(b)     Sanitation at public places :    In our country fairs are organised periodically. A large number of people participate in them. In the same way railway stations, bus depots , airports , hospitals are very busy places. Thousands of people visit them daily.                 Large amount of waste is generated here. It must be disposed off properly otherwise epidemics could break out.
        The government has laid down certain standards of sanitation but, unfortunately, they are not strictly enforced.
        However, all of us can contribute in maintaining sanitation at public places. We should not scatter litter anywhere. If there is no dustbin in sight, we should carry the litter home and throw it in the dustbin.

(c)     Vermi - processing toilet : A design of a toilet in which humans excreta is treated by earthworms has been tested in India. It has been found to be a novel, low water-use toilet for safe processing of human waste. The operation of the toilet is very simple           and hygienic. The human excreta is completely converted to vermi cakes-a resource much needed for soil.

                                          Key words

1.    Aeration : Air is pumped to clarified water to help aerobic bacteria to grow.
2.    Aerobic bacteria : Those bacteria which require oxygen to live are called aerobic bacteria.
3.    Anaerobic bacteria : Those bacteria which can survive without oxygen are called anaerobic bacteria.
4.    Biogas : It is a gaseous fuel, which is produced by the fermentation of  organic matter.
5.    Contaminants : The harmful substances which have dissolved and suspended as impurities are called contaminants.
6.    Saintation : The proper disposal of sewage and garbage from the houses or nearby areas is callled saintation.
7.    Sewage :Sewage is wastewater released by homes, industries, hospitals, offices and other sewers.
8.    Sewers: The network of big and small pipes to carry wastewater to treatment plant is called sewers.
9.    Sewerage : Drainage system of sewers.
10.    Sludge : Solids like faeces which settle at the bottom of a large tank and are removed with a scraper are called sludge.