Carl Weber
Carl Weber

Public Works Director (retired)
City of Janesville, Wis.
Population served: 64,000
Employees: 110
Budget: $50 million (CIP and operating)
Favorite technology: Conversion of methane into fuel

Carl Weber is a pro at making municipal fleets more efficient. As the City of Janesville’s public works director, he oversaw converting to automated garbage and recycling collection, which included single-stream recycling. While serving as director for the City of Green Bay, Wis., he introduced one-man leaf collection vehicles and computerized routing of bulk waste and brush collection.

But Weber’s most recent favorite technology is the conversion of methane into vehicle fuel. “We’ve been using methane from our sewage treatment plant to generate electricity for years, but we’ve recently added the capability to condition it for vehicle fuel,” he explains.

The 140-scfm (standard cubic feet/minute) biogas conditioning system concentrates methane from 60% to more than 90% by removing carbon dioxide, moisture, hydrogen sulfide, siloxane, and other particulates. The cleaned gas is then routed to a compressed natural gas (CNG) vehicle fueling station, where it is further dried and compressed for use in CNG vehicles.

So far the department has replaced five small vehicles in its utility fleet with CNG-running vehicles. “We started with just a riding lawnmower and then purchased three pickup trucks and a car,” he says.

“To date, we have used about 3,780 gallons of CNG. It costs us about 88 cents a gallon to produce. Assuming purchased fuel costs us $3.50/gallon, we’ve saved about $9,900,” says Weber. “We’ll monitor this for a few years to determine if we should continue purchasing CNG vehicles, including large trucks.”

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