DRAFT Great Bay Total Nitrogen General Permit Importance Structure - - PowerPoint PPT Presentation

DRAFT Great Bay Total Nitrogen General Permit

• Importance
• Structure
• Compliance
• Costs
• Opportunities
• Risks
• Next Steps

March 2, 2020 DRAFT Great Bay Total Nitrogen General Permit 1

National Pollutant Discharge Elimination System (NPDES) Permits

March 2, 2020 2

Pease WWTF NPDES Permit Peirce Island WWTF NPDES Permit Municipal Separate Storm Sewer System Permit (MS4)

Wastewater Stormwater Point and Non-Point Sources

Total Nitrogen General Permit WWTF Limits

Total Nitrogen General Permit Optional Stormwater/Non-Point Source Reduction

Importance

• New Regulatory Framework With Potential Advantages
• Areas Of Concern

– Growth Limiting Aspects – Potential Impacts on Private Property – Costs for Compliance Are Unknown But Significant

• Action Tonight

– Peer Review Request to Evaluate Basis Of Permit

March 2, 2020 DRAFT Great Bay Total Nitrogen General Permit 3

Structure

• Estuary Wide Load Target

– Annual Load From All Sources

• Wastewater Effluent Limits

– Annual Load Instead of Growing Season Concentration

• Water Quality Monitoring Program
• Optional Stormwater and Non-Point Source (NPS) Nitrogen

Reduction Pathway

– 20+ Year Implementation

March 2, 2020 DRAFT Great Bay Total Nitrogen General Permit 4

Structure

• Total Annual Nitrogen Load Target

– 100 Kilograms/Hectare-Year

• From All Sources Of TN:

– Wastewater Treatment Facilities

• End Of Pipe

– Stormwater/NPS

• Septic System (Human Waste)
• Fertilizers
• Atmospheric Deposition
• Animal Waste

March 2, 2020 DRAFT Great Bay Total Nitrogen General Permit 5

GBES Watershed

12 Regulated NH Comm. 30 Other NH Comm. 10 ME Comm. 52 Total

Watershed Limits ME WWTFs Not Included MS4 NPDES Limits (Approx) NH WWTFs in Permit NH Communities in Permit

Structure

March 2, 2020 DRAFT Great Bay Total Nitrogen General Permit 6

• Annual Water Quality Testing Paid By

Communities

– City Responsible For ~30% Of Costs – No Ability To Adjust Scope And No End

• Robust Program

– Head Of Tide (River Inputs) – Continuous Data Sondes Estuary Wide – Benthic Organisms And Sediment Surveys – Eelgrass Mapping – Program Management And Reporting

• Costs Estimated >$1M Annually

– Portsmouth $300k To $500k annually

Compliance

• Short Term (0 to ~ 10 Years)

– Reduce Nitrogen Loads At Peirce Island WWTF

• Cannot Achieve Stormwater/NPS Reduction Target Using BMPs

– Need To Closely Track Land Use Change(s) To Keep Stormwater/NPS Nitrogen Discharge In Check – Upgrade Pease WWTF For Maximum Nitrogen Removal

• Long Term (~10+ Years)

– Continue To Optimize Nitrogen Removal At WWTFs – Likely Need to Address Stormwater/NPS Nitrogen Discharge

• Structural And Non-Structural Stormwater/NPS Nitrogen Controls
• Land Use Restrictions And/or Private Property Improvements

March 2, 2020 DRAFT Great Bay Total Nitrogen General Permit 7

Costs

• WWTF Capital and Operations

– Peirce Island WWTF Nitrogen Removal – Pease WWTF Upgrade for Nitrogen Removal – Effluent Water Quality Sampling for Nitrogen

• Land Use Tracking for Stormwater/NPS TN
• Water Quality Monitoring

– Current Costs Unknown and No End – Costs +/- Depending on Number of Communities

• Stormwater/NPS Nitrogen Reduction Projects

March 2, 2020 DRAFT Great Bay Total Nitrogen General Permit 8

Unknown Uncontrolled Costs Planned Controlled Costs

Opportunities

• Flexibility To Manage Nitrogen Removal At Both WWTFs

(“bubble”)

• Ability To Offset Stormwater/NPS Nitrogen Reduction Target

Using WWTFs

• Provides Structure for Credits For Non-WWTF Projects That

Reduce Nitrogen

– Requires Clarity In Permit

March 2, 2020 DRAFT Great Bay Total Nitrogen General Permit 9

Risks

• Significant Costs for Long Term Water Quality Monitoring Plan
• Accepting Permit Structure and Scientific Basis “Locks In” Nitrogen

Impairment

– Will Result In Further Stormwater MS4 NPDES Permit Requirements

• Technology May Not Be Adequate to Keep Stormwater/NPS

Nitrogen Discharges In Check

– Likely Result In Limits On Growth And Private Property Nitrogen Controls – Growth Shift From Communities With WWTFs To Communities Without

• Future Reductions In TN Limits Likely

– Reopener Clauses – Other Communities Are Not Included

March 2, 2020 DRAFT Great Bay Total Nitrogen General Permit 10

Risks

11

Baseline GBTN GP

From DES Model Measured

New TN Wastewater Effluent Limits

100 kilograms/hectare-year

Not Regulated Storm/NPS Regulated Storm/NPS ME WWTFs NH WWTFs NH WWTFs ME WWTFs Regulated Storm/NPS Not Regulated Storm/NPS

March 2, 2020

Next Steps

• Decision On Peer Review Support

– Concern That 100 kg/ha-yr Threshold Not Applicable – 9 Out of 12 Communities To Date Have Requested

• Develop and Submit Comments on DRAFT Permit April 8, 2020

March 2, 2020 DRAFT Great Bay Total Nitrogen General Permit 12

Questions and Answers

March 2, 2020 DRAFT Great Bay Total Nitrogen General Permit 13