green building premise plumbing: identifying public
TRANSCRIPT
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
0.0
10.0
20.0
30.0
40.0
50.0
60.0
29 MGD
Wat
er D
eman
d (
MG
D)
Water Demand – Newport News Waterworks
Data: Brian Ramaley and Newport News, VA Waterworks
32.7
0.0
10.0
20.0
30.0
40.0
50.0
60.0
29 MGD
Wat
er D
eman
d (
MG
D)
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.
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
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
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