Impurities of water . characteristics of water.

1. Definition
Water quality management is
concerned with control of
pollution from human activity so
that the water is not degraded to
the point that it is no longer
suitable for intended uses.

2. Water Pollutants
A large amount of effluents discharge to surface
waters can be grouped into broad classes and
they are called water pollutants.
They may be :
 Point source pollutants
 Non-point source pollutants.

3. Some common types of pollutants are:
Oxygen demanding material
Nutrients
Pathogenic organisms
Suspended solids
Salts
Toxic metals and toxic organic compounds
Endocrine disrupting chemicals
Heat

5. Point sources
• Domestic sewage
• Industrial wastes
Both are called point sources because
they are generally collected by a network
of pipes and conveyed to a single point of
discharge into the receiving water.

8. Non-point sources:
Urban and agricultural runoffs are characterized
by multiple discharge points called non point
sources.
They result from rain storms and spring
snowmelt resulting in large flow rates that
make treatment even more difficult.
They were collected in combined sewers that
carry both storm water and municipal sewage

9. Combined Sewer Overflow (CSO)
The CSO demands expanded treatment
facilities to treat storm water so it is difficult
to execute.
CSO is expensive because it frequently occurs
in oldest most developed portions of city so
paved streets , utilities , and commercial
activities will be disrupted.
The installations of combined severs is now
prohibited in USA.

10. Dissolved oxygen (DO) refers to
microscopic bubbles of
gaseous oxygen (O2) that are mixed in
water and available to aquatic
organisms for respiration—a critical
process for almost all organisms.
Primary sources of DO include the
atmosphere and aquatic plants.

11. Nutrients
Nitrogen and phosphorus , two nutrients of
primary concern are considered pollutants
because they are too much for a good thing.
If their level become excessive they will disturb
the natural ecosystem causing pollution.
They turn into oxygen demanding material when
they deteriorate and settle to bottom of water
thus play role in oxygen deficiency and pollution.

14. Pathogenic organisms
The definition of a pathogenic organism is
an organism capable of causing disease in
its host. A human pathogen is capable of
causing illness in humans. Common
examples of pathogenic organisms include
specific strains of bacteria like
Salmonella, Listeria and E. coli, and viruses
such as Cryptosporidium.

15. Pathogens cause typhoid and cholera

16. Cholera and typhoid
are endemic diseases
in the world with over
384,000 cases of
cholera and 16 million
cases of typhoid per
year.

17. Organic and inorganic particles that are
carried by wastewater into receiving water are
termed as suspended solid. (SS)
They occur due to slow speed of water flow
into a pool and a layer of sediment is formed
at the bottom.
They destroy natural habitat as that of salmon
species.

18. Salts
Total dissolved solids (TDS) is a measure
of the combined content of all inorganic
and organic substances contained in a
liquid in molecular, ionized or micro-
granular suspended form.
The excessive salt concentration in water results in
crop damage and disturb the river or pond
ecosystem.

19. Toxic materials and compounds
Agricultural runoffs often contains
pesticides and herbicides that have
been used on crops and urban runoffs
is major source of zinc in many water
bodies.
These toxic materials have destroyed the health as well
as natural ecosystem.

20. These EDCs alter the normal physiological
system of endocrine system and effect the
synthesis of hormones.
They effect reproductive system and
developmental processes in mammals birds
reptiles and fish.

24. Water Quality Management In Rivers

25. BOD
Biochemical oxygen demand (BOD, also
called biological oxygen demand) is the
amount of dissolved oxygen needed (i.e.,
demanded) by aerobic biological organisms
to break down organic material present in
a given water sample at certain
temperature over a specific time period.

28. ThOD

30. The actual BOD is less than ThOD
due to incorporation of some of
carbon into the new bacterial cells.

31. Factors for BOD constant k
o Nature of waste
o Ability of organisms in system to utilize the
waste
o The temperature

33. Lake Acidification
One of the causes of fresh
water acidification is acid rain. That
means rain that is unusually acidic (low
pH). Acid rain has harmful effects on
soil (soil acidification), animals, plants
infrastructure and water. Another
cause of freshwater acidification is the
Buffer solution.