Birchtech is a small environmental technology company with two businesses: a core Air segment selling mercury emissions control solutions to coal-fired power plants, and an early-stage Water segment targeting PFAS removal from drinking water. In the Air business, Birchtech's patented SEA (Sorbent Enhancement Additive) technology uses a two-part process combining activated carbon sorbents with proprietary chemical formulations tailored to each plant's coal type, boiler, and flue gas chemistry. Birchtech argues SEA outperforms conventional activated carbon injection, particularly at high mercury reduction levels, while also preserving fly ash quality so plants can sell it for use in concrete. Customers — coal-fired power plants required to comply with the EPA's MATS regulation — pay both a license fee and ongoing product supply fees. Birchtech also pursues patent infringement litigation to convert unauthorized users of its technology into paying license and supply customers. As of late 2025, Birchtech had 16 power generation units under contract, representing roughly 15% of the approximately 400 remaining U.S. coal-fired units. In the Water business, Birchtech is developing granular activated carbon (GAC) solutions for PFAS removal from drinking water, with a focus on "Carbon Rejuvenation" — thermally reactivating spent GAC for reuse — to reduce costs for municipal water utilities. Birchtech has opened two laboratory Design Centers to develop these technologies and expects commercial product sales to begin in the second half of 2025.