Tertiary Wastewater Treatment

CWC Position

All wastewater throughout Indian River County should be processed through tertiary treatment to reduce nutrient compounds, regardless of how the treated wastewater is ultimately released into the environment.

About Tertiary Treatment of Wastewater

Wastewater is collected by a sewer system, and delivered to one or more wastewater treatment plants to be treated for removal of contaminants.  

As the name implies, tertiary treatment is a three-step sequence of wastewater treatment:

  1. Primary Treatment.  Solids settle by force of gravity, and are removed from the bottom, while grease and oils are skimmed off the top.  
  2. Secondary Treatment.  Microorganisms feed off of organic contaminants, the whole of which are removed as both suspended and settled solids. 
  3. Tertiary Treatment.  Wastewater is further treated for removal of nitrogen and phosphorus, prior to release into the environment as effluent or reuse irrigation water.

Effectiveness of Tertiary Treatment

Traditional “Secondary” treatment process only removes about half of the nitrogen and phosphorus found in wastewater.  For reference, reuse irrigation water from a secondary process contains about fifty times (50x) the concentration of nitrogen as found in the Indian River Lagoon.  

Secondary treatment only removes about half of the nutrient pollution in wastewater before it is released into the environment.  In contrast, tertiary treatment removes 96% of Nitrogen, and 98% of phosphorus compounds, making the reuse water suitable for environmentally-sensitive areas.  

Tertiary treatment typically removes 96% of nitrogen and 98% of phosphorus compounds found in untreated wastewater.  About half of the nutrient removal is accomplished in the tertiary treatment process.  For more information about tertiary treatment, please click here

Current Status

There are two wastewater treatment system operators in Indian River County.  

Indian River County

The Indian River County West Regional Wastewater Treatment Plant employs a system of tertiary treatment.  Tertiary-treated wastewater is then discharged to a system of wetlands for further “polishing.”  A portion of treated wastewater is distributed as reuse irrigation water, mostly for local mainland golf courses.   

The City of Vero Beach

The City of Vero Beach operates an older wastewater treatment plant at 17th Street and Indian River Boulevard.  The City system does not employ tertiary treatment.  Consequently, its reuse water deliveries are high in both nitrogen and phosphorus.  Most of this reuse water is used for irrigation of golf courses and individual homes on the barrier island, from John’s Island to as far south as the Moorings.