a. Reduction of Plant size & space requirement of ETP (Effluent treatment plants) & STP (Sewage Treatment Plants) - Saving HUGE capital costs.
This is because the water is largely improved at the initial stage, along with drastic reduction of BOD & COD at inlet stage, hence the plant requirements are reduced hugely.
There are some nominal prerequisites of correcting some parameters like pH, temperature, etc before Ozonation, depending upon the kind of wastewater.
b. Reduction of MBBR sizes in Wastewater treatment plants - Saving HUGE capital costs & space requirements too. This is because the BOD Loading Rate is greatly reduced due to low levels of BOD obtained by Ozonization at inlet stage.
c. MBBR / SBR can be totally nullified for Sewage Treatment Plants (STP)
d.High Dissolved Oxygen levels (Reduced aeration / blower requirement)
e. No toxic residue created or left
f. Alkaline pH maintained
g. E-Coli reduction
... and many more.