Is there some reason why the industry practice of dosing with sodium hypochlorite is not the case here for disinfection ? Glutaraldehyde is also used as an additional biocide where required.
Materials selection for the concentrated hypo solution for injection into supply caisson requires some attention to details.
Apparently some plants use Bromation process (Bromine Chloride, gaseous Bromine, Bromochlorodimethylhydantoin, Bromine salts), Ozone, Chlorine Dioxide, Hydrogen Peroxide, and the "MIOX" system:
Yes, there are other chemicals. Other disinfection processes too, such as UV.
However, there are no alternatives that are as cost effective as chlorine.
Ozone and UV are not recommended for cooling towers since there is no residual disinfection. These technologies would have to be used in conjunction with a disinfectant to maintain a residual.
Your chemical treatment program supplier should be able to provide some assistance.
I will throw chlorine dioxide out on the table as well but as bimr put it, they all come down to cost.
There are pluses and minuses with each method and sometimes several are employed as oxidizing and non-oxidizing biocides.
