Sustainability: Water Reuse

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Arizona State University’s Decision Center for a Desert City has released a new report on water reuse in Central Arizona. Dave White, who co-authored the report, will talk about water reuse.

Ted Simons: ASU's decision center for a desert city release add report on water reuse in central Arizona recently and how best to use effluent as part of the state's water sustainability plans. Dave White is the co-director and joins us. Good to have you.

Dave White: Great to be here.

Ted Simons: What is decision center for desert city. What's that all about?

Dave White: Thank you for asking. We're a unit of the Global Institute of Sustainability at ASU. So it's a research center. We're focused on the issues of water sustainability and helping to improve the decisions that are made about the future of this critical resource in our state.

Ted Simons: This report now is water reuse in central Arizona. Talk about the report and how you would like to see it used.

Dave White: Well the report was developed by our research center, authored I should say by Arianna Miguel, Ray Clay and myself. The focus of the report is to continue and stimulate an ongoing dialogue in the policy community about issues critical to water sustainability for the future of our state. So there have been a number of reports from places like the Morrison Institute for Public Policy, from the governor's office, had a blue ribbon panel on water sustainability. We're trying to continue that dialogue and push the conversation about particular critical issues in this case the idea of water reuse.

Ted Simons: Let's get a definition here. What does water reuse mean?

Dave White: Well there have been times in the past where wastewater, the water produced as a waste product from homes and businesses, was thought of as just that, a waste product to be disposed of, but increasingly communities around the United States are seeing this as a critical resource to be reused for beneficial purposes including industrial purposes, urban irrigation, agricultural irrigation, ground water recharge. Other purposes. So it's seen as an important management strategy to stretch our existing water supply.

Ted Simons: I used the word effluent like I know what it is. Give me a definition.

Dave White: Effluent is simply a treatment, type of water that has been wastewater that's been treated to a particular standard. So we can talk about wastewater that flows from homes and businesses, goes to wastewater treatment plants. That water can be treated to a variety of different qualities or levels for different types of uses. For uses on golf courses, in lakes and ponds and fountains, or it can be treated to higher level uses that involve human contact. It can also be treated to the level of indirect potable reuse where we're adding not treated effluent to other water supplies and then eventually reusing that for human consumption.

Ted Simons: Can you use effluent for recharging aquifers? Is there a concern there?

Dave White: Absolutely we can. That's one of the important uses of our municipal effluent is to use that water. We inject it into what's called the VADOS zone. We let it percolate down through the ground into the ground water supply and it's purified by natural processes in that way. It's an excellent way to take excess water that's being produced through the wastewater system and recharge those aquifers to help create a buffer or a bank of water for future use.

Ted Simons: I know golf courses and irrigation, we're seeing treated water there. Burr are we actually seeing this ground water recharged right now with effluent?

Dave White: Yes. This is occurring now in Arizona. It's one of the major uses of the treated effluent is for groundwater recharge. The biggest uses are for irrigated agriculture. Treating it to a certain standard then it can be applied to crops such as cotton, it can also be used for urban irrigation for lawns and golf courses. Can be recharged to the aquifer or used for industrial cooling processes such as at the Arizona Public Service nuclear generating station.

Ted Simons: I would imagine that important plant uses a lot of water. Is a lot of it effluent? Treated water?

Dave White: Absolutely. In fact they take about 80,000 acre feet of water. an acre foots is the amount of ward used to flood one acre of land to the depth of one foot or the amount that would be used for two households a year in Arizona. 80,000 acre feet a year going to the Palo Verde nuclear generating station for their cooling purposes. They are one of the largest users, one of the largest nuclear power plants not located on a permanent body of water. It's an excellent example of how we can take this reused water and put it to use to support power generation in our community.

Ted Simons: From your report it sounded like the cost concerns are there, but they are there for an interesting reason in that competition for water kind of finds its own level, if you will, and impacts everything.

Dave White: Absolutely. What we're seeing is the potential for increased competition, increased cost for municipal effluent into the future. One of the important things we try to achieve in this report is to set up a policy dialogue to encourage a conversation just with our raw water or surface water supplies from the Salt and Verde River systems. We want people to have an open, transparent dialogue about what are the best and highest uses for this effluent. Should we be using it, for instance, to support the golf course industry in North Scottsdale? That provides important milk benefits and tourism dollars. Should we use it for cooling the power plant? For recharging the aquifer? Just like regular water supplies we'll come to a place where we don't have enough water for every beneficial purpose.

Ted Simons: Indeed. Back to the cost, if something happens, if the competition means all of a sudden ground water winds up cheaper than effluent, that's not a good thing.

Dave White: Right. We want to in the central Arizona area encourage policies, behaviors, incentivize the conservation vacation of our ground water and the main -- for the state does just that. It's one of the most progress ground water conservation laws in the United States. It was passed in 1980. If it were passed today, it would be one of the most progressive groundwater conservation laws. We want to keep that supply as a buffer for times of drought and to mitigate and adapt to the potential impacts of climate change.

Ted Simons: I was going to ask about drought and climate change. How much was that factored into what you guys were reporting on?

Dave White: We were considering that very carefully. One of the reasons we wrote this report is that several commissions, boards and other reports have focused on the issue of climate change. One of the common conclusions is we must increase the amount of water reuse as a strategy to deal with potential supply deficits into the future that may occur as a result of climate change impacts or drought or population growth. So while we agree wholeheartedly with this as a primary policy goal, we want to point out some of the challenges that we need to address. Thinking about competition, thinking about cost, thinking about dealing with the increasing concern over contaminants like pharmaceuticals and other contaminants in the wastewater supply. Let's deal with those now so that we can use this important supply.

Ted Simons: Are we dealing with those now?

Dave White: Yes, absolutely there are a number of important organizations both at the university and in the cities and in the regulators, department of water resources who are focused on exactly those concerns. What are the appropriate levels for things like pharmaceuticals that are making their way into that wastewater supply? We're able to detect those at much smaller concentration now but we yet have developed environmental quality standards for many of those pharmaceuticals either at the federal or state level.

Ted Simons: Last question here. This involves perception. Is it a concern and is it an issue with the yuck factor, if you will, the fact that folks hear effluent they hear wastewater, treated water and they say get that stuff away from me.

Dave White: I think one thing that's changing is Arizonans are increasingly coming to grips with the idea we should use the appropriate water quality for the appropriate use. We don't need to use our potable water supply for watering our lawns, for instance or our golf courses. I think people are really coming to grips with there are different qualities of water including treated wastewater that makes sense to use in different purposes. Will we reach a point where like in California and Florida we come to a place of direct potable reuse, where we treat that wastewater and return it directly to the drinking water treatment plants for delivery to households? It's possible. It's not in the immediate future, but it's possible. I think people will come to grips with that over time.

Ted Simons: All right, great information. Good to have you here.

Dave White: Thanks for having me.

Ted Simons: Tomorrow on "Arizona Horizon," our weekly political update with the Arizona Capitol Times and we'll look at a new report on the economic self-sufficiency of low income Arizona women. That is tomorrow at 5:30 on the next "Arizona Horizon."

Dave White:Co-Director, ASU's Decision Center for a Desert City;

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