| refractory | Refractory Materials: The Unsung Heroes… | Water Purification |
| refractory organics | The Challenge of Refractory Organics: U… | Wastewater Treatm… |
| refrigerant | Refrigerants: Cooling Our World, But at… | Climate Change Mi… |
| refueling emissions | Refueling Emissions: The Hidden Pollute… | Air Quality Manag… |
| refuse | Refuse: The Unsung Hero of Environmenta… | Waste Management |
| refuse derived fuel (RDF) | Refuse Derived Fuel (RDF): A Waste-to-E… | Waste Management |
| refuse reclamation | Transforming Trash into Treasure: Refus… | Waste Management |
| Regal | Regal: A Legacy of Reliability in Envir… | Water Purification |
| Regenair | Regenerative Air Blowers: A Breath of F… | Wastewater Treatm… |
| regenerant | Restoring the Power: Understanding Rege… | Water Purification |
| regenerate | Regenerating the Guardians of Clean Wat… | Water Purification |
| regenerative catalytic oxidizer (RCO) | Regenerative Catalytic Oxidizers: A Cle… | Air Quality Manag… |
| Regenerative Environmental Equipment | Dürr Environmental Expands Regenerative… | Sustainable Water… |
| regenerative thermal oxidizer (RTO) | Regenerative Thermal Oxidizers: A Power… | Air Quality Manag… |
| Re-Gensorb | Re-Gensorb: A Powerful Tool for VOC and… | Air Quality Manag… |
| Regional Administrator | Guardians of the Environment: Regional … | Environmental Pol… |
| Reg-U-Flo | Reg-U-Flo: Revolutionizing Flow Control… | Sustainable Water… |
| regulated asbestos-containing material (RACM) | Regulated Asbestos-Containing Material … | Environmental Hea… |
| regulated medical waste | Regulated Medical Waste: A Critical Com… | Environmental Hea… |
| Rehydro-Floc | Rehydro-Floc: A Powerful Tool for Water… | Water Purification |
