What are all the reasons for reduction in MLSS in STP?

In STP, MLSS level to be maintained is 3500mg/ ltr or 35%. For example if you are taking a sample water in a 1 ltr beaker, in 30 mins your sediment level should be till 350ml level. If sediment is not happening or floating till the top, it means bacterias are not matured. then you need to check the following: 1.. Indefinite temperature in the incoming water.( probably hot water is mixing nore) 2. Oil content is more than 10 ppm. It must be less than that. 3. Dissolved oxygen level must be between 3-5 ppm in the aeration tank. 4. Water TDS must be below 3000. 5. PH level must be between 7 – 9.

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