My Show and Tell


Every student int our Green Communities class gets the opportunity to do a show and tell: to share something with our peers that provokes, inspires, and uplifts us.

With my research focus on water, the topic of my show and tell was a foregone conclusion. But, at first, what to share stymied me.

I considered the city of Tucson’s decision to use its surplus Central Arizona Project water to create a “pulse” flow, which allowed the Colorado River to reach its mouth at the Sea of Cortez for the first time in fifty years.

I considered the local rainwater harvesting initiative championed by the Utah Rivers Council – an effort to decrease contaminated stormwater runoff and reduce outdoor water use.

I considered my own project to revitalize Red Butte Creek on the University of Utah campus as a social, economic, and environmental asset.

Ultimately, I decided to go for something more straightforward.


A crucial challenge in water resources management is to create closed-loop, rather than open-loop systems. A closed loop is water neutral. You use the same water again and again. As a large scale example, the global hydrological cycle is a closed loop: the planet has a finite amount of water, moving through different phases and different locations in the soil, rivers, lakes, oceans, icebergs, and atmosphere.

We can think about closed water loops at all sorts of scales. Orange County pumps water from a massive underground aquifer, pumps recycled “waste” water back into the same aquifer, and pumps it out again. Las Vegas pumps water from Lake Mead, then diverts “waste” water through Las Vegas Wash and back into the Lake. (Of course, if climate change slows the Colorado River to a trickle, Lake Mead will dry up and Vegas will still be shit out of luck.)

My show and tell looked at technologies that close the water loop at smaller scales. The first image above is the Janicki Omniprocessor. It converts sewer sludge and other toxic, contaminated water sources into clean drinking water, electricity to continue running the machine, and ash that can be used for soil fertilizer. It is a large contraption, but considering that it can serve 100,000 people, not all that large.

The second image above is the Slingshot water purifier. Like the Omniprocessor, the Slingshot can convert horribly contaminated water into clean, purified drinking water. It can serve 100 people, running on less energy that a toaster oven.

The implications here are profound. As long as people are generating sewer sludge – meaning as long as we’re eating – we have machines that can recycle the water, using almost no energy or even largely powering themselves. Right now, the primary thinking around these innovations focuses on their use in the third world – providing clean drinking water for the millions of people who lack safe access. This the obvious, and probably the most immediately important application.

On a slightly longer time horizon, however, these energy efficient water purifying machines may become crucial to urban water management everywhere. In Salt Lake City, for example, major water supply deficits are anticipated in the coming decades. The de facto solution for local resource managers is to build huge new supply infrastructure, costing billions of taxpayer dollars and threatening sensitive ecosystems. But this strategy will only kick the problem down the road – what happens when we use all of that water, too?

A more sustainable solution is to close the urban water loop in Salt Lake City now. With a back of the envelope calculation, I estimated that implementing Omniprocessor or Slingshot machines to supply water in Salt Lake County would cost 1% or less than large infrastructure proposals, without damaging the environment and while generating local capacity, sustainability, and resilience.

It’s a no-brainer, right?

Let’s make it happen.


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