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Questions How do resource use (energy+ water) and CO2 emissions compare in 9 cities across the U.S for 1 average swimming pool? Evaluation of potential energy and water savings from simple measures in Phoenix 2

Importance of the Research Connection to our in-class reading “When the rivers run dry” First research of its kind that focuses on environmental implications of a residential pool. Water issue 1)Water scarcity 2)Arid climate in Arizona and reliance on distant and nonrenewable resources. Chemical issue (chlorine and acids) 1)Manufacture of chlorine mercury emissions 2)Chlorine effluents-water toxicity 3)Atmospheric emissions from swimming pools 4)Ozone layer formation 3

Energy Use Issue Pool pumps are second after space heating in terms of energy use in an average household. Goals: Water depletion, energy consumption, global warming potential. 4

Methods Hybrid Life Cycle Assesment Energy =process + EIO-LCA (economic input-output) Process – material input (can be estimated) Such as electricity use. Direct energy input. EIO-LCA – economic data of production impact. (can not be estimated such as energy cost). Secondary consumption of energy (how is water delivered, pipe systems) They use literature, regional water and electricity data to calculate it. 3. Regional energy consumption, state electric consumption, generation and emissions data (CO2) 5

Life Cycle Consider: 1) Input, Output and Impact of 1 swimming pool in 1 year. 2) Operation and Maintenance 6

Purpose of LCA Inform decision makers of environmental impacts of products (chemicals) and processes. Make reasonable and appropriate choices 7

The pool system showing inputs, outputs, and processes Published in: Nigel Forrest; Eric Williams; Environ. Sci. Technol. 2010, 44, DOI: /es100422s Copyright © 2010 American Chemical Society 8

Results 9 Model results for a standard pool system in 9 different U.S cities. a)Annual water use (gallons) by process. b)Annual energy use (killowatt- hours) by source. c)Annual carbon emissions (kg of CO2)

Importance Sending “message to the public” about the potential impact and measures of consumptions and emissions Measures - Pool covers - Efficient pumps - Reduction of pumping schedule 10

Phoenix area energy and water savings from pool impact mitigation measures ActionWater (gallons)Energy (kW per hour) Reduced pump schedule (3-5 h summer, 2-3 h winter) 1720 Warm climate winterization (cover pool and extend winter by 1 month) Efficient central air conditioning 1420 Low flow shower heads 2650 Efficient clothes washer 4630 Efficient lightning (switch all bulbs to fluorescent bulbs)

Relevance to Sustainability “Hope” for environmental improvement Water and energy savings from measures are significant and easy to achieve Covering the pool Reducing pumping schedule Savings 12

Relevance to Sustainability Savings of water and energy use are especially important in such areas as Phoenix 1) A more vulnerable area to negative effects of swimming pools 2)Hot, arid climate 3)Reliance on distant (upstream of Colorado river) and non-renewable resources (ground water) for water supply 4) Every 4 th household has a swimming pool 13

Something Interesting Phoenix metro area. Portland metro area. Beaverton suburbs 14

Ways of Improvement A couple terms.. Backwash- process of cleaning the pool filter after it becomes insufficient Mitigation measures- minimization of the potential impact of a threat or warning More detailed explanation of the relationship between energy consumption and water consumption. 15

Future Experiments Compare different cities Focus on one aspect of swimming pools specifically, such as: -Ozone layer formation as consequence of atmospheric emissions of chlorine OR -Alteration of regional hydrology by chemical inputs (acids, chlorine etc) 16

References Niegel Forrest and Eric Williams. (2010) Life Cycle Environmental Implications of Residential Swimming Pools. Environmental Science and Technology. 44, What is Backwashing. Liner World. May 8, Retrieved from Purpose/Page1.html Purpose/Page1.html Wentz; Gober. Determinants of small-area water consumption for the City of Phoenix, Arizona. Water Resour. Manage. 2007, 21 (11),

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