I suppose this can be the potential reason of Filter clogging. Actually, because of algae mass pH of raw water (river water) has increased to a large (pH About 8.2-8.4). Coagulant PAC (Poly Aluminium Chloride) does not work efficiently in this pH range. Nor high Chlorination was giving good results. So, we Applied Alum as Coagulant with high dose. However, turbidity of water is between 20-26 NTU Low. Now, it is working well better than before. Thanks for your comments Sir Regards

Published March 11, 2017 19:13 by Lokesh Kumar, Chartered Chemist, Assistant Chemist at Delhi Jal Board, Government of NCT Delhi (Formerly: Municipal Water Supply & Sewage Disposal Undertaking)

I suppose this can be the potential reason of Filter clogging.

Actually, because of algae mass pH of raw water (river water) has increased to a large (pH About 8.2-8.4). Coagulant PAC (Poly Aluminium Chloride) does not work efficiently in this pH range. Nor high Chlorination was giving good results.

So, we Applied Alum as Coagulant with high dose.

However, turbidity of water is between 20-26 NTU Low.

Now, it is working well better than before.

Thanks for your comments Sir

Regards