Water pollution is classified as either coming from an industrial source or a municipal source. A municipal source is essentially that which comes out from residential dwellings. Wastewater from homes includes soaps, human excrement, some cleaning compounds, and whatever else goes into the residential sink. Eunice but wastewater is generally not considered hazardous as defined by regulation.

1. Water
Pollution
Lecture
Jack Caravanos

2. Topics
• 8.1 History
– Ancient Water Pollution Control
– Modern Regulatory History
• 8.2 Sources and Types of WP (EPA
categories)
• 8.3 Treatment (STW)
• 8.4 Health Concerns (global)
2

3. 3
8.2 Sources of Water Pollution
• Industrial Wastes (can be hazardous or
non-hazardous)
– Industrial wastes are often hazardous in
nature and require special treatment
• Municipal Wastes
– Municipal waste are more consistent &
treatment plants have been designed to
accommodate waste stream

4. 4
Point Source vs. Non-Point Source
Water Pollution
–Point source means are direct discharge
into receiving waters (e.g. a pipe)
–Non-point source refers to WP from either a
larger area or more diverse sources such
as run-off and atmospheric deposition (i.e.
you cannot point to a single source)

5. 5
Water Pollution Contaminants
• Oxygen Demanding Wastes
• Disease causing agents
• Synthetic Organic chemicals
• Plant Nutrients
• Inorganic chemicals and minerals
• Sediments
• Radiological chemicals
• Thermal Discharges

6. 6
Oxygen Demanding Wastes (aka
Biochemical Oxygen Demand)
• Agents added to water that remove oxygen and therefore cause waters to
become anaerobic
• Natural biodegradation process
• Pollutant + microbes + Oxygen → more microbes
• Reduction in Oxy levels change
ecology of water; may result in
large fish kills
• Anaerobic bacteria take over and
generate methane and odorous
hydrogen sulfide gas (swamp
gas)
• Human sewage has a BOD of
200 milligrams per liter, meaning
1 liter of human sewage will
remove 200 mg of O2 after 5
day. Food processing
wastewater has a BOD of 20,000
mg/l !!

7. Caravanos - Water Pollution 7
Disease causing agents (pathogens)
• Index Organism – Coliform Group
• Important US Waterborne pathogens
– Viruses – Hepatitis A, Rotavirus
– Bacteria – Shigella, cholera,
– Protozoa – Cryptosporidium,
– Giardia Llamblia
• See EPA Microbes website
• http://www.epa.gov/microbes
10
um

8. Caravanos - Water Pollution 8
Synthetic Organic Chemicals
• Non-aqueous (not
water soluble)
• BTEX (from gasoline)
Benzene, Toluene,
Ethylbenzene, Xylene
• Cleaning solvents:
perchloroethylene,
trichloroethylene

9. 9
Plant Nutrients
• Cause eutrophication, ie
accelerated biological
growth in surface waters
caused by excess
nutrient loading
• Usually phosphorous and nitrogen loading from human
inputs and agricultural runoff
• High algal growths on surface, blocking sunlight below
• Alters ecology of surface waters making them less
desirable as water supplies

10. 10
Inorganic chemicals and minerals
• Metals such as lead, copper,
zinc, arsenic can be
hazardous to your health
• Agents such as Calcium and
Magnesium cause Hardness.
These ions react with soaps
and detergents and reduce
their efficiency. They also
create “soap scum” and in
industrial boilers they cause
“scaling”. Questionable health
impact.

11. Caravanos - Water Pollution 11
Solids in Water / Sediments
• Many different classes
– Floatables – oils, greases, plastics
– Settleables – sand, grit, heavy solid particles
– Suspended solids – floating waste solids
(ultimately these will settle with time)
– Colloidal solids –very small solids that never
settle and cause cloudy conditions, “tea”
– Dissolved solids – salts, acids, sugars, metals

12. Caravanos - Water Pollution 12
Radiological Chemicals / Thermal Discharges
• Radiological chemicals: example tritium at
Brookhaven Laboratory
• Thermal Discharges: usually industrial and
power plant sources

13. Caravanos - Water Pollution 13