Laboratory Technique for Measurement of pH for Corrosion Control Studies and Water Not in Equilibrium With the Atmosphere

Schock, Michael R.; Mueller, William A.; Buelow, Ralph W.

doi:10.1002/j.1551-8833.1980.tb04516.x

Cited by 13 publications

(5 citation statements)

References 2 publications

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“…These showed that if the pH was only slightly different (6.44), both total alkalinity and DIC values became consistent well within the laboratory's documented analytical error. This follows well with the expected direction of the bias of a high‐CO 2 water exposed to the atmosphere during even a good field pH measurement (Schock et al, 1980) and with earlier measurements of the raw water at PCWD during exploratory testing. Therefore, when the estimated pH of 6.44 (rather than 6.6) is used, CO 2 removal efficiency was 96%, almost exactly what would be expected from the design of the diffused bubble system and predicted by general carbonate equilibria expressions commonly applied to aeration (Lytle et al, 1998a; Lytle et al, 1998b; Lytle et al, 1998c).…”

Section: Water Quality and Operational Effectssupporting

confidence: 88%

California's First aeration plants for corrosion control

Schock¹,

Holldber²,

Lovejoy³

et al. 2002

Journal AWWA

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The Idyllwild Water District and Pine Cove Water District are small groundwater systems with multiple wells. Both systems have soft, mildly acidic waters with high carbon dioxide content and dissolved inorganic carbon concentrations of approximately 18 mg/L C, and both systems exceeded one or both of the lead and copper action levels in 1993 and 1994. In 1997, aeration was investigated to increase pH and replace inhibitor or other chemical additions. Four designs were evaluated, and a deep bubble aeration system was pilot‐tested. Full‐scale systems were designed and built and became operational in October 1998. Aeration raised the pH from 6.1–6.3 to 7.1–7.6, and by January 1999, both systems easily met both the lead and copper action levels. Radon (Rn) samples taken at Pine Cove showed a 99% reduction to 33 ± 8 pCi/L, assuring compliance with the proposed Rn regulation. Using aeration for corrosion control has considerably simplified treatment and improved water quality in most respects. Treatment was integrated with system designs, enabling the use of one treatment plant for the multiple wells at each system, locating the treatment plants above storage to eliminate repumping, and maximizing electricity savings by increasing operation at off‐peak times.

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Section: Water Quality and Operational Effectssupporting

confidence: 88%

California's First aeration plants for corrosion control

Schock¹,

Holldber²,

Lovejoy³

et al. 2002

Journal AWWA

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“…The pH was measured using a series of benchtop pH/ion‐selective electrode meters under computer control to report stability. Measurements of pH used a closed‐system technique with repetitive re‐equilibrations following the technique of Schock and co‐workers (1980). The pH instrument was standardized daily using a two‐ or three‐point calibration with pH 4, 7, and 10 high‐precision standard solutions 1 .…”

Section: Methodsmentioning

confidence: 99%

Pitting corrosion of copper in waters with high pH and low alkalinity

Lytle¹,

Schock²

2008

Journal AWWA

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Corrosion of copper pipes has been associated with waters with high pH and low alkalinity that also contain significant levels of chloride and sulfate. This study systematically evaluated the effect of pH, alkalinity (or dissolved inorganic carbon [DIC]), orthophosphate, and sulfate on the nature of copper corrosion using a pilot‐scale experimental pipe loop system. Experiments were conducted in the absence of silica, aluminum, or organic carbon, which previously have been linked to pitting corrosion in drinking water systems, and all test waters contained moderate levels of chloride. The study also investigated the effect of chlorine concentration and form of chorine on copper‐pitting corrosion. Results showed that pitting corrosion of copper pipes was reproduced in the pilot‐scale systems after only 91 days of operation. Pitting corrosion occurred in water with low chlorine concentration and DIC and in pH 9 water in the presence of chloride. Pitting was not observed at pH 6.5 and 7 and was evident at pH 8 only when higher chlorine levels were maintained. Sulfate was not necessary to develop pitting corrosion; however, it did affect the composition of the corrosion by‐products

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“…While variability within a study is unavoidable, proper design and operating conditions can achieve reasonable control over water quality and material variables. Schock and Lytle (1994) highlighted the importance of proper measurements and control over certain water quality parameters (pH and dissolved inorganic carbon‐DIC) that have a significant impact on lead leaching over the course of a study.…”

Section: Discussionmentioning

confidence: 99%

A literature review of bench top and pilot lead corrosion assessment studies

Devine¹,

Triantafyllidou²

2023

AWWA Water Science

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Bench top and pilot lead corrosion studies are gaining more interest, considering revisions and upcoming improvements to the Lead and Copper Rule. This literature review identified studies ranging from simpler month(s)‐long bench top dump‐and‐fill stagnant water tests (coupon tests/standing pipe tests) to more complicated year(s)‐long intermittent flow pilot studies (recirculating pipe loops/once through pipe rigs). With increasing complexity in design and operation, studies more closely approximated real plumbing conditions (e.g., by incorporating harvested lead pipes and intermittent flow regimes) at increased cost, footprint, and duration. Comparison of bench top and pilot designs (in terms of lead test piece age/dimensions/configuration/replicates, study duration, sample collection, and other factors) can assist drinking water utilities, consultants, academics, and others to select a design that matches their needs and constraints. No matter the choice, surrogate systems cannot replace actual system water testing and are best complemented by other corrosion assessment tools.

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Laboratory Technique for Measurement of pH for Corrosion Control Studies and Water Not in Equilibrium With the Atmosphere

Abstract: Water quality analyses are very sensitive, and it is critical that the pH be measured as accurately as possible. This technique was developed after the authors observed that many water utility and research laboratory personnel follow poor techniques for determining pH.

Cited by 13 publications

References 2 publications

California's First aeration plants for corrosion control

California's First aeration plants for corrosion control

Pitting corrosion of copper in waters with high pH and low alkalinity

A literature review of bench top and pilot lead corrosion assessment studies

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