Strategies for assessing optimized corrosion control treatment of lead and copper

Historical Lead and Copper Rule (LCR) regulatory sampling data from the Philadelphia Water Department were examined to explore their potential value for guiding a water utility's progress with regard to optimal corrosion control treatment (OCCT). If a system has established a stable water treatment process with consistent corrosion control treatment (CCT) and has achieved continued decreases in lead levels during regulatory sampling, then the information collected during LCR monitoring can be used as an important data set of a broader OCCT evaluation and will help inform the benefit of additional changes in CCT. Since water utilities have LCR data dating back to 1992, these data should be used to make informed decisions. This research also showed that the addition of orthophosphate has resulted in a significant decrease in lead levels at the customer tap. Additionally, profile sampling was performed to show that first‐draw 1 L samples following a 6 h stagnation period provide a good representation of the lead concentrations measured from lead service line and home plumbing samples at the same sites and may be used to indicate overall changes in lead concentrations at the tap resulting from CCT for this system.

Section: Resultsmentioning

confidence: 99%

Using Historical LCR and Water Quality Data to Evaluate Corrosion Control Treatment

Bradley

Horscroft

2018

“…Utilities generally responded quickly and effectively to meet the new requirements of the LCR after the regulation's promulgation. Figure shows the 90th percentile lead distribution before and after the LCR for 166 utilities serving over 50,000 persons (Brown et al ). These utilities had 90th percentile lead data above the 15 μg/L action level (AL) before initiating measures to comply with the LCR—so these were the utilities serving more than 50,000 people with the highest lead levels at that time.…”

Section: A Daunting Taskmentioning

confidence: 99%

How Have We Done in Reducing Lead in Water Since the LCR?

Cornwell¹

2018

Self Cite

There has been renewed interest in water lead levels given recent localized events that have spotlighted the issue; with this in mind, it is an appropriate time to reflect on how successful the water industry has been in reducing lead levels in drinking water.Much of the current attention on lead focuses on communities that have lead service lines. Lead service lines can be a major source of lead in water, but home brass fixtures and old copper with lead or tin solder are also significant lead contributors. While there are many resources available for utilities (e.g., www.awwa.org/resources-tools/water-knowledge/lead.aspx), many consumers unfortunately do not understand the source of lead that ends up in the drinking water at consumer taps; too often, people believe that the lead is in the water coming from the city's water treatment plant. Despite the industry's efforts to educate the public, recent events that heightened awareness have also muddled the story with politics and management issues. Many utilities have been put on the defensive for practices related to the LCR. A water system's treatment and distribution implicitly require the trust of the public, so how has the industry done collectively on this front?

“…Therefore, corrosion control in the United States for Lead and Copper Rule (LCR) compliance has focused on treatment to reduce the distributed water's plumbosolvency, or capacity to dissolve lead from lead‐containing materials in the service lines or premise plumbing (Brown et al , EES , Schock ). Brown et al () identified three treatment strategies that generally encompass the corrosion control treatment (CCT) used by utilities for LCR compliance: Control of pH and alkalinity Development and maintenance of insoluble Pb(IV) scale under oxidized conditions Use of orthophosphate‐based corrosion inhibitors …”

mentioning

confidence: 99%

Impacts of Source Water Blending on Lead Release

Roth¹,

Wagner

Cornwell

2018

Self Cite

Historically, corrosion control in the United States for Lead and Copper Rule compliance has focused on treatment to reduce the distributed water's plumbosolvency. Corrosion control treatment (CCT) typically focuses on either control of pH and alkalinity, development and maintenance of Pb(IV) scale under oxidized conditions, or use of orthophosphate-based corrosion inhibitors. These CCT methods are influenced by source water quality parameters such as pH and dissolved inorganic carbon; thus, CCT can potentially be affected when source waters with different water qualities blend in the distribution system. If portions of the distribution system are exposed to blends of source waters with disparate water qualities, testing may be warranted to determine whether optimal CCT is being maintained where and when blending occurs, especially in transitional periods. This article discusses the theoretical impacts of blending source waters with different water qualities and presents research that was conducted on waters from two utilities to illustrate the potential impacts that source water changes can have on CCT.