flushing Regulation 84 Stakeholder Meeting August 17, 2017 Thank - - PowerPoint PPT Presentation
Proposed reclaimed water use for urinal and toilet flushing Regulation 84 Stakeholder Meeting August 17, 2017 Thank you for being here! Welcome Brandi Honeycutt Lillian Gonzalez Environmental Protection Specialist Unit Manager Permits
August 17, 2017
Brandi Honeycutt Environmental Protection Specialist Permits Section Water Quality Control Division CDPHE Lillian Gonzalez Unit Manager Permits Section Water Quality Control Division CDPHE
Lisa Beutler Executive Facilitator Stantec
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
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
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.
http://colowqforum.org/pdfs/code-of- conduct/CWQF%20Code%20of%20Conduct.pdf
Damian Higham Senior Planner Recycled Water Program Denver Water
Reclaimed Water Basics
wastewater treatment plant for discharge to surface waters
specific water quality standards
8/22/2017 8
Reclaimed Water Treatment
– Turbidity/TSS as overall water quality indicator – E. coli as a pathogen indicator
disinfection, Cat 2 & 3 add filtration
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Colorado Water Plan
ensure that health and environment are protected while water reuse expands”
– Increasing funding and incentives for water recycling and expanding the list of uses for which recycled water can be applied.
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Current major types of water reuse practiced in Colorado Potential paradigm for water reuse practice in Colorado
Cooling and other industrial uses Landscape irrigation (seasonal) Non-food crop irrigation (seasonal) Cooling and other industrial uses Landscape irrigation (seasonal) Other non-food crop irrigation (seasonal)
Toilet flushing (year round) Livestock washdown and watering
?
Food crop irrigation (seasonal)
Toilet Flushing Drivers
~25% toilet flushing
gallons used for flushing residential toilets
green options would have another use to put reclaimed water towards
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use of reclaimed water while protecting public health and the environment is the paramount goal of Reg 84.
permitted use would create additional water supply in a stressed system.
may not be necessary for urinal and toilet flushing.
permitted use will allow Colorado to join other states in this approach to reuse water efficiently.
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
Today’s discussion is divided into three topics:
The presentation slides and workbook provide a starting point for discussion.
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
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.
Reclaimed water in toilets, urinals, and premise plumbing Humans
Dermal Inhalation Direct consumption (if a cross connection error occurs)
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 Industrial Pre-Treatment Pollutants of special concern (toxic chemicals, metals, pesticides, etc.) Recycled Water Treatment Additional Treatment Disinfection Pollutants of special concern (particles, pathogens) are removed by various treatment methods; some removal of trace chemical constituents, etc. is achieved Kill pathogens
Recycled Water Domestic Wastewater Industrial Wastewater Wastewater Effluent Treated Wastewater Conventional water treatment plant Potable Water Other water sources
Questions for Consideration and Discussion:
using recycled water for toilet flushing?
– Category 1, 2 or 3?
– How much disinfection should be required? – Should a residual be required?
be followed when using recycled water for toilet flushing?
– Use of dye – Cross connection control inspections – Purple piping – Other best management practices ?
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Damian Higham Senior Planner Recycled Water Program Denver Water
Associate Professor Civil and Environmental Engineering Colorado State University
Sybil Sharvelle Colorado State University
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 0.2 – 4 mg/L NSF-350 Certified, Free Chlorine 0.2 – 4 mg/L, PE designed
Parameter Class Ra Class Cb Test Average Single Sample Maximum Test Average Single Sample Maximum CBOD5 (mg/l) 10 25 10 25 TSS (mg/l) 10 30 10 30 Turbidity (NTU) 5 10 2 5
14 240 2.2 200 pH (SU) 6.0-9.0 6.0-9.0 Storage vessel residual chlorine (mg/l) ≥ 0.5 - ≥ 2.5 ≥ 0.5 - ≥ 2.5
a Class R: Flows through graywater system are less than 400gpd b Class C: Flows through graywater system are less than 1500gpd
treated, and used for non-potable applications at the building to district/neighborhood scale generally at a location close to the point of generation.
Characterize Pathogens in Source Water Exposure (Based on End Use) Select Acceptable Level of Risk Set Log Reduction Target
Log10 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)
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
Scale Likelihood of Pathogen Occurrence Pathogen Dilution
Norovirus (genome copies)1 Mastadenovirus (TCID50) Rotavirus (FFU) Cryptosporidiu m (oocysts)2 Giardia (cysts) Campylo- bacter (CFU) Salmo- nella (CFU) Wastewater 1000-person collection Toilet flush water 9.7/9.5/6.9 NR 7.9 6.2/6.0/5.3 4.9 5.4 2.7 Unrestricted irrigation 10.5/10.2/7.7 NR 8.7 6.9/6.7/6.0 5.6 6.1 3.5 Indoor use3 11.2/10.9/8.4 NR 8.8 6.8/6.5/5.9 6.1 6.0 3.8 Drinking 14.5/14.3/11. 7 NR 12.7 11/10.8/10.1 9.7 10.2 7.6 Wastewater 5-person collection4 Toilet flush water 10.0/9.7/7.2 NR NR 0/0/0 Unrestricted irrigation 10.4/10.0/7.6 NR NR 0/0/0 Indoor use 10.2/9.9/7.4 NR NR 0/0/0 Drinking 14.8/14.5/12. NR NR 0/0/0 Table S21 (Schoen et al., 2017)
Damian Higham Senior Planner Recycled Water Program Denver Water
concentrations
pathogen concentrations
concentrations
pathogen concentrations
concentrations
pathogen concentrations
categories
practices
concentrations
pathogen concentrations
categories
practices
(extra “belts and suspenders”)
Colorado EPA Guidance Arizona California Idaho Category Category 3 Unrestricted Urban Reuse Category A Disinfected tertiary Class C1 Minimum Treatment Secondary treatment with filtration and disinfection Oxidation and disinfection Bacteri-
quality (MPN/100 mL)
a)0 in 75% samples b)126 single sample max Fecal coliform: None detectable Fecal coliform: a)0 in last 4 of 7 samples b)23 (single sample max) Total coliform: a)2.2 (7- sample median) b)23 (max 1 sample in 30 days) c)240 (single sample max) Total coliform: a)23 (5- sample median) b)230 (single sample max) Turbidity Limit (NTU)
a) < 3 mo. avg. b) max 5 in <5% samples in mo. ≤ 2 a) < 2 (24-h avg) b) < 5 (max) a) < 2 (24-h avg) b) < 5 (15 mins max) c) < 10 (max) Not specified
Chlorine Residual Not specified ≥ 1 mg/l Not specified Not specified Not specified
Proposal: Category 3 water Plus management and site controls Plus treatment objectives for removals of:
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).
categories of systems (flowrate, population, monitoring frequency, etc.)?
requirements are necessary? At all treatment scales?
proposed use?
Associate Professor and Extension Specialist – Water Quality Department of Soil Water & Environmental Science Maricopa Agricultural Center The University of Arizona
Channah M. Rock, PhD Water Quality Specialist & Associate Professor The University of Arizona Cooperative Extension President WateReuse AZ August 17th, 2017
A. Identify a responsible management entity B. Provide a Permit Application Report C. Certification statements D. BMP document
A. Field verification B. Commissioning report
A. Inspection, documentation B. Control access (only trained personnel) C. Signage D. Backflow prevention E. Color coding F. Dye and pressure testing
A. Wastewater collection BMPs B. Dye the recycled water blue/green
A. O&M Manual B. Qualified personnel C. Routine & incident reporting
Foundation grant (WRF-0804)
Reclaimed Water Aerosols (Drexel University)
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
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
5 mg/L - 20 mg/L <1 mg C/L - 10 mg C/L
<10 cfu/100mL – <1 cfu/100mL –
200 cfu/100mL Fecal coliforms <1-106 cfu/100mL <1 cfu/100mL - 103 cfu/100mL 14 for any sample, 0 for 90% Helminth eggs <1/L -10/L <0.1/L - 5/L
<1/L - 100/L <1/50L
<0.1 mg Ni/L -0.02 mg Ni/L Inorganic
1 mg/L Nitrogen 10 mg N/L - 30 mg N/L <1 mg N - 30mgN/L
0.1 mg P/L - 30 mg P/L <1 mg P/L - 20 mg P/L
Actively manage residual disinfectant in storage and distribution.
UV Distribution Chlorination MF DS-1 Conventional Chlorination Distribution Chlorination Distribution DS-2 RO MF Distribution Chloramination DS-3 UV Distribution Conventional DS-4
0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% Frequency of occurrence DS-1 (MF-UV) DS-2 (Cl) DS-3 (MF-RO) DS-4 (UV)
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.
DS-4 :UV Disinfection
lakes
DS-2 :Chlorine Disinfection
schools
stations, etc.
1.00E+00 1.00E+01 1.00E+02 1.00E+03 1.00E+04 1.00E+05
CFU/100 mL Distance (miles)
DS-2 (Cl)
Total Coliform E.coli Enterococci Aeromonas Legionella Mycobacterium
1.00E+00 1.00E+01 1.00E+02 1.00E+03 1.00E+04 0.55 2.12 2.47 7.6 CFU/100 mL Distance (miles)
DS-4 (UV)
Total Coliform E.coli Enterococci Aeromonas Legionella Mycobacterium
0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%
DS-2 (Cl)
HPC Aeromonas Total coliforms Somatic coliphage Legionella Mycobacterium Enterococci Male-specific
0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%
DS-4 (UV)
HPC Aeromonas Total coliforms Somatic coliphage Legionella Mycobacterium Enterococci Male-specific
Indicator organisms were uncommon in the chlorinated system while opportunistic pathogens were detected quite frequently. There were numerous instances in which opportunistic pathogens were present in the recycled water distribution systems in the absence of indicator organisms (E.coli). The decline of residual disinfectant in the system(s) was accompanied by an increase in the level of bacteria. 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
1Zhang, W.; Miller, C. T.; DiGiano, F. A. Bacterial regrowth model for water distribution systems incorporating
alternating split-operator solution technique ASCE J. Environ. Eng. 2004 130 9 932 941
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. 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.
ARB = antibiotic resistant bacteria ARG = antibiotic resistant gene Bacterial DNA
Plasmids
(WRF-0804)
Partners
and Technology (WET) Center
Programs
Lisa Beutler, Stantec
Lisa Beutler, Stantec
Contact Information: Damian Higham Senior Planner 303.628.6537 damian.higham@denverwater.org
2 4 6 8 10 12 14
Relative Exposure Risk Time Duration Acute Chronic
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