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Sewage as a renewable energy resource

Mr. Miller, Mr. Spencer and Mr. Keller go fishing at the wastewater treatment plant. They're hoping to catch some algae and turn it into diesel fuel. (Photo by Erik Eisele) (click for larger version)
November 11, 2009
BERLIN — Few people would look at a giant pool of contaminated water and human excrement and see opportunity.

But Andrew Kellar does.

Mr. Kellar is the founder of Simply Green Biofuels, a southern New Hampshire company that turns waste vegetable oil from restaurant frialators into diesel fuel. The diesel, called biodiesel, is then either sold as home heating oil or mixed with regular diesel to create a fuel suitable for trucks and heavy machinery.

But now Simply Green is looking for a new way to create green fuel, and the secret is in the pool.

The waste vegetable system works great, Mr. Keller said, except that waste vegetable oil has become a commodity so many people are doing this same process. So now Simply Green is trying to do something different.

Enter the sewage.

Actually, it's not just any sewage: enter the sewage at the Berlin wastewater treatment facility.

Berlin's sewage, like any sewage, is full of nutrients. Nutrients help things grow, and in sewage treatment plants, the thing that grows is algae.

And it's algae Mr. Kellar is interested in. Mr. Kellar's company is planning to partner with Clean Power Development to create an algae farm on the site of the CPD facility. The farm will grow algae in silos, using the nutrients from the wastewater treatment plant, lights powered by CPD, and the carbon dioxide from the stack of the CPD facility.

But before then, Mr. Kellar has to do some investigating in giant pools of muck.

Algae contains a certain amount of oil. Different algae create different amounts of oil, and certain algae grows better in certain environments. That oil is what Simply Green is hoping to turn into the next base product for biodiesel, something no one has really figured out how to do.

"That's the race that's on right now," Mr. Kellar said.

No one has a process for creating biodiesel from algae yet, he said, but he's hoping to do it right here in Berlin.

There is already algae growing in the wastewater treatment facility, according to Ted Miller, the Berlin facility chemist. But Mr. Keller needs to know if that algae is going to produce the most oil possible, or if any of the types of algae researchers have been working with will fare better in the Berlin effluent.

Enter Jon Spencer, the guy who gets his hands dirty.

Mr. Spencer is the lead scientist working for Mr. Keller. He is looking at the various wastewater sources from the Berlin facility, what kinds of algae are there already, and what level of growth the various algae types he's been working in the lab with would sustain in the Berlin waste.

And to look, he needs a bucket full of sewage. Or three.

Mr. Miller took Mr. Keller and Mr. Spencer out to the collect samples of Berlin wastewater last Thursday, in order to help them with their research into algae as a possible fuel source. They filled buckets of influent, effluent and leachate, three different sources of wastewater, for testing.

In addition to using nutrients from the sewage with light carbron dioxide from CPD's plant, the algae silo would be heated by the CPD's biomass plant. Simply Green plans to separate the oil from the algae and turn the oil into biodiesel. The separated algae would then be turned into pellets for animal feed or for heating purposes, or burned in the CPD facility.

To do this CPD would have to get a different permit. Currently they are only permitted to burn wood.

The Berlin wastewater treatment facility currently processes 1.6 million gallons of sewage every day, according to Mr. Miller. That includes waste from businesses, households, and the drainings from the old Dummer Pond landfill near the mill.

And it's the drainings from the landfill that really interest Mr. Spencer. He said this liquid, called leachate, is the best food for algae. The Dummer Pond site is one possible site for leachate collection. Another would be from Mount Carberry, which Mr. Keller said he hopes to be able to incorporate into his project.

But for now, he's working to take advantage of what he calls one of the most unique locations in the country. Nowhere else is a biomass facility planned so close to a wastewater plant, he said, making the project exceedingly viable. It is an exciting opportunity to be on the forefront of the green movement, he said, and at the same time take a product with no real value and put it to use.

But before that happens, he's going to need a few more buckets of sewage.

Martin Lord Osman
Tilton School
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