The Pima County Board of Supervisors is moving toward turning waste product, left over from treating sludge, into biogas. This could not only benefit the environment, but also generate revenue for the county, said Jackson Jenkins, director at the Pima County Regional Wastewater Reclamation Department.

"Most people think when you are dealing with wastewater, you end up with the water product and the solid product, but you also end up with the has product," he said.

The biogas, which is primarily composed of methane and carbon dioxide, is currently burned off in a flare adding to global warming when released directly into the atmosphere, a press release from the department explained.

The project aims to clean the gas, and its estimated cost is about $10 million.

The county will collect lease payments on the land and will be paid commission on gross sales of the cleaned biogas. Revenues that come from this will cover part of the cost for plan operations and management.

The contract will be for 15 years, with the option of a five-year extension, according to the release.

Converting biogas would have a positive impact in the air quality, and it would also increase the production of renewable energy sources.

The board authorized the wastewater department to enter into negotiations with Anaergia Inc. and Grannus Biogas to construct, own and operate a biogas facility adjacent to the Tres Rios Water Reclamation Facility, 7102 N. Casa Grand Highway, the press release said.

"The county has been very successful in leveraging the ingenuity of the private sector through several public-private partnerships," said Pima County Administrator Chuck Huckelberry in a statement. "This particular project has the advantage of not only benefiting Pima County ratepayers, but also making sure we're doing our part to address concerns over global climate change, and its effects on human health and the environment."

The Regional Wastewater Reclamation Department anticipates that the biogas facility will be in operation by the end of 2015, Jenkins said.