Berkeley research makes lead pipes safe
Historically, many municipalities installed iron water mains that were connected to individual buildings by lead water pipes. In a typical lead pipe, chemicals in the water cause the inside wall of the pipe to corrode, releasing lead ions into the water. To address this problem, municipalities add corrosion inhibitors to the water. Over time, these added phosphates react with the lead ions to create compounds that deposit on the inside of the pipe. This coating, or "scale," blocks other lead ions from leaching from the pipe into the water, making the pipe safe for water distribution.This process typically takes a couple of years, but researchers at UC Berkeley have come up with an electromechanical approach that can achieve this result in a couple of hours.
By applying a small external voltage to a sample of pipe, the researchers sped up corrosion. The freed lead ions then reacted with phosphates in the water to form scale. The researchers hope this process could quickly restore the protective coating in the pipes in Flint, where scale has still not recoated the pipes.