2023 Online Catalog - Flipbook - Page 498
17 National Secondary Drinking Water Regulations
Recognized Treatment Techniques
for Meeting the National Secondary Drinking Water Regulations
with the Application of Point-Of-Use Systems
National Secondary Drinking Water Regulations (NSDWRs or secondary standards) are non-enforceable guidelines for contaminants
that may cause cosmetic effects (such as skin or tooth discoloration) or aesthetic effect (such as taste, odor or color) in drinking
water. EPA recommends secondary standards to water systems
but does not require systems to comply. However, states may
choose to adopt them as
enforceable standards.
Note: This document addresses the United States Environmental
Protection Agency National Primary Drinking Water Regulations
in effect at its time of publication. These regulations are continually being reviewed and updated at the federal level. Accordingly,
this list of recognized treatment technologies will be reviewed and
amended periodically.
Copyright© 2011 by Water Quality Association
Contaminant
SMCL,MG/l+
Treatment Methods
Alkalinity
(measured as calcium carbonate,
CaCo )
No federal limit
Low alkalinity -
300 mg/L
Raise alkalinity by feeding 1.5 mg/L of soda ash
for each on mg/L of alkalinity needed or calcite filtration
Lower alkalinity by feeding white vinegar
(acetic acid), citric acid or any acid; add
carbon dioxide; ion exchange dealkalization;
reverse osmosis; distillation or electrodialysis
Aluminum (Al +3)
on case-by-case
0.05 to 0.2 depending
Reverse Osmosis
circumstances
Cation Exchange
Ultrafiltration
Distillation
Electrodialysis
Chloride (C1 -1)
250
Reverse Osmosis
Anion Exchange
Deionization
Distillation
Electrodialysis
Color
15 color units
Anion Exchange
Activated Carbon
Filtration
Chlorination
Reverse Osmosis
Distillation
Ozonation
3
Deionization
Note: Color units are based on the APHA recommended standard of 1 color unit being equal to 1 mg/L of platinum or chloroplatinate ion.
Technical & Engineering
Copper (Cu +2)
1.0
Reverse Osmosis
Cation Exchange (20-90%)
Corrosivity
Non-corrosive
Calcite or Calcite/Magnesium Oxide (Magnesia)
(5 to 1) Filter to raise pH
Soda Ash Chemical Feed
Polyphosphate Feed
Sodium Silicate Feed
Remove all hydrogen peroxide
Reduce TDS via Reverse Osmosis (partial, split
stream treatment)
Coatings
Insulating Unions with Ground straps around all
insulating breaks in metal pipe
Fluoride (Fl-1)
2.0
Activated Alumina
Reverse Osmosis
Electrodialysis
Distillation
Foaming agents (MBAS)
0.5
Chlorination
Activated Carbon
Ozonation
Reverse Osmosis
Distillation
Hard Water
(measured as calcium
carbonate CaCO3)
No federal limit
Soft -
180
Remove all calcium and magnesium ions with a
cation exchange water softener (general limit is
1710 mg/L total hardness. Above 70 grains per
gallon, install two softeners in a series.
14
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Corrosion Control
Distillation
