DMT Clear Gas Solutions: Iowa RNG plant begins operations

By DMT Clear Gas Solutions | January 13, 2021

Iowa’s second renewable natural gas (RNG) plant at Sioux City’s Wastewater Treatment Plant is operational thanks to Bartlett & West, a community-driven and nationally-ranked engineering firm, and DMT Clear Gas Solutions, a leading technology supplier for biogas conditioning and upgrading systems.

The water resource reclamation facility converts 800 standard cubic feet per minute (SCFM) of biogas to produce more than 99.5 percent pure renewable natural gas for direct injection into the natural gas pipeline. In doing so, this project generates enough renewable energy equivalent to removing 2,900 vehicles from U.S. roadways for one year or replacing 1.5 million gallons of gasoline annually.

“DMT is thrilled with the plant’s completion. We would like to thank our hardworking team and partners like Bartlett & West for a successful collaboration. Many wastewater treatment plants already have on-site anaerobic digesters to treat sewage sludge but do not have the equipment to use the biogas they produce and flare the gas instead. Our proven technology can turn these potential facilities into a net energy producer rather than a consumer,” said Robert Lems, General Manager of DMT.

Sioux City selected Bartlett & West as the wastewater treatment program manager, which entailed leading teams of consultants and individuals in designing several improvement projects for the City. Bartlett & West recommended improvements to the City’s existing anaerobic digestion system, using DMT’s SulfurexCR, a chemical desulfurization unit, to remove hydrogen sulfide (H2S), and DMT’s three-stage CarborexMS, a membrane separation technology, to extract carbon dioxide (CO2) from the methane (CH4) stream.

“Bartlett & West offers solutions that address concerns around funding, operations and maintenance, staffing, and budget over-runs. By partnering with experienced technology suppliers such as DMT, we help water resource recovery facilities like Sioux City conceptualize projects that contribute to their energy management goals while meeting compliance and performance targets,” said Randy Kenyon, senior project manager of Bartlett & West.

The Sioux City Wastewater Treatment Plant treats approximately 15 million gallons of wastewater per day, serves more than 30 industries, and serves five communities from three states including Iowa, Nebraska, and South Dakota. This $11 million renewable energy project is a significant upgrade to the existing wastewater treatment plant and offers significant advantages such as greenhouse gas emission reduction, odor control, and revenue for Sioux City. Additionally, this project will generate $4-7 million in city income after five years, making it a great return on investment for the people and state of Iowa.

“This project positions Sioux City as a leader in the Midwest region. As the second wastewater facility in the state of Iowa to produce renewable natural gas, we are currently taking biogas that was once wasted and now repurposing it for vehicle fuel consumption. We are proud to reduce our carbon footprint working with companies like Bartlett& West and DMT Clear Gas Solutions to make it happen,” said Mark Simms, utilities director for Sioux City.

Wastewater treatment plants typically generate biogas with high CH4 content and extremely low N2 and O2 contents, which make them attractive candidates for renewable natural gas projects. The additional benefits of renewable natural gas also include increased domestic energy security, improved waste management, and more jobs in rural areas.