|
Impurity or Contaminant |
Symptom |
Cause |
Health Effects |
Means of Treatment |
Turbidity
|
Dirt, salt, clay. |
Suspended matter in
surface water pond, stream or lake. |
Turbid water may contain
disease causing microorganisms |
"Calcite" or Neutralize
(media) type filter - up to 50 ppm |
|
Sand grit, silt or clay
substances. |
Well sand from new well
or defective well screen. |
Turbid water may contain
disease causing microorganisms |
Sand trap and/or new well
screen |
|
Rust in water. |
Acid water causing iron
"pick-up." |
Turbid water may contain
disease causing microorganisms |
Neutralizing calcite
filter to correct low pH acidity and remove precipitated iron |
|
Gray string-like fiber. |
Organic mater in raw
water algae, etc. |
Turbid water may contain
disease causing microorganisms |
Constant chlorination
followed by activated carbon filter to dechlorinate. |
Acid water
|
Green stains on sinks and silver, porcelain bathroom fixtures.
Blue-green cast to water. |
Water which has high carbon dioxide content (pH below 6.8) reacting
with brass and copper pipes and fittings. |
Could lead to health effects if acid water causes leaching of lead
and copper |
1. Neutralizing calcite
filter down to pH of 5.5, or
2. Calcite/ Magnesia -
oxide mix (5 to 1) for higher flow rate and to correct very low pH
water.
3. Soda ash chemical feed
followed by filtration. |
Discolored water red, "Iron" water
|
Brown-red stains on sinks and other porcelain bathroom fixtures.
Water turns brown-red in cooking or upon heating. Clothing becomes
discolored. |
1. Dissolved iron in
influent (more than 0.3 ppm Fe+) water appears clear when first
drawn at cold water faucet. Above 0.3 ppm Fe causes staining. |
Various
effects |
1. Can remove 0.5 ppm of
Fe+ for every grain/gal of hardness to 10 ppm with water softener
and minimum pH of 6.7.
2. Over 10 ppm Fe+
chlorination with sufficient retention tank time for full oxidation
followed by filtration/ dechlorination.
3. In warm climates
residual aerator and filtration will substantially reduce iron
content. |
|
2. Precipitate iron
(water will not clear when drawn). |
Various
effects |
1. Up to 10 ppm iron
removed by manganese greensand filter, if pH 6.7 or higher, or;
2. Manganese treated,
non-hydrous aluminum silicate filter where pH of 6.8 or higher and
oxygen is 15% of total iron content.
3. Down flow water
softener with good backwash, up to 1.0 ppm Fe. Above 1 ppm to 10 ppm
use calcite filter followed by down flow water softener.
Calcite media type filter
to remove precipitated iron. |
|
Brownish cast does not precipitate. |
Iron pick-up from old pipe with water having a pH below 6.8. Organic
(bacterial) iron. |
Various
effects |
1. Treat well to destroy
iron bacteria with solution of hydrochloric acid then constant
chlorination followed by activated carbon media filtration and
dechlorination.
2. Potassium permanganate
chemical feed followed by filtration. |
|
Reddish color in water sample after standing 24 hours. |
Colloidal iron. |
Various effects |
Constant chlorination followed by activated carbon media filter
dechlorination.
|
|
Yellow water |
Yellowish cast to water
after softening and/or filtering. |
Tannins (humic acids) in
water from peaty soil and decaying vegetation. |
Various
effects |
1. Adsorption via special
macro-porous Type I anion exchange resin regenerated with salt (NaCl)
up to 3.0 ppm.
2. Manganese greensand or
manganese treated sodium alumino-silicate under proper set of
conditions. |
|
Milky water |
Cloudiness of water when
drawn. |
1. Some precipitant
sludge created during heating of water.
2. High degree of air in
water from poorly functioning pump.
3. Excessive
coagulant-feed being carried through filter. |
1. Various
effects
2.
Aesthetic only
3. Various
effects |
1. Blow down domestic or
commercial hot water heater tank periodically.
2. Water will usually
clear quickly upon standing.
3. Reduce coagulant
quantity being fed, service filters properly. |
|
Very high chloride
content in water |
Blackening and pitting of
stainless steel sinks and stainless ware in commercial dishwashers |
1. Excessive salt
content.
2. High temperature
drying creates chloride concentration accelerating corrosion. |
Various
effects |
1. Use other chloride
resistant metals.
2. Reduce total dissolved
solids by reverse osmosis. |