to increase the filtration slow sand filters capacity of

to increase the filtration rapid sand filters capacity of

for isolated buildings like pools, hotels etc swimming

all of the above

(i) and (ii)

(ii) and (iii)

(i) and (iv)

(ii) and (iv)

removal of turbidity

removal of hardness

killing of disease bacteria

complete sterilisation

only (i)

both (i) and (ii)

both (i) and (iii)

only (iii)

applied chlorine

residual chlorine

sum of applied and residual chlorine

difference of applied and residual chlorine