Proposed reclaimed water use for urinal and toilet flushing

Transcription

1 Proposed reclaimed water use for urinal and toilet flushing Regulation 84 Stakeholder Meeting August 17, 2017 Thank you for being here!

2 Welcome Brandi Honeycutt Environmental Protection Specialist Permits Section Water Quality Control Division CDPHE Lillian Gonzalez Unit Manager Permits Section Water Quality Control Division CDPHE

3 Welcome & Overview Lisa Beutler Executive Facilitator Stantec

4 Workshop Goals Provide stakeholders an overview of the proposed changes to Regulation 84 and regulatory process Receive input from participants on benefits, concerns, and additional considerations regarding this proposed use of recycled water

5 Workshop Agenda Items Welcome and Overview Opening Remarks Overview of key topics for discussion Topic 1: Proposed regulatory framework to protect public health 1. Expert Presentation: background on toilet flushing with graywater and recycled water 2. Overview of regulatory proposal 3. Discussion Topic 2: Implementation 1. Expert Presentation: managing opportunistic pathogens 2. Discussion Topic 3: To be determined by stakeholders Wrap up, closing comments, evaluation, adjourn

6 Ground Rules Come prepared for the scheduled discussion. Speak up so that everyone can hear. Only one person should speak at a time. Be concise. Avoid personal attacks. Be respectful of others perspectives and responsibilities. Sort for similarities that may exist in spite of differences. Listen carefully and respond in a manner that moves the discussion forward. Clearly identify remaining differences that are not resolved. Avoid sneak attacks. Respect the process by letting others know of positions and actions that will be taken regarding the issues being discussed. Decision making method: Consensus (everyone understands and can live with the decision), Fall back method: Minority report Avoid end runs. Respect the process by letting others know if differences remain that will be pursed in other venues (e.g. directly with other members in the executive and/or legislative branches of state or federal government. Identify conversations that aren t working. Backtrack from poor results.

7 Opening Remarks Damian Higham Senior Planner Recycled Water Program Denver Water

8 Reclaimed Water Basics Regulation 84 governs reclaimed water in Colorado Source is wastewater that has been treated at a wastewater treatment plant for discharge to surface waters Further treated by reclaimed water plant to meet specific water quality standards Provided for non-potable uses Delivered in separate purple pipe distribution system 5.2 billion gallons of potable water saved with reuse 8 8/22/2017

9 Reclaimed Water Treatment 3 categories of water quality designations Uses tied to specific water quality categories Standards for: Turbidity/TSS as overall water quality indicator E. coli as a pathogen indicator Cat 2 max E. coli based off swim beach standards Category 1 is secondary wastewater treatment and disinfection, Cat 2 & 3 add filtration 9 8/22/2017

10 Colorado Water Plan The CDPHE is committed to working with stakeholders to ensure that health and environment are protected while water reuse expands 8 Actions specific to increasing reuse in Colorado Increasing funding and incentives for water recycling and expanding the list of uses for which recycled water can be applied. 10 8/22/2017

11 Current major types of water reuse practiced in Colorado Potential paradigm for water reuse practice in Colorado Landscape irrigation (seasonal) Cooling and other industrial uses Non-food crop irrigation (seasonal) Landscape irrigation (seasonal) Cooling and other industrial uses Other non-food crop irrigation (seasonal)? Toilet flushing (year round)? Food crop irrigation (seasonal) Livestock washdown and watering

12 Toilet Flushing Drivers Residential consumption comprised of ~25% toilet flushing At Denver Water alone, 4.4 billion gallons used for flushing residential toilets Commercial sites already exploring green options would have another use to put reclaimed water towards 12 8/22/2017

13 Premises 1. Promoting the use of reclaimed water while protecting public health and the environment is the paramount goal of Reg This newly permitted use would create additional water supply in a stressed system. 3. Potable water may not be necessary for urinal and toilet flushing. 7. This newly permitted use will allow Colorado to join other states in this approach to reuse water efficiently.

14 Overview Today s discussion is divided into three topics: 1. Regulatory proposal 2. Implementation 3. TBD by workshop participants The presentation slides and workbook provide a starting point for discussion. Regulation Items that need to be codified in regulation to protect public health and the environment Notional example: Disinfection requirements Guidance Items that can be covered in supplemental guidance documentation Notional example: Prescriptions for specific language on safety signs

15 Context of Discussion Topics Some topics that are important considerations in implementation, but not within the scope of a potential change to Regulation 84 or supplemental guidance are out of scope for today s workshop. Notional In Scope Example: Define a quality of water that is protective of human health Notional Out of Scope Example: Cost of installing dual-plumbing (potable and reclaimed water) inside a facility.

16 Exposure Pathways Dermal Reclaimed water in toilets, urinals, and premise plumbing Inhalation Direct consumption (if a cross connection error occurs) Humans

17 Industrial Wastewater Industrial Pre-Treatment Pollutants of special concern (toxic chemicals, metals, pesticides, etc.) Wastewater Treatment Preliminary Primary Secondary Tertiary/Advanced Disinfection Large materials (rags, plastic bags, rocks, etc.) Medium particles & floating oils/grease Organic matter (compounds that would drop oxygen levels in receiving river); some removal of trace chemical constituents and pathogens Some facilities go one step further to reduce specific pollutants (nitrogen, phosphorus, particles); some removal of trace chemical constituents and pathogens Kill pathogens Domestic Wastewater Treated Wastewater Wastewater Effluent Recycled Water Treatment Additional Treatment Pollutants of special concern (particles, pathogens) are removed by various treatment methods; some removal of trace chemical constituents, etc. is achieved Disinfection Kill pathogens Recycled Water Potable Water Conventional water treatment plant Other water sources

18 Questions for Consideration and Discussion: What level of treatment should be required when using recycled water for toilet flushing? Category 1, 2 or 3? Topic 1 Disinfection How much disinfection should be required? Should a residual be required? Are there best management practices that should be followed when using recycled water for toilet flushing? Use of dye Cross connection control inspections Purple piping Other best management practices? Topic /22/2017

19 Topic 1: Proposed regulatory framework to protect public health Dr. Sybil Sharvelle Associate Professor Civil and Environmental Engineering Colorado State University Damian Higham Senior Planner Recycled Water Program Denver Water

20 Background on Regulation 86 and WE&RF Framework for Decentralized Non-Potable Water Systems Sybil Sharvelle Colorado State University

21 Regulation 86 Irrigation Toilet Flushing Category A B C D Scale Single family, Non-single Family Single family Non-single family System Requirements Laundry to Landscape or Storage with 60 mesh filtration, BMPs Storage with 60 mesh filtration, BMPs NSF-350 Certified, Free Chlorine mg/l NSF-350 Certified, Free Chlorine mg/l, PE designed

22 NSF 350 Class R a Class C b Parameter Test Average Single Sample Maximum Test Average Single Sample Maximum CBOD 5 (mg/l) TSS (mg/l) Turbidity (NTU) E. coli (MPN/100 ml) ph (SU) Storage vessel residual chlorine (mg/l) a Class R: Flows through graywater system are less than 400gpd b Class C: Flows through graywater system are less than 1500gpd

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24 Decentralized Non-potable Water (DNW) Systems A system in which water from local sources is collected, treated, and used for non-potable applications at the building to district/neighborhood scale generally at a location close to the point of generation.

25 Differs from Existing Reclaimed Water Programs Targets decentralized systems Lower oversight Rigorous design of treatment process train Design to meet pathogen log reduction targets Verification that log reduction targets are met Continuous online monitoring for surrogate parameters Real time process controls for out of specification

26 Quantitative Microbial Risk Assessment (QMRA) Characterize Pathogens in Source Water Exposure (Based on End Use) Select Acceptable Level of Risk Set Log Reduction Target

27 Log 10 Pathogen Reduction Targets Log 10 Reduction Targets for 10-4 (10-2 ) / person y Benchmarks Water Use Scenario Enteric Virus Parasitic Protozoa Enteric Bacteria Domestic Wastewater or Blackwater (1000 persons) Unrestricted irrigation 8.0 (6.0) 7.0 (5.0) 6.0 (4.0) Indoor use 8.5 (6.5) 7.0 (5.0) 6.0 (4.0) Graywater (1000 persons) Unrestricted irrigation 5.5 (3.5) 4.5 (2.5) 3.5 (1.5) Indoor use 6.0 (4.0) 4.5 (2.5) 3.5 (1.5) Stormwater (10-1 Dilution) Unrestricted irrigation 5.0 (3.0) 4.5 (2.5) 4.0 (2.0) Indoor use 5.5 (3.5) 5.5 (3.5) 5.0 (3.0) Stormwater (10-3 Dilution) Unrestricted irrigation 3.0 (1.0) 2.5 (0.5) 2.0 (0.0) Indoor use 3.5 (1.5) 3.5 (1.5) 3.0 (1.0) Roof Runoff Water Unrestricted irrigation Not applicable No data 3.5 (1.5) Indoor use Not applicable No data 3.5 (1.5)

28 QMRA Impact of Scale Characterize Pathogens in Source Water Exposure (Based on End Use) Select Acceptable Level of Risk Set Log Reduction Target Likelihood of Pathogen Occurrence Dilution of Pathogens

29 Scale Likelihood of Pathogen Occurrence Pathogen Dilution

30 Table S21 (Schoen et al., 2017) Norovirus (genome copies) 1 Mastadenovirus (TCID50) Rotavirus (FFU) Cryptosporidiu m (oocysts) 2 Giardia (cysts) Campylobacter (CFU) Salmonella (CFU) Wastewater 1000-person collection Toilet flush water 9.7/9.5/6.9 NR /6.0/ Unrestricted irrigation 10.5/10.2/7.7 NR /6.7/ Indoor use /10.9/8.4 NR /6.5/ Drinking 14.5/14.3/11. 7 NR /10.8/ Wastewater 5-person collection 4 Toilet flush water 10.0/9.7/7.2 NR NR 0/0/ Unrestricted irrigation 10.4/10.0/7.6 NR NR 0/0/ Indoor use 10.2/9.9/7.4 NR NR 0/0/ Drinking 14.8/14.5/12. 0 NR NR 0/0/

31 Damian Higham Senior Planner Recycled Water Program Denver Water

32 Proposed Regulatory Delineation Large/Centralized systems Municipally operated systems Lab analysis Full-time, certified operators More dilution, lower max pathogen concentrations Small/On-site systems Building to district/neighborhood scale Located near point of generation Limited monitoring/staffing; automated operation Smaller population higher potential max pathogen concentrations

33 Proposed Regulatory Delineation Large/Centralized systems Municipally operated systems Lab analysis Full-time, certified operators More dilution, lower max pathogen concentrations Small/On-site systems Building to district/neighborhood scale Located near point of generation Limited monitoring/staffing; automated operation Smaller population higher potential max pathogen concentrations

34 Proposed Regulatory Delineation Large/Centralized systems Municipally Propose following operated past systems pattern of Reg 84 Lab categories analysis Full-time, Additional certified site controls operators and management More practices dilution, lower max pathogen concentrations Small/On-site systems Building to district/neighborhood scale Located near point of generation Limited monitoring/staffing; automated operation Smaller population higher potential max pathogen concentrations

35 Proposed Regulatory Delineation Large/Centralized systems Municipally Propose following operated past systems pattern of Reg 84 Lab categories analysis Full-time, Additional certified site controls operators and management More practices dilution, lower max pathogen concentrations Small/On-site systems Building to district/neighborhood scale As above, PLUS treatment requirements Located near point of generation (extra belts and suspenders ) Limited monitoring/staffing; automated operation Smaller population higher potential max pathogen concentrations

36 Large/Centralized systems Colorado EPA Guidance Arizona California Idaho Category Category 3 Unrestricted Urban Reuse Category A Disinfected tertiary Class C 1 Minimum Treatment Secondary treatment with filtration and disinfection Oxidation and disinfection Bacteriological quality (MPN/100 ml) Turbidity Limit (NTU) Chlorine Residual E. coli: a)0 in 75% samples b)126 single sample max a) < 3 mo. avg. b) max 5 in <5% samples in mo. Fecal coliform: None detectable 2 Fecal coliform: a)0 in last 4 of 7 samples b)23 (single sample max) a) < 2 (24-h avg) b) < 5 (max) Total coliform: a)2.2 (7- sample median) b)23 (max 1 sample in 30 days) c)240 (single sample max) a) < 2 (24-h avg) b) < 5 (15 mins max) c) < 10 (max) Total coliform: a)23 (5- sample median) b)230 (single sample max) Not specified Not specified 1 mg/l Not specified Not specified Not specified

37 Small/On-site systems Proposal: Category 3 water Plus management and site controls Plus treatment objectives for removals of: Viruses Bacteria Protozoa A guide for treatment objectives: Risk-Based Framework for the Development of Public Health Guidance for Decentralized Non-Potable Water Systems (Water Environment and Reuse Foundation, 2017).

38 Discussion 1. What are your general impressions? 2. What is your opinion of a regulatory demarcation between onsite and centralized systems? What should delineate the categories of systems (flowrate, population, monitoring frequency, etc.)? 3. Do you feel that both treatment and water quality requirements are necessary? At all treatment scales? 4. What level of disinfection should be required for this proposed use? 5. What, if any, recommendations do you have?

39 Topic 2: Implementation (site controls, management BMPs) options to protect public health Dr. Channah Rock Associate Professor and Extension Specialist Water Quality Department of Soil Water & Environmental Science Maricopa Agricultural Center The University of Arizona

40 - Implementation - Approaches to Maintain Consistently High Quality Recycled Water in Storage and Distribution Systems Channah M. Rock, PhD Water Quality Specialist & Associate Professor The University of Arizona Cooperative Extension President WateReuse AZ August 17 th, 2017

41 Implementation 1. Planning A. Identify a responsible management entity B. Provide a Permit Application Report C. Certification statements D. BMP document 2. Construction and commissioning A. Field verification B. Commissioning report 3. Cross-connection control A. Inspection, documentation B. Control access (only trained personnel) C. Signage D. Backflow prevention E. Color coding F. Dye and pressure testing

42 Implementation cont 4. Other site controls A. Wastewater collection BMPs B. Dye the recycled water blue/green 5. Backup potable supply 6. Signage 7. Training 8. Operational monitoring and reporting A. O&M Manual B. Qualified personnel C. Routine & incident reporting 9. Disinfectant residual

43 Recent Distribution System Research OBJECTIVES: Evaluate existing water infrastructure and management and provide insight to minimize water age and improve water quality in distribution systems and storage Microbial Water Quality of Recycled Water via WateReuse Foundation grant (WRF-0804) Evaluating the Health Risks from Exposure to Legionella in Reclaimed Water Aerosols (Drexel University)

44 Summary of Water Quality Parameters of Interest for Water Reuse Parameter Range in Secondary Effluents Treatment Goal in Reclaimed Water US EPA Guideline Suspended solids 5 mg/l - 50 mg/l <5 mg SS/L - 30 mg SS/L - Turbidity 1 NTU - 30 NTU <0.1 NTU - 30 NTU 2 NTU BOD5 10 mg/l - 30 mg/l <10 mg BOD/L - 45 mg BOD/L 10 mg/l COD 50 mg/l -150 mg/l <20 mg COD/L - 90 mg COD/L - TOC 5 mg/l - 20 mg/l <1 mg C/L - 10 mg C/L - Total coliforms <10 cfu/100ml <1 cfu/100ml cfu/100ml 200 cfu/100ml Fecal coliforms < cfu/100ml <1 cfu/100ml cfu/100ml 14 for any sample, 0 for 90% Helminth eggs <1/L -10/L <0.1/L - 5/L - Viruses <1/L - 100/L <1/50L - Heavy metals - <0.001 mg Hg/L - <0.01 mg Cd/L <0.1 mg Ni/L mg Ni/L Inorganic - <450 mg TDS/L - Chlorine residual mg Cl/L - >1 mg Cl/L 1 mg/l Nitrogen 10 mg N/L - 30 mg N/L <1 mg N - 30mgN/L - Phosphorus 0.1 mg P/L - 30 mg P/L <1 mg P/L - 20 mg P/L - ph

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46 Potential Microbes Hazards in Water Distribution Systems Enteric pathogens via leakage or intrusion events Environmental pathogens Legionella pneumophila Mycobacterium avium complex Helicobacter pylori Naegleria fowleri

47 Case Studies: Location of the Utilities Evaluated

48 Treatment Technology DS-1 MF UV Chlorination Distribution DS-2 Conventional Chlorination Distribution Chlorination Distribution DS-3 MF RO Chloramination Distribution DS-4 Conventional UV Distribution Actively manage residual disinfectant in storage and distribution.

49 Monitoring Non-traditional Microbial Indicators Aeromonas Mycobacteria Legionella Amoebic Activity

50 Frequency of occurrence 100% 90% 80% 70% 60% DS-1 (MF-UV) DS-2 (Cl) DS-3 (MF-RO) DS-4 (UV) 50% 40% 30% 20% 10% 0% Opportunistic pathogens, such as Aeromonas, Legionella, and Mycobacterium, seemed to occur more frequently in recycled water systems that did not maintain residual disinfectant in their distribution system regardless of treatment technology.

51 Disinfection Effects: Distribution System Case Studies DS-2 :Chlorine Disinfection Public Company 24 years 18 golf courses, 39 parks, 52 schools Managed residual, booster stations, etc. 255 Samples >25 miles DS-4 :UV Disinfection Private Company 6 years Municipal parks, golf courses, lakes No residual disinfectant 150 Samples 7.6 miles

52 CFU/100 ml 1.00E+05 DS-2 (Cl) 1.00E E E+02 Total Coliform E.coli Enterococci Aeromonas Legionella Mycobacterium 1.00E E+00 Distance (miles)

53 CFU/100 ml DS-4 (UV) 1.00E E+03 Total Coliform E.coli Enterococci 1.00E+02 Aeromonas Legionella Mycobacterium 1.00E E Distance (miles)

54 100% 90% 80% 70% 60% 50% HPC Aeromonas Total coliforms Somatic coliphage Legionella Indicator organisms were uncommon in the chlorinated system while opportunistic pathogens were detected quite frequently. 40% 30% 20% 10% 0% 100% 90% DS-2 (Cl) Mycobacterium Enterococci Male-specific Presump. Amoebic E. coli HPC There were numerous instances in which opportunistic pathogens were present in the recycled water distribution systems in the absence of indicator organisms (E.coli). 80% 70% 60% 50% 40% 30% Aeromonas Total coliforms Somatic coliphage Legionella Mycobacterium Enterococci The decline of residual disinfectant in the system(s) was accompanied by an increase in the level of bacteria. 20% 10% 0% DS-4 (UV) Male-specific Presump. Amoebic E. coli This data lends itself to the usefulness of certain indicators based on treatment technology. Samples collected throughout both distribution systems including point of use. n=20

55 Conceptual Diagram of Chemical Species and Physical Phases Within a Pipe Monad kinetics applies to model the process of chlorine inhibited microbial regrowth during transportation from the treatment facility to far stretching branches of the pipe network. 1 1 Zhang, W.; Miller, C. T.; DiGiano, F. A. Bacterial regrowth model for water distribution systems incorporating alternating split-operator solution technique ASCE J. Environ. Eng

56 What is unique about toilet flushing? Do aerosols created during flushing present an increased human health risk? Similar human health exposure as spray irrigation with recycled water Quantitative Microbial Risk Assessment (QMRA) research shows that less than 1 in 10,000 risk for low concentrations of Legionella Consider what is being flushed down the toilet?

57 Key Findings Waterbased pathogens (Legionella, Mycobacterium, Aeromonas) routinely found in utility distribution systems regardless of treatment. Fecal indicator organisms (E. coli, Enterococcus) were rarely detected, suggesting effective treatment (UV, Cl) vs. waterborne pathogens. Booster station re-chlorination reduced the concentration of waterbased organisms, but regrowth can occur.

58 Utility Perspective E.coli and Enterococcus are effective indicators of recycled water quality the point of entry, but not within the distribution system. It must be stressed that findings of waterbased pathogens in water distribution systems (reclaimed or potable) is not novel (e.g., Alonso et al., 2006; Jjemba et al., 2010).

59 Mitigation Strategies: BMPs for opportunistic pathogen control Pathogen mitigation within the distribution system may be achieved by reducing the total organic carbon (TOC) concentration. This creates a nutritionally stressed environment for heterotrophic microbes, reducing their concentrations in the distributed recycled water. Key finding: maintaining disinfectant residual is the key to controlling microbial growth and regrowth.

60 Recap on antibiotic resistance (from last workshop) ARB = antibiotic resistant bacteria ARG = antibiotic resistant gene 1. Potable water systems have been found to contain ARGs. ARGs are also found in the environment and in wastewater. 2. No proliferation or enhancement of ARB growth is seen through wastewater treatment. 3. Recycled water treatment for potable reuse has shown to reduce ARB concentrations in distribution systems. Bacterial DNA Plasmids

61 Acknowledgements WateReuse Foundation (WRF-0804) Municipal Recycled Water Partners UA Water Environment and Technology (WET) Center USDA ARS Internship Programs

62 Topic 3: To be determined by stakeholders Lisa Beutler, Stantec

63 Workshop Closing Lisa Beutler, Stantec

64 Thank you for your time! Please remember to fill out and turn in your workshop participation evaluation forms. Contact Information: Damian Higham Senior Planner

65 Extra slides

66 Relative Exposure Risk Acute vs. Chronic Exposure Risk Models Exposure risk models considered include acute and chronic risk factors, where Acute factors increase exposure risks in the near-term and generally signify an emergent or imminent risk. Chronic factors increase exposure risks over a longer period of time and could potentially develop into acute factors. Acute Chronic Time Duration