Innovative Septic Nitrogen Reduction

In 2015, the first of two demonstration Permeable Reactive Barriers (PRB) was installed at Windsor Meadows Condo Association, in Brentwood, NH.  A Permeable Reactive Barrier (PRB) is a new passive technology used to control nitrogen with a formulation of wood chips, exchange media, and sand or gravel to transform     inorganic nitrogen to nitrogen gas.  This patented technology (Nitrex System) can be used in conjunction with an existing or new septic system to prevent nitrogen migration to sensitive watershed areas.  The installation of the second demonstration site is scheduled for January 2016.  In 2014, RCCD was awarded a Watershed Assistance Grant from the New Hampshire Department of Environmental Services with funds from the Environmental Protection Agency to set up demonstration sites for this new technology to help reduce the amount of nitrogen leaching from septic systems.  Great Bay has been identified in New Hampshire as an impaired water body for excess total nitrogen levels. Many non-point sources have been identified, including nitrogen coming from septic systems  Conventional septic systems do not do an adequate job of removing nitrogen.  Active on-site septic system technologies to remove nitrogen from these systems are expensive and are subject to mechanical failure.  This study is testing the feasibility of the PRB technology for widespread use.  RCCD is partnering with the Town of Durham and the Town of Brentwood for the installations.  Initial water quality data was collected before the installations and post-water quality monitoring is planned for 2016.

trench mostly filled in

The Installation of the first demonstration site in Brentwood




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