Karen DuBoseMarch 11, 2009

The SituationCorvallis’ wastewater treatment plant will

exceed its TMDL water quality requirements as the city grows

Wastewater recycling is an excellent solutionNo need to discharge

into the riverAdvances the city’s

sustainability ethic

Goals of this studyDiscover what factors

influence the public acceptance of water reuse in Corvallis

Make recommendations to the city about how to pursue a wastewater recycling project

Factors that have been found to influence public opinion

AgeGenderEducationIncomeOccupationLength of residenceDegree of contactPrior knowledge of

water reuse

Awareness of water problems

Presence of childrenTrust in local public

utility Health effectsEnvironmental effectsCost of projectPublic opinion of reuse

MethodsDecember 2008 survey of registered voters,

46% response rate19 questions, six were demographicMultiple linear regression

A model of public acceptance in Corvallis

Acceptance = β0 + β1(Informed) + β2(Knowledge) + β3(Aware) + β4(Sustainability) + β5(Trust) + β6(Gender) + β7(Age) + β8(Children present)

+ β9(Education)

Dummy variables: knowledge, aware, gender, age, children present

Q-4 For the following terms, please indicate if you know what the term means, have heard of the term but don’t know its meaning, or have not heard of the term at all.

Have not heard of the term at all

Have heard of the term but don’t know

its meaning

Know what the term means  

a. Potable water 1 2 3  

b. Wastewater 1 2 3  

c. Greywater 1 2 3  

d. Sewage 1 2 3  

e. Recycled water 1 2 3  

f. Effluent 1 2 3  

Measuring knowledge

Measuring sustainability ethicQ-6 How important are each of the following when choosing an approach to meeting the new

water quality regulations in the Willamette River? If you have no opinion of one, please leave it blank.

Not Important

at All

Limited Importance

Somewhat Important

Important Very Important

a. Prevent pollution 1 2 3 4 5

b. Protect human health 1 2 3 4 5

c. Be a long term solution 1 2 3 4 5

d. Be energy efficient 1 2 3 4 5

e. Be financially sound 1 2 3 4 5

f. Protect fish and wildlife 1 2 3 4 5

g.Have low greenhouse gas emissions

1 2 3 4 5

Acceptance of recycled water usesQ-7 How much do you favor the use of recycled wastewater for each of the following? If you don’t know or

have no opinion of a use, please leave it blank.Highly

UnfavorableUnfavorable Neutral Favorable Highly

Favorable

a. Irrigate golf courses 1 2 3 4 5

b.Irrigate landscaping in business parks

1 2 3 4 5

c. Irrigate public parks 1 2 3 4 5

d. Irrigate school grounds 1 2 3 4 5

e.Irrigate non-edible agricultural crops (grass)

1 2 3 4 5

f.Irrigate agricultural crops for human consumption

1 2 3 4 5

g. Use in industrial processes 1 2 3 4 5

h. Use to cool buildings 1 2 3 4 5

i.Flush toilets in public buildings

1 2 3 4 5

j.Supply fire hydrants in the city

1 2 3 4 5

k. Supply car wash businesses 1 2 3 4 5

Percentage of respondents choosing "very favorable" or "favorable" for various recycled water uses.

Grouping uses of recycled water

Factor analysis looks for patterns in responses3 groups of recycled water uses:

High contact (irrigate schools, public parks, edible crops)

Low contact (irrigate business parks, golf courses, non-edible crops, use in industrial processes)

Other uses (building cooling, toilet flushing, fire hydrants, car washes)

Factor scores were used in 3 regressions, one for each group

Regression coefficients for factors of water reuse acceptanceIndependent Variable High Contact Low Contact Other Uses

Informed -0.018(0.794)

-0.088(0.184)

-0.093(0.157)

Knowledge of wastewater 0.004(0.909)

0.100(0.009)

0.059(0.120)

Aware of problem (1=yes) -0.394(0.000)

-0.019(0.862)

-0.043(0.694)

Sustainability index 0.026(0.051)

0.022(0.101)

0.040(0.003)

Trust to serve public interest

0.111(0.109)

0.125*(0.067)

0.080(0.237)

Gender (1=male) 0.279(0.004)

-0.208(0.029)

0.068(0.474)

Age -0.003(0.324)

-0.003(0.306)

-0.003(0.355)

Education -0.020(0.627)

0.029(0.485)

0.090(0.028)

Children present (1=no) -0.045(0.663)

-0.165(0.104)

0.172*(0.088)

P-values for the coefficients are in parenthesis. Red values are significant at 95%; * denote significance at 90%.

Policy implicationsCity should pursue water reuse; there is high

acceptance of most usesLow contact uses are most acceptedMake sure a program adheres to the

principles of sustainability Educate public about wastewater treatment,

water reuse, technologies, and reason for water reuse

If high contact uses are chosen, make a special effort to include women

Study limitationsResults should be considered hypothetical

Studies show that factors influencing acceptance change when specific plans are presented

Little information about water reuse was presented due to spaceMany respondents stated they wanted more information

Questions?

Support provided by

Institute for Water and Watersheds Master of Public Policy Program