Wash Water Disinfection Measuring Effectiveness Pulse

1
Wash Water Disinfection Measuring Effectiveness
Pulse Instruments www.pulseinstrument.com
Karan Khurana
2
Water Applications

• Pre-Cooling Operations
• HydroVac
• Ice Injection
• Hydro-Cooling
• Wash and Dip Tanks
• Flume Wash Systems
• Spray Wash Systems
• Growing and Irrigation
• Water Distribution systems
• Cooling Canals
• Cooler Pasteurizer

3
Associated Waterborne Microbes

• Special concern for enteric pathogens
• E. Coli O157H7
• Salmonella
• Contamination may persist for 161 up to 231 days
• Escherichia Coli
• Salmonella spp.
• Vibrio cholerae
• Shigella spp.
• Cryptosporidium parvum
• Giardia lamblia
• Cyclospora cayetanensis
• Toxiplasma gondii
• Norwalk virus
• Hepatitis A virus

4
Bio-film

• Water Distribution Systems
• Biofilm buildup
• Recontamination

5
Scale in Water System
6
Scale with Bio-film

• Scale interacts with Bio-film
• To remove Bio-film it is essential to remove scale

7
Fresh Cut Salad Flume Wash
Flume Process Water Treament Sanitizer is used
to provide disinfection to the water used to
process Fresh Cut Salads Typically is added to
the water at each of the chillers before the
water is returned to the process tanks
8
Leafy Green Marketing Agreement

• Specific Guidance
• Water in process
• Water in irrigation
• Indicator Organisms
• Water Testing
• Treatment Protocols
• Industry Acceptance

9
Objective of Wash Water Disinfection

• Prevent Cross Contamination
• Reduce Microbial Load
• Will NOT Sterilize the Product
• Irradiation of produce does not eliminate or
  reduce the need for wash water disinfection or
  for maintaining clean produce.

10
Romaine Wash Line
Heinzen Manufacturing
11
Spinach Wash
Heinzen Manufacturing
12
Celery Water Cuts
Heinzen Manufacturing
13
Washing Will Not Remove 100 of Firmly Attached
Pathogens
Tertiary Wash 99.9 Removal
Primary Wash 93 Removal
Triple washed cilantro leaves
14
Types of Disinfection Methods

• Non Chemical
• Irradiation (for produce, not water)
• Heat
• Ultra Violet
• Filtration
• Chemical
• Oxidizer
• Oxidizer and Acid
• Non-Oxidizer

15
Chemical Disinfection Options

• Chlorination
• Form Hypochlorous Acid (HOCl)
• Chlorine Gas
• Sodium Hypochlorite
• Calcium Hypochlorite
• Chlorine Dioxide
• Chlorobromination
• Form Hypobromous Acid
• Peroxyacetic Acid
• FIT Acid Surfactant
• Ozone

16
The Problem What is the right treatment level?

• Multiple Chemical Choices
• Multiple Product Types
• Various Microbe Types
• Different Load Throughput
• Varying Wash Conditions
• Different Equipment Designs
• Different Retention Times

17
Oxidizer Activity

• HOCl H -OCl
• pKa 7.53
• ORP
• Measures the Potential

18
ORP Measures Effectiveness

• Oxidation is a Transfer of Electrons
• Microbes lose electrons and are oxidized
• Oxidizer disrupts the cell function and integrity

19
E. Coli Kill Time

• ORP Kill Time
• 450 mV Infinite
• 500 mV 1 hour
• 550 mV 100 seconds
• 600 mV 10 seconds
• 650 mV 0 seconds

20
Treatment Conclusions

• Produce Wash Water
• ORP of 650 mV (E. Coli)
• ORP of 750 800 mV (Spoilage pathogens, yeast,
  molds)
• pH of 6.5 to 7.0
• Exception Peroxide and POAA Peroxy acetic acid
  based products efficacy is related to
  concentration (ppm or mg/l). Typically 25 to 30
  ppm 450 mV of ORP

21
Chlorination Advantages

• Most widely used method
• Relatively inexpensive
• Readily available
• Sodium Hypochlorite (liquid)
• Broad spectrum of activity (yeasts, molds,
  bacteria, viruses, algae)
• Requires pH management
• Effective biocide and cleans bio-film
• Treatment 2 to 5 mg/l free Cl (ppm)

22
(No Transcript)
23
pH and Chlorine

• Combined Chlorine
• Total Chlorine
• Free Chlorine
• pH HOCl -OCl
• 6.5 95 5
• 7.0 80 20
• 7.5 50 50
• 8.0 20 80

24
Table 1. Example of relationship between
chlorine, non-adjusted pH, ORP, and bacterial
inactivation.
From T.Vgt Suslow. 2007. Practical Considerations
in the Application of Oxidation Reduction
Potential (ORP) as a Water Quality Metric for the
Leafy Green Products Handler Marketing Agreement
and the Produce Industry
25
Chlorine Disadvantages

• Potential for toxic chlorine gas formation
• Poor penetration
• Corrosive
• Irritation
• Unstable (out of pH range lt6.0, high temp), short
  half-life
• Hydrophilic Substitution Reaction
• Formation of potentially toxic by-products
  (THMs, chloramines)
• Contributes high levels of Sodium

26
Chlorine Byproducts

• Hydrophilic substitution reactions with organics
• Form THMs Trihalomethanes EPA max 80 ppb
• Reaction mechanismCH3COCH3 HOCl -gt
  CH3COCCl3CH3COCCl3 H2O -gt CH3COOH CHCl3
• Form Chloramines
• 3HOCl NH3 -gt NCl3 3H2O

CHCl3 Chloroform
27
Environmental Impact

• Addition of Sodium
• Addition of Calcium
• Addition of Chlorides
• Addition of Chlorite
• Formation of THMs (Trihalomathane)
• Formation of Chloramines
• Impact on soil permeability
• Phyto-toxicity
• Product quality

28
Salt Effects of Chlorination

• High Sodium or Calcium content
• Sodium and Calcium may accumulate in leaf tissue
  causing spots
• Soil accumulation leads to poor soil permeability
  in Irrigation Water
• Calcium reaction with carbonates and bicarbonates
  lead to insoluble salts CaCO3

29
Chlorine Dioxide ClO2

• Oxidizer 2.5x more effective than Chlorine
• Low Sodium, Low Chlorite
• No hydrophilic substitution reaction with
  organics
• Does not form THMs
• Does not form Chloramines
• Effective at wide pH ranges

30
pH Dependency of Sanitizers

• Water Treated With Hypochlorite
• Liquid or Granular Hypochlorite or Chlorine Gas
• Acid Addition for pH Control (6.8 7.2)

31
Chlorine Dioxide ORP
32
Chlorine Dioxide Methods

• 3 Chemical Generator
• 2 Chemical Acidified ClO2
• Sachet Bag Generation
• 2 Chemical powder
• 2 Tablet format
• 1 Tablet format

33
Chlorine Dioxide System
Production of Chlorine Dioxide
Chlorine Dioxide Solution
Chlorite
NaOCl
HydrochloricAcid
Eductor
Water Flow
To Batch Tank
Liquid Phase ClO2 Generation
34
Chlorine Dioxide Generators
35
Ozone (O3) Advantages

• Powerful oxidizing gas
• Broad spectrum antimicrobial activity

36
Ozone (O3) Disadvantages

• Unstable (short half life)
• Difficult to monitor concentrations
• Difficult to adjust needs based on demand
• May require use of secondary disinfectant
• Must be generated on site
• Worker Safety Issues, Toxicity
• Corrosive

37
Peroxyacetic Compounds

• H2O2 CH2COOH H3COOH
• Hydrogen Acetic
  Peroxyacetic
• Peroxide Acid
  Acid

38
Peroxyacetic Acid (POAA) Advantages

• Relative tolerance to organic matter and soil -
  Low Foam
• Combine sanitizing and acid rinse
• ORP Metabolic Poison
• No residue Environmentally responsible
  (phosphate free breaks down to water, oxygen and
  acetic acid)
• Generally non-corrosive to stainless steel and
  aluminum

39
Peroxyacetic Acid Advantages

• Broad spectrum of antimicrobial activity
  (particularly good on psychrotrophs and spores)
• Active over broad pH range up to pH 7.5

40
Peroxyacetic Acid Disadvantages

• Corrosive to soft metals and skin
• Strong, pungent odor of concentrate and
  dilution
• Varied activity against fungi
• Build up of byproducts in water
• Need to keep water clean
• Prolonged exposure to product may cause tissue
  damage

41
Antibacterial Efficacy Model

• Low/High pH helps disrupt bacterial cell wall
  and membrane
• (citric acid, other organic acids, NaOH,
  carbonates)
• Surfactants assist cell membrane disruption and
  enable pH to be more effective can also penetrate
  cell membrane to affect cellular metabolism (SLS,
  fatty acids)
• pH buffering is necessary for maximum effect
  (citrate, phosphates, carbonate, etc.)

42
Oxcide as Oxidizer

• Unique HOCl formulation
• Removes scale and bio-film
• Neutral pH
• Non-Toxic
• Non Hazardous
• Low TDS

• Dissolves Hard Scale
• Changes Chemical interaction
• Changes Morphology
• Odorless at 650mV ORP

43
Unique Oxcide Oxidation

• CaCO3 2HOCl
• Ca2 CO2 H2O 2ClO- (gt 300 mV ORP)
• MgCO3 2HOCl
• Mg2 CO2 H2O 2ClO- (gt 300 mV ORP)
• Oxidation by Oxcide in the absence of TDS,
  hydroxyls, and Sodium results in de-scaling of
  Calcium and Magnesium Carbonate.

44
Scale and Biofilm Removal

• Oxcide dissolves scale within 30 days
• Does not allow biofilm to deposit

45
Disinfection Byproducts
46
Clean Water

• Minimize organic loading
• Keep wash water clean
• Improves sanitizer action
• Reduces Chemical Demand
• Minimizes NCl3 and Chloramines
• Improves Product Quality
• Improves Product Safety

47
Measurement

• Spot Checking
• Chemical Test Kit
• Chemical Test Strips
• Colorimeter
• Direct Measurement Meter
• Portable ORP and pH Meter
• Fixed Continuous Meter
• ORP and pH Meter
• Direct Measurement Meter

48
Analysis Methods - Colorimeter
Analytical Methods

• Ion Chromatography (IC - Instrumental)
• Starch/Iodide (Titration)
• DPD (Spectrophotometric)
• Chlorophenol Red (Spectrophotometric)
• UV Spectrophotometry (Direct Read)
• Amperometric End Point (Titration)
• Lissamine Green B (Spectrophotometric)

49
Ion Specific Test Strips

• Fast Spot Checking
• Simple Dip Read 1 Step
• Colorimetric Analysis
• Visual Reading
• Low Cost

50
Portable Hand Meters

• Spot Checking
• Simple Dip Read 1 Step
• Very Fast
• Electrochemical Test
• Higher Accuracy
• Calibrated Measurements
• Digital Reading
• Relatively Low Cost

51
Simple Chemical Injection
52
Continuous Monitoring Automation
53
Chemical Injection Management

• Monitoring Disinfection Treatment
• Control Chemical Injection
• Alert Limit Alarms
• Data Recording
• Data Reporting
• Data Management
• Remote Telemetry communications
• Remote Telemetry alarm notification

54
Continuous Recording
55
Data Logger with USB

• Simple
• Single Channel
• Compact Size
• 4-20 mA
• USB Connection
• Simple Graph
• Easy Reader
• Software Included

56
Recording and Reporting
57
Recording and Reporting
58
Recording and Reporting
59
Treatment Conclusions

• Identify the Water Process
• Identify your Wash Product
• Select your Chemistry
• Select a Spot Check Device
• Select Monitoring System
• Select Recording Method
• Maintain Records !!!!