Dear Zhengzhi Zhao, There ...

Dear Zhengzhi Zhao,

There are many points to focus for MLSS reduction in the Bio Reactor, you can make a check list as follows;

1) Inlet Water might containing any antibiotic (disinfectants like Chlorine), please check if any change for any new chemical usage in the Processing Area?

2) As you said, it is from Petrochemical Industry, any seepage/leakage of oil/petrol reaching to the Bio Reactor which inhibits Oxygen Transfer to Bacteria

3) RAS Pump is not sufficient or may be clogged not returning sludge properly

4) Temperature of the Bio Reactor is within the range (max. 37C), not increased?

5) If you are giving Air by Blowers/Piping Grid with Diffusers, please check if these are not chocked (this could easily be done by checking DO Level 2 - 4 mg/l in the Reactor)

6) Check Inlet Pollution Load, if it has sufficient to feed to bacteria, if COD is much less then you can add Jaggery (Sweet/Cane Sugar or else) for Bacteria to to have nutrients

7) Please check inlet/outlet wastewater characteristics if different then designed?

8) These could be the possible areas / checks to observe and rectify.

Hope this would be enough by now.