Optimizing Phosphorus-Based Chemicals for Lead and Copper Control and the Impact on Wastewater Plants

​When controlling lead and copper release from pipes into drinking water, choices can be limited. Orthophosphate addition and pH/alkalinity adjustment are two commonly used control strategies and are the focus of the Lead and Copper Rule (LCR). The science behind these methods is well understood, but how do these chemical interactions happen in actual water systems where many other chemical and microbiological interactions are occurring at the same time? This question was explored in Optimization of Phosphorus-Based Corrosion Control Chemicals Using a Comprehensive Perspective of Water Quality (project #4586).  

The research found that LCR compliance in public water systems is best maintained through a comprehensive approach, rather than focusing solely on orthophosphate and pH. This research also investigated the impact of phosphate-based corrosion control chemicals on receiving wastewater treatment plants. When using phosphate as a corrosion control chemical, its financial and environmental repercussions should not be ignored.

This webcast showed how the use of these two common lead control techniques could not compete with the realities of 8 water systems studied. Specific recommendations were given that can be carried out in any water system using existing information. The ultimate question was answered: Should orthophosphate be added to drinking water or not?

This project challenged common understandings of lead and copper corrosion control. The goal of the project was not to tear down institutional concepts, but to build up a larger perspective by looking at lead and copper release more comprehensively.