2 Basic Types of Criteria:

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1 Cit Criteria i that tare Protective ti of fpublic Health to Evaluate Treatment Technologies for Direct Potable Reuse Strawman - Overview Trussell Technologies, Inc. August Basic Types of Criteria: Contaminant Criteria 1. Water is free of pathogens 2. Water is free of toxic chemicals Aesthetic Criteria 1. Water is free of WW Properties obvious to the uninformed consumer 2. Water is free of WW properties evident to the informed consumer 2 1

2 Structure of Potable Water Scenarios Potable Water Treatment Blending The Water Consumer Environmental Buffer/blending The Water Environment Blending Engineered Storage Buffer Advanced Wastewater Treatment Traditional Paradigms Emerging Paradigms Advanced Wastewater Treatment Conventional Wastewater Treatment Source Control Structure Assumed For Criteria (WRRF-11-02) Potable Water Treatment Blending The Water Consumer Blending Environmental Buffer/blending The Water Environment Engineered Storage Buffer Advanced Wastewater Treatment Emerging Paradigm Advanced Wastewater Treatment Conventional Wastewater Treatment Source Control 4 2

3 Structure Assumed For Criteria (WRRF-11-02) Contaminant Criteria must be met Here Potable Water Treatment Blending The Water Consumer Blending Environmental Buffer/blending The Water Environment Engineered Storage Buffer Advanced Wastewater Treatment Advanced Wastewater Treatment Conventional Wastewater Treatment Source Control 5 Structure Assumed For Criteria (WRRF-11-02) Contaminant Criteria must be met Here Potable Water Treatment Blending The Water Consumer Blending Environmental Buffer/blending The Water Environment Engineered Storage Buffer Aesthetic Criteria Must be met Here Advanced Wastewater Treatment Advanced Wastewater Treatment Conventional Wastewater Treatment Source Control 6 3

4 Look at the Aesthetic Criteria First Contaminant Criteria 1. Water is free of pathogens 2. Water is free of toxic chemicals Aesthetic Criteria 1. Water is free of WW Properties obvious to the uninformed consumer 2. Water is free of WW properties evident to the informed consumer 7 Basic Criteria for Potable Reuse Contaminant Criteria 1. Water is free of pathogens 2. Water is free of toxic chemicals Aesthetic Criteria 1. Water is free of WW Properties obvious to the uninformed consumer 2. Water is free of WW properties evident to the informed consumer 8 4

5 Aesthetic Criteria Criteria - Free of WW Properties obvious to the uninformed consumer 1. Color must be 15 apparent color units (ACU) 2. Odor Threshold Odor Number (TON) 3 Flavor profile No off-flavors 3. Mineralization TDS and hardness similar to local supplies 9 Basic Criteria for Potable Reuse Contaminant Criteria 1. Water is free of pathogens 2. Water is free of toxic chemicals Aesthetic Criteria 1. Water is free of WW Properties obvious to the uninformed consumer 2. Water is free of WW properties evident to the informed consumer 10 5

6 Aesthetic Criteria Criteria - Free of WW properties evident to the informed consumer 1. Water is free of Dissolved Organic Matter (DOM) of wastewater origin 2. Trace organic chemicals (TOrCs) have been reduced to acceptable levels 11 Aesthetic Criteria Criteria - Free of WW properties evident to the informed consumer 1. Water is free of Dissolved Organic Matter (DOM) of wastewater origin - Total organic carbon (TOC) concentration is 0.5 mg/l, or - Effluent organic matter (EfOM) has been sufficiently transformed into natural organic matter (NOM) 12 6

7 EfOM to NOM Tools used in the past: USGS Studies (Leenheer) SUVA SDPBFPs (tthmfp/doc & HAA 5 FP/DOC) Traditional Humic fractions (HPOA, TPIA, HPIA, etc,) FTIR, 13 C-NMR, Electrospray GCMS More recent Studies MW Fractionation UF, SEC-UV, SEC-UV & DOC UV & Fluorescence spectra UV absorbance Excitation-Emission Spectroscopy (EEM) EEM looks particularly promising 13 EEM of Secondary Effluent 3-dimensional analysis Excitatio on wavelengt th Emission 7

8 EEM as an Indicator of Transformation from EfOM to NOM Soil-Aquifer Treatment Montabello Forebay Laws, B., Dickenson, E., Johnson, T., Snyder, S., and Drewes, J., 2010, Attenuation of Contaminants of emerging Concern During Surface-/Spreading Aquifer Recharge, Science in the total environment, V409, pp EEM as an Indicator of Transformation from EfOM to NOM O 3 /BAC/O Gwinette 2 Effluent After O 3/BAC/O 3 After GMF 8

9 EEM as an Indicator of Transformation from EfOM to NOM 2 Effluent After MF GWRS After RO After UV/AOP Basic Criteria for Potable Reuse Contaminant Criteria 1. Water is free of pathogens 2. Water is free of toxic chemicals Aesthetic Criteria 1. Water is free of WW Properties obvious to the uninformed consumer 2. Water is free of WW properties evident to the informed consumer 18 9

10 Risk Understanding Risk When we gather scientific data about what our collective risks are, a consensus is often possible Heart disease 25% Cancer 23% When we discuss the appropriate level of risk to which we should all be exposed, consensus is harder to find 20 10

11 De minimis risk This is where the concept of de minimis risk comes in The term comes from the Latin: de minimis non curat lax or The law does not concern itself with trifles In risk management, a de minimis risk is a risk that is too small to be concerned with. Someone exposed to that risk is considered virtually safe 21 The de minimis Concept: a Dilemma Many U.S. regulators prefer to avoid the term de minimis risk, preferring to describe it as a risk Below Regulatory Concern (BRC) Nevertheless most do use de minimis i i criteria in managing risk*: CA OEHHA sets de minimis risk at 10-6 FDA generally uses 10-6 also EPA ODW & CDPH which both try to manage in a 10-4 to 10-6 window 22 11

12 Understanding Risk In establishing regulations or guidelines for the quality of drinking water, two levels of risk are useful: De minimis risk Acceptable risk } (my words) 23 Acceptable Risk Involves Compromise The process of establishing regulatory limits is a process of balancing risk, benefit and cost to determine an acceptable level of risk Thus the regulations for disinfection byproducts in drinking water are set above what most consider their de minimis level because we do not wish to compromise disinfection risk cost 24 12

13 Proposed Approach for Potable Reuse (WRRF 11-02) Pathogens WRRF Pathogens and de minimis risk Recommendation: Use U.S. de minimis standard of 10-4 infections/cap/y Logic: Potable Reuse projects must meet or exceed the standard applied to local conventional drinking water sources WRRF

14 Revised Removal Goals Units Viruses Crypto- Salmonella Giardia? Gada sporidium Raw WW IU/L DW goal IU/L 2x10-7 3x10-5 2x10-5 7x10-6 Ratio - 5x x10 9 2x x10 10 Log-Removal Proposed Approach for Potable Reuse (WRRF 11-02) Chemicals Bis phenol a Carbamazepine PFOS PFOA Caffeine NDMA Triclosan WRRF

15 Proposed Policy 1. Meet all criteria where a judgment has been made on acceptable risk, e.g. EPA MCL, WHO DWGL, State MCL or NL, etc. 2. Where no judgment of acceptable risk is available, seek de minimis risk (virtual safety) WRRF Chemicals and de minimis effects Over the past five or six decades the developed world has built a sophisticated infrastructure for consideration of de minimis risk where chemicals are concerned. These are reflected in guidelines, advisories, regulations, etc. regarding human exposure to chemicals in medicine, agriculture, food, water, etc. issued by recognized authorities like EPA, WHO, etc

16 Several Examples of De Minimis Benchmarks Benchmark Symbol Units Agency Sponsor Reference dose RfD mg/kg/d EPA IRIS Minimal risk levels MRL mg/kg/d ASTDR Acceptable daily intake ADI mg/kg/d WHO Acceptable daily dose ADD mg/kg/d CA OEHHA Long-term health advisory* HA mg/l EPA Predicted no-effect concentration *EPA s Has are a particularly valuable source PNEC ng/l EPA 31 Chemicals and de minimis effects (continued) For pharmaceuticals, there is also a huge body of work done on drug tolerance in humans These data are not, themselves, de minimis but they can be used as a point of departure in estimating a de minimis benchmark 32 16

17 Chemicals and de minimis effects (continued) There have also been several studies done, using these benchmarks, and other literature, to estimate de minimis levels for emerging chemicals Many of these studies present a summary of results for a large number of chemicals These are secondary sources 33 Approach to Compounds of Special Interest in Monitoring 1. Start with NRC list 2. Add or subtract compounds as required 34 17

18 Consider the DBPs and the PPCPs separately DBPs First 18

19 Consider the DBPs and the PPCPs separately Hormones, Pharmaceuticals And Personal Care Products 19

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21 Conclusion Just ran through an outline of removal criteria Much more detail in report But removal criteria are just the beginning g 41 finito 21