Direct, Indirect, and Potable Reuse Panel

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Presentation at the TWCA mid year conference 2012 www.twca.org


Guy Carpenter, PE
Vice President - Water Supply & Reuse

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  • Note to presenter – same text states that there is little value in the environmental buffer if FAT is used.
  • Picture of reverse osmosis
  • Without an ocean, and if 100% reclaimed water recovery is your goal, RO brine elimination costs more than the cost of advanced treatment and is not a good solution.
  • Direct, Indirect, and Potable Reuse Panel

    1. 1. Direct, Indirect, and Potable Reuse Panel TWCA Mid Year Meeting June 2012 Guy Carpenter, PE Vice President - Water Supply & ReuseCarolloTemplateWaterWave.pptx
    2. 2. CarolloTemplateWaterWave.pptx Direct Reuse 2
    3. 3. Indirect Potable Reuse Groundwater AugmentationCarolloTemplateWaterWave.pptx 3
    4. 4. Indirect Potable Reuse Surface Water AugmentationCarolloTemplateWaterWave.pptx 4
    5. 5. Indirect Potable Reuse Surface Water AugmentationCarolloTemplateWaterWave.pptx 5
    6. 6. CarolloTemplateWaterWave.pptx Direct Potable Reuse 6
    7. 7. Texas Reuse Regulations • Direct Reuse – Title 30, Chapter 210 of the Texas Administrative Code; administered by the TCEQCarolloTemplateWaterWave.pptx 7
    8. 8. Texas Reuse Regulations • Direct Reuse – Title 30, Chapter 210 of the Texas Administrative Code; administered by the TCEQ • Indirect Reuse (Surface Water Augmentation) – Texas PDES Permit – Texas Surface Water Quality Standards – T.A.C Chapters 295 and 297 - rules and process for water rights • Indirect Reuse (Groundwater Augmentation - ASR) – T.A.C. Chapter 331- meet or exceed SDWA requirements and TCEQ DW standards (T.A.C. Chapter 290) – No specific regs for spreading (percolation) basinsCarolloTemplateWaterWave.pptx • Potable Reuse (DPR) – No regulations , but not prohibited – TWDB looking for a path forward 8
    9. 9. TWDB Project Seeks Path for Direct Potable Reuse • Focused on removal of “environmental buffer” • Examine the range and incidence of contaminants of concern for potable reuse in Texas • Benchmark water quality goals and treatment strategies for potable reuse projects • ID treatment performance indicators for range of implementation (costs, energy, residuals, advantages/disadvantages) • Guidance document summarizing water quality goals and recommended treatment approaches for potable reuse inCarolloTemplateWaterWave.pptx Texas. 9
    10. 10. What do we lose by not having an environmental buffer?CarolloTemplateWaterWave.pptx 10
    11. 11. Response Time is the Ultimate Value of the Environmental Buffer “The primary benefit of an environmental buffer is to provide time to react should treatment be inadequate due to process failure or other factors” – Direct Potable Reuse, A Path ForwardCarolloTemplateWaterWave.pptx 11
    12. 12. NRC Report on Potable Reuse (January 2012)CarolloTemplateWaterWave.pptx 12
    13. 13. Planned Potable Reuse – Key Findings from NRC Report • Natural systems are employed in most potable water reuse systems to serve as an environmental buffer, which may provide: – Retention time – Attenuation of contaminants – Blending (or dilution) • Engineered processes can be designed to achieve these same functions – Cannot be demonstrated that “natural” barriers provide public health protection that is not also available by other engineered processes – Science required to design for uniform protection from one environmental buffer to the next is not available • Potable reuse of highly treated reclaimed water without an environmental buffer is worthy of consideration, if adequate protection is engineered within the systemCarolloTemplateWaterWave.pptx • Distinction between indirect and direct potable reuse is not scientifically meaningful to product water quality 13
    14. 14. Full Advanced Treatment “FAT” How “Phat” does FAT need to be?CarolloTemplateWaterWave.pptx 14
    15. 15. Two Projects Specifically Addressing Risk & Treatment • Evaluation of Risk Reduction Principles for Direct Potable Reuse (WRRF-11-10) • Equivalency of Advanced Treatment Trains for Potable Reuse (WRRF-11-02)CarolloTemplateWaterWave.pptx 15
    16. 16. Evaluation of Risk Reduction Principles for Direct Potable Reuse (WRRF-11-10) • NASA • Nuclear Energy Industry • Structural Engineering (bridges & buildings) • Focus on: – Reducing human error • Training • Checklists – Minimize close coupling of complex systemsCarolloTemplateWaterWave.pptx – Improvements in monitoring and controls 16
    17. 17. HAZARD ANALYSIS AND CRITICAL Analyze Hazards ID hazards and potential control solutions. CONTROL POINTS ID CCPs • Developed by NASA in Identify and label the critical control points throughout the process. the early 1960’s, widely adopted in the ID Prevention Measures food industry, among Establish protocols for minimizing failures at others. the CCPs. • Centers around the Develop “Fail-Safe” idea of “Critical Control Response Points.” Establish protocols for minimizing the effect of CCP failures. • Focus is put onCarolloTemplateWaterWave.pptx managing the CCPs Document CCP Events Keep a log of how well the system works. Review and modify the protocol periodically. 17
    18. 18. Project Observations to Date • Current FAT technologies provide for sufficient treatment barriers, if they are all properly working. • Additional treatment or storage can be provided to counter the loss of the environmental buffer. • Online monitoring techniques can increase operational confidence. • How much time is needed to properly monitor (and respond) is yet to be determined. • From the Outside Experts: – Training, Training, Training…and Motivation! – Avoid “Complex and Closely Coupled” systems as much asCarolloTemplateWaterWave.pptx possible. – Make alarms meaningful. 18
    19. 19. Equivalency of Advanced Treatment Trains for Potable Reuse (WRRF-11-02) • MF/RO + AOP is the “Gold Standard” • RO brine difficult to deal with (concentrated everything) • What is the performance of other technologies for EDCs if salts are not a concern? • Focused entirely on replacing the RO process Moving Away from FATCarolloTemplateWaterWave.pptx 19
    20. 20. Alternatives to RO Treatment Are Available • Match pathogen reduction (4+ log protozoa, 4+ log virus) – At Ct of 1 mg-min/L, Ozone achieves greater than 5 log removal of viruses and bacteria • Match trace pollutant reduction (95% removal of most pollutants) – Ozone provides robust removal of trace organicsCarolloTemplateWaterWave.pptx 20
    21. 21. Ozone Provides a Robust Barrier to Trace PollutantsCarolloTemplateWaterWave.pptx 21
    22. 22. …but, Ozone does make byproducts • Bromate • Biodegradable dissolved organic carbon • NDMA • AldehydesCarolloTemplateWaterWave.pptx 22
    23. 23. Biological Filtration Solves these Issues NDMACarolloTemplateWaterWave.pptx 23
    24. 24. Biological Filtration Solves these IssuesCarolloTemplateWaterWave.pptx 24
    25. 25. Polishing Treatment with UV is Recommended to Provide a Multiple Barrier to Pollutants and Pathogens  >5-log Virus  >5-log Bacteria  >5-log Protozoa  Plus NDMA destructionCarolloTemplateWaterWave.pptx 25
    26. 26. Summary • Current research is helping us: – Determine how much treatment is necessary for IPR and DPR – Reduce the risk of not having the response time afforded by the environmental bufferCarolloTemplateWaterWave.pptx 26

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