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OBG PRESENTS: Innovative Technologies for Treating Emerging Contaminants
AGENDAEmerging Contaminants of Concern
Other Emerging Contaminants
Analytical Techniques
Treatment Technologies Available
Other Treatment Technologies in Development
Summary of Some Challenges
Perfluorooctane Sulfonate (PFOS) and Perfluorooctanoic Acid (PFOA)
1,4-Dioxane
Algal Toxins – Microcystins, Clindrospermopsin
Emerging Contaminants of Concern (ECCs)
In the news
Often with another contaminant, in a commercial product, or a breakdown product
Not on typical analyte lists… requires special analytical procedures / methods
Limited science on health / ecological effects (or limited agreement on results)
No enforceable standards; no, limited or changing guidance values / health advisories
Widespread occurrence … but limited fate / transport info
No or limited info on treatment technologies
New acronyms
Common Characteristics of Emerging Contaminants
EXODUS 7:20-21 1,000 BC
…all the water that was in the Nile has turned to blood. And the fish that were in the river died. And the river stank, and the Egyptians could not drink of the water in the river.
Pharmaceuticals –approximately 3,000 substances, including:
Painkillers Antibiotics Antidiabetics Beta-Blockers
Lipid Regulators Antidepressants Impotence Drugs Contraceptives
Other ECCs
Personal Care Products
Fragrances Sunscreens Insect Repellant Anti-fungal Agents
Other ECCs
Miscellaneous
Micro-fibers
Micro-beads
Disinfection By-Products
Other ECCs
Analytical Techniques
Identification and Quantification• mg/L = parts per million
• Equivalent to about 32 seconds out of a year• µg/L = parts per billion
• Equivalent to about three seconds out of a century
• ng/L = parts per trillion• Equivalent to about thirty seconds out of
every million years
Analytical Techniques
Tools AvailableChromatography, liquid and gas
UV/Vis Spectroscopy
Mass Spectroscopy
Capillary Electrophoresis
Immunoanalytical Techniques, ELISA
Microbiological Analysis
Conventional Potable and Municipal Wastewater Treatment• Potable Water
• Physical – screens and racks• Sand Filtration – slow, rapid, mixed-media• Diatomaceous Earth (DE)• Coagulation, Flocculation, Sedimentation• Reverse Osmosis (RO)• Adsorption and Ion Exchange (IE)• Disinfection – Chlorine, Ultra-violet light (UV)
Treatment Technologies Available
Conventional Potable and Municipal Wastewater Treatment• Municipal Wastewater
• Biological – aerobic activated sludge w/various configurations
• Biological Nutrient Removal (BNR)• Enhanced Nutrient Removal (ENR)• Membranes – Membrane Bioreactor (MBR)• Fixed-Film Aerobic Biological – Moving Bed Bioreactor
(MBBR)• Anaerobic Technology – variety of configurations• Disinfection – Chlorine, Ultra-violet light (UV), Peracetic
Acid (PAA)
Treatment Technologies Available
Adsorptive Technologies• Activated Carbon (AC) – both granular (GAC)
and powdered (PAC)• Frequently used – highly porous• Can remove > 90% of a lot of the CECs • The source of the carbon makes a difference
in the performance of the carbon – wood, coconut, biochar (bamboo, rice hulls, etc.)
• GAC can be reactivated by exposing the spent carbon to high temperatures, or a mixture of chemicals
Treatment Technologies Available
Adsorptive Technologies• Carbon Nanotubes – graphite structure
• Possess unique physicochemical, electrical, and mechanical properties that make them suitable for potential applications as environmental adsorbents, sensors, membranes, and catalysts
• Clay Minerals• Performance is based on the specific clay
and the specific amounts of N and Fe, as well as other minerals in its makeup.
Treatment Technologies Available
Adsorptive Technologies•Other Adsorbents
•Zeolites – porous material•Resins – adsorb by ion interaction•Metal Oxides – adsorb by ion
interaction•Proprietary Adsorbents -
Rembind™
Treatment Technologies Available
Membrane TechnologiesBased or pore size, surface
charge, hydrophobicityoUltra-Filtration (UF)oMicro-Filtration (MF)oReverse Osmosis (RO)
Treatment Technologies Available
Membrane Cutoffs
UV UV/H2O2 UV/Ozone Hydrodynamic Cavitation
Ozone/ H2O2Ozone/
H2O2/UV Fenton Process TiO2
Ozone H2O2 / O3 (perozonation) Photo-Fentons Electron Beam
Advanced Oxidation Process (AOP)
Works by the production of hydroxyl OH- radicals
Many variations have different routes to produce the OH- radicals
PFAS Treatment Options
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1, 4-Dioxane Treatment Options
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Advanced Oxidation
• Utilizes OH- radicals
• Hydrogen peroxide with UV light
• Hydrogen peroxide with Ozone
Algal Cell Removal Options
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Option Algae Removal Details Relative LCC
Pre-treatment oxidation
Often lyses cells releasing toxins
Dissolved Air Flotation
Avoids Lysing, proven high removal rates
Low
Sedimentation/Plates
May grow algae, sludge management
Low
Micro-strainers
May lyse cells, uncertain removal rates
Moderate
Ozone –BAC/ biological degradation
Coordinated cell and toxin removal process, high capital cost, additional research needs
High
Membranes
May lyse cells, additional research needed
High
Phys-Chem Treatment Options Summaryfor Algal Toxins
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Oxidation Treatment Options Summaryfor Algal Toxins
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Microcystin-LRCT Table
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What will the next generation of treatment plants look like?
Contaminant detection may be viewed as a need for treatment
Flexible designs that accommodate advanced treatment Ozone / Bio-AC UV AOP GAC Tight membranes
Planning for spatial needs, hydraulics, connections, utilities, and process and odor control
Key Take-Aways
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To “Minimize” risk, doesn’t mean to “Eliminate” it….this will be a challenge as we continue to learn about these ECCs
Whether its Dioxane, algal toxin, PFASs, or other emerging contaminants, elected officials and utility managers will need to balance the risk against the economics of removal….this proving to be difficult
As the threats are multi-faceted, so too must be the treatment approaches…not your typical treatment systems will soon be part of our future
When it comes to algal toxin, more research needs to be performed on the ecology and the conditions that lead to cyanotoxin production…this is ongoing
