Microbiologically influenced copper corrosion in potable water with emphasis on practical relevance

Abstract

The physical and chemical properties of biofilms, incombination with metabolic and degradation products ofbiological origin, influence the nature and localchemistry of the aqueous phase at the copper/biofilmphase boundary. The pitting susceptibility of copperis determined by this change of water composition atthe copper/biofilm phase boundary and is supported bythe mixture of solid corrosion products and thebiofilm at the copper surface. Several factors influence the susceptibility of copperto MIC: commissioning, design and operatingconditions; the chemical composition of the water andthe relevant biological activity. Field experience andtheory showed that a combination of methods should beused to protect existing copper installations. Insummary, water chemistry seems to be a majorinfluencing parameter for the described corrosionproblems. Raising the alkalinity of the potable waterwhilst optimising the chloride/sulphate ratio isconsidered as the most promising preventative measureto overcome the described problems.