graywater use by urban households: a sustainability issue david zahler geo 300 environmental...

Graywater Use byGraywater Use byUrban Households:Urban Households:

a sustainability a sustainability issueissue

DAVID ZAHLERDAVID ZAHLER

GEO 300GEO 300

Environmental Environmental ConservationConservation

OLGAOLGA

Oregon Legal Graywater Oregon Legal Graywater

AssociationAssociation

OutlineOutlineOutlineOutline

• The SceneThe Scene• OLGAOLGA

– MissionMission– VisionVision

• ConservationConservation– Water UseWater Use– Potential benefitsPotential benefits– Other Conservation Other Conservation

MeasuresMeasures– Graywater RulesGraywater Rules

• ConclusionsConclusions

The Scene The Scene – OLGA – Conservation – Conclusion – OLGA – Conservation – Conclusion

http://www.oasisdesign.net

• Graywater:Graywater:– Water from laundry, bathtub, shower Water from laundry, bathtub, shower

and (some) sinks;and (some) sinks;– Water that has been used and is no Water that has been used and is no

longer drinkable;longer drinkable;– BUT, graywater has NEVER come in BUT, graywater has NEVER come in

contact with human wastecontact with human waste• OLGA wants to use this graywater for OLGA wants to use this graywater for

irrigation purposesirrigation purposes

The SceneThe SceneThe SceneThe SceneThe SceneThe Scene –– OLGA – Conservation – Conclusion OLGA – Conservation – Conclusion

The SceneThe SceneThe SceneThe Scene

• 2003 Corvallis Pop: 2003 Corvallis Pop: 50,00050,000

• In 20-40 years: 60-In 20-40 years: 60-80,00080,000

• Water sources:Water sources:– Rock CreekRock Creek– Willamette RiverWillamette River– Groundwater: 5 wells Groundwater: 5 wells

The SceneThe Scene – OLGA – Conservation – Conclusion – OLGA – Conservation – Conclusion

http://sarasota.extension.ufl.edu/

• Water Use by Customer ClassWater Use by Customer Class

Source: Mark Taratoot, Corvallis Public Works

The SceneThe SceneThe SceneThe Scene

38% 1% 17% 1% 38% 5%38% 1% 16% 1% 39% 5%0%

5%

10%

15%

20%

25%

30%

35%

40%

45%

All Commercial Fraternity -Sorority

Multi Family Schools Single Family Metered Free

Percent of Total Consumption

2002

2003

OLGAOLGA

The SceneThe Scene – OLGA – Conservation – Conclusion – OLGA – Conservation – Conclusion

• Projection of Water Demand by Projection of Water Demand by PopulationPopulation

Source: Economic and Engineering Services, inc

The SceneThe SceneThe SceneThe SceneThe SceneThe Scene – OLGA – Conservation – Conclusion – OLGA – Conservation – Conclusion

Population Average Daily WaterDemand, CFS (mgd)

Maximum Daily WaterDemand, CFS (mgd)

50,000 11.6 (7.5) 23.2 (15)

60,000 15.4 (10.0) 30.9 (20)

80,000 20.9 (13.5) 41.8 (27)

120,000 30.9 (20.0) 61.9 (40)

• Projection: Anticipated rate of water Projection: Anticipated rate of water withdrawal from the Willamette River withdrawal from the Willamette River

Source: Economic and Engineering Services, inc

The SceneThe SceneThe SceneThe SceneThe SceneThe Scene – OLGA – Conservation – Conclusion – OLGA – Conservation – Conclusion

Population Peak Day Demand Anticipated Rate of Diversionfrom Taylor WTP

50,000 (present) 23.0 cfs (14.9 mgd) 32.3 cfs (20.9 mgd)

60,000 (10 - 20 years) 30.9 cfs (20.0 mgd) 43.8 cfs (28.3 mgd)

120,000 (build-out) 61.9 cfs (40.0 mgd) 93.0 cfs (60.0 mgd)

• Projections based on Projections based on current Urban Growth current Urban Growth BoundaryBoundary

• Changes in use patterns of Changes in use patterns of any or all customer any or all customer classes would change classes would change future water demandfuture water demand

• Other unforeseen changes Other unforeseen changes may reduce future water may reduce future water demanddemand– City of Corvallis is exploring City of Corvallis is exploring

the possibility of recycling the possibility of recycling treated wastewater treated wastewater

The SceneThe SceneThe SceneThe SceneThe SceneThe Scene – OLGA – Conservation – Conclusion – OLGA – Conservation – Conclusion

• Corvallis can produce Corvallis can produce enough drinkable water enough drinkable water to support population to support population projectionsprojections

• But… single family But… single family dwellings are a major dwellings are a major consumer of this water, consumer of this water, and a significant volume and a significant volume is used for reasons other is used for reasons other than drinking or eatingthan drinking or eating

• ““Graywater” can be used Graywater” can be used as/considered a as/considered a resource, not a waste resource, not a waste item item

The SceneThe SceneThe SceneThe SceneThe SceneThe Scene – OLGA – Conservation – Conclusion – OLGA – Conservation – Conclusion

• Organizational Vision Organizational Vision Statement:Statement:– ……dedicated to the creation of dedicated to the creation of

sustainable Oregon Communities with sustainable Oregon Communities with respect to water use. respect to water use.

– Water use as an important indicator for Water use as an important indicator for sustainability: sustainability:

• A gallon used twice is a gallon that stays A gallon used twice is a gallon that stays unprocessed in our waterways;unprocessed in our waterways;

• Energy used for water transport and Energy used for water transport and purification is reduced;purification is reduced;

• City saves money on water coming and City saves money on water coming and going;going;

OLGAOLGAOLGAOLGAThe Scene The Scene –– OLGA OLGA – Conservation – Conclusion – Conservation – Conclusion

One gallon of One gallon of graywater used by graywater used by urban households is urban households is one gallon of one gallon of potable water potable water reserved for its reserved for its highest and best usehighest and best use—human —human consumption.consumption.

OLGAOLGAOLGAOLGAThe Scene The Scene –– OLGA OLGA – Conservation – Conclusion – Conservation – Conclusion

• Organizational Mission Statement:Organizational Mission Statement:

… … assist the State of Oregon to assist the State of Oregon to develop, test (through household develop, test (through household demonstration sites), and demonstration sites), and adopting graywater use adopting graywater use regulations that facilitate reduced regulations that facilitate reduced water consumption in urban water consumption in urban households through safe, households through safe, effective, graywater use.effective, graywater use.

OLGAOLGAOLGAOLGAThe Scene The Scene –– OLGA OLGA – Conservation – Conclusion – Conservation – Conclusion

• Household Water Use for an Household Water Use for an Average Home:Average Home:

ConservationConservationConservationConservationThe Scene The Scene –– OLGA – OLGA – ConservationConservation – Conclusion – Conclusion

Use GPCD Percent of indoor use

Toilets 18.5 26.7%

Showers 11.6 16.8%

Faucets 10.9 15.7%

Baths 1.2 1.7%

Dishwasher 1.0 1.4%

Clothes Washer 15.0 21.7%

Leaks 9.5 13.7%

“Other” 1.6 2.2%

• Household Water Use for an Household Water Use for an Average Home:Average Home:

ConservationConservationConservationConservationThe Scene The Scene –– OLGA – OLGA – ConservationConservation – Conclusion – Conclusion

Use GPCD Percent of indoor use

Toilets 18.5 26.7%

Showers 11.6 16.8%

Faucets 10.9 15.7%

Baths 1.2 1.7%

Dishwasher 1.0 1.4%

Clothes Washer 15.0 21.7%

Leaks 9.5 13.7%

“Other” 1.6 2.2%

Blackwater Sources (?)

• Household Water Use for an Household Water Use for an Average Home:Average Home:

ConservationConservationConservationConservationThe Scene The Scene –– OLGA – OLGA – ConservationConservation – Conclusion – Conclusion

Use GPCD Percent of indoor use

Toilets 18.5 26.7%

Showers 11.6 16.8%

Faucets 10.9 15.7%

Baths 1.2 1.7%

Dishwasher 1.0 1.4%

Clothes Washer 15.0 21.7%

Leaks 9.5 13.7%

“Other” 1.6 2.2%

“Easy” Graywater Sources

(some faucets)

• Graywater Savings:Graywater Savings:– Use 9 gallons/person/day from showersUse 9 gallons/person/day from showers– Use 5 gallons/person/day from faucetsUse 5 gallons/person/day from faucets– Use 10 GPD from clothes washer…Use 10 GPD from clothes washer…

– ……to water your garden perennials, you to water your garden perennials, you conserve about 25 GPD for “highest and best conserve about 25 GPD for “highest and best use”use”

… … 60 gallons per day in an average household!60 gallons per day in an average household!

ConservationConservationConservationConservationThe Scene The Scene –– OLGA – OLGA – ConservationConservation – Conclusion – Conclusion

• Other Conservation Measures: Other Conservation Measures: SAVINGSSAVINGS– Install high efficiency toilet: Install high efficiency toilet: 10 GPCD10 GPCD– Install efficient showerhead:Install efficient showerhead: 3 GPCD 3 GPCD– Install efficient clothes washer:Install efficient clothes washer: 5 GPCD 5 GPCD– Fix leaks!Fix leaks! 5 GPCD 5 GPCD

TOTAL Savings:TOTAL Savings: 23 GPCD23 GPCD

• The irony: Increased efficiency leads to less The irony: Increased efficiency leads to less available graywater for irrigation purposes.available graywater for irrigation purposes.

ConservationConservationConservationConservationThe Scene The Scene –– OLGA – OLGA – ConservationConservation – Conclusion – Conclusion

• Graywater Rules:Graywater Rules:– Defines how a system should be Defines how a system should be

constructedconstructed

ConservationConservationConservationConservationThe Scene The Scene –– OLGA – OLGA – ConservationConservation – Conclusion – Conclusion

• Graywater Rules:Graywater Rules:– Defines how a system should be Defines how a system should be

constructedconstructed– Defines where a system can be Defines where a system can be

constructedconstructed

ConservationConservationConservationConservationThe Scene The Scene –– OLGA – OLGA – ConservationConservation – Conclusion – Conclusion

• Graywater Rules:Graywater Rules:– Defines how a system should be Defines how a system should be

constructedconstructed– Defines where a system can be Defines where a system can be

constructedconstructed– Defines when a system can be usedDefines when a system can be used

ConservationConservationConservationConservationThe Scene The Scene –– OLGA – OLGA – ConservationConservation – Conclusion – Conclusion

• Graywater Rules:Graywater Rules:– Defines how a system should be Defines how a system should be

constructedconstructed– Defines where a system can be Defines where a system can be

constructedconstructed– Defines when a system can be usedDefines when a system can be used– Defines how graywater is appliedDefines how graywater is applied

ConservationConservationConservationConservationThe Scene The Scene –– OLGA – OLGA – ConservationConservation – Conclusion – Conclusion

• Graywater Rules:Graywater Rules:– Defines how a system should be Defines how a system should be

constructedconstructed– Defines where a system can be Defines where a system can be

constructedconstructed– Defines when a system can be usedDefines when a system can be used– Defines how graywater is appliedDefines how graywater is applied– Defines graywater and what nasty Defines graywater and what nasty

things shouldn’t be in itthings shouldn’t be in it

ConservationConservationConservationConservationThe Scene The Scene –– OLGA – OLGA – ConservationConservation – Conclusion – Conclusion

• Graywater Rules:Graywater Rules:

– Such rules can make Such rules can make graywater use for irrigation graywater use for irrigation purposes safe and part of purposes safe and part of the water conservation the water conservation “toolkit” for urban “toolkit” for urban householdshouseholds

ConclusionConclusionConclusionConclusionThe Scene The Scene –– OLGA – Conservation – OLGA – Conservation – Conclusion Conclusion

The State of Oregon, The State of Oregon, through DEQ rules, can through DEQ rules, can proactively change the proactively change the culture of domestic culture of domestic water consumption water consumption through safe, legal through safe, legal graywater use.graywater use.

ConclusionConclusionConclusionConclusionThe Scene The Scene –– OLGA – Conservation – OLGA – Conservation – ConclusionConclusion