What does the variable 'mW' represent in the context of UV dosage?

The variable 'mW' in the context of UV dosage represents milliwatts. This unit is a measure of power, specifically in this scenario pertaining to the intensity of ultraviolet (UV) light used in disinfection processes. UV dosage is crucial in wastewater treatment as it reflects the amount of UV energy that is being delivered to the microorganisms in the water, effectively helping to inactivate them and reduce pathogen levels.

Understanding milliwatts is important because it provides a concrete measurement of how powerful the UV lamp is at any given moment. Higher milliwatt outputs can lead to more effective disinfection if maintained at appropriate exposure times. The relationship between power (in milliwatts), exposure time, and the resultant UV dose is fundamental to ensuring that the wastewater is treated effectively before being released into the environment or reused.

The other options involve different measurements that are not applicable to the context of UV dosage. Milligrams and milliliters relate to mass and volume, respectively, while millimeters is a unit of length. None of these directly address the aspect of power measurement necessary for understanding UV dosage.