A little description about sewage pollution

1. By Saptarshi Das
IX-A
Roll no. 37

2. SO WHAT IS POLLUTION?
• Pollution is the introduction of contaminants
into the natural environment that cause
adverse change. Pollution can take the form
of chemical substances or energy, such as
noise, heat or light. Pollutants, the
components of pollution, can be either
foreign substances/energies or naturally
occurring contaminants.

5. ORIGINS OF SEWAGE
• Sewage is generated by residential, institutional, commercial and
industrial establishments.
• It includes household waste water from toilets, baths, showers,
kitchens, sinks and so forth that is disposed off via sewers. In
many areas, sewage also includes liquid waste from industry and
commerce.
• Sullage is applied to waste water which does not contain human
excreta e.g. Waste water from bathroom and kitchen.
[Sullage is waste water from household sinks, showers, and baths, but
not waste liquid or excreta from toilets.]

6. Causes of Sewage Pollution
 Domestic sewage - It is waste water generated from household
activities.
[sewage also includes liquid waste from - industry & commerce].
 Domestic sewage water contains -
 - Organic materials & inorganic materials such as - phosphates &
nitrates.
 Organic - from food & vegetables & inorganic - from soaps &
detergents.
 Improper handling of waste water is the main reason behind pollution.
EFFECTS:-
 Spreading of diseases - Pathogenic micro-organisms enter the water
system through sewage and the bacteria & viruses may cause - malaria
& typhoid.
 BOD [Biological oxygen demand] increases through sewage water
pollution.
[BOD is a measure of oxygen utilized by micro-organisms during
oxidation of organic matter. Higher the amount of BOD, more polluted
is the water.]

7. EFFECTS (contd.)
• Waste water and sewage from various sources may carry
pathogenic organism that can transmit disease to humans and
other animals. Sewage also contains organic matter that can cause
odour and nuisance problems of receiving water bodies, and can
lead to eco toxicity. Also there is an economic loss as sewage
discharged in water bodies makes it unfit for agricultural and
drinking purposes.
• NOTE : Ecotoxicity is the subject of study of the field of
ecotoxicology which refers to the potential for biological, chemical
or physical stressors to affect ecosystems.
• Sewage-contaminated water causes eutrophication, which is the
increase in concentration of chemical elements required for life.

11. AN UNSPECIFIED NUMBER OF RESIDENTS LIVING
DOWNSTREAM OF THE SPILL WHO DRAW THEIR DRINKING
SUPPLIES FROM THEIR PRIVATE WELLS HAVE REPORTED
WATER DISCOLORATION.
SEWAGE POLLUTION SPOILS SOUTH COAST

12. An image of untreated sewage being
discharged into a water body.