Transcript Agenda

Well Water Quality
Home*A*Syst
& UGA Water Testing
Frank Henning, UGA Watershed Extension Agent
Potential Pollutants
ex) Cleaning products, Gasoline, Oil, Pesticides,
fertilizers, animal waste, septic systems…
Easier to exclude pollutants than clean up!!!!
Minimize contamination
Maximize filtration/purification
Direction and Rate of Movement
Well
Safe Drinking Water
Who is protecting drinking water supplies?
Who is testing for contamination?
Using Home*A*Syst
to
Protect Your Water Supply
Self Assessment:
- a or b = few problems
- c or d = potential problems
- c or d  Consider making
changes to protect drinking water
*Adapted from National Home*A*Syst Program &
NCSU Home*A*Syst Publication
1. Where is your well located?
a. Uphill from all pollution sources.
No surface runoff reaches well.
Surface water flows away from well.
b. Uphill from most pollution sources. No surface water
runoff reaches the well if drainage is working correctly.
c. Downhill from many pollution sources, or one hazardous
source. Some surface runoff may reach well.
d. Settling or depressions around casing. Surface water
runoff collects near well, or do not know.
2. Which best describes your well?
500 feet - Landfill
100 feet – Sewage , Animal waste, Chemicals and
other potential contaminants.
50 feet – Building foundations, surface water
a. All separation distances are greater than
minimum requirements.
b. Separation distances are at least ¾ the minimum
c. Separation distances are a least ½ the minimum
d. Some separation distances are less than ½ the
minimum, or do not know.
3. How well does soil filter
out pollutants?
a. Fine textured soils (clay loam, silty clay)
b. Medium textured soils (silt, silt loam)
c. Medium or coarse textured soils with low
organic matter
d. Coarse textured soils (sands, sandy loam), or
do not know.
4. How quickly does water reach your well?
a. Water Table or fractured bedrock deeper than
50 feet.
b. Water table or fractured bedrock deeper than 25
feet.
c. Water table or fractured bedrock deeper than 10
feet
d. Water table or fractured bedrock shallower than
10 feet, or do no know.
5.What is the condition of your well casing?
a. No holes or cracks. Cap tightly
secured. Screen vented
b. No defects visible. Well is vented,
but not screened.
c. No holes or cracks visible. Cap
easily removed.
d. Holes or cracks visible. Cap loose
or missing. Can hear water
running; or do no know.
6. Are casing and grout deep enough?
Which best describes the casing
and grouting of your well?
Cased and grouted to required depth.
a. Cased and grouted below water
table of well
b. Cased, but not grouted.
c. No casing. No grout; or do not
know.
7. Is the well protected at the
ground surface?
Which best describes your wellhead?
a. Casing extends more than 12 inches above surface
and concrete pad extends 2 feet in all directions
b. Casing above ground level and concrete pad 1 to 2
feet in all directions
c. Casing above ground level and no concrete pad.
d. Casing below ground level or in pit or basement and
no concrete pad; or do not know
8. How old is your well?
a.
b.
c.
d.
Less than 15 years old
15 to 30 years old
30 to 60 years old
More than 60 years old;
or do not know
9. Was your well drilled or dug?
a.
b.
c.
d.
Drilled well
Jetted or bored
Driven (sand point)
Dug; or do not know.
Types of Wells
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Bored
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Large diameter (2 ft or larger)
Shallow (uaually less than 60 ft)
Vulnerable to surface influences
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Bacteria
Chemicals
Drilled
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Small diameter
(usually 6 in)
Deep (usually greater
than 200 ft)
Less susceptible to
surface influences
10. Are you preventing backflow?
a. Check valves are installed on all faucets
with hose connections and there are no
cross-connections between water supplies.
b. Check valves are installed on some faucets
with hose connections, or one check valve
at well pump
c. No check valves installed. Air gap
maintained.
d. No check valves installed. Air gap not
maintained. Cross connections between
water supplies; or do no know.
11. Do you have any unused wells?
a. No unused, unsealed wells.
b. Unused wells sealed and filled.
c. Unused well on property more than 100
feet from supply well. Not capped or
filled.
d. Unused well less than 100 feet from
supply well. Not capped or filled; or do
not know.
12. Has your well been tested recently?
a. Consistent, satisfactory water quality. Bacteria,
nitrate, and other tests meet standards.
b. Occasional deviation from standards with
bacteria, nitrate, and other tests.
c. Bacteria, nitrate and other tests often do not
meet standards.
d. No water tests done; or water discolored after
rainstorms, or noticeable changes in color,
clarity, odor or taste; or do not know.
Indicator Organism Concept
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Correlated to the presence of pathogens
Population large enough to isolate in small
water samples (100 mL)
Rapid
Inexpensive
Safety, not culturing pathogens
Standard Bacteria Test
Cost: ~$25
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Total coliform
Escherichia coli
total coliform
fecal
coliform
E. coli
Pathogen Problems
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Numerous water borne pathogens
Individual pathogen numbers may be too low
to detect in a reasonable sized water sample
Isolation and detection of some pathogens can
take several days, weeks, or months
Absence of one particular pathogen does not
rule out the presence of another
Primary Standard
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These are the elements
and compounds that can
cause adverse health
effects when above the
maximum contaminant
level (MCL) set by the
EPA.
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Cadmium (0.005 ppm)
Chromium (0.005 ppm)
Copper (1.3 ppm)
Fluoride (4.0 ppm)
Nitrate-N (10 ppm)
Secondary Standards
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These are not generally
considered threats to
health, but cause
nuisance problems such
as staining, bad tastes
and odors when above
threshold levels.
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Aluminum (0.2 ppm)
Chloride (250 ppm)
Copper (1.0 ppm)
Fluoride (2.0 ppm)
Iron (0.3 ppm)
Manganese (0.05 ppm)
Sulfate (250 ppm)
Total Dissolved Solids
(500 ppm)
% Above Standards (Statewide)
30.1
35
30
17
6.4
5.6
7.2
4.4
3.6
0.9
Low High
pH pH
Al
Cu
Pb
Fe
NO3 NO3
MCL AL
25
20
15
10
5
0
Basic Water Test
~$15
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pH
Hardness
Aluminum
Boron
Cadmium
Calcium
Chromium
Copper
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Iron
Magnesium
Manganese
Molybdenum
Phosphorus
Sodium
Zinc
Expanded Water Test Package
basic + more ($48)
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Alkalinity
Conductivity
Saturation Index
Total Dissolved Solids
Silica
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Nitrate-N
Chloride
Fluoride
Sulfate
Phosphate
When to Recommend the
Expanded Test
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When client hasn’t previously done this test package
When client is having a problem
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Blue green staining
Bitter tasting water
Numerous leaks
Mineral deposits
Salty tasting water
Muddy water
Etc.
When a water treatment system is being considered
Interpretations
Test
Nitrate-N
Chloride
Sulfate
Fluoride
Silica
Importance
Indicates impact from fertilizer, animal
waste, wastewater, or shallow groundwater
Indicate saltwater intrusion or wastewater
Geologic deposits of gypsum, pyrite, or
wastewater
Excessive from industrial wastewater
High levels can produce scale and grit in
strainers and filters
Hardness (basic test)
units: mg CaCO3/L (ppm)
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Sum of the calcium (Ca) and magnesium
(Mg)
Expressed as mg CaCO3/L (ppm)
Usually from the alkalinity or dissolved
limestone
However, can be from other non-alkalinity
minerals like gypsum (CaSO4 )
Compare Hardness and Alkalinity
Alkalinity (expanded test)
units: mg CaCO3/L (ppm)
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Capacity to neutralize acid and can consist of:
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Bicarbonate
Carbonate
Hydroxides
Silicates
Borates
Phosphates
Bicarbonate form in most natural water of Georgia and
derived from limestone (CaCO3 and MgCO3)
Hardness vs. Alkalinity
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Hardness = Alkalinity
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Hardness > Alkalinity
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Hardness is from the calcium or magnesium carbonates that
account for the alkalinity
There are sources of Ca and Mg that are not from the
carbonate alkalinity such as other neutral salts of Ca or Mg
like gypsum (CaSO4)
Hardness < Alkalinity
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There are sources of alkalinity that are not from Ca or Mg
carbonates such as hydroxides or sodium carbonates
Corrosive, Scaling
or Balanced?
Scaling
Corrosive
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Reduces the lifetime of the
pump and plumbing
Leaks
Toxic metals can be leached
from plumbing
Stains on fixtures
Metallic taste
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Fills hot water heaters
with solids
Causes blockages in
plumbing
Reduces flow
Spots on glassware,
utensils, and dishes
Using the Saturation Index
Index
< -5.00
Interpretation
Severe Corrosion-corrosion control is
recommended
< -2.00
Moderate Corrosion-corrosion control
should be considered
0.00
Balanced-no treatment is recommended
> 2.00
Mild Scale-softening will decrease hardness
and reduce scaling
> 5.00
Severe Scale-scale build-up in hot water
heaters and other plumbing will be excessive
Conductivity
Seimans (S)/cm = mhos/cm
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Ability to conduct electricity
Increases proportional to the dissolved ionic solids
Inorganic compounds are good conductors but organic
compounds are poor conductors
Levels
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Distilled water: 0.3 to 5 S/cm
Drinking water: 50 to 1500 S/cm
Sea water: 64,000 S/cm
Conductivity (S/cm) X 0.55 = estimation of total
dissolved solids (ppm)
Total Dissolved Solids
mg/L (ppm)
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Residue remaining after filtered water is dried
If primarily inorganic salts then closely related to
conductivity
Exceptions to this would be the “Blackwaters” that are
high in organic compounds like tannin
Levels
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Distilled water: 0.2 to 3 ppm
Drinking water: 28 to 825 ppm
Sea water: 35,000 ppm
Background Information
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The expanded test package is also good for developing a history
of background information, which is useful for tracking changes
in water quality due to:
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Deterioration of the well casing
Saltwater intrusion into the aquifer
Treatment system efficiency
Development in the watershed
Can fall back to the Basic (W1) package when the parameter or
parameters of interest have been identified by the Expanded
(W2) package and these are in the Basic package.
Questions?