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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@hdrinc.com. Overview. Numeric Nutrient Criteria Levels Limits of Wastewater Treatment Technology
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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@hdrinc.com
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
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
EPA’s 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
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
EPA’s Sources of Impairment Nationwide by Category from the 1998 303(d) List 47% Combination of Point and Nonpoint Sources 43% Impaired by Nonpoint Sources Only Only 10% Impaired by Point Sources Only!
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
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
Numeric Nutrient Criteria Are Very Low • MDEQ’s March 1, 2007 WPCAC Presentation • “Typical Concentrations That Protect Uses Are Low” • Total Phosphorus • 0.05 mg/l • Total Nitrogen • 0.30 mg/l
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
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
Treatment Costs Escalate Substantially as Approach Limits of Technology • Secondary Treatment • Biological Nutrient Removal • Enhanced Nutrient Removal • Limits of Treatment Technology • Reverse Osmosis
Variability in Algal Growth Response to Nutrients In-Stream Periphyton Levels Drive Nutrient Limits and Vary with Location • Narrative Standards for Nutrient Enrichment • Nuisance Algae Growth • What Constitutes Nuisance Conditions? • What are N and P Levels Associated with Nuisance Conditions
Multiple Factors Control Algal Growth in Streams • Adequate Nutrient Concentration For Enrichment • Stream Velocity and Scour • Light Penetration • Grazing • Substrate Stability • Temperature
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
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
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
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
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?
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 Zero Discharge -- Cascade Reservoir, ID TMDL 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."
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
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
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 < 1% Cost Bearable • MPS 1% to 2% Midrange Impact • MPS > 2% Unreasonable Cost • “Widespread”
“Municipal Preliminary Screener” 1% to 2% Midrange Impact • Typical Threshold for Economic Hardship 1.5% of Median Household Income
“Municipal Preliminary Screener” > 2% Unreasonable Cost • Little Comfort That “Substantial” and “Widespread” Economic Thresholds Reflect Expectations for Reasonable Wastewater Rates
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
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 Author’s Don’t Write Permits • Permit Writer’s Perspective is Key • Pre-formulated Permit Guidance from EPA and States Often Focused on Toxics
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
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
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
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
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
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