There are nearly 170,000 public drinking water systems located throughout the U.S. Ground water storage tanks and elevated water towers are components in most water distribution systems, including municipal water systems. Water tanks are typically made of steel or steel and reinforced concrete (composite tanks). Steel naturally reacts with oxygen and water, which releases energy and returns it to its more stable chemical state of iron oxide. This oxidation-reduction reaction in steel is more commonly known as corrosion. Corrosion can be accelerated by a number of factors, including acidity (low pH), high mineral concentrations, stray current electrolysis, dissimilar metals, and water temperatures.
Steel water storage tanks are subject to corrosion on all of their external and internal surfaces, which can hurt water quality and cause leaks, premature failures, damage to structural integrity, and disruptions in service during repairs. The zones in water tanks require corrosion protection using a combination of material selection, protective coatings, and/or cathodic protection. Protective coatings form a physical barrier between the cathode (water) and the anode (steel wall), which prevents electrons from moving out of the steel wall.
Cathodic protection introduces electrical currents from external sources to counteract the normal corrosion reactions.
Cost of Corrosion
A study released by NACE in 2016 found that worldwide “the cost of corrosion is $2.5 trillion, and that replacing over one million miles (1.6 million km) of corroded water and wastewater pipelines would cost $2.1 trillion. It was reported that 35 to 50% of this cost could have been avoided through proper design, operation, and corrosion prevention.” https://www.nace.org/resources/industries-nace-serves/water-wastewater
A 2018 study in the U.S. and Canada showed that water main breaks increased 27% in the six years prior to the study. The percentage of water mains over 50 years old increased from 22% to 28% during that time. The study also found that smaller municipal utilities had twice the water main break rates as larger utilities. https://waterfm.com/study-water-main-breaks-27-percent-past-six-years/
Hiring Qualified Contractors
Protective coatings need to be properly selected and applied to keep water flowing safely to people living in the community. The choice of protective coatings is based on environmental factors, such as salt air, temperature, chemicals, toxins, and acidic and alkaline environments. Make sure you have certified contractors working on your projects who know what they are doing.
If you have water tanks or other structures that need to be protected from corrosion, contact us today at (410) 564-5876 or [email protected] to be connected with CAS certified protective coatings contractors in your area.