Water Quality

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Water Quality Water Test Results
Chemicals in water
Microbes in water
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Water Quality Water Test Results
Remember More knowledge more control
more informed decisions will be.
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Water Test Results common tests
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Water Test Results
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• Conductivity
• measures total dissolved solids (TDS)
• eg any salt or any minerals in water

Measures ability of water to conduct electricity
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Water Test Results
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• pH
• how acid is your water
• Low pH - like vinegar
• High pH - like soap
• Ideal pH 7.0 - 8.5
• (In accordance with Drinking Water Standards)

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pH
Colourimetric Measurement of pH
Comparing colours
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pH
Colourimetric Measurement of pH
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pH
Electrometric Determination of pH
Need careful maintenance calibration
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Water Test Results
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Alkalinity
Measuring pH protection buffering - Helps
stabilise pH
Measured by titration using a burette
Acid added until pH changes
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Alkalinity
Measured by titration using a burette
Acid drips
Acid drips
Rainwater
Tap water
(absorbs pH-changing chemicals)
Minimal alkalinity
Alkalinity often added to water
Minimal pH change
Instant pH change
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Water Test Results
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Hardness
Measures minerals (like calcium) in water from
rocks and earth
If too high, can leave deposits of hard scale
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Hardness
Measured by titration using a burette
If too low, can erode copper pipes blue/green
staining
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Water Test Results
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Chlorine
Disinfection levels - residuals
Uses DPD indicator which turns pink-red
FAC Free Available Chlorine That which is
free to disinfect TAC Total Available
Chlorine FAC Combined Available Chlorine
(CAC)
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Chlorine
Disinfection levels - residuals
Uses DPD indicator which turns pink-red
FAC uses DPD 1 reagent TAC uses DPD 4
reagent TAC FAC CAC
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Chlorine
If FAC shows no colour, do a TAC test It could
mean no chlorine or too much chlorine! If the
TAC test is clear, there is no chlorine. If
the TAC test is red, there is only CAC. If
the TAC test is yellow, there is excessive FAC.
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Chlorine test methods
DPD Colorimetric Method visual comparison
Test strips easily contaminated
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Chlorine test methods
DPD Colorimetric Method - photometer
Powder packet accurate
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Chlorine test methods
Eg Chlorine via photometer
24mm light path
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Chlorine test methods
DPD Colorimetric Method - titration
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Water Test Results
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Turbidity
Measures dirt dust in water could be
microscopic bugs!
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Water Test Results
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E.coli bacteria - testing
Indicator bacteria - specialist laboratory needed.
Membrane filtration methods
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E.coli bacteria - testing
Glows under UV light Yes its E coli
No reaction No E coli
Colour change Possible E coli
Colour-changing methods
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Water Test Results
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Water Test Results
meaning?
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Online/continuous monitoring
Manufacturers specifications know what they are
reading
(eg FAC, pH, Temperature, Turbidity)
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Sampling needs to be representative

• Handling of Samples
• Depends on analyses
• Preservative needed?
• Mixing needed?
• Will exposure to air interfere?
• Label
• Immediately after the collection

where, why, when, who, how Chain
of Custody best in fill in the gaps forms.
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Overall
The more knowledge we have The more control is
possible The more informed decisions will be.