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Groundwater Rule Workshop DEC Drinking Water Program September 22-23, 2009

Groundwater Rule Workshop DEC Drinking Water Program September 22-23, 2009. Treatment Technique Requirements. Vanessa Wike, PE Statewide Engineering Coordinator DEC Drinking Water Program vanessa.wike@alaska.gov. Topics. GWR Treatment Goal When ? What?

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Groundwater Rule Workshop DEC Drinking Water Program September 22-23, 2009

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  1. Groundwater Rule Workshop DEC Drinking Water ProgramSeptember 22-23, 2009 Treatment Technique Requirements Vanessa Wike, PE Statewide Engineering Coordinator DEC Drinking Water Program vanessa.wike@alaska.gov

  2. Topics • GWR Treatment Goal • When ? What? • Treatment Method Highlights (Virus Treatment) • Removal • Conventional/Direct Filtration/Slow Sand/Diatomaceous Earth • Alternative Filtration • Bag/Cartridge • Membrane • Inactivation • Ultraviolet Radiation (UV) • Ozone • Chloramines • Chlorine • Summary

  3. Topics • GWR Treatment Goal • When ? What? • Treatment Method Highlights (Virus Treatment) • Removal • Conventional/Direct Filtration/Slow Sand/Diatomaceous Earth • Alternative Filtration • Bag/Cartridge • Membrane • Inactivation • Ultraviolet Radiation (UV) • Ozone • Chloramines • Chlorine • Summary

  4. GWR Treatment Objective • 4-Log Virus Treatment by Removal and/or Inactivation (4 Log = 99.99%) • PWS approved* for 4-log treatment is not required to conduct source water monitoring * Must be formally awarded treatment credit through engineering plan approval.

  5. When is Treatment Required? • Risk Targeted Approach: The source is determined to be vulnerable or at a higher risk to contamination based on poor well construction or proximity to sources of fecal contamination; or • Triggered Approach: The water system has a history of fecal contamination.

  6. When is Treatment Required? • Risk Targeted Approach: The source is determined to be vulnerable or at a higher risk to contamination based on poor well construction or proximity to sources of fecal contamination; or • Triggered Approach: The water system has a history of fecal contamination. Based on current sampling results, we are estimating that less than 5% of existing PWS using a groundwater source will be require treatment based on the triggered approach.

  7. What are Treatment Options? • Same treatment options , DEC review criteria and review process as is currently used. • Proposed treatment will be assessed with respect to effectiveness at 4 log virus removal. • Treatment Credit (new and existing PWS’s) • Formally issued through DW engineering plan review. • Operational Certificate will specify treatment credit.

  8. Treatment Method Overview • Guidance & References • Treatment Credit Awarded • Major Selection Considerations/Plan Review Requirements • General Operation and Maintenance Considerations • Performance and Compliance Monitoring • Advantages and Disadvantages • Potential Applications for Large and Small Systems

  9. Treatment OptionsRemoval Conventional/Direct Filtration/Slow Sand/Diatomaceous Earth

  10. Treatment Options – Removal Conventional/Direct Filtration/Slow Sand/Diatomaceous Earth Guidance / Reference(s) • SWTR Guidance Manual. EPA. March 1991 • Treatment Credit • Monitoring/Reporting Requirements • Recommended Standards for Water Works (aka “10 States Standards”) • General Design Criteria

  11. Treatment Options – Removal Conventional/Direct Filtration/Slow Sand/Diatomaceous Earth Treatment Credit – Virus (SWTR Guidance) • Conventional: 2.0 Log • Direct: 1.0 Log • Slow Sand: 2.0 Log • Diatomaceous Earth: 1.0 Log

  12. Treatment Options – Removal Conventional/Direct Filtration/Slow Sand/Diatomaceous Earth System Design Requirements • Conventional: Coagulation – Sedimentation – Flocculation – Filtration Steps • Direct: Coagulation - Flocculation – Filtration Steps • Slow Sand: “Schmutzdecke,” smaller grain size, no backwash, removal of surface media • Diatomaceous Earth: Pre-coat or “Diatomite Media”, no backwash, removal of surface media Important Note for Filtration Classification - Media Type and Grading must meet 10 States Standards.

  13. Treatment Options – Removal Conventional/Direct Filtration/Slow Sand/Diatomaceous Earth Operation & Maintenance • Identical to Filtration under SWTR • High Operator Oversight • Water Demand • Raw Water Quality • Filter Backwash Cycles • Chemical Dosing

  14. Treatment Options – Removal Conventional/Direct Filtration/Slow Sand/Diatomaceous Earth Performance and Compliance • Same as SWTR Guidance • Filtration Performance • Turbidity Monitoring • Compliance Reporting Note: Credit for virus removal is based on specified filter performance in SWTR Guidance.

  15. Treatment Options – Removal Conventional/Direct Filtration/Slow Sand/Diatomaceous Earth Advantages and Disadvantages • More disadvantages than advantages • Unlikely New Treatment Option: • High capitol cost • High O&M • Low treatment credit • Additional treatment required to meet 4 Log

  16. Treatment Options – Removal Conventional/Direct Filtration/Slow Sand/Diatomaceous Earth Potential Applications • Larger Systems • Existing filtration may be able to receive credit with: • Approval from Department • Modification likely required to add filtration steps (coagulant) • Media may need to be changed (10 States Standards) • Turbidity Monitoring would need to be added

  17. Treatment OptionsRemoval Bag and Cartridge Filtration

  18. Treatment Options – RemovalAlternative Filtration - Bag and Cartridge Filtration Bags & Cartridge Filtration • Does not include membrane-type cartridges • Not appropriate treatment for virus removal • Particle Filtration ability too course for virus removal • Finest particulate filtration is ~1 um • Virus size is ~0.1 um or less

  19. Treatment OptionsRemoval Membrane Filtration

  20. Treatment Options – Removal Alternative Filtration - Membranes Guidance / Reference(s) • Membrane Filtration Guidance Manual. EPA. November 2005 • Design • Treatment Credit • Challenge Testing • Monitoring/Reporting Requirements • GWR Corrective Action Guidance Manual (Draft). EPA. June 2008 • Overview • Treatment Credit

  21. Treatment Options – Removal Alternative Filtration - Membranes Membrane Filtration Types: • Microfiltration (MF) • Ultrafiltration (UF) • Nanofiltration (NF) • Reverse Osmosis (RO) • Type defined by range of removal and operating pressure.

  22. Treatment Options – Removal Alternative Filtration - Membranes Treatment Credit – Virus (GWR Corrective Action Guidance) • Micro Filtration (MF): Not Appropriate • Ultra Filtration (UF): Challenge Test Dependent • Nano Filtration (NF): 4.0 + Log * • Reverse Osmosis (RO): 4.0 + Log * *Treatment credits awarded based on challenge test results at State discretion. 3rd Party challenge test results will be required.

  23. Treatment Options – Removal Alternative Filtration - Membranes Treatment Selection/Design Considerations • Validation / Challenge Testing • Raw water quality dependant • Added complexity to treatment system if pre-treatment is required – Operator Certification Level • May increase corrosiveness of water – Lead/Copper issues possible • Performance and compliance monitoring

  24. Treatment Options – Removal Alternative Filtration - Membranes Product Validation - Challenge Testing • One time, product specific test completed for manufacturer by 3rd Party Lab • Verifies the maximum “contaminant” removal capability - basis for treatment credit • DW Program requires challenge test results of a device, using an approved protocol, before issuing credit • *Important* Most challenge tests do not use a surrogate representative of virus contaminants. • There are currently no validated membranes on the market eligible for 4-log removal credit of viruses (at this time).

  25. Treatment Options – Removal Alternative Filtration - Membranes Operation & Maintenance • Generally follows EPA Membrane Filtration Guidance • Product-specific Operator Training • Membrane performance monitoring may be more stringent than compliance performance limits. • Direct Integrity Testing used to validate proper membrane function

  26. Treatment Options – Removal Alternative Filtration - Membranes Performance and Compliance • Monitoring Requirements (EPA Membrane Guidance) • Turbidity Monitoring – Standard Alternate Filtration • Compliance Reporting • Direct Integrity Testing and Reporting • Indirect Integrity Testing (continuous turbidity) • Inactivation credit dependant on challenge test results • Challenge test review is extremely detailed and time consuming. • Recommend submitting challenge test report to DEC prior to unit selection. • Plan for extended plan review period due to multiple reviews and approval • Draft membrane monitoring and operator reporting forms have been developed. May be modified for system specific conditions.

  27. Treatment Options – Removal Alternative Filtration - Membranes Disadvantages • High installation cost • Performance and compliance monitoring • Operator certification level • Lead/Copper Issues Advantages • High effluent water quality • Compact installation • Relatively simple operation

  28. Treatment Options – Removal Alternative Filtration - Membranes Potential Applications • Large Systems – Requires healthy financial capacity or ample funding source due to high capitol cost. • Small Systems – Unlikely option due to lack of product availability that meets challenge test protocol. • Operator expertise required. Specialized training beyond standard Operator Certification may be required. ** Point of Use / Point of Entry type membrane units are not approved for use for microbial treatment.

  29. Treatment OptionsInactivation Ultra-Violet Radiation UV

  30. Treatment Options – InactivationUltra-Violet Light (UV) Guidance / Reference(s) • UV Disinfection Guidance Manual (UVDGM). EPA. November 2006 • Design • Treatment Credit • Challenge Testing • Monitoring/Reporting Requirements Note: This is the most comprehensive guidance for regulating UV treatment units available today.

  31. Treatment Options – InactivationUltra-Violet Light (UV) Treatment Credit – Virus • Inactivation credit dependant on challenge test results • Challenge test review is extremely detailed and time consuming. • Recommend submitting challenge test report to DEC prior to unit selection. • Plan for extended plan review period due to multiple reviews and approval. ** There are no UV units that have been approved in Alaska for inactivation credit of viruses.

  32. Treatment Options – InactivationUltra-Violet Light (UV) Treatment Selection/Design Considerations • Validation / Challenge Testing • Establishes design criteria and treatment credit • Raw water quality dependant – 1 year of transmissivity data recommended • Added complexity to treatment system if pre-treatment is required – Operator Certification Level • Design around UV unit must emulate validated conditions • Performance and compliance monitoring

  33. Treatment Options – InactivationUltra-Violet Light (UV) Operation & Maintenance • Follows UV Disinfection Guidance • High level of product-specific Operator Training • Added complexity to treatment system if pre-treatment is required • May reduce free chlorine concentration • Units must have specific monitoring capability • Relatively simple operation and maintenance • Maintenance is critical • High power consumption and quality requirements

  34. Treatment Options – InactivationUltra-Violet Light (UV) Performance and Compliance • Performance measures to follow EPA UV Guidance • Monitoring Requirements • Very unique to other treatment types - measurements of light intensity. • Compliance Reporting – Monthly Operator Reports ** Draft UV monitoring and operator reporting forms have been developed for certain types of UV units.

  35. Treatment Options – Inactivation Ultra-Violet Radiation (UV) Disadvantages • High dose for virus inactivation • Disinfection effectiveness difficult to monitor • UV lamps contain mercury • Power cost • Stable power source required Advantages • High Crypto & Giardia Inactivation • No known DBP formation • Compact installation • Relatively simple operation

  36. Treatment Options – InactivationUltra-Violet Light (UV) Potential Applications • Large Systems – Unlikely due to capitol cost and high power requirements to meet virus inactivation in comparison to other options. • Small Systems – Unlikely option (at this time) due to lack of product availability that meets challenge test protocol. • Operator expertise required. Specialized training beyond standard Operator Certification may be required. • Operator dedication required for routine maintenance for successful operation.

  37. Treatment OptionsInactivation Ozone Disinfection

  38. Treatment Options – InactivationOzone Guidance / Reference(s) • SWTR Guidance Manual. EPA. March 1991 • Treatment Credit • CT Table • Alternative Disinfectants and Oxidants Guidance Manual. EPA. April 1999 • General Design Criteria

  39. Treatment Options – InactivationOzone Treatment Credit – Virus • CT dependant on following: • Water temperature (Celsius) • Ozone residual concentration (mg/L) • 0.5 Log to 4.0 log credit possible

  40. Treatment Options – Inactivation Ozone Disinfection Treatment Selection/Design Considerations • Seasonal water quality data to establish ozone demand, including: Fe, Mn, TOC. • Ozone unit output size critical. Unit is sized to highest ozone demand raw water quality. • Stable power source • Pretreatment may be necessary • Possible DBP formation if Bromide is present in raw water. • Contact tank volume size appropriately for system demand • Tank design to address short circuiting (baffle factor)

  41. Treatment Options – InactivationOzone Operation & Maintenance • Safety concerns for ozone off-gassing • High Operator Oversight • Venturi or injection port fouling • High wear parts replacement (electrodes) • Redundant system or back-up disinfection system recommended.

  42. Treatment Options – InactivationOzone Performance and Compliance • Similar to chlorine residual monitoring • CT verification based on established CT and daily ozone residual monitoring • Compliance Reporting ** Initial ozone monitoring and operator reporting forms have been developed.

  43. Treatment Options – InactivationOzone Potential Applications • May be a viable option for system with: • Year-around high water quality. • Stable power source • Dedicated operator • May not be financially justifiable compared to chlorination unless: • Foot print is limited • Chemical storage and/or access is limited • Chlorine taste is an issue

  44. Treatment OptionsInactivation Chloramines

  45. Treatment Options – InactivationChloramines Guidance / Reference(s) • Alternative Disinfectants and Oxidants Guidance Manual. EPA. April 1999 • General discussion on virus inactivation Potential Application • Generally not appropriate if virus inactivation is the sole treatment objective. • Chlorine dose required to meet CT is about an order of magnitude greater than standard chlorination.

  46. Treatment OptionsInactivation Chlorination

  47. Treatment Options – InactivationChlorine Disinfection Guidance / Reference(s) • SWTR Guidance Manual. EPA. March 1991 • Treatment Credit • CT Table • Monitoring/Reporting • Alternative Disinfectants and Oxidants Guidance Manual. EPA. April 1999 • Simultaneous Compliance Guidance Manual for the LT2 and Stage 2 DPB Rule. EPA. March 2007

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