Wastewater Biosolids are Fertilizing Sunflower for Biodiesel Production

In North Carolina, biosolids from a wastewater plant outside Raleigh are spread to a nearby field where sunflower is grown.

The biosolids from the wastewater treatment plant is applied to the field as a fertilizer for the sunflower. The sunflowers in turn use the nitrogen keeping it from washing into the streams and rivers. The sunflowers are also harvested and their seeds are used to produce biodiesel.

In past studies, the City harvested the fuel crop from the site and processed it elsewhere. This year, the City will process the oil on site. A company called New Earth Fabricators is constructing a trailer-mounted process unit for the City of Raleigh.

Based on the pilot study, each acre of sunflowers produces about 46 gallons of fuel. The City mixes each gallon of the biodiesel with four gallons of traditionally-produced diesel and uses it to operate the farm equipment at the plant.