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How wastewater’s circular economy can help fight climate change

September 09, 2021

By Arthur Umble

It’s time to change our linear Industrial Revolution ways. We must close the loop and return products from the waste stream to the economic stream.

The Industrial Revolution of the 18th and 19th centuries changed life on our planet. It transformed the global economy—and helped create great nations and massive companies.

That industrial model—which is still quite common today—is very linear. The economic development was built around the ideal of extracting materials from the earth, processing those resources into products, using those products, and disposing of them at the end of their life.

Energy was the driver of the Industrial Revolution. The energy came mostly from fossil fuels—and it still does. What started so many years ago, has led us to today’s world of climate change.

The environment paid the ultimate price. And it has a limit. So, what are we going to do about it?

It’s time to switch from a one-way, linear model. It’s not sustainable. And we have better options. We must decouple economic development from the environment, which is paying the price.

We need to move to a circular economy, which I’ve talked about previously. Naturally, the circular economy crosses all sectors, but I want to talk about how it can work within the wastewater treatment industry.

Of course, wastewater is just a small piece of the puzzle. But it’s my piece. And I know we can be part of the climate change solution.

Finding what we need in wastewater

This may seem odd, but wastewater is full of good stuff. It includes resources in energy, minerals, carbon, and industrial chemicals. The circular economy is simply removing those resources from “waste” and putting them back into product processing.

It’s critical that our clients—the utilities we all use—understand that we have all the resources we need already. We don’t need to go to Morocco and mine more phosphorus, we’ve got all the phosphorus we need right there in the wastewater. This is an example of how we decouple economic development from the environmental impact that is caused by the extraction of that resource.

Here’s another example: We can grow microalgae from the nutrients present in wastewater. We can convert the algae into energy, displacing coal-burning power plants with electricity generated right from the wastewater. And we can extract alginate from the algae and use it in processed foods, medicines, and a host of household products. That is the circular economy. That is how we address climate change on many levels.

Instead of extracting everything we need from Earth’s finite resources, we need to shift our thinking—and our priorities. Returning products from the waste stream to the economic stream adds value.

When we close the loop, we no longer need to rely solely on traditional extraction. And these are not just fanciful ideas. They are happening.

In the European Union, they are mandating a circulatory system for their waste. If Europe wants to be sustainable it must decouple. They are much more land-constrained for their population base than we are here, so it’s a critical priority for Europe. But it should be in North America, too.

Here in Colorado, we are working with Metro Water Recovery in Denver on multiple projects. One of those projects is extracting phosphorus from the wastewater. Phosphorus is a fundamental ingredient in every living cell. By recovering it, Metro can recycle that phosphorus into agricultural fertilizer, displacing the extraction of this finite resource and offsetting the greenhouse gases generated from the production of fossil fuel-based commercial fertilizers.

There will be challenges

Making changes of this magnitude are not easy. But they are necessary. Utility owners face multiple questions:

  • How do I pay for it?
  • How do I gain public acceptance?
  • How do we develop a market for the products we generate?

Let’s briefly look at each of these. And we’ll talk about them more thoroughly in future blogs.

How do I pay for it? Of course, there is an initial investment to go from our traditional wastewater treatment method to a resource recovery method. But the long-term benefits are clearly there.

While the recent Infrastructure Bill passed here in the US is exciting and addresses many woefully underfunded needs, we can’t expect the government to simply write a big check to pay for a circular economy. It must pay for itself.

And it can.

What we need now is a “Circular Revolution,” where instead of simply extracting, processing, using, and disposing, we think and use what already exists.

One quick example is the digester at your local wastewater facility. There is likely a lot more capacity there than the utility realizes. Instead of simply continuing at their current capacity, if we utilize the full capacity, we can create more biogas. More biogas means we can generate more power—and we can put that back into the grid. That plant can be net zero or even net-positive in its energy consumption.

We must convince those in the “know”—those in the scientific arena or those running the local utility—that even though energy use in the water industry is relatively small compared to other economic sectors, we still must do our part.

How do I gain public acceptance? This is critical. Without the public on board, the idea of creating a circular economy—and reusing waste—isn’t going anywhere. Again, in Europe they are ahead of the curve, but here in the US we must gain acceptance of circularity.

But we have an ideal example in reusing the water from wastewater. At first, it was unacceptable to most. Over time, the recycled water was shown to be safe for irrigation. Now, we are seeing it frequently used in indirect potable use—recharging aquifers or reservoirs. And direct potable reuse is rapidly becoming a larger part of the discussion.

By explaining the process and demonstrating that it works, we developed acceptance.

How do we develop a market for recovered resources? For this all to work, we must have a viable market. In this country, a barrier in all avenues of recycling is that we have very little policy or regulatory oversight of recycled product quality and standards. This affects value. When value is diminished, markets either disappear or never emerge.  

Without regulatory oversight, it’s also hard to promote a viable supply chain to stabilize markets. Without viable markets, the incentives to reclaim or reuse fall away.

Again, I’ll refer to the EU and the United Kingdom. Quite simply, they have more consistent regulatory frameworks for their supply chain. Now they can close the loops in a more coordinated manner. Here in the US, we have a lot of work to do in that arena to make a circular economy second nature to all of us.

Circularity is the future

The Industrial Revolution was a long time ago. However, it’s impacts are still with us—and in some very negative ways.

What we need now is a “Circular Revolution,” where instead of simply extracting, processing, using, and disposing, we use what already exists. It’s the way to help fight climate change. And it’s the way to a better future.

  • Arthur Umble

    As the lead for Stantec's Institute for Applied Science, Technology & Policy, Arthur’s position involves developing strategies and providing solutions for complex wastewater treatment challenges.

    Contact Arthur
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