What is water pollution? Describe sewage pollution briefly.

Explanation

It's the undesirable change in physical, chemical and biological characteristics of water resources adversely affecting human health and life of animals.
The four main types of water pollution are,
- Sewage pollution
•Industrial pollution.
• Biocide pollution.
• Thermal pollution
• Sewage pollution : Sewage is a biodegradable pollutant concentrated with human feces, animal excreta, food residues, domestic wastes, detergents and several dissolved chemicals (sulphates, phosphates, alkalies, nitrates, acids). Sewage also contains pathogenic bacteria, eggs, cysts and spores of parasites. Sewage is discarded from homes, hotels, and choultries and hostels getting dumped constantly into nearby water resources like lakes, ponds, rivers and oceans causing water pollution.
Effects:
• Presence of sewage increases turbidity of water, which reduces solubility of oxygen and penetration of light, both of which adversely affect the photosynthetic and respiratory activities of aquatic organisms.
• Sewage water provides good breeding ground for mosquitoes and favours growth of pathogenic bacteria and parasites. Thus it forms a source for the outbreak of diseases like malaria, typhoid, cholera, jaundice and dysentery.
• Sewage dumping causes sudden nutrient enrichment resulting in plankton bloom This process is called eutrophication. It creates biological oxygen demand (BOD). and oxygen shortage to fishes, which suffocate to death.
To prevent these effects, sewage treatment should be done before letting it out.