Chambers Creek Regional Wastewater Treatment Plant Layout | Sewer Division | Public Works and Utilities

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How the Treatment Plant Works - Plant Layout

This diagram shows how the treatment plant works. Read below for details.

Wastewater treatment is a multi-stage process involving the separation of wastewater from solids. This process involves screening, grit removal, clarification, aeration, digestion and pressing, and final treatment of both the liquids and solids.

The liquid is further processed through ultraviolet technologies to erradicate pathogens within the wastewater. The solids, after undergoing initial processing as Class B biosloids are then sent to the new Fertilizer Manufacturing Facility where further processing results in the production of a 100% organic 'Exceptional Quality' Class A dry pelletized fertilizer that can be used for residential and commercial uses.

Pierce County produces 'SoundGRO', a 100% organic fertilizer, available for home lawn and garden and commercial use.

Perforated Plate Screens/Step Screens
Two types of screens prevent large pieces of debris and other solids from entering the plant. All materials trapped by the screens are removed and are sent to a dumpster where they are disposed of in a sanitary landfill.

Grit Tanks
Grit tanks use air diffusers to keep the solids suspended in the wastewater allowing sand and grit to settle to the bottom of the tank.

Primary and Secondary Clarifiers
The Primary Clarifiers initially treat effluent (wastewater) while automatic skimmers remove particulate matter and grease that floats to the top. The grease is then pumped to the digesters or to a rotastrainer at the headworks. Secondary Clarifiers further treat the effluent by removing fines (small particles) and microorganisms used in the treatment process. The grease is then pumped to a concentrator tank at the headworks to remove excess water, it is then pumped into digester tanks for anaerobic bacteria digestion.

Aeration Basins
There are five operational aeration basins that infuse air into the process providing a source of oxygen for aerobic bacteria. The bacteria consume and break down organic material to complete the biologic portion of the treatment process.

Digesters
This biologic process significantly decreases the volume of solids through anaerobic digestion and produces biogas as a byproduct. The biogas is utilized as a fuel source for gas fired boilers ans as a primary fuel source in the fertilizer manufacturing process.

Fertilizer Manufacturing
Dewatered solids coming off the centrifuges are sent to the Fertilizer Manufacturing Facility where they are further processed, dried, and bagged as an 'Exceptional Quality ' Class A pelletized fertilizer product for residential and commercial use.

Ultraviolet Light
Ultraviolet light is used to destroy any pathogens left in the wastewater prior to release of the treated wastewater into Puget Sound.