Across the U.S., interest is growing in developing ways to generate clean energy. Many communities are beginning to take note of the benefits and opportunities that can come from the process of producing biogas, a form of renewable natural gas (RNG), from biosolids and other organic materials.

To generate biogas, organics — everything from industrial byproducts and food waste to wastewater biosolids and residuals — can be put into a digester to be processed, and through decomposition create a form of gas known as biogas. Upon being cleaned, this biogas can be used in place of the natural gas that is produced through traditional extraction methods. The biogas can used to generate electricity, converted for use as transportation fuel or even injected back into a natural gas pipeline.

While communities have long used digesters to manage wastewater and produce biogas, the current trend is looking beyond the typical wastewater residuals for biogas generation. This means taking into consideration commercial and institutional generators of large quantities of food wastes as well as fats, oils and grease (FOG) from restaurant grease traps.

Some communities are working with residents and businesses to discontinue the use of kitchen garbage disposals and landfills for food wastes, and instead are offering mutually beneficial partnerships. As an example, your community could partner with a local school or business cafeteria. Typically, cafeteria food waste is picked up by a local waste hauler from the dumpster and taken to a landfill. Instead of disposing of that food waste at the landfill, it could be used beneficially as organic material for producing RNG. Biogas could then be treated and used to generate electricity for your wastewater plant, helping offset the cost of the electricity your facility needs to operate. Ultimately, this approach will reduce your community’s cost to manage wastewater. RNG could also be utilized as a vehicular fuel, offsetting your city’s fleet fuel costs.

An additional economic benefit for your community could be to appeal to new businesses interested in sustainability goals. As businesses search for the next best place to call home for their corporate office, they’ll pay attention to things like cost of living and tax benefits, but they may also be seeking out a community that puts sustainability at the forefront in its list of priorities.

The trends driving the use of renewable biogas include federal and state financial incentives fostering clean energy development and increased sustainability through organics recovery. These trends are increasing interest in biogas projects across the U.S. to include the development of RNG from biosolids and other organics in new and updated facilities.

Some local governments and communities already have digesters, meaning required capital improvements are more limited. In that case, the next steps would be to assess the capacity and capabilities of the existing infrastructure and to work with commercial and institutional food waste generators in your community to develop a partnership that makes the biogas process cost-effective for both parties.

 

Interested in incorporating this renewable energy process into your wastewater treatment plant or community? Learn about different infrastructure considerations for managing renewable biogas.

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by
Bob Craggs is national technical services leader for solid waste and resource recovery. Bob serves on the Solid Waste Association of North America (SWANA) International Board as division representative for the Planning and Management Technical Division.