Controlling Algae-related Tastes and Odors

80 Pages·2016·3.97 MB·English

Controlling Algae-related Tastes and Odors:
From Source to Tap
VAAWWAWaterQualityandResearch
CommitteeSeminar
March23,2016
Gary C. Schafran
Old Dominion University
Drinking Water Taste and
Odor Events are Common
and Occur World Wide
And as a consequence most
utilities have had to respond to
customer T&O complaints
The importance of T&O events to the
water industry is clear and based on the
customer’s perspective that:
If it doesn’t look, taste, or smell
“good” or “right”– it is not good
quality water.
Aesthetics are not covered by
NPDWR, but secondary MCLs address
aesthetic conditions of water
Table of Secondary Drinking Water Standards
Contaminant Secondary MCL Noticeable Effects above the Secondary MCL
Aluminum 0.05 to 0.2 mg/L* colored water
Chloride 250 mg/L salty taste
Color 15 color units visible tint
Copper 1.0 mg/L metallic taste; blue-green staining
Corrosivity Non-corrosive metallic taste; corroded pipes/ fixtures staining
Fluoride 2.0 mg/L tooth discoloration
Foaming agents 0.5 mg/L frothy, cloudy; bitter taste; odor
rusty color; sediment; metallic taste; reddish or
Iron 0.3 mg/L
orange staining
black to brown color; black staining; bitter metallic
Manganese 0.05 mg/L
taste
Odor 3 TON (threshold odor number) "rotten-egg", musty or chemical smell
low pH: bitter metallic taste; corrosion
pH 6.5 - 8.5
high pH: slippery feel; soda taste; deposits
skin discoloration; graying of the white part of the
Silver 0.1 mg/L
eye
Sulfate 250 mg/L salty taste
Total Dissolved hardness; deposits; colored water; staining;salty
500 mg/L
Solids (TDS) taste
Zinc 5 mg/L metallic taste
Table of Secondary Drinking Water Standards
Contaminant Secondary MCL Noticeable Effects above the Secondary MCL
Aluminum 0.05 to 0.2 mg/L* colored water
Chloride 250 mg/L salty taste
Color 15 color units visible tint
Copper 1.0 mg/L metallic taste; blue-green staining
Corrosivity Non-corrosive metallic taste; corroded pipes/ fixtures staining
Fluoride 2.0 mg/L tooth discoloration
Foaming agents 0.5 mg/L frothy, cloudy; bitter taste; odor
rusty color; sediment; metallic taste; reddish or
Iron 0.3 mg/L
orange staining
black to brown color; black staining; bitter metallic
Manganese 0.05 mg/L
taste
Odor 3 TON (threshold odor number) "rotten-egg", musty or chemical smell
low pH: bitter metallic taste; corrosion
pH 6.5 - 8.5
high pH: slippery feel; soda taste; deposits
skin discoloration; graying of the white part of the
Silver 0.1 mg/L
eye
Sulfate 250 mg/L salty taste
Total Dissolved hardness; deposits; colored water; staining; salty
500 mg/L
Solids (TDS) taste
Zinc 5 mg/L metallic taste
Algae-related T&O not directly seen in
these Secondary MCLs …
and only through the Threshold Odor
Number (TON) do we see some type
of guidance
Focus of This Presentation – Controlling Algae-
Related Tastes and Odors
Managing your
Source Water
Treatment Options
Point of Use
Devices
Distribution System
Not Considered
If you have a surface water, you
have the potential for a
biologically-induced Taste and
Odor event …ChineseProverb
To Address T&O Issues You Have to
Know Causative Agent/Condition
Local, National, and International Surveys of
Utilities and Customers Concerning
Tastes and Odors in DW