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Groundwater Rule Workshop DEC Drinking Water Program September 22-23, 2009 1 Treatment Technique Requirements Vanessa Wike, PE Statewide Engineering Coordinator DEC Drinking Water Program vanessa.wike@alaska.gov Slide 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 2 Slide 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 3 Slide 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. 4 Slide 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. 5 Slide 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. 6 Slide 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 PWSs) Formally issued through DW engineering plan review. Operational Certificate will specify treatment credit. 7 Slide 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 8 Slide 9 Conventional/Direct Filtration/Slow Sand/Diatomaceous Earth 9 Slide 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 10 Slide 11 Treatment Credit Virus (SWTR Guidance) Conventional:2.0 Log Direct:1.0 Log Slow Sand:2.0 Log Diatomaceous Earth:1.0 Log 11 Treatment Options Removal Conventional/Direct Filtration/Slow Sand/Diatomaceous Earth Slide 12 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. 12 Treatment Options Removal Conventional/Direct Filtration/Slow Sand/Diatomaceous Earth Slide 13 Operation & Maintenance Identical to Filtration under SWTR High Operator Oversight Water Demand Raw Water Quality Filter Backwash Cycles Chemical Dosing 13 Treatment Options Removal Conventional/Direct Filtration/Slow Sand/Diatomaceous Earth Slide 14 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. 14 Treatment Options Removal Conventional/Direct Filtration/Slow Sand/Diatomaceous Earth Slide 15 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 15 Treatment Options Removal Conventional/Direct Filtration/Slow Sand/Diatomaceous Earth Slide 16 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 16 Treatment Options Removal Conventional/Direct Filtration/Slow Sand/Diatomaceous Earth Slide 17 Bag and Cartridge Filtration 17 Slide 18 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 18 Treatment Options Removal Alternative Filtration - Bag and Cartridge Filtration Slide 19 Membrane Filtration 19 Slide 20 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 20 Treatment Options Removal Alternative Filtration - Membranes Slide 21 21 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 - Membranes Slide 22 22 Slide 23 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. 3 rd Party challenge test results will be required. 23 Treatment Options Removal Alternative Filtration - Membranes Slide 24 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 Slide 25 Product Validation - Challenge Testing One time, product specific test completed for manufacturer by 3 rd 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 Slide 26 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 Slide 27 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 Slide 28 28 Treatment Options Removal Alternative Filtration - Membranes Advantages High effluent water quality Compact installation Relatively simple operation Disadvantages High installation cost Performance and compliance monitoring Operator certification level Lead/Copper Issues Slide 29 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 Options Removal Alternative Filtration - Membranes Slide 30 Ultra-Violet Radiation UV 30 Slide 31 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 Inactivation Ultra-Violet Light (UV) Slide 32 32 Slide 33 33 Slide 34 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. 34 Treatment Options Inactivation Ultra-Violet Light (UV) Slide 35 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 35 Treatment Options Inactivation Ultra-Violet Light (UV) Slide 36 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 36 Treatment Options Inactivation Ultra-Violet Light (UV) Slide 37 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. 37 Treatment Options Inactivation Ultra-Violet Light (UV) Slide 38 Treatment Options Inactivation Ultra-Violet Radiation (UV) Advantages High Crypto & Giardia Inactivation No known DBP formation Compact installation Relatively simple operation 38 Disadvantages High dose for virus inactivation Disinfection effectiveness difficult to monitor UV lamps contain mercury Power cost Stable power source required Slide 39 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. 39 Treatment Options Inactivation Ultra-Violet Light (UV) Slide 40 Ozone Disinfection 40 Slide 41 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 41 Treatment Options Inactivation Ozone Slide 42 Treatment Credit Virus CT dependant on following: Water temperature (Celsius) Ozone residual concentration (mg/L) 0.5 Log to 4.0 log credit possible 42 Treatment Options Inactivation Ozone Slide 43 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) 43 Slide 44 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. 44 Treatment Options Inactivation Ozone Slide 45 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. 45 Treatment Options Inactivation Ozone Slide 46 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 46 Treatment Options Inactivation Ozone Slide 47 Chloramines 47 Slide 48 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. 48 Treatment Options Inactivation Chloramines Slide 49 Chlorination 49 Slide 50 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 50 Treatment Options Inactivation Chlorine Disinfection Slide 51 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 51 Treatment Options Inactivation Chlorine Disinfection Slide 52 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 52 Slide 53 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. 53 Treatment Options Inactivation Chlorine Disinfection Slide 54 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. 54 Treatment Options Inactivation Chlorine Disinfection Slide 55 55 Slide 56 Groundwater Rule Workshop DEC Drinking Water Program - September 22-23, 2009 Treatment Technique Requirements Summary Vanessa 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 56