Aeration troubleshoot or Solution of Aeration sludge bulking and slow settling

Hello friends,
Sometime we faces problems at our ETP plants related to less settling rate of Activated sludge/biomass in Aeration Tank and Secondary clarifier. Due to which this activated biomass overflows from Secondary clarifier to Filter feed tank and creates filtration issue or to meet pollution control board norms. Now how we can troubleshoot this problem.
This problem mainly occur due to in sufficient nutrients presence in Aeration tank or growth of Filament bacteria’s. This problem generally occur in summers when temp. reaches above 35°C.
To solve this problem we have to add. Nitrogen and phosphorous nutrients in Aeration tank and continue we have to check settling rate in measuring cylinder. We have to maintain Phosphate above 0.5 ppm and nitrogen 1 ppm. We may also add iron compounds such as ferric chloride or ferrous sulfate for chemically bind the sulfide, making it unavailable for the microorganisms.
Nutrients supply to Aeration tank should be at every 4-6 hrs interval. This problem will be resolved with 14 days and after 7 days you will see that settling rate is improved and mlss is maintained.