Not Wastewater, "Enriched Water"

George Hawkins, general manager of DC Water, talks to Water Online Radio about the forward-looking, energy-producing approach the utility is taking in the nation’s capital.

The following is an excerpt from the Q&A. Click on the Radio Player above to hear the full interview.

Water Online Radio: We’re hearing more and more about zero energy, and I understand there’s a very significant refuse-to-energy product that you’ve got going. Tell us about that?

George Hawkins: It’s one of the ways where we, among many in our industry, are rethinking our work. When we get water back from people after they’ve used it, we tend to call it “wastewater.” We’re trying to look at more like “enriched water.”

There are a lot of things in that wastewater that, in fact, have value. And with this plant we’re trying to transform it. We’re seeking to use what we’re taking out of the wastewater and turn it in to a useable product.

What we’ve discovered, as many have known, is that solid has material a lot of energy in it, and what we’re building here — and it’s a cost of $470 million, so this is not a small project — but we’re putting in a technology that’s never been used at this scale anywhere in the world, and actually never been used in North America at all. 

It’s called Cambi digesters, and it’s like a turbo charger for your car. What happens is that these solid materials can be digested and generate methane which, of course, you can burn to create energy. But with this much solid material, you need to break apart the molecules and the connections between the solid materials to make the reaction more efficient.

That’s what the Cambi digesters do – they heat up the solid material at very high temperature and high pressure, and break down the materials.  Then we put them into digesters, and we’ll generate 13 megawatts of permanent clean energy. That’s enough power to light up 16,000 homes.