What does the term "wastewater" refer to in the context of nutrient recovery?

The term "wastewater" refers to any water that has been adversely affected in quality by the addition of waste substances. This can include water from various sources that might contain pollutants, nutrients, and organic materials. In the context of nutrient recovery, wastewater is crucial because it is often rich in nutrients such as nitrogen and phosphorus, which can be repurposed through treatment processes. By recovering these nutrients from wastewater, treatment facilities can contribute to sustainable practices and reduce the need for synthetic fertilizers in agriculture.

Untreated sewage is just one component of wastewater and does not encompass the broader definition needed for nutrient recovery. Rainwater runoff, while it can carry pollutants, is typically not classified as wastewater in the same way that water from domestic, industrial, or agricultural processes is. Similarly, pure drinking water is not considered wastewater at all, as it does not contain waste substances that would necessitate treatment or recovery processes. Thus, understanding wastewater in its entirety is key to effective nutrient recovery initiatives.