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The objective of this project was to investigatethe effect of total organic carbon and ammonia on copper corrosion under stagnant flowconditions and to discover the diversity of the biofilm in a simulated plumbing system. Amodified version of the commonly used CDC reactors developed at the Center forBiofilm Engineering at Montana State University was used in this project. In the first set of experiments two types ofcopper coupons (new and old, i.e. pre-exposed to 0.1N NaOH solution) were used. Thesereactors were fed with water with different carbon (2~4ppm) and ammonia(0.36~0.71ppm) concentrations and biologically treated tap water to supply the bacterialpopulation. Water in the reactor was stagnant for eight hours and then flowed for fiveminutes. Copper corrosion increased with an increase of organic carbon content.Heterotrophic plate counts also showed higher numbers for high carbon reactors. Thisexperiment was conducted for three months but did not show any sign of nitrification. Inthe second set of experiments, pre-aged copper and PVC coupons were used with highcarbon (4 ppm) and ammonia (0.36 and 0.71 ppm) feed. After three months of operation,the PVC reactors showed evidence of nitrification, while the copper reactors alsoexpressed nitrification within five months. This difference in onset may be due to thetoxicity of the copper to microbial growth. The microbial population in those reactorswas analyzed using PCR and DGGE. Includes 17 references, figure.

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Edition: Vol. - No. Published: 11/01/2006 Number of Pages: 8File Size: 1 file , 360 KB