What is defined as treated wastewater that is discharged from a treatment plant?

The term that refers to treated wastewater discharged from a treatment plant is effluent. This is the water that has undergone various treatment processes to remove contaminants and is now released back into the environment, often into water bodies such as rivers or oceans. The treatment processes aim to ensure that the effluent meets regulatory standards for safety and environmental protection before it is discharged.

Influent describes the raw or untreated wastewater that enters the treatment plant, which is in stark contrast to effluent. Greywater refers to slightly used water from domestic activities like bathing or washing, which is less polluted than sewage but is not specifically related to treated wastewater from a treatment plant. Sewage generally refers to a mix of wastewater and human waste, which contains a higher level of contaminants requiring extensive treatment before it can be classified as effluent.