Lake Mills Light & Water (LML&W) has been working to reduce resident’s exposure to lead in drinking water for a couple of years by removing lead service lines, but another approach is being tested that will may be more effective and lower cost.
According to the Environmental Protection Agency, lead can enter drinking water when service pipes that contain lead corrode. Corrosion is a dissolving or wearing away of metal caused by a chemical reaction between water and your plumbing. The most common problem is home plumbing lines, brass or chrome-plated brass faucets, or fixtures that contain lead solder. Significant amounts of lead can enter into the water, especially hot water, from these sources.
A number of factors are involved in the extent to which lead enters the water, including:
· the chemistry of the water (acidity and alkalinity) and the types and amounts of minerals in the water,
· the amount of lead it comes into contact with,
· the temperature of the water,
· the amount of wear in the pipes,
· how long the water stays in pipes, and
· the presence of protective scales or coatings inside the plumbing materials.
LML&W has been adding small amounts of phosphate corrosion inhibitors, or protective coatings, to help reduce corrosion and prevent lead from leaching from service lines to the water. The utility is now working with the Wisconsin Department of Natural Resources (DNR) to test several new or different water treatment options as a means to determine the most effective corrosion control treatment for Lake Mills.
To do this, LML&W built a special corrosion control test rack. The test rack is installed at one of the well pumps in the city and is designed to simulate water usage at a typical residence. The test rack is set up to investigate three different products and concentrations of phosphate additives. The test rack also includes a control loop to demonstrate the difference between the current situation and the experimental products.
This is one of two such test racks the DNR has required in the state. It will be in operation for at least a year, and depending on the results, the investigation may be extended using different products or concentrations of product.
“Removing lead service lines is a highly effective way to reduce lead exposure,” according to Director of Public Works Paul Hermanson. “But it is also very expensive and inconvenient.” Finding the best way to reduce corrosion and maintain safe drinking water is more cost effective and helps reduce exposure from lead in plumbing and fixtures in the home. “This potentially provides a greater benefit at lower cost,” he said.
The construction and initial set-up of test rack is nearly complete with the introduction of test products scheduled to begin early next year. All water used for the test rack is discharged to the sanitary sewer system. This not only ensures none of the test water goes in the drinking water, but also allows the products to be evaluated in terms of how they affect the wastewater treatment plant.