Water Conservation, K Jones, GBF2008

EDUCATION - CONSULTING - SOLUTIONS

Water Conservation & Reuse
Greywater Recycling and Rainwater Harvesting

Green Building Festival
September 2008

Geoff Jones

Copyright © 2008 ECOShift – 6819109 Canada Inc
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Overview
Content
• Current Water Situation and Importance of
Conservation
• Overview of Greywater Recycling
– Applications / Considerations / Benefits / Case Studies
• Overview of Rainwater Harvesting
– Applications / Considerations / Benefits / Case Studies

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Fresh Water Statistics
• Only 2.5% of the water in the World is Fresh Water
• > 1.5% of fresh water is locked in Glaciers
• < 1% of fresh water is available through ground and surface
water sources

97.50%

Salt Water

Glacial Fresh Water

Accessible Fresh Water

<1% >1.50%

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Global Water Usage
Statistics
• Water use in the 20th century increased more than six fold,
and continues to increase about twice as fast as the human
population is increasing
• There are 1.1 billion people, or 18 per cent of the world's
population, who lack access to safe drinking water
(WHO/UNICEF, 2005 : 40)
• Water consumption in industrialized countries runs as high
as 380 liters/capita/day in the United States (USGS, 2004)
and 129 liters/capita/day in Germany (Statistisches
Bundesamt, 2000)
• In developing countries 20-30 liters/capita/day are
considered enough to meet basic human needs

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The Great Lakes
• The Great Lakes are the largest system of fresh surface
water on earth, containing roughly 18% of the world supply.
• The Great Lakes support 33 million people, including nine
million Canadians and eight of Canada's 20 largest cities.
• The Great Lakes support 25% of Canada's agricultural
capacity.
• Approximately 60% of Canada's fresh water drains north,
while 85% of the population lives within 300 kilometers of
the southern border with the United States.
• Only 1% of the waters of the Great Lakes are renewed
each year by snow melt and rain.
How much longer will they be referred to as “Great Lakes”?

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Water Conservation
What are some other ways we can conserve and be more
efficient in how we use water?

Greywater Recycling

Rainwater Harvesting

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Greywater Recycling
What is Greywater?
• Greywater is generally known as non-industrial wastewater
from bathing/showering, washing dishes and laundry.
• Greywater represents approximately 70% of all wastewater
from domestic use.
• Typically two types of Grey Water are identified.
1. Light Greywater – water from Baths/Showers, Bathroom Sinks
and Laundry
2. Dark Greywater – water from Kitchen Sinks and other kitchen
wastewater

NOTE: Most often greywater is generically used to refer to either light or dark greywater and
this classification is often not used

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Greywater Recycling
Water Usage In The Home
Water used in the bathroom accounts for over 60% of the
water we use in our homes

Source: Environment Canada Water Use Surveys

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Greywater Recycling
Benefits
• Conserve Water and Reduce Wastewater
• Save Money
• Reduce Demand on Your Well
• Reduce Load on Your Septic System or Holding Tank
• Delay or reduce costly infrastructure updates
• Gain LEED & Built Green Points
• Reduction in Municipal water treatment and pumping can
result in significant reductions in electricity usage
• Supply and demand not affected by environmental
conditions (i.e. rainfall patterns)

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Greywater Recycling
Greywater Recycling is the reuse of greywater in domestic and
Industrial / Commercial / Institutional (ICI) applications for
flushing of toilets etc.
Applications
• Toilet Flushing (2006 Ontario Building Code): Reuse of
greywater for flushing toilets can reduce potable water use
by approximately 30%
• Irrigation (Code Permitting): Although not recommended for
edible crops greywater is used for irrigation of
plants/shrubs/grass in some areas of the world
• Other Potential Future Uses (Code Permitting): With
appropriate treatment greywater uses can include
bath/shower, laundry, and possibly drinking water

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Greywater Recycling
When implementing a greywater recycling system some
considerations must be made.
Considerations
• Supply / Greywater Sources:
Bath/Shower: Typically sufficient volume to address toilet
flushing needs
Laundry: Additional filtration for lint may be appropriate
Sinks: Generally very little volume of water (not
recommended in retrofits)
Kitchen: Contains high amounts of food waste and
grease/oil (not recommended)

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Greywater Recycling
Considerations (cont’d)
• Dual Plumbing: Capture/distribution of greywater must be
done through dedicated drain/supply lines which are clearly
marked to avoid cross contamination with potable water
• Filtration: To remove soap residues, soap solids, hair and
lint greywater typically requires some form of filtration
• Treatment: To prevent bacterial growth and odors
greywater typically requires some form of treatment (i.e.
Chlorine etc.)
• Recirculation System: During periods of inactivity
recirculation ensures continued disinfection of stored
greywater

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Greywater Recycling
Residential Application: Cambridge, Ontario
System Overview
• Separate drains from Bath/Shower redirect greywater into a
250 liter Greywater Recycling system
• Greywater is filtered and then disinfected to kill bacteria and
prevent odors
• Treated greywater is then provided to the toilets through
dedicated, clearly marked, grey water lines
• A recirculation timer allows for circulation of stored
greywater to ensure continued disinfection
• Excess greywater overflows into existing sewage drain

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Greywater Recycling
System Overview (cont’d)
• If there is insufficient greywater make-up water is
automatically provided into the tank to ensure there is
always enough water for flushing
• Greywater captured from Bath/Shower is sufficient to
address daily toilet flushing needs
Maintenance
• Wash and rotate filter approximately once a month
• Replace chlorine puck every 4-6 weeks

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Greywater Recycling
Water Demand / Wastewater Reduction
Calculated statistically
• According to Environment Canada toilets represent about
30% of domestic water use in the home (~42 L/d per
person)
• Potable water and sewage outflow reductions of
approximately 76,000 liters per year for a family of 5
• Annual savings of approximately $165 a year at 2008 water
rates (based on 7 flushes/person, 6L Toilets, $2.12m3)
• Annual savings of approximately $370 a year at 2015 rates
(based on current proposed rate increases (13.5% annual)
(NOTE: Savings vary based on usage patterns, # people, toilet flush volume, and water rates)

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Greywater Recycling
Water Demand / Wastewater Reduction
Based on measured water consumption reduction
• Current savings represent a 41% reduction of domestic
water use in the home
• Potable water and sewage outflow reductions of
approximately 100,000 liters per year for a family of 5
• Annual savings of approximately $210 a year at 2008 water
rates (based on demand reduction observed after 4 months)
(based on current proposed rate increases)
(NOTE: Savings vary based on usage patterns, # people, toilet flush volume, and water rates)

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Greywater Recycling
Measured Water Consumption / Wastewater Reduction

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Greywater Recycling
System Cost (Retrofit)
• 2 Story Retrofit – Approximately $1600 (parts and labor)
• System Cost approx $2200
• Total: $3800-$4000
NOTE: Total costs can vary based on family size, building design, and many other factors

Cost Benefit Analysis (Retrofit)
• System payback approximately 18-20 years at 2008 rates
• System payback approximately 8 years at proposed 2015
rates

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Greywater Recycling
Savings Perspective

An average family of 4 using a greywater recycling system will
save between 45,000 and 62,000 liters of water per year.

That’s enough water to meet the basic needs of up to 8 people
for 1 year in a developing country.

According to UN Water For Life, in developing countries 20-30 liters per day is considered enough to meet basic
human needs.

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Greywater Recycling
Commercial Application: Correctional Facility, Mississippi
System Overview
• Separate drains from Bath/Shower redirect greywater into a
6600 liter Greywater Recycling system
• Greywater is used for flushing of all toilets and urinals
• 15 Greywater recycling systems serving 1668 beds in total
• Greywater is filtered to remove soap solids, residue, hair
and dirt
• Greywater is disinfected using chlorine to kill bacteria and
prevent odors

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Greywater Recycling
• An electronically controlled, constant pressure pumping
system supplies greywater to toilets and urinals
• An independent pump controls recirculation of greywater in
the cistern to maintain sufficient levels of chlorine as per
local regulations
• Excess greywater overflows into existing sewage drain
• If there is insufficient greywater the make-up water system
automatically ensures there is always enough water
available for flushing

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Greywater Recycling
System Overview

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Greywater Recycling
Maintenance Plan
• Alarms monitored daily via visual drive by inspection
• Filters checked weekly and rotated as necessary depending
on usage
• Fresh water and greywater counters are monitored and
logged to track water savings
Savings
• Savings projected to represent approximately 30% of total
potable water
• Potable water and sewage outflow reduction estimates of
approximately 25,000,000 liters per year

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Greywater Recycling
System Cost
• Total cost of system approximately $600,000
(Cost Includes: Units, Installation, and Shipping)
NOTE: System costs can vary based on site conditions, geographic location, building design, and many other factors

Cost Benefit Analysis
• System payback estimated at 42 months (3 ½ years)
• System payback for retrofit installations estimated at 52
months (4 1/3 years)

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Greywater Recycling
Applications Around the World

Germany
• Hotel Arabella Sheraton in Offenbach, Germany is saving
approximately 20m3/d using greywater for toilet flushing

Jordan
• Greywater is used for “restricted irrigation” (WHO Standard)
which applies to trees and crops that must be cooked before
eaten

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Overview
• Rainwater harvesting is not a new technology
• Rainwater harvesting was used in ancient Rome and in
many other parts of the world centuries ago
• Rainwater harvesting is used in many areas throughout the
world today
• Rainwater is soft water deposited as part of the earth’s
natural hydrological cycle

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Benefits
• Conserve Potable Water
• Save Money
• Help control / manage stormwater flows
• Provide a primary source of water where municipal water or
wells are not possible
• Delay or avoid costly infrastructure updates/maintenance
(municipal and/or individual)
• Gain LEED & Built Green Points
• Reduce high water demand due to irrigation in the summer
months

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Rainwater harvesting can provide water for many domestic
uses and help to manage stormwater flows
Applications
• Irrigation : One of the most common uses for rainwater
harvesting in Canada is irrigation. Water demands can
increase by up to 50% during summer months. Rainwater
harvesting can eliminate or significantly reduce this demand.
• Toilet Flushing: Using rainwater for flushing toilets can also
reduce potable water use by approximately 30% or more
• Other Uses: It is also possible to use Rainwater in some
areas for domestic uses such as bath/shower, laundry,
dishwashing and with appropriate treatment, drinking water
(always check local codes)

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When implementing a rainwater harvesting system some
considerations must be made.
Considerations
• Supply: Rainfall patterns (supply) for the area must be
assessed
• Demand: Application End Uses must be determined
• Catchment Area: Roof size and type have an impact on the
amount of water that can be captured for a given rainfall
• Pre/Post Treatment: Depending on the environment and
end use application either pre-treatment/filtration, post
treatment/filtration, or a combination of both may be
required to maintain/improve water quality

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Considerations (cont’d)
• Storage: Above or in ground storage (i.e. concrete cistern,
polyethylene cistern, bladder tanks etc.)
• Overflow: During overflow events design must ensure
excess rainwater is properly managed
• Dual Plumbing: Rainwater must be delivered through
clearly marked dedicated supply lines to avoid cross
contamination with potable water systems
• Make-Up Water: Depending on the application it maybe
necessary to provide make-up water to ensure the system
doesn’t run dry (if supply is critical to end use)

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Commercial Application: Metro Label, Toronto
System Overview
• Catchment Area of approximately 10,000 sqft (968m2)
• Rainwater Cistern capacity of 18m3 (18,000 liters)
• Rainwater is used to supply 6 toilets (3/6 liter dual flush) and
1 of 2 hose bibs for light irrigation (primary irrigation is
handled via an irrigation system connected to municipal
water)
• Flow meters were installed on both the municipal potable
water line and one on the cistern water supply line to allow
for demand / usage monitoring

Source: TRCA May 2008 – Performance and Evaluation of Rainwater Harvesting System
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• Sensors were installed in both the drawdown and
sedimentation tank to monitor water levels
• Estimated Total Demand: 728 L/d Women, 243 L/d Men
(waterless urinals), 101 L/d hose bib = 1060 L/d
Savings
Calculated
• Water savings calculated at 327 m3/yr during a year with
normal precipitation (~798mm)
• Reduction in Stormwater Run-off of approximately 42%
• Reduction in municipal water use of approximately 89%

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Savings (cont’d)
Measured
• Measured Water Savings during 2007 ranged between
20m3 and 27m3 per month (~1m3 per work day)
• Cistern was able to significantly reduce potable water
demand, and displace it 100% during some months
• Total water saved from October 2007 – December 2007
was approximately 65m3

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Savings (con’t)

• System Cost (excluding internal pipework) approx $18,000

• System payback approximately 32 years at current rates
• System payback approximately 20 years at future proposed
rates

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Commercial Application: Same Project – Different Location
Savings – Waterloo Region

• System Cost (excluding internal pipework) approx $18,000

• System payback approximately 24 years at current rates
• System payback approximately 12 years at future proposed
rates

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Adoption around the World
Belgium
• National legislation - all new construction to have rainwater
harvesting systems for the purposes of flushing toilets and
external water uses
Germany
• In Europe, Germany is a leader in encouraging widespread
utilization of rainwater catchment systems for domestic
supply and other purposes
• Germany legalized RWH systems in 1980 and Hamburg
was the first city to provide subsidies in 1988

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Adoption around the World

US
• Texas has had tax relief for commercial/industrial RWH
systems since 1993
• Texas introduced a sales tax exemption in 2001 for all RWH
systems (TRHEC, 2006)
• Santa Fe, New Mexico requires RWH systems on all
residential buildings greater than 2500sqft (TRHEC,2006, C
of A, 2007)

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THANK YOU

EDUCATION – CONSULTING - SOLUTIONS

519-620-7385
Geoff@ECOShift.ca
www.ECOShift.ca

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Water Conservation, K Jones, GBF2008

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