ENVIRONMENTAL SCIENCE AND ENGINEERING
WATER QUALITY MANAGEMENT
B

a.
b.
Water of a particularly high quality is needed for
drinking water supplies. In many parts of the world,
the introduction of pollutants from human activity
has seriously degraded water quality, even to the
extent of turning pristine streams into foul open
sewers with few life forms and fewer beneficial uses.




a.
b.
c.
controlling pollution from human activity to
ensure that the water is suitable for its intended
uses
amount of waste that can be tolerated
(assimilated) by a water body,
type of pollutants discharged and the way they
affect water quality
effects of natural factors such as
mineral heritage of the watershed
geometry of the terrain
climate of the region
Water Pollutant Sources
A


B
Oxygen-Demanding Material
Anything that can be oxidized in the receiving
water resulting in the consumption of dissolved
molecular oxygen
Usually, biodegradable organic matter but also
includes certain inorganic compounds (human
waste, food residue, animal droppings, crop
residues, or leaves)
Nutrients

Nitrogen and phosphorus, two nutrients of
primary concern, are considered pollutants when
they become too much.

They pose primary issue of eutrophication of
surface waters and the contamination of
groundwaters with nitrate.
Point Sources
C

Urban and agricultural runoff
characterized by multiple discharge points
occurs during rainstorms or spring snow melt,
resulting in large flow rates that make treatment
even more difficult
Water Pollutants
A
Water quality management deals with
Nonpoint Sources
Domestic sewage and industrial wastes act as point
sources because they are generally collected by a
network of pipes or channels and conveyed to a
single point of discharge into the receiving water.

Domestic sewage consists of wastes from homes,
schools, office buildings, and stores.

Municipal sewage includes domestic sewage along
with any industrial wastes that are permitted to be
discharged into the sanitary sewers.
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Pathogenic Organisms

Pathogenic microorganisms found in wastewater
include bacteria, viruses, and protozoa excreted by
deceased persons or animals.

Results: water becomes nonpotable (unsafe for
drinking), unsafe for swimming and fishing.
Certain shellfish can be toxic because they
concentrate pathogenic organisms in their tissues,
making the toxicity levels in the shellfish much
greater than the levels in the surrounding water.
ENVIRONMENTAL SCIENCE AND ENGINEERING
Bacteria that have developed immunity to antibiotics
are of major concern to environmental professionals.
A recent study showed that even well-treated
municipal wastewater does not effectively destroy
cells carrying antibiotic resistance genes (ARGs).
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