Risk Management of Pipeline Corrosion in the Water and Wastewater Industries

Abstract

The water utility industry has a unique perspective on corrosion and corrosion control as compared to other industries that regularly implement corrosion control, such as oil, gas or other hazardous materials. The hazardous materials industries are compelled by state, local and federal regulatory requirements to implement corrosion control in order to minimize the risk associated with failure of their piping systems and facilities. There is as yet no such compelling motivation for external corrosion control in the water utility industry. A water utility can, if it so chooses, do nothing to control corrosion, and accept the consequences. Currently the major motivating factors in the water utility industry are to provide uninterrupted water service with a high quality product, preservation of assets, reduction of operating costs (leaks), minimization of possible sources of contamination to the water supply, and pride of ownership. Corrosion leaks, just like any other pipeline break, can result in contamination of the water supply. Reducing corrosion leaks reduces the potential for negatively affecting water quality and the possible public safety and. health effect issues associated with any contamination of the water supply. The growth of the pipe rehabilitation industry is evidence of the wastewater utility industry's dealing with the consequences of poor design assumptions regarding the risk of internal corrosion. Concrete pipes designed on the basis of corrosion rate assumptions, and force mains designed assumed to be full, for example, have had design lives significantly lessened by changes in flow regimes. Like the water industry, the wastewater industry is motivated by reduction of leaks that can lead to contamination of groundwater. The risks assumed by the utilities investing in rehabilitation of pipe and manholes lie in the assumption of design life extension of the buried assets.