Impact of Secondary Disinfectants on Copper Corrosion under Stagnation Conditions

Rahman, Sazzadur; McDonald, Brian; Gagnon, Graham A.

doi:10.1061/(asce)0733-9372(2007)133:2(180)

Cited by 13 publications

(7 citation statements)

References 19 publications

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“…Ammonia has a strong complexation constant for cupric ion (Schock et al, 1995). On the other hand, according to MacQuarrie et al (1997) and Rahman et al (2007), application of monochloramine results in a decrease in copper pipe corrosion. Current results found higher total and dissolved copper concentrations in the reactors where the disinfectant was added.…”

Section: Chloraminementioning

confidence: 99%

Nitrification and potential control mechanisms in simulated premises plumbing

2011

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Indigenous drinking water organisms were used to establish nitrification in glass reactors containing copper or polyvinyl chloride (PVC) surfaces. The reactors were fed soil-derived humics as the organic carbon source and ammonium sulfate as the nitrogen source in biologically treated tap water. Water in the reactors was stagnant for 8 h and then flowed for 5 min to simulate conditions in household plumbing. Following the establishment of complete nitrification (conversion of ammonia to nitrate) in both reactor types, various inhibitors of nitrification were tested followed by a period where recovery of nitrification was observed. In one PVC reactor, copper was gradually introduced up to 1.3 ppm. To ensure that most of the copper was in the ionic form, the pH of the influent was then gradually lowered to 6.6. No significant change in nitrification was observed in the presence of copper. Chlorite was introduced into copper and PVC reactors at doses increasing from 0.2 ppm to 20 ppm. There was limited effect on the PVC system and inhibition in the copper reactor only at 20 ppm. Chloramine was tested at chlorine to ammonia ratios ranging from 0.5:1 to 5:1. Nitrification activity was impacted significantly at a 5:1 ratio and ultimately stopped, with the fastest response being in the copper system. Whenever a control mechanism was tested, there was increased release of copper from the reactors with copper coupons. In all cases, nitrification recovered when inhibitors were removed but the rates of recovery differed depending on the treatment method and coupon surface.

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Section: Chloraminementioning

confidence: 99%

Nitrification and potential control mechanisms in simulated premises plumbing

2011

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“…Higher levels of free chlorine can sometimes decrease copper or lead solubility by producing lower solubility surface solids (Lytle and Schock 2005;Nguyen et al 2011a) or increase copper leaching in some cases by accelerating copper corrosion rates (Boulay and Edwards 2001). Rahman et al (2007) observed that even though both chlorine and chloramines reduced copper release relative to a control without disinfectant, chloramines induced more copper release than the free chlorine conditions. Higher levels of chloramine have also been associated with increased lead levels in some cases (Edwards and Dudi 2004;Triantafyllidou et al 2012) or higher levels of copper and lead if nitrification depresses pH (Douglas et al 2004;Nguyen et al 2012).…”

Section: Introductionmentioning

confidence: 96%

Distribution system water age can create premise plumbing corrosion hotspots

Masters

Parks

Atassi

et al. 2015

Environ Monit Assess

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Cumulative changes in chemical and biological properties associated with higher "water age" in distribution systems may impact water corrosivity and regulatory compliance with lead and copper action levels. The purpose of this study was to examine the effects of water age and chemistry on corrosivity of various downstream premise plumbing pipe materials and configurations using a combination of controlled laboratory studies and a field survey. Examination of lead pipe, copper pipe with lead solder, and leaded brass materials in a replicated lab rig simulating premise plumbing stagnation events indicated that lead or copper release could increase as much as ∼440 % or decrease as much as 98 % relative to water treatment plant effluent. In field studies at five utilities, trends in lead and copper release were highly dependent on circumstance; for example, lead release increased with water age in 13 % of cases and decreased with water age in 33 % of conditions tested. Levels of copper in the distribution system were up to 50 % lower and as much as 30 % higher relative to levels at the treatment plant. In many cases, high-risks of elevated lead and copper did not co-occur, demonstrating that these contaminants will have to be sampled separately to identify "worst case" conditions for human exposure and monitoring.

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“…Depending on its concentration, previous works have reported two distinct effects of chlorine on copper corrosion [4,7,8,9,10,11,12,13,14,15,16]. In moderate to high chlorine concentrations, a direct relationship between chlorine concentration and copper release has been reported [4,9,10,11,12,13,14].…”

Section: Introductionmentioning

confidence: 99%

“…In moderate to high chlorine concentrations, a direct relationship between chlorine concentration and copper release has been reported [4,9,10,11,12,13,14]. For low and moderate chlorine concentrations (below ~2.6 mg/L), chlorine may prevent microbial influenced corrosion episodes [7,8,15,16]. Based on this evidence, research developed during the 90s recommended chlorine concentrations of ~2 mg/L to control biocorrosion episodes and to secure disinfection [4,8].…”

Section: Introductionmentioning

confidence: 99%

Chlorine Reduction Kinetics and its Mass Balance in Copper Premise Plumbing Systems During Corrosion Events

et al. 2019

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Hypochlorous acid has been reported as the main oxidant agent responsible for the corrosion of copper plumbing systems in chlorinated water supplies. However, there is little information about chlorine consumption kinetics in a combined system (i.e., with dissolved oxygen (DO) and free chlorine), as well as its complete mass balance within a copper pipe during stagnation. The results of our experiments using copper pipes filled with synthetic drinking water, with a moderate alkalinity (pH = 7.2; dissolved inorganic carbon = 80 mg as CaCO3 /L), and tested under chlorine concentrations from 0 to 8 mg/L, show that chlorine depletion is associated with pipe wall reactions (i.e., copper oxidation and scale formation processes). Free chlorine was depleted after 4 h of stagnation and its kinetic constant depend on the initial concentration, probably due to diffusion processes. Surface analysis including scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and total reflection X-ray fluorescence (T-XRF) suggest chlorine precipitation, probably as CuCl. The obtained kinetics of chlorine and DO reduction would be critical for modeling and prediction of corrosion events of copper premise plumbing systems. In addition, our results indicate that the pipe’s surface reactions due to corrosion induces a loss of free chlorine in the bulk water, decreasing chlorine added for disinfection and the subsequent effect on water quality.

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Impact of Secondary Disinfectants on Copper Corrosion under Stagnation Conditions

Cited by 13 publications

References 19 publications

Nitrification and potential control mechanisms in simulated premises plumbing

Nitrification and potential control mechanisms in simulated premises plumbing

Distribution system water age can create premise plumbing corrosion hotspots

Chlorine Reduction Kinetics and its Mass Balance in Copper Premise Plumbing Systems During Corrosion Events

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