sciences; Buildings. Public works; Exact sciences and technology; TECHNICAL PAPERS; Water supply. Pipings. Water treatment; Drinking water; Water treatment; Chlorination; Evolutionary computation; Trihalomethane; Disinfection; Concentration; Forecast model; Potable water; Optimization; Result; Case study; Algorithms; Simulation; Genetic algorithm; Simulated annealing
• ISSN: 0887-3801; 1943-5487
• DOI: 10.1061/(ASCE)0887-3801(2005)19:3(248)

Chlorination is an effective method for disinfection of drinking water. Yet chlorine is a strong oxidizing agent and easily reacts with both organic and inorganic materials. Trihalomethanes (THMs), formed as a by-product of chlorination, are carcinogenic to humans. Models can be derived from linear and nonlinear multiregression analyses to predict the THM species concentration of empirical reaction kinetic equations. The main objective of this study is to predict the concentrations of THM species by minimizing the nonlinear function, representing the errors between the measured and calculated THM concentrations, using the genetic algorithm (GA) and simulated annealing (SA). Additionally, two modifications of SA are employed. The solutions obtained from GA and SA are compared with the measured values and those obtained from a generalized reduced gradient method (GRG2). The results indicate that the proposed heuristic methods are capable of optimizing the nonlinear problem. The predicted concentrations may provide useful information for controlling the chlorination dosage necessary to assure the safety of water drinking.