the use of uv/peroxide for treating algal derived contaminants in drinking water

34 Pages·2017·1.81 MB·English

by  Terry Keep 2011

THE USE OF UV/PEROXIDE FOR TREATING
ALGAL DERIVED CONTAMINANTS IN
DRINKING WATER
Terry Keep
AWWA NYS Tifft Water Supply Symposium
September 21, 2017
WATER STRESS
IN AN
INTERCONNECTED
WATER SUPPLY
Sources of contaminants in our
water supply:
Extraction
Injection
- Industrial discharge Well
Well
- Agricultural runoff
- Chemical releases
- Municipal Wastewater
Nutrients  increase in Algae Blooms  Taste & Odour, Algal Toxins
2
EXAMPLES OF MICROPOLLUTANTS
Nitrosamines (e.g. NDMA)
Disinfection byproducts
Pesticides & Herbicides
Metaldehyde, Atrazine, Isoproturon, others
Petroleum Additives
Including MTBE
Pharmaceuticals & Personal Care Products
Includes potential endocrine disruptors
Taste & Odour Compounds
Seasonal occurrences of MIB, geosmin and others
Algal Toxins
Chronic and acute effects from cyanobacteria-derived
toxins
3
TASTE & ODOUR, ALGAL TOXINS
Seasonal algae blooms occur in surface
waters
Decaying algae blooms result in MIB,
geosmin, algal toxins, other T&O
compounds
Earthy/musty, fishy, swampy, grassy tastes
& odours at low ppt concentrations
Difficult to remove with conventional
technologies
T&O episodes compromise public
confidence in the safety of the water
4
TASTE AND ODOUR TREATMENT STRATEGIES
• Potassium Permanganate
– Limited Effectiveness
• Powdered Activated Carbon
– Messy PAC & Sludge Handling, no Performance Guarantee
• Granular Activated Carbon
– Frequent & Expensive Change-outs, no Performance Guarantee
• Ozone
– Complicated System & Carcinogenic by-product (Bromate)
• UV-Oxidation
– Simple, Effective for T&O with Simultaneous Disinfection, Guaranteed
Performance for life of system
5
UV / H2O2 FOR TASTE AND ODOUR TREATMENT
UV Advanced Oxidation: Using UV and Hydrogen Peroxide to destroy trace
organic contaminants in water by:
UV-Photolysis
UV-Oxidation
6
UV-PHOTOLYSIS
Chemical bonds are
broken by UV light
7
UV-OXIDATION
Hydrogen peroxide
Hydroxyl
radical
Chemical bonds are
broken by hydroxyl
radicals
8
CONTAMINANT DESTRUCTION BALANCE
6.0

l
a
UV + H2O2
t
o
T )
A UV Photolysis

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t i
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ta it
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l
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o n
h o
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NDMA Atrazine Geosmin Microcystin-LR
9
ALGAL TOXINS OXIDIZED MORE EASILY THAN MIB
10