Rapid migration of people from rural to urban areas creates problems in
terms of water consumption and water quality . Stress on water resources
is oftentimes increased in order to supply for a greater population .
Urban environments also produce a large amount of wastes , which in some
large poorer cities are directly discharged into water systems . Even
countries with effective sewage treatment systems still contribute to
water pollution through non-point sources such as urban run offs .
Wastes coming from urban areas create three kinds of water pollution :
organic pollution , chemical pollution and heat pollution . Organic
pollutants are generated by sewage treatment plants and other effluents
rich in decomposable material . These kind of pollutants affect the
water in three ways : depletion of the water 's oxygen content , promotion
of eutrophication and introduction of pathogenic microorganisms .
Chemical pollutants include nitrogen-derivatives , trace elements and
chlorinated solvents , which have deleterious effects on the health of
humans and aquatic organisms . Heat pollution is generated by
infrastructures and shallow ponds that both absorb and store the sun 's
heat during the dry season and produces warm water during a storm .
Increased water temperature could lead to the disappearance of sensitive
aquatic species .
The use of technology facilitates the prevention of continued water
pollution . Organic pollutants can be removed by the use of effective
wastewater treatment systems . Chemical pollutants are addressed by the
use of physico-chemical processes such as precipitation , adsorption , ion
exchange and membrane filtration .
Water quality management strategies are the answer to the world 's need
to prevent degradation and enhance water quality . These strategies
include designation of the uses of water bodies in order to formulate
water quality criteria for these water systems the creation of water...