Preliminary treatment involves screening out objects such as personal hygiene products, wipes and other debris. Trash that is removed from the system is taken to the landfill.
Treatment/Aeration Tanks and Clarifiers
Secondary treatment creates ideal food and oxygen conditions that allow bacteria and other microscopic organisms to work quickly and efficiently to digest dissolved waste, just as they would normally in the natural environment but on a much larger scale. At the end of secondary treatment, nearly all waste has been removed from the water.
Disinfection is the final step in the liquids treatment process. Instead of chlorine, which was typically used in past decades, the plant uses ultraviolet lamps. This is a safer process than chemical disinfection. Water passes through chambers containing ultraviolet lamps that kill any remaining disease-causing bacteria and pathogens.
Following treatment, effluent (treated wastewater) from the plant is transported by pipeline and discharged into Lake River via the plant outfall pipe. The State of Washington’s Department of Ecology closely monitors this process to ensure that all effluent meets strict environmental standards. The diffuser is periodically inspected by a diver to ensure efficient operations.
All solids collected during the main treatment process are transported 2-3 times per week to the Salmon Creek Treatment Plant in the Felida area where they are further processed.
Plant operation requires constant monitoring and quality control testing. Liquids and solids are carefully monitored by certified operations staff and tested and evaluated at each stage of the treatment process to ensure compliance with stringent regulatory requirements.