So-called “digesters” turning sewer waste into money at the DC Water Blue Plains Wastewater Treatment Plant
So-called “digesters” turning sewer waste into money at the DC Water Blue Plains Wastewater Treatment Plant - 
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Can you run a stodgy water utility like a business? Turn sewer water into money? This is the premise behind what’s called the “digester” process at DC Water’s Blue Plains wastewater plant. 

“That’s why we don’t call this a waste treatment facility,” says DC Water CEO George Hawkins. “It is an enriched water facility, that’s a resource.” 

By all accounts, Hawkins is a star among water utility managers, an energetic executive from outside the sector (he’s a lawyer). In our interview, Hawkins routinely drops phrases you might expect in business school. For starters: 

I want to be like Nike.

We have the most important marketplace, the marketplace of public opinion

We fight for the support and loyalty of every customer

60% of the people who take a blind taste-test will rank our water better or the same as bottled water.

We have got the best product ever. Who gets to deliver water?

I consider myself kleptocrat-in-chief. I take good ideas from all over.

Here’s the good idea when it comes to the digester. Simply put, it takes human waste and processes it into sellable goods, like fertilizer.

“The farmers value it at $300 an acre,” says Chris Peot, director of resource recovery  at DC Water. “If I worked for a Fortune 500 company and said that we were going to give this asset away for free, I’d probably be fired on the spot.”

Walking me through the digester area, Peot explains most steps occurs in pipes and cylinders. So you can’t see much of the action, for obvious reasons: it stinks. First, waste is routed into centrifuges, to separate out the water from the economic “resource.” 

The centrifuge spins and separates water from the solids, solids then heat up in a stage called thermal hydrolysis. DC Water has the only digester in the country with this step, designed to yield more economic product in the end.

“The thermal hydrolysis process makes the food much more available for the microbes in the digesters,” Peot says, “which gives us better gas production.”

Better gas production — insert your own joke here. This comes out of the key stage: the digester. A huge cylinder, it operates like an actual stomach, mixing bacteria with the product to make gas. Instead of being released, this gas is captured and burned in a power plant to make electricity. That powers about a third of the plant for free.

The other byproduct: High-end fertilizer that, thanks to the thermal stage, has fewer germs and less stink. This Grade-A fertilizer can be sold in urban areas — think home garden. And someday, this place could sell phosphorous, a captured nutrient ... or cleaned-up water.

“We call it N-E-W,” says Matt Ries of the Water Environment Federation. “Nutrients, energy and water that can now be recycled as resources.”

Ries explains water utilities are looking into new business models out of financial necessity. Most ratepayers are using and buying less water (due to more efficient toilets, washing machines, shower heads, etc). Pipes need replacing. Federal clean water standards are going up, without accompanying grants. Heavier or less predictable rainfalls demand more treatment, more planning.

“All of that means you need additional capital coming into the system,” Ries says. “There’s now a realization that we’ve got to operate differently as a business.”

This all comes as a challenge to a utility sector that is understandably conservative, DC Water CEO Hawkins says this business is no place for risky trial-and-error. 

“It is not one where you can start a new product and then it fails so you go back to a different one, like New Coke,” Hawkins says.

Follow Scott Tong at @tongscott