Ariyadasa, P. G. S. H; Wahala, W. M. P. S. B; Gunawardene2, R
(Belihuloya, Faculty of Management Studies, Sabaragamuwa university of Sri Lanka, 2016-10-10)
The survival of the organisms in the earth will depend on three factors, Water, Air &
food. Among these three, water is more important. With the increasing of population
and industrial activities the demand for the ...