Theoretical equilibrium lead(<scp>II</scp>) solubility revisited: Open source code and practical relationships

Wahman, David G.; Pinelli, Matthew D.; Schock, Michael R.; Lytle, Darren A.

doi:10.1002/aws2.1250

Cited by 7 publications

(9 citation statements)

References 31 publications

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“…The results from both demonstration studies indicate a point of diminishing returns at higher orthophosphate doses. These findings are consistent with lead solubility models shown in Figure 6 as well as other studies that have found diminishing returns for especially above 1.5-2 mg/L as PO 4 in the pH 7-8 range (Bradley & Horscroft, 2018;Cardew, 2009;Schock, 1980;Schock et al, 1996;Schock & Gardels, 1983;Wahman et al, 2021).…”

Section: Comparison Of Orthophosphate Treatment In Coupon and Pipe Ra...supporting

confidence: 92%

“…The ideal pH range for orthophosphate effectiveness for controlling lead corrosion is between 7.2 and 7.8 (Schock, 1989; Schock et al, 1996), similar to the finished water quality in the Denver Water system before March 2020. Orthophosphate also tends to be more effective at controlling lead corrosion in low alkalinity waters (Schock, 1989; Wahman et al, 2021). Typical orthophosphate doses are between 0.5 and 3 mg/L as PO 4 (Vik et al, 1996).…”

Section: Resultsmentioning

confidence: 99%

“…Typical orthophosphate doses are between 0.5 and 3 mg/L as PO 4 (Vik et al, 1996). While a significant amount of our understanding about lead corrosion control is based on demonstration studies, equilibrium solubility models can be an important tool for understanding potential changes in the soluble lead (Schock, 1980; Schock & Gardels, 1983; Wahman et al, 2021).…”

Section: Resultsmentioning

confidence: 99%

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Comparison of coupon and pipe rack studies for selecting corrosion control treatment

Masters

Poncelet‐Johnson²,

Walsh³

et al. 2022

AWWA Water Science

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This study directly compared the data obtained from coupon studies and flow‐through pipe rack studies from two sources in the Denver Water system. The pipe rack study was completed over multiple years using harvested lead service lines. The coupon studies were completed in about 2 months using pure lead coupons. Orthophosphate at 2 mg/L was found to reduce lead concentrations by about 81% in the pipe racks, whereas 74%–81% was observed in the coupons. At an orthophosphate dose of 1 mg/L lead concentrations were reduced by 62%–65% in the pipe loop and by 55%–75% in the coupons, pH at 8.8 reduced lead by 45%–60% in the pipe racks and by 27%–48% in the coupons. The pipe racks were able to give insights into the transition from one condition to another, which is time‐based and dependent on existing pipe scales. Both types of demonstration studies produced similar conclusions about treatment options. The pipe rack was more representative of conditions in the distribution system while the coupon studies were performed in a fraction of the time.

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Section: Comparison Of Orthophosphate Treatment In Coupon and Pipe Ra...supporting

confidence: 92%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Comparison of coupon and pipe rack studies for selecting corrosion control treatment

Masters

Poncelet‐Johnson²,

Walsh³

et al. 2022

AWWA Water Science

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“…Models which account for the diverse, interconnected mechanisms of lead release, including bulk thermodynamic and kinetic factors, the effects of environmental changes (e.g., temperature and increased salinity from rising sea levels), additives, disturbances in pipelines, and flow rates, are lacking. − In particular, the ultimate structure and mechanisms by which corrosion inhibitors form solid scales in pipes that limit lead (II) release are not fully understood. ,, For example, it has been shown that the addition of orthophosphate as a corrosion inhibitor causes the formation of scales dominated by hydroxylpyromorphite and Pb 3 (PO 4 ) 2 . ,, Although studies have directly observed lead carbonate scales to form on pipes expected under operating conditions, other data on lead phosphate scales are unable to identify such scales despite current models predicting their stability. , We note that characterizing the growth of scales is challenging in part because of limited spectral ranges for Raman spectroscopy, inadequate solution control, little initial starting scale monitoring, and the ex situ testing nature due to removal and recovery of scales on pipes for laboratory characterization. These limitations necessitate the integration of literature covering multiple experimental techniques here and elsewhere to best support solid lead phase formation.…”

Section: Introductionmentioning

confidence: 99%

Density Functional Theory-Based Thermodynamic Model for Stable Scale Formation in Lead-Water Systems

et al. 2022

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Current safety standards for water treatment to reduce indigestible lead in drinking water utilize decades-old data and models to define risk mitigation. Limitation is achieved in part by utilizing additives to control particulate and soluble Pb(II) release through scale formation in lead pipes that rely on thermodynamic and kinetic factors. Advances in state-of-the-art computational materials science techniques allow fresh comparisons to older thermochemical data and thereby enable the formulation of new ab initio-based thermodynamic models. Here, we perform first-principles calculations to simulate electrochemical Pb Pourbaix and stability diagrams that include a limited number of non-ideal solution effects and account for variable concentration, additives, and temperature. Our data show that lead carbonates are thermodynamically driven to form a cerussite scale across a large range of conditions. Orthophosphate is a known lead corrosion inhibitor; however, the formation of lead phosphate scales, such as Pb (PO ) (OH) 5 4 3 2(s) , may rely on transient high Pb(II) concentrations with trace alkaline-earth elements. Moreover, their previously reported stability may be due to overestimated free energies of formation. Acceptable thermodynamically stabilized soluble lead levels in water can only be maintained under specific thermal and aqueous boundary conditions. Our work defines critical environmental limits on lead scale formation and provides a renewed look of E-pH lead stability and solid stabilities of lead (II) carbonate and phosphate species as a function of Pb(II) and pH using here-to-fore unavailable computational approaches for comparison to other data.

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“…According to the U.S. Environmental Protection Agency (USEPA), it was standard protocol throughout the 20th century to use lead pipes for commercial and domestic water supplies. These pipelines were damaged because of lead concentrations in water, increasing concentrations of organic, and inorganic contaminants with various microorganisms, and the duration of water stay in these pipelines (Wahman, D. G., et al, 2021;Enning D, and Garrelfs J., 2014). All these happening are because of physical, biological, and chemical reactions in water throughout its passage from the water supply system to the consumer as shown in figure 1.…”

Section: Occurrence Of Contamination In Water Suppliesmentioning

confidence: 99%

Microbial Degradation of Water Pipelines and Effects of Polluted Water on Human Health

Saqib¹,

Hassan²,

Saeed³

et al. 2022

Int. J. Res. Publ. Rev.

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The degradation of water supplies is linked with poor anthropogenic activities. This study determines that contamination of water supply occurs because of destabilization of pipe material and deposits in the water distribution system due to physiochemical and microbiological processes that have developed over decades and cause health issues (Hepatitis C, and GIT disorders) which result in the death rate of 3.4 million people over the globe. This study was conducted in Gujrat, Pakistan and the primary source of data collection was a survey questionnaire while secondary sources involved a comprehensive literature review. ANOVA test, Correlation, and reliability analysis were applied to test the variables. The results of this study revealed that contaminated water supplies, oxyhydroxide products of corrosion, the mixture of sewage, and industrial effluents were significantly associated with the contamination of water supplies. The findings of this study also explore the contamination of household store water (HSW), contaminated water supplies, and the mixture of sewage, and industrial effluents that were responsible for water contamination, whereas; the condition of underground water supply pipelines was very worse. The use of upgraded water supply systems and water purification technologies is a common global practice that would be useful to reduce water supply contamination. The findings of this study will contribute to the literature on water supply contamination, the framework of water quality parameters, and low-cost adaptable water treatment techniques.

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Theoretical equilibrium lead(II) solubility revisited: Open source code and practical relationships

Cited by 7 publications

References 31 publications

Comparison of coupon and pipe rack studies for selecting corrosion control treatment

Comparison of coupon and pipe rack studies for selecting corrosion control treatment

Density Functional Theory-Based Thermodynamic Model for Stable Scale Formation in Lead-Water Systems

Microbial Degradation of Water Pipelines and Effects of Polluted Water on Human Health

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