Bay Restoration Fund Best Available Technology for Removing Nitrogen from Onsite Systems
The Maryland Department of the Environment’s (MDE) Best Available Technology (BAT) Review Committee determines which nitrogen reducing onsite sewage disposal technologies should be considered BAT and therefore grant-eligible under the Bay Restoration Fund.
The BAT Review Committee reviews applications for any system wishing to be designated BAT. To qualify for this designation, a system must achieve either a 50% or higher reduction of TN at the arithmetic mean and/or a treated effluent TN of 30 mg/L or less, based on an influent of at least 60 mg/L or influent to effluent comparison.
MDE’s technology approval is based on data obtained from third party verification of the technology. Third party verification is defined as: independent third party testing to confirm the nitrogen removal performance of the technology. The data gathered from the third party testing is analyzed by the BAT Review Committee to determine if the system performs to the standards required by MDE. For the initial analysis of the technology, the BAT Review Committee requires a minimum of 48 composite effluent samples with at least 12 of the samples collected in winter, reflecting weather conditions in Maryland. Systems that meet MDE’s BAT requirements will receive provisional entry into the Bay Restoration Fund as BAT.
Once a technology receives initial, provisional, approval for the entry into the BRF as BAT, that technology must undergo a Maryland Field Verification Process. The Field Verification process consists of collecting 48 composite effluent samples over a period of 4 consecutive quarters from representative systems installed within the state of Maryland. At least 12 (one quarter) of the samples must be collected between December 15 and February 15 of a given winter season. The effluent sampling data must demonstrate that the technology is meeting the MDE’s BAT criteria (50% or higher reduction of TN at the arithmetic mean and/or a treated TN of 30 mg/L or less based on a standard influent value of 60 mg/L). Systems that satisfy this requirement will be classified “Best Available Technology, Field Verified.” Spot samples and further testing may be required.
Further details are outlined in the Bay Restoration Fund’s, “BAT Field Verification Program Flowchart 2012.” For a copy of this flowchart, please click link below.
“BAT Field Verification Program Flowchart 2012”
The BAT Review Team consists of the following members:
Joshua Flatley, Bay Restoration Fund, MDE, (Chair)
Dr. Ching-Tzone Tien, Division Chief, MDE, (Engineer)
Leigh Broderick, Carroll County Environmental Health, (County Representative)
Application packages should be submitted to:
Water Management Administration
Wastewater Permits Program
Maryland Department of the Environment
1800 Washington Blvd.
Baltimore, MD 21230
For additional information about the review process call: 410-537-3635 or email
Field Verified Technologies as Best Available Technology (BAT) as of June 30, 2012, include:
1. Orenco Advantex AX20
2. Orenco Advantex AX20RT
3. Hoot BNR
4. Norweco Singulair TNT
5. Norweco Singulair Green
6. Septitech M400 denite
7. Bio-Microbics RetroFAST (size restrictions)
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