Eight million gallons of human waste is processed at the Persigo Wastewater Treatment Plant that turns the sludge into RNG or Biomethane.
Alternative Energies reports:
The RNG becomes the fuel used by 40 fleet vehicles like garbage trucks, dump trucks, street sweepers and even transit buses.
The human waste is turned into raw biogas due to a process called anaerobic digestion, and to become RNG is collected and suffers a little upgrade in order to meet the quality requested, and only after is used to produce electricity, heat and transportation fuel.
The idea to turn wastewater into biogas is not new in the U.S., but until now, the raw biogas was released into the atmosphere instead of being used to produce energy for the local community.
Due to the fact that today the 40 fleet of vehicles is using RNG instead of gasoline or diesel, and some of the electricity and heat of the town is produced by RNG, the city managed to reduce the level of greenhouse gas emissions by 60% to 80%.
The entire project is valued at $2.8 million, and the cost of producing RNG is around 80 cents per GGE (gasoline gallon equivalent), while the cost paid by the fleet department is $1.50 per GGE.
Bret Guillory, utility engineer for the city of Grand Junction, says that the project will pay for itself in about seven years.
The RNG is transported into compressed form through a six mile long underground pipeline from the wastewater plant to the city’s fueling station.
During the night, all the vehicles from the fleet are filled with RNG, and they are ready for a new day of work in the morning.
Grand Junction has installed its first compressed natural gas fueling station in 2011, but today the natural gas is replaced by RNG.
The wastewater plant produces every day about 500 GGE of RNG, and the human waste is not the only source of waste water used by the power plant, food waste, animal manure, and also the landfills are considered ideal sources that can be used to produce RNG.
The Environmental Protection Agency (EPA), says that greenhouse gas emissions are decreasing when a fossil resource like the natural gas is replaced by RNG also because the methane produced by rotting waste is no longer released into the atmosphere, but is upgraded to be used as a source of renewable energy.
RNG can be used in everything that runs on natural gas and produces less carbon emissions, so it was classified by the EPA as a low-carbon cellulosic biofuel under its Renewable Fuel Standard (RFS) program.