Standard EDTA (ethylene diamine tetra acetic aciD. solution is used to determine the_______________?

A. 1/3
B. 2/3
C. 3/4
D. 1.0

A. inlet
B. manhole
C. drop manhole
D. catch basin

A. 10 to 15
B. 20 to 25
C. 30 to 35
D. 40 to 50

A. to increase the filtration slow sand filters capacity of
B. to increase the filtration rapid sand filters capacity of
C. for isolated buildings like pools, hotels etc swimming
D. all of the above