Management of Legionella in Water Systems

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doi:10.17226/25474

Cited by 33 publications

(63 citation statements)

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“…Water heater operation can be altered in periods of low or no water use in the building (e.g., turning off a water heater in a summer home during winter). Legionella management in large buildings typically relies on thermal control NASEM, 2019). In large buildings, recirculation loops (Table 1) are often used to move hot water continuously throughout the building, reducing the time for hot water delivery and maintaining high temperatures for stored volumes.…”

Section: Prevention Of Water Quality Issues During Periods Of Low Usementioning

confidence: 99%

Considerations for Large Building Water Quality after Extended Stagnation

Proctor¹,

Rhoads²,

Keane³

et al. 2020

Preprint

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The coronavirus (COVID-19) pandemic prompted the closure and reopening of previously shutdown large buildings globally. Building water stagnation has been identified as a potentially serious chemical and microbiological health concern for occupants. Health officials, building owners, utilities, and other entities are rapidly developing guidance. A synthesis of peer-reviewed, government, industry, and nonprofit literature relevant to the implications of water stagnation in plumbing systems and decontamination practices for water quality and health was conducted. A primer of large building plumbing preventative and remedial strategies is provided to inform ongoing efforts to develop recommissioning guidance. Preventative practices to help avoid the need for recommissioning and specific actions, challenges, and limitations associated with recommissioning were identified and characterized. Considerations for worker and occupant safety were also indicated. The responsibility for building water safety was identified to be shared between the building owner, drinking water provider, and local and state public health authorities. [First uploaded April 7, 2020. Minor changes (funding, acknowledgments) made April 8, 2020.]

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Section: Prevention Of Water Quality Issues During Periods Of Low Usementioning

confidence: 99%

Considerations for Large Building Water Quality after Extended Stagnation

Proctor¹,

Rhoads²,

Keane³

et al. 2020

Preprint

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“…When chlorine was applied to a low TOC water at a warm temperature (37 • C), only 11% of the initial residual remained after 24 h without any plumbing or biofilm interactions (Table 2). Chlorine decayed more rapidly at warm temperature in glass containers [7,37,38,42] and had little disinfecting effect in the presence of iron [10,26,45], a magnesium anode, high TOC [10,11,52], or the combination of all three. The findings here are consistent with field studies where chlorine was ineffective in the presence of similar factors.…”

Section: Discussionmentioning

confidence: 99%

“…Legionella pneumophila is identified as the causative agent in 90 percent (%) of LD, but other members of the genus also cause LD, even though their association is less commonly diagnosed [5]. Another opportunistic pathogen capable of growth in premise plumbing (OPPP) is Acanthamoeba, which can cause eye infection/meningitis, as well as acting as a host organism for Legionella proliferation [6][7][8][9]. While traditional LD risk is managed at the building-scale, the potential responsibility of water utilities to deliver at least some chlorine residual (≈0.5 mg/L) via the municipal distribution system has recently been gaining attention in the wake of a major LD outbreak that occurred in Flint, MI, in which case chlorine residuals were frequently absent [10][11][12].…”

Section: Introductionmentioning

confidence: 99%

“…While traditional LD risk is managed at the building-scale, the potential responsibility of water utilities to deliver at least some chlorine residual (≈0.5 mg/L) via the municipal distribution system has recently been gaining attention in the wake of a major LD outbreak that occurred in Flint, MI, in which case chlorine residuals were frequently absent [10][11][12]. Thus, there is need to complement existing research on supplemental disinfection in buildings by systematically assessing the effects of building point-of-entry chlorine levels on growth of OPPPs, such as Legionella and Acanthamoeba [7,13].…”

Section: Introductionmentioning

confidence: 99%

“…A key challenge is that, as distributed water travels through mains, service lines, and premise plumbing, the chlorine or chloramine disinfectant residual is often lost or otherwise rendered ineffective due to a range of biological and chemical reactions [7,10,[18][19][20][21]. Deficiencies within the premise plumbing system have been associated with 85% of LD outbreaks between 2000-2014, including a lack of adequate disinfectant residual (70%) and water storage in the optimal temperature range for Legionella growth (52%) [1].…”

Section: Introductionmentioning

confidence: 99%

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Chlorine Disinfection of Legionella spp., L. pneumophila, and Acanthamoeba under Warm Water Premise Plumbing Conditions

et al. 2020

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Premise plumbing conditions can contribute to low chlorine or chloramine disinfectant residuals and reactions that encourage opportunistic pathogen growth and create risk of Legionnaires’ Disease outbreaks. This bench-scale study investigated the growth of Legionella spp. and Acanthamoeba in direct contact with premise plumbing materials—glass-only control, cross-linked polyethylene (PEX) pipe, magnesium anode rods, iron pipe, iron oxide, pH 10, or a combination of factors. Simulated glass water heaters (SGWHs) were colonized by Legionella pneumophila and exposed to a sequence of 0, 0.1, 0.25, and 0.5 mg/L chlorine or chloramine, at two levels of total organic carbon (TOC), over 8 weeks. Legionella pneumophila thrived in the presence of the magnesium anode by itself and or combination with other factors. In most cases, 0.5 mg/L Cl2 caused a significant rapid reduction of L. pneumophila, Legionella spp., or total bacteria (16S rRNA) gene copy numbers, but at higher TOC (>1.0 mg C/L), a chlorine residual of 0.5 mg/L Cl2 was not effective. Notably, Acanthamoeba was not significantly reduced by the 0.5 mg/L chlorine dose.

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Managing Legionella pneumophila in Water Systems

LeChevallier¹

2020

Journal AWWA

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Key Takeaways Utilities might be in compliance with water treatment regulations, but is this enough to safeguard against pathogens such as Legionella? Keeping Legionella in check in a distribution system involves a systematic program of disinfection, hydraulic management, nutrient limitation, and temperature control. If a utility decides to monitor for Legionella, several options are available. Certain questions should be considered, and a plan should be in place in case Legionella is detected.

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Management of Legionella in Water Systems

Cited by 33 publications

References 0 publications

Considerations for Large Building Water Quality after Extended Stagnation

Considerations for Large Building Water Quality after Extended Stagnation

Chlorine Disinfection of Legionella spp., L. pneumophila, and Acanthamoeba under Warm Water Premise Plumbing Conditions

Managing Legionella pneumophila in Water Systems

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