Moving Beyond “Waste” Water

SLO Water Plus increases the WRRF's ability to recover resources traditionally classified as waste, moving the facility closer to full resource recovery. The upgrade will improve the plant’s efficiency while helping reduce our dependency on reservoir and groundwater supplies long into the future. 

Here's How Resource Recovery Works

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Currently, 10% of the treated water is used by industrial customers and for irrigation on local golf courses. The upgrade sets the foundation for an increase in beneficial reuse in the future.

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A multi-level treatment process is used to treat the water to prepare it for beneficial reuse or discharge.

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Recovered waste is converted into onsite energy and compost.

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Wastewater is sent to the SLO WRRF.

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The treated water is discharged to the San Luis Obispo Creek, which helps support the environmental health of the community including supporting a threatened steelhead trout population. ​

INFLOW

RECOVERY

DISCHARGE

TREATMENT

REUSE

 
 

A Modernized Wastewater Treatment Process

The SLO WRRF will use a multi-stage treatment process that will deliver a high quality effluent that will be adaptable for future uses. Here’s how the treatment process will work:

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1. Collection

Wastewater flows from homes to the treatment facility through a system of pipelines.

4. Settling and Separation

Large clarification tanks will then be used to allow suspended solids to settle and separate from the wastewater.

2. Primary Screening

This is the first stage of the process where large objects such as rags and sticks will be removed.

3. Sand and Grit Removal

The flows will then pass into a grit chamber, where cinders, sand and small stones will settle to the bottom. 

5. Biological Treatment

The flows will then get mixed with air and waste-eating microbes that will break down organic matter to remove remaining contaminants. 

Solids/Energy Production

Solids removed in earlier parts of the process will be treated for beneficial uses, including biogas/energy and compost production. A cogeneration system will produce electricity for the WRRF from biogas made in the solids treatment process.

6. Membrane Bioreactors

The membrane bioreactor system will filter wastewater through membranes with pore openings that are 1/300th the diameter of a hair! This microfiltration process will remove microorganisms, bacteria, pathogens and other remaining suspended solids.

7. Ultraviolet (UV) Disinfection

UV light will then disinfect the wastewater and kill any microorganisms that remain.

8. Complete!

Discharge or reuse.