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Groundwater Rule Workshop DEC Drinking Water Program September 22-23, 2009. Treatment Technique Requirements. Vanessa Wike, PE Statewide Engineering Coordinator DEC Drinking Water Program [email protected] Topics. GWR Treatment Goal When ? What?

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Groundwater rule workshop dec drinking water program september 22 23 2009
Groundwater Rule Workshop DEC Drinking Water ProgramSeptember 22-23, 2009

Treatment Technique Requirements

Vanessa Wike, PE

Statewide Engineering Coordinator

DEC Drinking Water Program

[email protected]


Topics
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


Topics1
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


Gwr treatment objective
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.


When is treatment required
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.


When is treatment required1
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.


What are treatment options
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.


Treatment method overview
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


Treatment options removal

Treatment OptionsRemoval

Conventional/Direct Filtration/Slow Sand/Diatomaceous Earth


Treatment options removal conventional direct filtration slow sand diatomaceous earth
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


Treatment options removal conventional direct filtration slow sand diatomaceous earth1
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


Treatment options removal conventional direct filtration slow sand diatomaceous earth2
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.


Treatment options removal conventional direct filtration slow sand diatomaceous earth3
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


Treatment options removal conventional direct filtration slow sand diatomaceous earth4
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.


Treatment options removal conventional direct filtration slow sand diatomaceous earth5
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


Treatment options removal conventional direct filtration slow sand diatomaceous earth6
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


Treatment options removal1

Treatment OptionsRemoval

Bag and Cartridge Filtration


Treatment options removal alternative filtration bag and cartridge filtration
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


Treatment options removal2

Treatment OptionsRemoval

Membrane Filtration


Treatment options removal alternative filtration membranes
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


Treatment options removal alternative filtration membranes1
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.


Treatment options removal alternative filtration membranes2
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.


Treatment options removal alternative filtration membranes3
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


Treatment options removal alternative filtration membranes4
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).


Treatment options removal alternative filtration membranes5
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


Treatment options removal alternative filtration membranes6
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.


Treatment options removal alternative filtration membranes7
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


Treatment options removal alternative filtration membranes8
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.


Treatment options inactivation

Treatment OptionsInactivation

Ultra-Violet Radiation

UV


Treatment options inactivation ultra violet light uv
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.


Treatment options inactivation ultra violet light uv1
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.


Treatment options inactivation ultra violet light uv2
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


Treatment options inactivation ultra violet light uv3
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


Treatment options inactivation ultra violet light uv4
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.


Treatment options inactivation ultra violet radiation uv
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


Treatment options inactivation ultra violet light uv5
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.


Treatment options inactivation1

Treatment OptionsInactivation

Ozone Disinfection


Treatment options inactivation ozone
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


Treatment options inactivation ozone1
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


Treatment options inactivation ozone disinfection
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)


Treatment options inactivation ozone2
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.


Treatment options inactivation ozone3
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.


Treatment options inactivation ozone4
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


Treatment options inactivation2

Treatment OptionsInactivation

Chloramines


Treatment options inactivation chloramines
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.


Treatment options inactivation3

Treatment OptionsInactivation

Chlorination


Treatment options inactivation chlorine disinfection
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


Treatment options inactivation chlorine disinfection1
Treatment Options – InactivationChlorine Disinfection

Treatment Credit – Virus

  • CT dependant on following:

    • Water temperature (Celsius)

    • pH

    • Chlorine residual concentration (mg/L)

  • 0.5 Log to 4.0 log credit possible


Treatment options inactivation chlorine disinfection2
Treatment Options – Inactivation Chlorine Disinfection

Treatment Selection/Design Considerations

  • Contact tank volume size appropriately for system demand

  • Tank design to address short circuiting (baffle factor)

  • Possible DBP formation – simultaneous compliance issue (suggest reading the guidance).

  • Potential safety issues addressed through design for gaseous chlorine/chlorine dioxide


Treatment options inactivation chlorine disinfection3
Treatment Options – InactivationChlorine Disinfection

Performance and Compliance

  • Chlorine residual monitoring

    • CT verification based on established CT and daily chlorine residual monitoring

    • Compliance Reporting

      ** Chlorine monitoring and operator reporting forms have been developed for statewide use.


Treatment options inactivation chlorine disinfection4
Treatment Options – InactivationChlorine Disinfection

Potential Applications

  • Most likely the most viable option for virus treatment for most systems.

  • Various types of media for chlorination.

    • Hypochlorite

    • Onsite chlorine generation from salt

    • Chlorine Gas

    • Chlorine Dioxide

  • The potential for DBP formation may be a concern.



Groundwater Rule Workshop DEC Drinking Water Program - September 22-23, 2009 Treatment Technique Requirements SummaryVanessa Wike, PE

  • Less than 5% of systems will be affected by this treatment component of this rule (rough estimate).

  • Proposed treatment will be reviewed in the same manner as is currently used – using the treatment objective of 4 log virus removal.

    • Treatment Credit is formally issued through DEC DW Plan Review.

    • Operational Certificate will specify treatment credit.

  • Most systems required to treat are expected to select some form of chlorination.

    Engineering Submittal Checklists available online at:

    http://www.dec.state.ak.us/eh/dw/dwmain/engineering.html


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