Optimizing silicate formulation and dose for lead and biofilm control in drinking water

Health Canada has recently proposed changes to the guideline for lead in drinking water. These changes would reduce the maximum acceptable concentration of lead in drinking water to 5 µg/L and specify sampling protocols for determining lead levels in residential and non-residential buildings.While the water industry, in general, has observed positive outcomes with phosphate as a chemical product for corrosion control, challenges remain. Specific challenges include concern for the role phosphates may play in biofilm formation and the long-term availability of phosphates in the marketplace. Silicates are an alternative that have been used in the drinking water industry for iron and manganese control for decades; however, their reported application for corrosion control in drinking water has been relatively limited in the peer review literature. National Silicates has identified an opportunity to capitalize on the need in the water industry to better understand corrosion control products to address concerns with lead and other metals. There are presently relatively few published studies concerning silicates, both in application and at a fundamental level. Accordingly, this project aims to close that gap.The overall goal of this 24-month project is to enhance the water community's understanding of sodium silicates for controlling lead and biofilms in drinking water distribution systems. The research project will utilize a new product formulation provided by National Silicates designed for the drinking water industry. The research project will be conducted at the laboratory-scale level and the pilot-scale level to obtain an understanding of sodium silicates at both a fundamental and applied level.