How is backwash from sand filters categorized?

Backwash from sand filters is categorized as non-hazardous wastewater due to the nature of the materials filtered out during the process. Sand filters are designed to remove a variety of contaminants from the wastewater, including small solids and some pathogens. When backwash occurs, the filtered contaminants are removed from the system and are typically made up of organic matter, dirt, and other particles trapped in the sand.

This backwash does not contain the high levels of dangerous substances that would qualify it as high pollution waste or industrial effluent. Additionally, it is not considered regular sewage because it is specifically a byproduct of the filtration process and does not include the same types of organic and inorganic materials typically found in household or commercial sewage. Thus, classifying it as non-hazardous wastewater reflects its relatively low risk and toxicity, affirming its suitability for certain disposal or treatment methods.