Dear Zyaad, The scum is a ...

Dear Zyaad,

The scum is a normal phenomena floating in the secondary clarifier. Please explain if you have tube/lamellar settlers or normal circular clarifier woth bottom scrapper.

If you have lamella/tube settlers then no need to worry about removing this scum as this will be beneficial in having a cleaner outlet water from weirs. However you can remove manually (simply using floor washing wiper with gentle hands) after every two weeks or so if you have a scape point made for this. Otherwise use swimming pool cleaning net with long rod to clean it.

If you have circular clarifier with bottom scrapper then just simply make adjustment on the moving arm by putting rubber to skim out or guide the floating s to a scape point or use simple swimming pool cleaning rod with net.

Also you need to look into if MLSS in you aeration are increased then or SV is increased then increase WAS flow rate to adjust and decrease RAS ratio.

Please do any of the above will solve your problem.

Best regards

Mansoor Ahmed