| reject | The "Rejected" Side of Treatment: Under… | Water Purification |
| rejection | Rejection: A Crucial Concept in Water T… | Water Purification |
| reject staging | Reject Staging: Maximizing Water Recove… | Sustainable Water… |
| relative humidity | Relative Humidity: A Key Parameter in E… | Environmental Hea… |
| release | Understanding "Release" in Environmenta… | Environmental Hea… |
| Reliant | Reliant on Reliability: Roberts Filter … | Water Purification |
| rem | REM: A Measure of Radiation's Impact on… | Environmental Hea… |
| REM | REM in Environmental & Water Treatment:… | Environmental Hea… |
| remedial action | From Blueprint to Reality: Remedial Act… | Environmental Hea… |
| remedial investigation and feasibility study (RI/FS) | Remedial Investigation and Feasibility … | Environmental Hea… |
| remedial response | Remedial Response: A Long-Term Solution… | Environmental Hea… |
| remediation | Cleaning Up the Mess: An Introduction t… | Environmental Hea… |
| Remedi-Cat | Remedi-Cat: A Catalyst for Clean Water … | Wastewater Treatm… |
| REMS | REMS: A Crucial Tool for Environmental … | Environmental Hea… |
| rendering plant | The Not-So-Glamorous Side of Sustainabi… | Environmental Hea… |
| renewable resource | Renewable Resources: Powering Sustainab… | Sustainable Water… |
| Renneburg | Renneburg: A Legacy in Sludge Drying an… | Wastewater Treatm… |
| RenovAir | RenovAir: Breathing Easy with Envirogen… | Air Quality Manag… |
| Reo-Pure | Reo-Pure: A Clean Water Revolution for … | Water Purification |
| reportable quantity (RQ) | Reportable Quantities: A Crucial Elemen… | Environmental Hea… |
