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Feed It! Visit Us At Weftec! Booth #3647 Constructed of stainless steel and available with a wide range of accesories, The Eagle Microsystems Dry Chemical Feeder is a rugged, versatile, and simple solution to your process needs! tance to biogenic sulfuric acid as compared to portland concretes and to calcium aluminate cement bonded siliceous aggregates. Field exposures do not reflect the laboratory results. In the field, there is no difference in the performance of CAC with calcium aluminate aggregate and silica aggregate. The same laboratory tests were reported to prove that biofilms were more difficult to establish on CAC concretes. Again, results from the field do not bear this claim out. Biofilms in a wastewater system are prevalent throughout, regardless of the base concrete. Conclusion The corrosion mechanisms at play within an active sewer system are complex and involve many different microorganisms including bacteria, molds, yeasts, and fungi. Other microorganisms such as rotifers and worms may also play a role, especially within the sewage sludge. Fungi, molds, and yeasts do not secrete mineral acids such as sulfuric acid. They do, however, secrete amino acids and SCFAs. These are also active in the corrosion processes occurring within the mutualistic microbial communities common to sewage systems. It has been found that some types of protective coatings can be attacked by fungi, whereas they resist sulfuric acid. The composition of the microbial population will vary somewhat from sewage system to sewage system, but the primary corrodents will remain fairly constant. The role of fungi and bacteria must be considered when evaluating microbiologically influenced corrosion within a sewer system. Based upon the likelihood of concrete corroding in a wastewater collection and treatment system, it becomes imperative to apply appropriate corrosion control methodologies such as protective linings in order to extend the service life of concrete in MIC environments. References: 1. Parker CD. The isolation of a species of bacterium associated with the corrosion of concrete exposed to atmospheres containing hydrogen sulfide. Australian Journal Exp Biol Med Sci 1945; 23:81-90. 2. Bergey's Manual of Systematic Bacteriology. Second Edition. Volume Two Part A, Appendix 1, p. 188 and pgs.60-61, Springer, NY 2001 Research Trends Features: •Stainless-Steel Construction •Multiple Feed Rates •Electronic Speed Control •Low Maintenance •Wide Range of Options •Two Year Warranty More Eagle Products •scales •analyzers •gas detectors Your Source for Precision Process Solutions! EagleMicrosystems.com 800•780•8636 366 Circle of Progress Pottstown, Pa 19464 50 Water Online The Magazine, Wastewater Edition ■ wateronline.com Heather M. Ramsey has been a chemist for Sauereisen, Inc., since 2006, and is involved in the research and development of both inorganic and organic corrosion-resistant materials as well as technical cements. A graduate of the University of Pittsburgh, she is a member of SSPC, ASTM, Pittsburgh Society for Coatings Technology (PSCT), and the American Chemical Society (ACS). Ramsey has co-authored several published papers and has presented at trade-shows such as SSPC. John E. Davis is a marketing specialist with Sauereisen, Inc., a manufacturer of corrosion- resistant materials distributed globally for several industries. He joined the company in September 2000 in a production capacity before assuming responsibilities in marketing and inside sales. His current roles at Sauereisen combine advertising, marketing, sales, and trade show logistics. Davis frequently contributes to professional journals on the topics of specialty materials and the rehabilitation of wastewater infrastructure. Davis graduated with a bachelor's degree in business management and minor in marketing from Penn State University with honors. Gary R. Hall is the manager of Organic Technology for Sauereisen, Inc., a leading manufacturer of organic coatings and linings as well as ceramic adhesives and refractories. Hall has been employed at Sauereisen for more than 40 years. A graduate of the University of Pittsburgh, he started in the laboratory, became chief chemist and then transferred to sales. He returned to Research and Development in 1997; he now has Research and Development responsibility for all organic products manufactured by Sauereisen, accounting for 70% of the company's total sales. Hall is a member of the American Institute of Chemical Engineers, National Association of Corrosion Engineers, and various ASTM committees. He also has additional responsibilities at Sauereisen for Environmental, Health, and Safety management.