Byline : John W. Salm, III, P.E.

Part 3

The Reaeration Bed aerates the water from the Denitrification Bed and allows its chemical characteristics to readjust to an oxidizing environment.  In addition, natural disinfection is provided as the water trickles through the aerobic sand.  The Reaeration Bed is particularly effective for final polishing of residual contaminants and for preparing the water for discharge.

Each bed performs a different treatment function in addition to preparing the water for the following process and backing up the previous process.  The final effluent quality from the constructed wetland tertiary treatment system is very stable and has essentially been converted back to clean water prior to leaving the treatment system.  This effluent is highly suitable for intensive recharge and also for beneficial reuse, if the conditions warrant.

Organics, Nitrogen and Phosphorus are the primary contaminants from which impacts surface and ground waters.  Nitrogen is often times the toughest parameter to treat for, therefore, the HIRP constructed wetlands is designed to optimize Nitrogen removal.  As a result of the intensive treatment for Nitrogen removal, other contaminants (i.e. BOD, TSS, Phosphorous, Metals, Trace Organics) are also removed to exceptionally low values.  Typical performance for one HIRP system is shown below.

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