a)What would be the advantage of placing softening before cascade aeration?

(Only one answer can be correct).

Low oxygen concentration /Less pumping phases /High ammonium concentration /Less carbondioxide removal during cascade aeration

b)
What would be the disadvantage of placing softening before cascade aeration?

More energy consumption/ More use of chemicals /More pellet production/ More maintenance

c)Which (one) water quality parameter is reduced by powdered activated carbon?
Ammonium /Nitrite/ Nitrate /Chloride /Total iron /Oxygen /Carbon dioxide Temperature/ Hardness/ pH /Pesticides

2 answers

a) Less pumping phases

b) More use of chemicals
hi I don't know the answers where can I found them please?/