1. Impurities in
Wastewater & Problems
Caused by It
By:
Nikhil Sharma
BE/8034/09

2. What is Waste Water?
Wastewater is any water that has been adversely affected in quality
by anthropogenic influence.
It is usually produced from by-products of otherwise purposeful
human activities.
Classification:
Industrial Waste Water
Waste Water
Sewage (Domestic
Waste Water)

3. Wastewater quality indicators or how to determine
the quality of the waste water?
The BOD5 test:
BOD measures the rate of oxygen uptake by micro-organisms in a
sample of water at a temperature of 20°C and over an elapsed period
of five days in the dark.

4. Origins:
•Human Waste (Blackwater)
•Surface Runoff:
•Detergents
•Disinfection by-products
•Insecticides and herbicides
•Petroleum hydrocarbons
•Ammonia from food processing waste
•Fertilizers containing nutrients(Nitrates and Phosphates)
•Heavy Metal Industries
•Thermal Power Plants (Heated Water)
•Nuclear Power Plants
•Deep Sea Mining
•Oil Spills
•Heavy Metal Mining

5. Consequences:
•Ocean Acidification: Oceans are carbon sinks but cannot cope
with increase in CO2 .
•Eutrophication
•Bio Magnification/Bio Accumulation
•Increase in BOD (Biochemical Oxygen Demand)
•Marine Debris
•Still Water Bodies
•Reduction of natural reserve of potable water Fig: Acidification of the
ocean has caused the
fringing of coral reefs in
the Maldives
Fig: Direct discharge of
Fig: Polluted Lagoon Fig: Marine Debris
heavy metals to water
bodies

6. Problems Arising:
•Toxic waste reaches humans through animals upon consumption.
•Great loss of wildlife.
•Spread of water borne diseases. (ex. Malaria,Cholera,Jaudice,etc.)
•Excessive water treatment required before water is fit for
consumption
•Pressure on groundwater reserve leading to decrease in water
table.
•Presence of choliform microorganisms leading to health problems
•Consumption of heavy metals (Hg,Pb,As,Cd,Ni) causing birth
defects and other disorders (ex. Mercury causes Mina Marta, Lead
causes Akai Akai
•Oil spills lead to many complications in marine animals and life
directly or indirectly dependant on it

7. Methods of Control:
•Oil spill (coordinated cleanup)
•Domestic sewage treatment plant
•Bacterial Treatment

8. Fig: Dissolved Air flotation
System
•Industrial waste water treatment plant
•Cooling ponds: Through evaporation, convection, and radiation
•Dissolved air flotation system
•On site water treatment plant for large industries

9. The End