First U.S. Human Waste to Energy Biogas Plant Saves Utility $200,000 a Year
San Antonio Water System to use human waste to energy biogas plant to capture biomethane generated during sewage treatment and sell on open market
The San Antonio Water System (SAWS) announced yesterday that it has opened the very first biogas plant in the United States that converts human waste to energy, located at the Dos Rios Water Recycling Center. Although England recently released news of a plant manufacturing biofuel from human waste, the SAWS biogas project is the first sustainable project of its kind in the U.S., capturing biogas generated during the sewage treatment process and selling it through a commercial gas pipeline. The human waste powered biogas plant, which was developed in a partnership between SAWS and the utility company Ameresco, is expected to save SAWS at least $200,000 per year.
To convert human waste to energy, Ameresco first captures the methane gas that is generated by the sewage treatment process at the biogas plant. Normally, this biomethane would get burned, but in this case Ameresco will sell the biomethane on the open market as energy, and SAWS ratepayers will get a royalty on the sales. Ameresco expects to generate at least 900,000 cubic feet of biomethane per year from its new human waste to energy biogas plant. The plant generates money both from the sale of the biomethane and from the reduced cost of treating the sewage.
In addition to converting human waste to energy at its new biogas plant, SAWS is also composting biosolids and recycling up to 115 million gallons of water per day. SAWS has therefore managed to recycle almost all of the waste that is processed at its Dos Rios Recycling Center, a feat that it is calling a "recycling trifecta."