Water, Our Lifeline
Clean water that is fit for drinking is called potable water.
The three-fourth of earth’s surface is covered with water, it is not equally distributed in all the areas.
Water contains many dissolved substances like gases from air, bacteria, germs, soil particles, etc. waterworks makes water fit for drinking before it reaches us.
22nd March is celebrated as World Water Day to bring awareness amongst people for safe water, fit for human consumption.
On World Water Day, on 22 March 2005, the General Assembly of the United Nations proclaimed the period 2005–2015 as the International Decade for action on “Water for life”.
What is Sewage?
The water containing wastes from various sources is called sewage.
Sewage contains many dissolved and suspended impurities are called contaminants.
The various contaminants in the sewage are as follows:
- Organic impurities: These include human wastes, animal wastes, food wastes, soaps, detergents, pesticides, etc.
- Inorganic impurities: These include nitrates, sulphates, phosphates, metals, etc.
- Nutrients: These include nitrogen and phosphorous.
- Bacteria and other micro-organisms: These may cause diseases like typhoid, cholera, dysentery, etc.
If the sewage remains untreated, it can lead to many problems which can be summed up as follows:
- Untreated sewage contains lots of harmful bacteria, parasites, fungi, viruses, etc. that can cause infections and diseases.
- It contains lots of toxic chemicals that can kill marine life.
- Sewage from leaking sewer pipes can enter drinking water pipes and contaminate them.
- Untreated sewage may cause blockages in drains which encourage mosquito and fly breeding.
- It can lead to dirty and stinking surroundings.
A network or transport system consisting of sewers is called Sewerage.
Water Freshens Up — An Eventful Journey
The pipes which carry away wastewater or sewage from houses and other buildings are buried under the ground. An underground pipe that carries away dirty drainage water and waste matter is called a sewer.
The provision of drainage at a place by laying sewers under the ground is called sewerage.
Sewerage is an underground network of interconnected pipes called sewers that carries the sewage from the place where it is produced to the sewage treatment plants, where it is processed.
Manholes: A manhole is a covered vertical hole in the ground, pavement, or road, above the underground sewer pipeline through which a worker can go down up to the sewer pipes for inspection, cleaning, etc. Manholes are provided at every 50-60 m distance in the main sewer pipeline.
Wastewater Treatment Plant (WWTP)
Steps of Wastewater Treatment Plant:
- Screening
- Grit and sand removal tanks
- Sedimentation tanks
- Aeration
Screening: This is the first step in which wastewater is passed through bar screens to remove large objects like rags, wood pieces, sticks, stones, etc.
Sedimentation tanks: Water is now allowed to pass through large tanks called sedimentation tanks. These tanks are large enough so that organic solid matter like feces sinks slowly to the bottom and materials like grease and oil float at the surface and are skimmed off.
The organic solid matter collected at the bottom of the sedimentation tank is called sludge which is continuously removed by scrapers.
The sludge collected is sent to separate tanks called digesters where it is broken down by anaerobic bacteria and biogas is released.
Aeration: The clarified water is passed into an aeration tank which contains aerobic bacteria. These bacteria rapidly grow and consume organic matter like human and animal wastes and convert it into carbon dioxide. The suspended microbes settle down at the bottom as activated sludge. Water is removed from the top and safely discharged into the rivers or lakes.
The sludge is then separated from the water with the help of a Scrapper.
The sludge so obtained is passed into a tank where anaerobic bacteria can decompose it and produce biogas. The biogas is then used as fuel.
Wastewater includes biological, physical and chemical matter and hence involves biological, physical and chemical processes of removal of the contaminants.
Better Housekeeping Practices
Used oils and fats should not be poured into the sink which may choke the pipes. We should always throw oils and fats in the dustbin as in an open drain the fats clog the soil pores and the filtration of water.
Many household chemicals like paints, motor oil, insecticides, etc. should not be allowed to go down as these are very toxic and harmful to both humans and microbes.
Used tea leaves, solid food remains, soft toys, cotton, sanitary towels, etc. should also be thrown in the dustbin which may choke the drains as it does not allow the free flow of oxygen and thus hamper the degradation process by microorganisms.
Sanitation and Disease
Poor sanitation and polluted drinking water can lead to many diseases.
Sanitation refers to the health conditions of people related to the disposal of sewage, human excreta, and the provision of clean drinking water.
Contaminated water and poor sanitation practices are the major causes of the number of infectious diseases in our country.
Safe sewage disposal facilities are still not available in many cities and villages in India. So, people go to open places and defecate. This causes an increase in the insect-vector population which transmits diseases like cholera, typhoid, meningitis, etc.
Vermi-processing Toilets: In the vermi-processing toilets, human excreta is treated by earthworms in a pit. The earthworms usually eat up all organic matter present in human excrete and turn it into compost. These are tow water-use toilets for the safe processing of humans.
Alternative Arrangement for Sewage Disposal
Low cost outside the sewage disposal system has been developed to take care of places where there is no sewage system, e.g. rural areas, and isolated buildings.
Septic tanks: Septic tank is a low-cost onsite sewage disposal system. Septic tanks are suitable where there is no sewerage made. These tanks need cleaning every four to six months.
Composting pits: These are self-sustained human waste disposal units that are not connected to a sewer line or a septic tank. A composting toilet breaks down and dehydrates human waste to compost.
Chemical toilets: These toilets have limited storage capacity for human waste and need to be emptied periodically. These are the toilets that use a chemically treated reservoirs located just below the toilet seats.
Sanitation at Public Places
There are numerous places in our country which are very busy such as airports, railway stations, and bus depots.
Many times large gatherings such as fairs and festivals are also organized where a large number of people visit. This results in the generation of large amounts of waste and if the waste is not treated properly it can lead to several diseases and even an epidemic.
If we adopt certain practices in public places we can help in maintaining their sanitation, for instance:
- We should not throw garbage in public places and always use dustbins.
- We should not spit around in a public place.
