Comparison of three corrosion inhibitors in simulated partial lead service line replacements

Aki Kogo; Sarah Jane Payne; Robert C Andrews

doi:10.1016/j.jhazmat.2017.01.039

Comparison of three corrosion inhibitors in simulated partial lead service line replacements

J Hazard Mater. 2017 May 5:329:211-221. doi: 10.1016/j.jhazmat.2017.01.039. Epub 2017 Jan 23.

Authors

Aki Kogo¹, Sarah Jane Payne², Robert C Andrews¹

Affiliations

¹ Department of Civil Engineering, University of Toronto,35 St. George Street, Toronto, ON M5S 1A4, Canada.
² Department of Civil Engineering, University of Toronto,35 St. George Street, Toronto, ON M5S 1A4, Canada. Electronic address: sjo.payne@utoronto.ca.

PMID: 28178636
DOI: 10.1016/j.jhazmat.2017.01.039

Abstract

Partial lead service line replacements (PLSLR) were simulated using five recirculating pipe loops treated with either zinc orthophosphate (1mg/L as P), orthophosphate (1mg/L as P) or sodium silicate (10mg/L). Two pipe loops served as ⿿inhibitor-free⿿ (Pb-Cu) and ⿿galvanic free⿿ (Pb-PVC) controls. Changes in water quality (CSMR [0.2 or 1], conductivity [⿿330mS/cm or ⿿560mS/cm], chlorine [1.4mg/L]) were not observed to provide a significant impact on lead or copper release, although galvanic corrosion was shown to be a driving factor. Generally, both orthophosphate and zinc orthophosphate provided better corrosion control for both total and dissolved lead (30min, 6h, 65h) and copper (30min, 6h), when compared to either the inhibitor-free control or the sodium silicate treated system. This work highlights the importance of understanding the complex interplay of corrosion inhibitors on particulate and dissolved species when considering both lead and copper.

Keywords: Chloride-to-sulfate mass ratio; Galvanic corrosion; Orthophosphate; Partial lead service line replacement; Sodium silicate; Zinc orthophosphate.