Contents
From biotechnology to bioethics, Biology Topics have significant implications for society as a whole.
What are the Alternative Sewage Systems?
Name and describe an alternative arrangement for sewage disposal where there is no sewerage system.
In order to improve sanitation and prevent water-borne diseases, low-cost, onsite sewage disposal systems are being encouraged for those people who do not have sewerage facilities. The examples of onsite sewage disposal systems for human waste are:
- Septic tanks
- Composting pits, and
- Chemical toilets. These are the arrangements for the hygienic disposal of human waste (or human excreta).
Septic tanks and composting pits are called ‘onsite’ sewage facility because they treat the sewage close to the place where it is generated (and not carried elsewhere). Septic tanks and composting pits provide us toilets (or lavatories). We will now discuss all the alternative arrangements for the disposal of human waste briefly.
1. Septic Tanks (or Septic Tank Toilets)
A septic tank usually consists of a big, covered, underground tank made of concrete having an inlet pipe at one end and an outlet pipe at the other end (see Figure). The toilet seat is connected to the inlet pipe of the septic tank. The human excreta from the toilet seat enters into the septic tank through the inlet pipe. The solid part of excreta keeps on collecting at the bottom of the septic tank in the form of a sludge whereas watery waste remains above it (see Figure). The anaerobic bacteria break down most of the solid organic matter present in human excreta due to which the volume of solid waste is reduced too much.
The digested solid waste keeps on depositing at the bottom of septic tank. The watery waste is also cleaned by anaerobic bacteria. The excess water goes out of the septic tank through the outlet pipe and gets absorbed in the soil. Septic tanks (or septic tank toilets) are suitable for those places where there is no sewerage system. Septic tanks are suitable for providing toilet facilities to single houses, a cluster of 4 or 5 houses, and other isolated buildings (where sewer lines do not exist for carrying away human waste). A septic tank works for a fairly long time after which it has to be cleaned.
In our villages, biogas (or gobar gas) is produced from cattle dung (or cow dung). The human waste (or human excreta) can also be used in a biogas plant (alongwith cow dung) for making biogas. So, in many villages, human excreta from the toilet seats in the homes flows directly into biogas plant through covered drains, The biogas produced is used as a fuel. Thus, the use of human excreta in biogas plants is another way of safe disposal of human waste (where sewers are not available).
Composting Pits (or Composting Toilets)
Composting pits are used to provide composting toilets. A composting toilet is a self-contained human waste disposal unit which is not connected to a sewer line or a septic tank. A composting toilet breaks down and dehydrates human waste to a compost (or manure) which can be added to soil to make it fertile. A composting toilet consists of a toilet seat fixed atop a composting chamber which is further connected to a drying chamber.
The composting chamber breaks down the human excreta with the help of aerobic micro-organisms (such as aerobic bacteria) and converts it into a compost. The drying chamber allows the moisture to escape from compost and make it solid. This solid compost is removed periodically and used as a manure. The composting toilets are used where the water supply is limited or not available at all. An advantage of these toilets is that they supply us compost (or manure) and hence help in conserving useful plant nutrients. A composting pit toilet treats the sewage close to the place where it is generated.
Chemical Toilets
A chemical toilet uses a chemically treated reservoir located directly below the toilet seat. The chemicals reduce the odour (foul smell) coming from the human waste and carry out partial disinfection of the human waste. Chemical toilets have a limited storage capacity for human waste, so their reservoirs need to be emptied into a sewer line after a certain time. All the portable toilets are chemical toilets. They can be shifted from one place to another. Chemical toilets are used at construction sites, and at large outdoor gatherings such as music festivals and marriages, etc. The portable chemical toilets are, however, not low-cost toilets.
Vermi-Processing Toilet
In the vermi-processing toilet, the human excreta is treated by earthworms in a pit. The earthworms gradually eat up all the organic matter present in human excreta, decompose it and pass o.ut from their body in the form of worm castings (also called vermi-cakes). The vermi-cakes are a kind of high quality manure which can be added to soil for growing plants. The vermi-processing toilet is a low water-use toilet for the safe processing of human waste. A design of the vermi-processing toilet has been tested successfully in India.
Toilets in Aeroplanes
The aeroplanes have special type of toilets called Vacuum toilets’. So, the human excreta (or sewage) in an aeroplane is disposed of through vacuum toilets. When we flush the toilet in an aeroplane, then a valve opens in a pipeline which has vacuum inside it. The vacuum in the pipeline sucks the human excreta from the toilet seat with a great force (making a loud noise), and carries it into a tank on board the aeroplane. When the aeroplane lands at an airport, then the tank containing all the human excreta is emptied into a sewer line in the ground through connecting pipes.
From the above discussion we conclude that it is possible to have safe disposal of human waste (or human excreta) through low-cost , onsite sewage disposal systems such as septic tanks, composting pits and vermi- processing toilets. So, at those places where underground sewerage system is not available, these low-cost, onsite sewage disposal methods can be adopted for the safe disposal of human waste and prevent the contamination of surface water and groundwater. This will save the people from many water-borne diseases.
Sanitation At Public Places
If we go to a railway station, a bus depot, an airport, a hospital, a cinema hall, a market place or a park, we find that all these places are crowded with a large number of people. In fact, thousands of people visit these public places daily. So, a large amount of waste is generated at all these places everyday. Similarly, in our country, fairs and exhibitions are organised regularly in many areas.
A large number of people also visit these fairs and exhibitions, and generate a lot of waste there. Poor sanitation in crowded public places can result in the spread of diseases. So, all the waste materials produced at public places must be disposed of properly. If all the wastes produced at public places are not disposed of regularly and properly, even epidemics could break out (An infectious disease that spreads quickly through a large part of the population, is called an epidemic).
It is the responsibility of the Municipality of the area to maintain sanitation (hygienic conditions) at public places but we can also contribute in this effort. We can contribute in maintaining sanitation at public places by observing some simple practices given below:
- We should not scatter rubbish such as paper, food wastes, packets, empty plastic water bottles, etc., in public places. The rubbish should be put in dustbins provided for this purpose. If, however, a dustbin is not available at a public place, the rubbish should be carried home by us and thrown in the dustbin.
- We should not spit in public places.
- After eating a banana, we should not throw banana peels on the roadside or any other public place,
- We should never urinate on the roadside.
Become an Active Citizen
The generation of waste is an essential part of human activities. But we can limit the type of waste and quality of waste produced. We can also help in the proper disposal of wastes. One of the biggest eye-sore around us are the open, dirty water drains. The sight of open drains is disgusting. We often feel suffocated by the foul smell emitted by the stinking dirty water drains when we happen to pass near them. The situation worsens in the rainy season when the dirty water drain starts overflowing (because of rainwater entering into it), and we have to wade through mud and dirty drain water which collects on the roads. The open drain system creates the most unhygienic and unsanitary conditions in its neighbourhood. Open dirty water drains are breeding places for flies, mosquitoes and other disease-causing organisms.
We can become an active citizen and approach the Municipality (or Gram panchayat) and insist that the open dirty water drains in our area be covered at the earliest. The covering of open drains will make the environment healthy which will be free from disease-causing organisms. If the sewage of a particular house leaks from the pipes, spills on the road and makes the neighbourhood dirty, we should ask the house owner to be more considerate about other’s health and get the leakage of sewage rectified.
All of us have a role to play in keeping our environment clean and healthy. Adopting good sanitation practices should become our way of life. It will keep all of us healthy and happy.