Tag: water pollution

Let us now study the causes of water pollution:

1. Industrial waste

2. Sewage and waste water

3. Mining activities

4. Marine dumping

5. Accidental Oil leakage

6. Burning of fossil fuels

7. Chemical fertilizers and pesticides

8. Leakage from sewer lines

9. Global warming

10. Radioactive waste

11. Urban development

12. Leakage from the landfills

13. Animal waste

14. Underground storage leakage

Fresh water is naturally occurring water on Earth's surface in ice sheets, ice caps, glaciers, icebergs, bogs, ponds, lakes, rivers and streams, and underground as groundwater in aquifers and underground streams.

The definition of freshwater according to The United States Geological Survey is water containing less than 1,000 milligrams per liter of dissolved solids, most often salt.

The water temperature should preferably standard temperature or room temperature for balanced ecology. Hence, it should be preferably less than 25 degree Celsius. 

Water pollution is the contamination of water bodies (e.g. lakes, rivers, oceans, aquifers and groundwater). This form of environmental degradation occurs when pollutants are directly or indirectly discharged into water bodies without adequate treatment to remove harmful compounds. Agricultural discharges, sewage and other wastes and industrial effluents all cause water pollution.

Explosive growth of plants and algae is a response to the addition of excess nutrients, mainly phosphates, which induces, the decaying of which consumes oxygen from the water causing water pollution. Phosphates are among the major nutrients that is required by plants for growth. 

Biochemical oxygen demand is the amount of dissolved oxygen needed by aerobic biological organisms to break down organic material present in a given water sample at certain temperature over a specific time period. The BOD value is most commonly expressed in milligrams of oxygen consumed per litre of sample during 5 days of incubation at $20^{\circ}C$ and is often used as a surrogate of the degree of organic pollution of water.

BOD is similar in function to chemical oxygen demand (COD), in that both measure the amount of organic compounds in water. However, COD is less specific, since it measures everything that can be chemically oxidized, rather than just levels of biodegradable organic matter

In general, all common methods of sewage purification use sedimentation processes by which solids (sludge) sink to the bottom – in some cases this primary sludge is removed for further treatment.

After this comes the secondary or biological treatment of sewage purification, this involves biological processes and the use of microorganisms that “eats” away a lot of the hazardous contaminants. Use of oxygen by various implementation techniques is very important.

After the secondary stage of sewage purification comes final settlement of biological solids and then a tertiary treatment that removes even better the rest of the biological and organic materials in the water. 

Potassium permanganate is an inorganic chemical compound and it is a strong oxidizing agent. Potassium permanganate is used in water treatment to remove odor-causing compounds and is also used to remove iron and manganese in water.

Sodium carbonate, $Na _2CO _3$, is also known as washing soda. It can remove temporary and permanent hardness from water. Sodium carbonate is soluble but calcium carbonate and magnesium carbonate are insoluble. The water is softened because it no longer contains dissolved calcium ions and magnesium ions.

Factors responsible for the depletion of water table-