Implications of Instream Numeric Nutrient Criteria for Wastewater Utilities

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Implications of In-stream Numeric Nutrient
Criteria for Wastewater Utilities

• Helena
• June 28, 2007
• David L. Clark
• HDR Engineering, Inc.
• 208-387-7025
• dclark_at_hdrinc.com

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Overview

• Numeric Nutrient Criteria Levels
• Limits of Wastewater Treatment Technology
• Altered Stream Conditions and Ambient Water
  Quality Exceeding In-stream Numeric Nutrient
  Criteria Levels
• Interpretation of In-stream Limits for TMDLs and
  MPDES Permitting
• Economic Impacts of Cost Implications for
  Treatment at Limits of Technology
• Recommendations

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Numeric Nutrient Standards for Surface Waters of
Montana

• March 1, 2007 WPCAC Presentation
• Michael Suplee, Ph.D., Department of
  Environmental Quality
• Characterization of Water Quality Conditions in
  Montana Streams
• Numeric Nutrient Criteria are Very Low
• Dischargers will have Concerns
• Economic Impact Analysis

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EPAs National Nutrient Strategy

• Numeric standards reduce States time and effort
  to establish TMDLs and permits to control
  nutrient levels
• EPA Office of Water Themes
• Direct Assistance to States Close to Adopting
  Numeric Criteria
• Build Capacity of States That Are Further From
  Adopting Numeric Criteria
• Build a Science-based Foundation for Developing
  New Section 304(a) Criteria for Estuaries,
  Wetlands, and Large Rivers
• Clearly and Effectively Communicate the Dangers
  of Nutrient Pollution and the Merits of Numeric
  Nutrient Criteria to States, Nutrient Sources,
  and the General Public

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Why Do Numeric Nutrient Standards Concern
Wastewater Utilities?

• In-Stream Numeric Nutrient Standards Based on
  Natural Conditions Are Very Low
• Lower Than Treatment Technologies Are Capable of
  Achieving If Applied End-of-Pipe
• Wastewater Utilities Rely on Surface Waters for
  Effluent Management
• MPDES Permitted Discharges Are Regulated First
  and Most in TMDLs
• Over-Regulation of Point Sources May Have
  Unintended Consequences
• Reducing In-Stream Flows
• Altering Development Patterns
• Skewed Economic Impacts
• Reduction in Point Sources Alone Will Not Protect
  Montana Rivers
• Progress Made in Wastewater Load Reductions May
  Be Lost To Increases in Other Nonpoint Source
  Loadings

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EPAs Sources of Impairment Nationwide by
Category from the 1998 303(d) List
43 Impaired by Nonpoint Sources Only
47 Combination of Point and Nonpoint Sources
Only 10 Impaired by Point Sources Only!
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Wastewater Utilities Perform Much of the Nutrient
Removal Heavy Lifting to Protect Watersheds

• Wastewater Utilities Provide
• Assured Compliance
• Advanced Wastewater Treatment is Very Effective
• Nutrient Loads will be Reduced
• Predictable Performance
• MPDES Reporting
• Strict Compliance Standards

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Wastewater Utility Needs

• Predictable Future for Facilities Planning
• 20 Year Capital Improvement Programs
• Multi-Million Dollar Capital Investments
• Commitment to Long-Term Debt Service
• Regulatory Framework with Practical Consideration
  of Modified Stream Conditions
• TMDL Wasteload Allocations and MPDES Permit
  Limits within Limits of Treatment Technology
• Definition of Reasonable Economic Hardship
  Thresholds
• MPDES Permit Conditions Spanning Multiple 5-Year
  Cycles

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Numeric Nutrient Criteria Are Very Low

• MDEQs March 1, 2007 WPCAC Presentation
• Typical Concentrations That Protect Uses Are
  Low
• Total Phosphorus
• 0.05 mg/l
• Total Nitrogen
• 0.30 mg/l

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Comparison of Numeric Nutrient Criteria with
Limits of Wastewater Treatment Technology

• Most Montana Treatment Plants at Secondary
  Treatment Level
• Advanced Treatment for Nutrient Removal
• Kalispell
• Missoula
• Hamilton
• Columbia Falls
• Others

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Pilot Study Results Illustrated Challenges at
Limits of Technology

• Performance Sensitivity of Enhanced Nutrient
  Removal Technologies (ENR)
• No Treatment Technology Available for Refractory
  Dissolved Organics (rDOP, rDON) and May Not Be
  Bioavailable

Pilot Effluent Percentage Phosphorus Fractions
Pilot Effluent Phosphorus Comparison
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Treatment Costs Escalate Substantially as
Approach Limits of Technology

• Secondary Treatment
• Biological Nutrient Removal
• Enhanced Nutrient Removal
• Limits of Treatment Technology
• Reverse Osmosis

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Variability in Algal Growth Response to Nutrients

• Narrative Standards for Nutrient Enrichment
• Nuisance Algae Growth
• What Constitutes Nuisance Conditions?
• What are N and P Levels Associated with Nuisance
  Conditions

In-Stream Periphyton Levels Drive Nutrient Limits
and Vary with Location
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Multiple Factors Control Algal Growth in Streams

• Adequate Nutrient Concentration For Enrichment
• Stream Velocity and Scour
• Light Penetration
• Grazing
• Substrate Stability
• Temperature

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Variability in Numerical Standards and Effluent
Limits

• Clark Fork River
• TP 0.039 mg/L Downstream of Missoula
• TP 0.020 mg/l Upstream of Missoula
• TN 0.30 mg/l
• Snake River/Hells Canyon TMDL/Pending Boise River
  TMDL
• 0.070 mg/l
• Spokane River Dissolved Oxygen TMDL
• TP 0.010 mg/l

Clark Fork Tributary
Snake River Tributary
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Potential for Unrealistic Targets Based on
Natural Reference Conditions

• Paradise Creek, Idaho
• IDEQ Prepared TMDL
• In-Stream P Target Based On Natural Background
  Conditions at Idlers Rest Nature Conservancy
• In-Stream TP 0.136 mg/l
• City of Moscow Permit
• Requires 96 TP Reduction

Paradise Creek, Idaho
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Avoid Application of Natural Background Targets
to Downstream River Segments Impacted by Multiple
Alterations

• Truckee River TMDL -- Difficult, If Not
  Impossible Requirements
• Flow Alteration
• Out-of-Basin Transfer by Federal Dam with Senior
  Water Right
• In-Stream Target Setting
• Dissolved Oxygen Downstream of Derby Dam
• State P Standard TP 50 ug/l
• Truckee Meadows Water Reclamation Facility
  (Reno/Sparks, NV)
• TP 1 mg/l and TN 3 mg/l
• At Limits of Technology for TN
• Total Nitrogen Limit Difficult at Low Levels
  Since Essentially all TIN Removed
• Now Considering Revised TMDL
• Very Difficult to Define Appropriate Pathway
  Post-TMDL

Lake Tahoe
Derby Dam, Truckee River, Nevada
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Interpretation of In-stream Criteria for TMDLs
and MPDES Permitting

• Appropriate Stream Classifications
• Are Alternative Classifications Required?
• Avoid Unintended Consequences
• Reduce In-Stream Flows
• Available Capacity for Community Growth
• Shift Development Patterns to Increase Nonpoint
  Source Loadings
• Increased On-Site Septic System Use in TMDL
  Watersheds
• Use Attainability Analysis (UAA)
• Cumbersome and Expensive Process
• No Assured Outcome
• Variances
• Temporary

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Ambient Water Quality Exceeding In-stream Numeric
Nutrient Criteria Levels

• Numeric Nutrient Criteria are Very Low
  Concentrations
• Frequently, Ambient Conditions in Montana Streams
  Exceed Nutrient Targets (i.e. TMDLs)
• Establishing Discharge Conditions Challenging
• Zero Discharge?
• Apply In-Stream Standards End-of-Pipe?
• Define Acceptable Discharge Conditions in Context
  Reasonable Treatment Technology?

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Zero Discharge -- Cascade Reservoir, ID TMDL

• Phosphorus TMDL
• In-reservoir Total Phosphorus Concentration of
  0.025 mg/L
• In-reservoir Chlorophyll a of 10 µg/L

• City of McCall, ID
• Zero Discharge Permit
• Expensive Winter Storage Reservoir
• Multiple Missteps
• Potential Bankruptcy

May 11, 2007 McCall flirts with bankruptcy MCCALL
Officials in the resort town of McCall plan a
town hall meeting Monday to announce whether they
plan to file for bankruptcy protection after a
series of losing court battles involving
construction of a wastewater treatment facility.
U.S. District Judge B. Lynn Winmill late last
month ordered the city to pay 6 million
immediately. "We don't have the cash," Mayor
Bill Robertson said. "What the judge is trying to
extract is three times more than our tax revenue.
So our options are very limited."
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In-Stream Standards Applied End-of-Pipe --
Spokane River

• Dissolved Oxygen TMDL
• D.O. Limits Cannot be Met in Hypolimnion
• In-Stream Target Setting
• Based on Upstream Oligotrophic Lake but Applied
  to Downstream Reservoir
• Strictest Effluent Limits in Nation
• TP 0.010 mg/l
• Below Limits of Treatment Technology
• Effluent Limits Apply End-of-Pipe
• No Effluent Mixing Dilution

Long Lake Reservoir, Spokane River
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Realistic Approach -- Clark Fork River Voluntary
Nutrient Reduction Program (VNRP)

• In-Stream Nutrient Target Setting
• TP 20 ug/l and 39 ug/l (Missoula area)
• TN 300 ug/l
• Evaluated Implementation Efforts in Conjunction
  with Development of the VNRP
• Analysis of Alternative Load Reduction Scenarios
• Realistic Wastewater Discharge Permit Limits
• Requires TP 1 mg/l and TN 10 mg/l
• Successful Implementation

Clark Fork River, Montana
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Definition of Reasonable Economic Hardship
Thresholds

• Federal Reference Points
• Substantial
• Widespread
• EPA Recommendations
• Substantial
• Municipal Preliminary Screener
• Mean Total Pollution Control Cost per
  Household/Median Household Income
• MPS lt 1 Cost Bearable
• MPS 1 to 2 Midrange Impact
• MPS gt 2 Unreasonable Cost
• Widespread

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Montana Single Family Monthly Wastewater Rates,
July 2006
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Municipal Preliminary Screener 1 to 2
Midrange Impact

• Typical Threshold for Economic Hardship 1.5 of
  Median Household Income

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Municipal Preliminary Screener gt 2
Unreasonable Cost

• Little Comfort That Substantial and
  Widespread Economic Thresholds Reflect
  Expectations for Reasonable Wastewater Rates

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Balanced Regulatory Framework for Surface Water
and Ground Water
East Gallatin River

• Growing Montana Communities Need Capacity
• Avoid Economic Driving Forces Away from Advanced
  Treatment
• Avoid Unintended Shift of Nutrient Loadings from
  Surface Water to Ground Water
• Shift Development Patterns to Unsewered Areas
  Which Increase Nonpoint Source Loadings
• Establish N and P Standards for Groundwater
  Discharge from On-Site Septic Systems in TMDL
  Watersheds

Bozeman WWTP
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Appropriate Discharge Permits for Nutrients

• Translation of In-Stream Criteria to TMDLs to
  Permit Limits
• Critical Interpretation of Water Quality Issues
• TMDL Implementation Plans Often Not Well
  Understood
• TMDL Authors Dont Write Permits
• Permit Writers Perspective is Key
• Pre-formulated Permit Guidance from EPA and
  States Often Focused on Toxics

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Selection of Appropriate Flow Conditions for
Nutrients

• Default Selection of 7Q10 Flows Overly
  Restrictive
• Western Rivers Often Have Extremely Low Late
  Summer Flows which Limit Effluent Dilution
• Leads to In-Stream Standards Applied at
  End-of-Pipe
• Nuisance Conditions and Algal Response
• Longer Averaging Period Appropriate for Nutrients
• Clark Fork River TMDL 30Q10 Flow
• Seasonal or Annual Average Flows Appropriate

Clark Fork River, Montana
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Recognition of Daily Treatment Process
Variability at Very Low Levels

• Excellent Overall Nutrient Removal Achieved
• Although Process Performance Varies Daily
• Median or Average Conditions
• Annual or Seasonal
• Maximum Daily or Weekly Limits Inappropriate

CWS Durham Plant Effluent Phosphorus, mg/l
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Seasonal Reuse Opportunities May Be Available to
Offset Some Loadings
Water Reclamation Facility
River

• Urban Irrigation
• Parks, Schools, Fairgrounds

• Industrial Reuse
• Paper Mill, Rock Crushing, Concrete

Reuse

• Groundwater Recharge
• Surface Percolation

• Wetlands Restoration
• Creation, Restoration, Enhancement

• Other
• Agricultural Land, Poplar Farms

• Limited Opportunities for All Effluent
• Limited Opportunities Spring and Fall

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State Support Needed to Facilitate and Promote
Beneficial Reuse

• Regulatory Framework for Reclaimed Water
  Production and Reuse
• Some Montana Definitions In Place Now
• Reference California, Washington, Arizona, Texas,
  Florida
• Treatment Technology Review Processes
• Well Developed Permitting Processes
• Facilitated Permitting Process
• Generate Public Support for Beneficial Reuse
• Pilot Tests and Demonstration Programs
• Washington Reuse and Groundwater Recharge
  Demonstration Projects

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Recommendations -- 1

• Judicious Application of Numeric Nutrient
  Standards
• Account for Modified Stream Conditions
• Advanced Planning for Realistic Stream Conditions
• Avoid Unintended Consequences that Reduce
  In-Stream Flows
• Balanced Regulatory Framework for Surface Water
  and Ground Water
• Implement N and P Standards for Groundwater
  Discharge from On-Site Septic Systems in TMDL
  Watersheds

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Recommendations -- 2

• TMDL Wasteload Allocations and MPDES Permit
  Limits within Limits of Treatment Technology
• Advanced Consideration of Reasonable Economic
  Thresholds for Hardship
• Effluent Reuse Standards and MDEQ Support for
  Beneficial Recycling
• Establish Appropriate MPDES Permit Conditions
• MPDES Permit Conditions Spanning Multiple 5-Year
  Cycles