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Michael Watts, PhD, PE Water Technology Leader Garver Paving a Path to Potable Reuse Flexible Treatment for To Be Determined Regulations.

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Presentation on theme: "Michael Watts, PhD, PE Water Technology Leader Garver Paving a Path to Potable Reuse Flexible Treatment for To Be Determined Regulations."— Presentation transcript:

1 Michael Watts, PhD, PE Water Technology Leader Garver Paving a Path to Potable Reuse Flexible Treatment for To Be Determined Regulations

2 Reuse Drivers – Shrinking Water Supplies September, 2011

3 Reuse Drivers – Legislative House Bill 3055 – Water for 2060 Act No more fresh water consumption in 2060 than in 2010

4 Reuse Drivers - Financial Water Conservation = Diminishing Water Revenue Non-Potable Reuse Can Recover Some of this Lost Revenue Potable Reuse Maintains Current Water Price Structure, while avoiding costly conservation measures

5 CategoryTreatmentReuses 1A, 1CReserved (for potable reuse)IPR, DPR 2Secondary Treatment (nutrient removal, coagulation, filtration & disinfection) Drip irrigation on orchards & vineyards; spray or drip on sod farms, public landscapes, golf courses, and toilets, fire protection, vehicle washing, and range cattle watering. 3Secondary Treatment plus disinfection Subsurface irrigation of orchards or vineyards; restricted access landscapes; livestock pasture, concrete mixing, dust control, restricted golf course 4Primary Lagoon Treatment and Lagoon Storage plus disinfection Soil compaction, similar construction activities, and restricted access golf course. 5Primary Lagoon Treatment and Lagoon Storage Restricted access pasture irrigation for range cattle, fiber, seed, forage, silviculture. Oklahoma Reuse Regulations Under Development

6 Category 1A Reuse Indirect Potable Reuse (IPR) through Reservoir, Lake, or Stream Augmentation WTP WRRF

7 Addressing Category 1A (IPR) Reuse Regulation Hurdles Receiving Water Conditions (Sensitive Water Supply) Defined Regulation for Municipal Reuse Projects Pathogen Removal Criteria Effluent Concentrations of Conservative Substances

8 Category 1A (IPR) Reuse in OK Regulations are Currently Being Defined –Meet defined Water Quality Standards and Beneficial Uses –Category 2 Reuse Disinfection (no residual at discharge point) –No long-term concentration of conservative substances above Water Quality Standards Development of New Category for Sensitive Water Supplies (SWSr) –Must maintain chlorophyll-a standard in SWS (< 10  g/L) –Only municipal reuse projects will be permitted in SWSr watersheds

9 The Engineering Challenge for Category 1A (IPR) Reuse From Conventional Activated Sludge to Water Resource Recovery Facility (WRRF) PRIMARY CLARIFICATION SECONDARY CLARIFICATION FROM HEADWORKS RAS/WAS PUMPING Aeration cBOD < 10 mg/L Mean Effluent TSS < 15 mg/L TDS < 500 mg/L Ammonia-N < 0.5 mg/L Nitrate-N < 20 mg/L Phosphorus < 10 mg/L

10 Scope of Additional Treatment for Category 1A (IPR) Reuse cBOD < 10 mg/L Mean Effluent TSS < 15 mg/L TDS < 500 mg/L Ammonia-N < 0.5 mg/L Nitrate-N < 20 mg/L Phosphorus < 10 mg/L More Organics Oxidation? YES / Likely Ensure protection of SWS from Title 785- Ch. 45 Organics

11 Scope of Additional Treatment for Category 1A Reuse cBOD < 10 mg/L Mean Effluent TSS < 15 mg/L TDS < 500 mg/L Ammonia-N < 0.5 mg/L Nitrate-N < 20 mg/L Phosphorus < 10 mg/L Coagulation and/or Filtration? YES / Likely Many OK SWS are already impaired for turbidity

12 Scope of Additional Treatment for Category 1A Reuse cBOD < 10 mg/L Mean Effluent TSS < 15 mg/L TDS < 500 mg/L Ammonia-N < 0.5 mg/L Nitrate-N < 20 mg/L Phosphorus < 10 mg/L Dissolved Minerals Removal? Maybe As a conservative pollutant which can impair public water supplies, this determination will likely be case-by-case

13 Maybe Scope of Additional Treatment for Category 1A Reuse cBOD < 10 mg/L Mean Effluent TSS < 15 mg/L TDS < 500 mg/L Ammonia-N < 0.5 mg/L Nitrate-N < 20 mg/L Phosphorus < 10 mg/L Enhanced Nitrification/ Denitrification ? As a semi-conservative pollutant (NO 3 - ) which can impair public water supplies, this determination will likely be case-by-case

14 Scope of Additional Treatment for Category 1A Reuse cBOD < 10 mg/L Mean Effluent TSS < 15 mg/L TDS < 500 mg/L Ammonia-N < 0.5 mg/L Nitrate-N < 20 mg/L Phosphorus < 10 mg/L Phosphorus Removal? OK SWS are often phosphorus-limited for chlorophyll-a production YES / Likely

15 Biological Phosphorous Removal (BNR) Design Zone Possible HRT 1 (hr) % of Total Volume 216% 2.520% 864% Total12.5 (1) Based on average day flow of MGD. Goal of Treatment: Reduce Total Phosphorus from 10 to < 1 mg/L as P

16 Phosphorus Accumulating Organisms in Action Biological Nutrient Removal

17 Chemical Phosphorous Removal Goal of Treatment: Reduce Total P from ~1 to < 0.5 mg/L as P Chemical Feed & Storage A Secondary Clarifiers Conventional Disinfection Chemical Feed & Storage B Alum Samples to Phosphate Analyzer Aeration Basins Tertiary Filters Category 1A Disinfection

18 FiltrationBNRCNR Effluent Water Quality cBOD < 5 mg/L TSS < 5 mg/L TDS < 500 mg/L Ammonia-N < 0.5 mg/L Nitrate-N < 10 mg/L Phosphorus < 0.5 mg/L

19 Category 1A Disinfection? If Category 2 Rules are Promulgated for Category 1A: –3-log Giardia inactivation –5-log Salmonella inactivation –5-log Adenovirus inactivation Can be accomplished with sequential –UV (UV Doses ≥ 40 mJ/cm 2 ) –Free Chlorine Residual CT for 4 to 5-log virus inactivation

20 Water Cycle for Cat. 1C (DPR) Direct Potable Reuse WTP WRRF

21 Addressing Category 1C (DPR) Reuse Regulation Hurdles Pathogen Removal Concentration of Conservative Substances Contaminants of Emerging Concern?

22 Category 1C (DPR) Disinfection? WateReuse Foundation (2012) – Study of Innovative Treatments for Reclaimed Water Evaluated Disinfection/Oxidation Technologies BacteriaVirusProtozoaCECs UV O3O3 UV AOP O 3 AOP Free Chlorine Chloramines Peracetic Acid (PAA)

23 Questions? Michael Watts, PhD, PE


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