Having determined that chloramine disinfectant residuals were corroding copper in household plumbing, an effort was made to reduce the chloramine concentrations applied in the Willmar, Minnesota water distribution system. This involved controlling microbial-mediated nitrification, which led to the formation of nitrite during distribution. Nitrite ion, in turn, depleted the applied residual. Controlling the formation of nitrite then allowed less chloramine to be applied to the system.
This paper was presented at the Minnesota Chapter, American Water Works Association, in 1998.
A year later, after further trials of alternative methods, chlorite ion was adopted to control nitrification.