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Reuse Regulation Roundup: The Standards for Reuse Melanie Holmer, P.E. Water Reuse Leader
• Introduction • Types of water reuse • Standards for reuse • Reuse regulatory outlook
Agenda
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Drivers for water reuse: • extreme weather (drought) • nutrient/permit limits • seawater intrusion • industrial water supply • agricultural water supply • Water supply diversity • Water supply reliability • NEED MORE WATER!
Reuse – it’s not just for golf courses anymore
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Increasing reliability,
resiliency and diversity in the
water supply portfolio
Uses that are not intended for eventual human consumption.
Non-potable reuse
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• Reclaimed and purified wastewater that is intended for human consumption.
• Potable reuse can be: • Indirect. • Direct.
Potable reuse
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The
cont
inuu
m o
f Pot
able
Reu
se
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7
Groundwater Augmentation
Reservoir Water Augmentation
Raw Water Augmentation
Treated Water Augmentation
WateReuse
Indirect Potable Reuse
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Source: www.wrd.org
Purified water
Disinfection/ Treatment
Distribution to customers
Tertiary or Purified Effluent
Groundwater augmentation
Drinking WTP
Purified water
Distribution to customers
This Photo by Unknown Author is licensed under CC BY-SA
Reservoir water augmentation
Indirect Potable Reuse
Direct Potable Reuse
Drinking WTP
Purified water
Distribution to customers
This Photo by Unknown Author is licensed under CC BY-SA
Raw water augmentation
Direct Potable Reuse
Drinking WTP
Purified water
Distribution to customers
This Photo by Unknown Author is licensed under CC BY-SA
Treated water augmentation
What’s the underlying logic behind reuse treatment and distribution regulations?
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• Acute risk is the primary target. Seek to protect against exposure from outbreaks.
• Chronic risk is also important, but not viewed as significant. More emphasis in potable reuse applications. • Regulated organic and inorganic species.
• “No degradation” of GW quality is a common, but not universal, third goal.
Goals for Reuse Regulations
• Start with well-treated secondary wastewater effluent
• EPA-suggested guidelines: • pH = 6-9 • BOD5 ≤ 10 mg/L • Turbidity ≤ 2 NTU • Escherichia coli = NONE • Residual Cl2 ≥ 1 mg/L
A National Guideline on Wastewater Plant Secondary Effluent Quality for Reclamation
• There are no federal reuse regulations
• EPA has relied on framework of the CWA and SDWA and reuse guidelines
• Reuse is implemented state-by-state; rules are set to be protective of end use
The 2017 EPA Potable Reuse Compendium informs current practice on potable reuse: • Regulatory summary • Current practices • Case Studies • Indirect Potable Reuse • Direct Potable Reuse
EPA Guidelines
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Treatment Goals
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Secondary
Primary
Advanced Treatment
Disinfection
Filtration
Coag/Floc/Settling
Disinfection
Source Control
Pathogen reduction
Remove particles to allow for efficient
disinfection Groundwater Recharge Reservoir Water Augmentation
Pathogen reduction and chemical
contaminant removal
“Full Advanced Treatment” Train
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Secondary
treatment
Advanced
oxidation
Pre- Treatmen
t Equalization MF/
UF Reverse Osmosis
15-20% 5-10%
FAT = RO + AOP
The Urban Water Cycle
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River, GW, Reservoir Drinking
WTP / Disinfectio
n
Community
WWTP / Reclamation
To river, ocean, land
Non-potable uses
AWPF
GW aquifer
Reservoir
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River, GW, Reservoir Drinking
WTP / Disinfectio
n
Community
WWTP / Reclamation
SDWA LT2ESWTR
SDWA Lead and Copper Rule
Local Ordinances
CWA (NPDES) To river, ocean, land
Non-potable uses
AWPF
GW aquifer
Reservoir
State Regs
(Anti-degradation)
State Regs
State Regs
State Regs
State Regs
Local Ordinances
Potable Reuse Framework/Regulations
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Non-potable regulations
IPR regulations and policy
DPR reg framework DPR regs / case by case
No reuse regulations, or case by case
Updated based on: 2012 EPA Guidelines for Water Reuse 2017 EPA Potable Reuse Compendium
Studying DPR
Trends • Water quality and/or technology-based requirements in regulations
• Increased agency partnering to develop reuse projects, sometimes on a regional basis
• Shifting public perception of potable reuse towards acceptance
• Advances in RO technology
What’s Next?
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Questions? Melanie Holmer [email protected]
