Commissioning of the Brookings Biogas RNG Facility in Estelline, South Dakota, was completed in September 2024. The $50 million project converts mostly agricultural waste into natural gas suitable for energy generation. PENETRON ADMIX SB, a crystalline waterproofing admixture, was specified to waterproof the facility’s concrete tanks.
Renewable natural gas (RNG) is a gas that can be drawn from a range of sources, including landfills, digesters at wastewater treatment plants, livestock farms, food production facilities, and organic waste management operations. Also known as biomethane, RNG is produced by anaerobically digesting and upgrading waste from these sources to energy concentration levels equal to fossil-based natural gas, with a methane content of around 90%. This is done at a gas upgrading facility like Brookings, before being delivered into the local natural gas distribution system.
UGI Energy Services (UGIES), a subsidiary of UGI, a natural gas and electric power distribution company, is part of MBL Bioenergy, a joint venture together with Sevana Bioenergy and a subsidiary of California Bioenergy (CalBio). MBL Bioenergy is developing three clusters of dairy manure waste-to-RNG projects in South Dakota. The Brookings Biogas RNG facility was located close to three farms near Estelline, South Dakota. At full capacity, the facility is set to generate approximately 300 million cubic feet of RNG annually.
Exposed to the industrial scale processing of agricultural waste, the concrete digester tanks in an RNG facility are typically subjected to an aggressive mix of toxins and bacteria that can penetrate through the walls of the tanks (and into the soil and underlying groundwater). As a result, Poet Design & Construction, architect and engineer for the Brookings project, required a robust concrete waterproofing solution as part of the design.
“Penetron products have been used in countless construction projects with similarly aggressive environments, which can be anything from wastewater treatment plants, meat production plants, to copper mining operations,” explains Christopher Chen, Director of The Penetron Group. “To ensure the upmost durability for the Brookings RNG facility, Penetron collaborated with Buffalo Ridge Concrete, the ready-mix concrete supplier, to meet the specified requirements for an optimal concrete waterproofing solution.”
As part of the collaboration, Penetron provided the necessary test data to Poet Design & Construction and Brooks Construction to confirm the 1% dosage rate for PENETRON ADMIX SB, a crystalline waterproofing admixture. Delivered in pre-measured soluble bags, the admixture was added to the mix during the batching phase to treat about 2,000 yds3 of concrete used for the digester tanks.
Once added to the concrete mix, PENETRON ADMIX SB reduces concrete permeability, increases chemical resistance, and enables the self-sealing of any new or future hairline cracks – enhancing durability and extending the service life of the Brookings facility’s concrete digester tanks.
“In addition to providing economic benefits for dairy farmers, RNG facilities can deliver significant environmental benefits by supplying clean burning diesel replacement fuel,” states Christopher Chen. “Penetron is pleased to be part of a project that contributes to reducing greenhouse gas emissions.”
Without Penetron treatment: The concrete digester tanks of an RNG facility are exposed to an aggressive mix of toxins and bacteria that can penetrate through untreated concrete tank walls.
Protection for Brookings: When added to the concrete mix, PENETRON ADMIX SB reduces concrete permeability, increases chemical resistance, and enables the self-sealing of any new hairline cracks.
