GREEN BUILDING PREMISE PLUMBING: IDENTIFYING PUBLIC

GREEN BUILDING PREMISE PLUMBING: IDENTIFYING PUBLIC

HEALTH AND AESTHETIC CONCERNS

William Rhoads

Marc Edwards

What’s different about green water systems?

• New Sources of Potable Water/On-site Water Treatment

• Water Age: The amount of time that passes from the time the water enters a system to the time it is used

– Should water have an expiration date?

Problems Associated with Higher Water Age

• Lower or No Chlorine Residuals

• Microbial Regrowth

• Taste and Odor

• Opportunistic Pathogen Growth

• More Problems with Copper and Lead Corrosion

Legionella Legionellosis

• 8,000 – 18,000 hospitalizations/year in U.S.1

–5-30% are fatal2

• 1/3 of waterborne disease outbreaks occur in premise plumbing3

–~90% are caused by Legionella pneumophila3

Most frequently reported pathogenin drinking water in the U.S.3

1. CDC, 2013, 2. U.S. DOH, 2005, 3. CDC, 2008

How do green systems increase water age?

• Water Conservation (30-50%)

– Reduced Use Campaigns

– Metered and sensor faucets

– Low-flow showerheads and taps

– Dual flush, or compost toilets

– Grey water reuse

– Black water treatment and reuse

• Water Storage (2-10X)

– Rainwater collection

– Solar “pre-heat”

www.airdelights.com; Amazon.com; blog.oyster.comwww.buildingwithawareness.com;http://reuseofwaterandrestrictions.weebly.com/

gallery.html;www.tamarac.org

32.7

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29 MGD

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Water Demand – Newport News Waterworks

Data: Brian Ramaley and Newport News, VA Waterworks

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0.0

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29 MGD

Wat

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Water Demand – Newport News Waterworks

Data: Brian Ramaley and Newport News, VA Waterworks

Even if a given building does not reduce water consumption, water quality will still be affected by the

cumulative savings of other buildings.

USA Today – Too easy to be green?

Implication:

a

growing

trend

Pathogen Proliferation in Green Devices?

• Lower flow

• Low pressure

• Pipe materials

• Temperature

• Magnetic mixing value

Sydnor et al. 2012

Overview of Exploratory Research

Exemplar Green Building Characteristic Issue Observed

UNC Water age (low demand)Alternate water source (toilets only)

Elevated PbHigh disinfectant demandBacteria, Taste/Odors

TJU Water age (low demand) High L. spp. host organismsHigh disinfectant demandElevated copper

Baltimore Water age (storage)Solar water heating

Large storage reservoir,Rotten egg odor, Elevated Pb and pathogens

St. Louis Water age (Low flow + Storage)On-site treatmentRainwater used as potable water

Large storage reservoir,Elevated L. spp.

Overview of Exploratory Research

Exemplar Green Building Characteristic Issue Observed

UNC Water age (low demand)Alternate water source (toilets only)

Elevated PbHigh disinfectant demandBacteria, Taste/Odors

– Low-flow fixtures

– Waterless urinals

– Rainwater for toilet flushing

UNC – Extreme Differences in Water Demand

Building TypeAverage potable water

use (gal/ft2/month)

Conventional Lab 63

New Lab with Green Devices 26

Conventional Classroom Bld 10

New Classroom Bld with GreenDevices and Rainwater for Toilet

Flushing2

2.5X

5X

30X

213 minutes

continuous flushing

Water holding times in some lines of UNC buildings

are estimated to be on the order of weeks/months

10” diameter118’ long

booster pumps

3” diameter39’ long

domestic cold waterbackflow preventer

3” diameter70’ long

3” diameter8’ long

3” diameter78’ long

1” diameter16’ long

1” diameter12’ long

0.5” diameter7’ long

lower basement fountain

3” diameter20’ long

3” diameter14’ long

upper basement fountain

0.5” diameter7 long

Slide credit: Carolyn Elfland and University of North Carolina

UNC – High Pb in Water

• Worst situations in cases with high water age

• Source was leaded brass plumbing devices

• Lead(Pb) sustained at very high levels (> 100 ppb) for months; only resolved by finding/removing problematic in-line devices

UNC – High Pb in Water

UNC – Green Building Water Waster

SOLUTION:Flush <1% total daily

flow at end of plumbing system

Overview of Exploratory Research

Exemplar Green Building Characteristic Issue Observed

TJU Water age (low demand) High L. spp. host organismsHigh disinfectant demandElevated copper

– Very low use (coupled with a large number of taps)

Issues with Chlorine Residuals

• Extreme flushing needed to see residuals at taps

– >80 minutes of flushing at 1.4. gpm

• Rapid chloramine decay after residuals established at taps

– <15 minutes for residual to completely disappear

Overview of Exploratory Research

Exemplar Green Building Characteristic Issue Observed

Baltimore Water age (storage)Solar water heating

Large storage reservoir,Rotten egg odor, Elevated Pb and pathogens

Baltimore

• Net-zero energy

• Water Age – Storage

– Solar pre-heat hot water

– 2 tanks

• 80 gallons and 120 gallons

• 2-2.5 hot water heater volume

• “foul” odor in hot water system

– SRB?

• Raised Temp > 60 temporarily, no odor

Overview of Exploratory Research

Exemplar Green Building Characteristic Issue Observed

St. Louis Water age (Low flow + Storage)On-site treatmentRainwater used as potable water

Large storage reservoir,Elevated L. spp.

• “Net-zero” energy and water

• 3,000 gal rainwater cistern

– Automatically circulates water

– GAC + UV treatment (+1 µm filter for potable water)

St. Louis

St. Louis – “Net-Zero”

• Detected high (>1,000 gene copies/mL) Legionella spp.!

• Used groundwater for maintenance

– Low use, high storage = primarily groundwater in cistern

• Groundwater used for “maintenance” represents nearly 60% of TOTAL water use.

• Based on their reported use, the cistern would last them >1.5 years

St. Louis

Illustrates extreme scenarios in pursuit of green infrastructure.

UNCHARTED TERRITORY!

Conclusions

– We are at the earliest stages of a green building revolution and there is some cause for concern that current strategies might create potable water that tastes bad, has high Pb/Cu, and perhaps high levels of harmful pathogens

– The large scale impact of water conservation has been to increase the water age for all consumers with implications for taste and odor control and human health

– In pursuit of obtaining “net zero” buildings or energy efficiency, impacts of some design elements, including water storage and green plumbing fixtures, deserve increased scrutiny

Questions/Comments?

• Water Research Foundation – Green Building Design: Water Quality and Utility Management Considerations

• Alfred P. Sloan Foundation - Effect of Pipe Materials, Water Flow, and Chemistry on the Building Plumbing Microbiome

• Edwards Research

Group