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Tertiary Treatment Systems

Rapid Sand Process


The purpose of tertiary treatment is to polish up the effluent being discharged from the secondary treatment system. This process involves removing a high % of the filterable  BOD5 and high % of the suspended solids.  In the rapid sand filtration process, the BOD and suspended solids are strained by a mixed media filter, allowing clean effluent to pass through the filter media while the filterable BOD5 will be returned back to the secondary treatment system through the mud well system.

Wastewater Depot, LLC specializes in the manufacture of rapid sand tertiary filtration systems with flows us to 300,000 gallons per day.

The Wastewater Depot, LLC tertiary filter system is a prefabricated factory-built unit complete and ready for easy installation at the project site.  The main components of the filter system are:  Tertiary filter cells, clear well chamber, backwash pumps, mud well chamber with pump, and automatic electrical controls.

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To meet many of the tertiary quality effluent limits being discharged from secondary wastewater treatment systems an advanced wastewater treatment processes is used The Wastewater Depot, LLC tertiary treatment system is available to meet those conditions. This filter is most often used with our secondary treatment systems. The process is called a rapid sand filtration process.


The tertiary filter unit is designed for automatic operation.  When the solids from the secondary treatment system are discharged they enter one of the filter cells. As these solids collect they cause the level to rise in the filtrate chamber to raise. When this level reaches a designated level, the automatic control system will air scour the filter cell causing the concentration of solids to rise to the top level of the filter media.  The filtering process will continue if this concentration is insufficient to cause a backwash cycle.  Once solids reach a concentration level too great for filtration, the automatic control system will activate the backwash pumps and then water wash the filter media.  The dirty water is dumped into the mud well chamber and recycled back to the secondary treatment system.  Once the wash cycle is complete, the filter is returned online.


Unique Features

The Wastewater Depot, LLC tertiary filtration unit features a compact design, PLC controlled automatic air wash and water wash control system, provided with quality components ideal for retro-fitting, ease of installation, and simple operation.

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