1Chapter 9 Biocides: Selection and Application
Biocide programs work together with scale and corrosion inhibitor programs to optimize cooling system performance. Biocides, for the purpose of this chapter, represent chemical agents and formulations to control harmful microorganisms that colonize industrial cooling systems. Biocides function to kill or inhibit the growth of microorganisms such as bacteria, fungi, and algae. Left unchecked, microbial growth can result in higher energy costs, increased maintenance procedures, shortened equipment life, and increased health risks. The objectives of this chapter are (a) reviewing the problems caused by microbial growth, (b) discussing the wide variety of biocides available to the industrial water treatment community, and (c) providing guidelines for proper biocide selection and application. It is not intended to be a thorough review, but rather to serve as a practical guide based on years of direct experience by the authors in the development, application, and service of oxidizing and nonoxidizing biocide chemistries. It should be recognized that a good biocide program is an important part, but not the sole part, of a cooling system maintenance program. Good engineering practices (i.e., minimizing system dead legs and reducing cooling tower drift), good water treatment practices (i.e., minimizing scale and corrosion of system surfaces), and good preventative practices (i.e., regular inspections and system cleanouts) are also necessary to promote ef cient system operation, prolong system service life, and minimize the impact of problem microorganisms.