# Overview of the Draft document: “Technologies for **Legionella** Control: Scientific Literature Review” November 9 , 2015 César Cordero U.S. Environmental Protection Agency OW/Office of Ground Water and Drinking Water Standards and Risk Management Division

# Legionella: A Major Public Health Problem • Legionellosis 1 

### is a major health concern associated with drinking water • CDC estimates 8,000 – 18,000 legionellosis hospitalizations occur in the U.S. annually, with up to a 30% fatality rate • Hospitalization costs for Legionnaires’ disease are estimated at $433 million/year 2 1 Legionellosis is a form of atypical pneumonia caused by Legionella bacterial infection. The disease can occur in two forms: a pneumonia- like infection (Legionnaires' Disease) or a flu - like illness (Pontiac fever).

### • Legionella bacteria are found naturally in the environment worldwide, usually in aquatic environments • Legionella colonizes biofilms2 

### in premise plumbing • Infection occurs primarily through inhalation or aspiration

– Showerheads, faucets and hot tubs – Mist machines, decorative fountains and cooling towers – Respiratory therapy devices and humidifiers 3 2 Biofilms form when microbes stick to surfaces in aqueous environments and excrete a slimy, gluelike substance that can anchor them to all kinds of material. 

# Legionella: A Major Public Health Problem

# Legionella: A Major Public Health Problem • Waterborne disease outbreaks (2009 -2012, reported by CDC)

– 40 of 65 (62%) of the waterborne disease outbreaks caused by Legionella – 32 of 40 (80%) Legionella outbreaks caused by environmental conditions within water systems of buildings 4

# Applicable Drinking Water Regulation • Surface Water Treatment Rule (SWTR) - 1989: – Applies to surface water (SW) and ground water under direct influence of SW – MCLGs of zero for Giardia , viruses and Legionella – The SWTR presumes that compliance with the treatment technique (TT) requirements 3 

### will control for Legionella in utilities 5 3 TT requirements: Remove/inactivate Giardia lamblia and viruses before distribution ; maintain a detectable residual disinfectant level in the distribution system.

# Premise Plumbing Issues • Premise plumbing refers to the pipes after the service connection line all the way to the tap, such as those in:

– Hospitals, schools, businesses, and private buildings 

## • Premise plumbing conditions can lead to Legionella proliferation (e.g. water heating, long residence time, low disinfectant residual areas) 6

# Legionella Document Overview

7 • EPA worked with a multi -agency team to develop this draft technical document that compiles peer reviewed literature on technologies that control for Legionella in premise plumbing • The multi -agency team participated in the data compilation, write up and review of the draft document

– EPA (Regions, OGC, OPP & ORD), CDC, ASDWA, state representatives 

### • The document summarizes literature for each technology – Effectiveness against Legionella – Potential water quality issues – Operational requirements 

### • The document does not recommend any particular technology nor the addition/installation of treatment • The document provides an overview of the regulatory context

## • Chlorine – Results of laboratory and pilot scale studies showed effectiveness but at wide range of dose and water quality conditions – Residual maintenance is important – Efficacy increases with increased temperature – Biofilms and inclusion of Legionella in amoeba shield organisms from chlorine – Potential water quality issues include disinfection byproducts (Trihalomethane (THM) and haloacetic acid (HAA)), taste and odors and corrosion 8 

# Control Technologies

## • Monochloramine – Laboratory studies showed wide range of inactivation under varying water quality conditions – Efficacy increases with increased temperature – Several studies concluded chloramine is more effective at penetration of biofilms than chlorine – Potential water quality issues include disinfection byproduct formation (nitrosamines), nitrification, and corrosion 9



# Control Technologies (Cont.)

## • Chlorine Dioxide – Laboratory and pilot scale testing showed effectiveness at low doses (<1 mg/l) – Effective against Legionella shielded in amoebae and at penetrating biofilms – Literature reports successful applications of chlorine dioxide disinfection systems in hospitals – Efficacy increased with increased water temperature – Potential water quality issues include formation of chlorite and chlorate, taste and odors, and corrosion 10



# Control Technologies (Cont.)

## • Copper-Silver Ionization (CSI) – Laboratory studies indicate that copper ions (at 0.4 mg/L) and silver ions (at 0.04 mg/L) can reduce cultivability of Legionella – Literature reports successful applications in building water systems – Biofilms and inclusion of Legionella in amoeba shield the organism from CSI – Legionella strains appear to develop resistance to copper and silver – Potential water quality issues include high copper concentrations, and corrosion 11 

# Control Technologies (Cont.)

## • UV Disinfection – Shown to be effective at decreasing and in some cases, eliminating Legionella from building water systems at low doses (40 mJ/cm2) – Only effective on water flowing through the reactor; when Legionella is already present in building water systems, supplemental treatment is required – Some UV reactors may not be tolerant of high temperatures (e.g. > 35 oC/ 95 o F) or certain chemical disinfectants – Iron, manganese, calcium and magnesium may affect the quartz lamp sleeves decreasing UV output 12



# Control Technologies (Cont.)

## • Ozone ‒ Laboratory studies showed wide range of inactivation under varying water quality conditions ‒ Decomposes quickly in water thus it is difficult to maintain a disinfectant residual

• Particularly at higher temperatures • Second form of disinfection may be needed ‒ Effects of biofilms and inclusion of Legionella in amoeba from ozone not well characterized ‒ Potential water quality issues include formation of disinfection byproducts and corrosion 13 

# Control Technologies (Cont.)

## • Emergency Disinfection – Superheat-and - Flush Disinfection • Involves raising the hot water temperature to 71 - 77 oC while flushing each outlet for at least 30 minutes • Has shown to be effective, particularly in hospital outbreak scenarios • Regrowth is an issue. May not provide long -term control unless combined with supplemental disinfection – Shock Hyperchlorination • Involves injecting elevated chlorine concentration (20- 50 ppm) for a specific contact time • Success for control of Legionella has been mixed • Legionella can be protected within Acanthamoeba , which can survive chlorine concentrations of 50 ppm 14 

# Other Control Technologies

## • Point-of- Use Filtration – Effectiveness demonstrated by several case studies – Dependent on pore size (≤ 0.2μm). – Depth filtration, including the use of silverincorporated BAC filtration, not effective – Filters may clog and failure could lead to release of high levels of pathogens. 15 

# Other Control Technologies (Cont.)

# Preventative and Remediation Strategies • Multi - barrier Approaches (e.g. Water Safety Plans, Water Management Plans, Hazard Analysis and Critical Control Points programs)

– Approaches for protecting building water systems from hazards that may occur – Case studies show effectiveness for controlling growth of pathogens in building water systems 16

# Next Steps • Evaluate and revise the document based on public input – Nov./Dec. 2015 • Independent external peer review – Jan. 2016 • Publish final document – Spring 2016 17

# Clarification Questions

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