PowerPoint Presentation Treatment Options for Waterborne Pathogens

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ofa Short Course 2005 Ratus
Fischer
Selected Treatment Options for
Waterborne Pathogens
Heat UV Slow Sand Filtration Copper
Ionization Ozone
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Point (non-residual) Treatment Systems
Filtration UV Heat
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• Point Treatment Systems
• (Non-residual)
• Filtration, UV, Heat, etc
• No effect on pathogens beyond point
• of treatment
• ?No effect on algae
• Predictable degree of pathogen kill
• ?No residues
• ?No Risk of damage to plants

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System-wide (residual) Treatment Systems
Ozone Copper Ion Chorine Peroxide etc.
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• System-Wide Treatment (residual)
• Ozone, Copper-Ion, Chlorine, Peroxide, etc.
• ?Pathogen reduction depends on
• Degree of contamination
• Contact time
• Safe concentrations for plants, people
• and the environment
• ?Lower risk of re-contamination of water
• ?Can control algae
• ?Can affect pathogens in soil and on roots

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Heat Treatment / Pasteurization
Filter
Examples 203 degrees F for 30 sec 195 degrees F
for 2 min
Boiler
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• Heat Treatment / Pasteurization
• Pros
• Reliable reduction or
• elimination of pathogens
• Best for low volume high sanitation
• Can handle certain solids in water
• Nothing is added to the water
• Initial investment moderate if heat
• source available

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• Heat Treatment / Pasteurization
• Limitations and Conditions
• Energy consumption relatively high
• Best in combination with cheap heat
• source, or when excess heat is
• available, such as from CO2 boiler
• Needs lowering of pH to prevent scaling
• of heat exchanger
• Can deplete dissolved oxygen in water

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Ultraviolet Light
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UV-Light

• Disrupts genetic material in cells
• Low, medium or high pressure Mercury
• vapor lamps are commonly used
• 254 nm wave length at
• 250 mJ/cm2 kills most pathogens

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• UV-Light
• Pros
• Wide spectrum of biocidal activity
• No substances added to water
• No effect on pH
• Moderate capital and operating cost at
• low flow rates and low turbidity

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• UV-Light
• Limitations and Conditions
• Turbidity reduces efficiency
• removal of solids is critical
• Water turbulence around lamp
• needed for good effect
• Lamps must be kept clean
• Lamp replacement typically every
• 10,000 hours
• Fe-chelates may be destroyed
• Relatively high capital and running cost
• for high volumes or dirty water

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Slow Sand Filtration
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Slow Sand Filtration

• Medium is colonized by microorganisms
• Physical and biological activity control
• Phytophthora, Pythium, Fusarium and
• others
• Suitable for low flow applications
• Typical 2 4 gph per sqft of filter area
• Low energy use, no chemicals added

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Copper Ion System
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Copper Ionization
An electric charge is passed between copper
bars, releasing copper ions into the
water. Automatic control of copper output
according to Flow and EC is essential Copper
ions act throughout system
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Copper Ion System
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Copper Ionization
Pros
Copper ions at concentrations as low as 1 ppm
kill pathogens and algae. Effect on Pythium and
Phytophthora documented others reported by
growers. Cost effective for high water volumes.
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Copper Ionization
Limitations and Conditions
Water must have EC gt.3mS/cm to sufficiently
conduct current Although copper concentrations
are a fraction of plant toxicity levels,
caution with long term crops is prudent until
more research is done.
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Ozone
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Ozone
An electrical arc is used to produce Ozone (O3)
on site from atmospheric or bottled Oxygen The
Ozone is bubbled through water and dissolved.
Typical concentration 10 mg per hour per m³
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Ozone
Pros Very potent oxidizer. Kills pathogens and
algae at low concentrations Turns into O2,
adding dissolved Oxygen to water
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Ozone
Limitations and Conditions
Organic matter in water depletes ozone. Good
filtration and/or other pre-treatments are
critical Proper design is essential to prevent
Ozone from escaping in to the air and creating
human health risk.
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• Finer bubbles transfer
• more O2 into water
• Saturation depends on
• temperature warmer
• water holds less O2
• Examples 50ºF?11.3 mg/l
• 82ºF? 7.8 mg/l

Aeration
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Aeration

• Dissolved oxygen shown to suppress
• pathogens such as Pythium
• (Mountain stream effect)
• Prevents fouling of water by
• supporting aerobic microorganisms
• Shown to promote root growth and
• plant health

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If your pond looks like this.
. and you prefer this, you may have to invest
into.
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..this (Example courtesy Pure-O-Tech)
Advanced Recycle Systems Dirty Water
System Disinfection
ARS Dirty water System High Organic Load System
Sizes in GPM 10, 25, 50, 75, 100, 150
Tank or pond
Advanced Filter module
Storage Tank
Nano Filter Membrane module
UV or Ozone module
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• Potential Water Problems
• (by Pure-O-Tech)
• Irrigation Runoff
• Pathogenic microorganisms
• High salts Sodium, chloride, sulfate, calcium
  magnesium, boron, silica, carbonate, iron, etc.
• Organic matter
• Algal growth
• Particles (silt, dirt)
• Nitrates
• Solutions
• Ozone and/or UV radiation for microorganisms
• RO for salts and nitrates
• NF for organic matter and partial salt removal
• MF or UF for particles
• Multimedia and bag filters for particles
• NF for removal of hardness (scale foramtion) on
  RO membranes

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Planning your Water Treatment System

• Determine quality of treated water you need
• Analyze quality and amounts/flow rates of dirty
  water
• Establish range of treatment options
• Determine payback periods
• Start out with lower end of treatment options,
  but design and prepare for future upgrades