What are the processes most municipalities use to treat wastewater before discharge?

Processes include:

• Preliminary treatment or screening to remove large solids,
• Primary clarification to remove floating and settleable solids,
• Biological treatment or secondary treatment to remove biodegradable organic pollutants and suspended solids, and
• Disinfection to deactivate pathogens.

Some facilities also provide more advanced treatment designed to lower constituents, such as nitrogen and phosphorus, that aren’t removed in any major quantity by conventional biological treatment processes.