An all-encompassing term used to describe pollution-control devices and systems, waste treatment processes, storage facilities and site remediation technologies and their components. It applies to any technology used to remove or prevent pollutants or contaminants from entering the environment. Examples include wet scrubbers, soil washing, granulated activated carbon units and air or water filtration systems. Usually, the term applies to hardware-based systems. However, it can also apply to methods or techniques used for pollution prevention, pollutant reduction or containment of contamination such as capping, solidification or vitrification and biological treatment.