Activated Sludge Process

Seek local, professional help, soon.

Throw in 50 kilos of dog food, to give the good-guy bacteria something to chew on.

You need to review the process waste water segregation of the tannery like chroming, sulphide treatment baths washings etc.

Another major important factors are temperature of the effluent not to exceed 40 degrees Centigrade, Extreme pH values of the effluent say too acidic or too alkaline.

If you have any primary treatment please mention the type of coagulants your plant is using & level of color & turbidity of primary clarifier exit water.

Very high salinity levels can also be a bothering factor, which may hinder bacterial growth.

Details of process of tanneries , inclusions & exclusions, segregation & above mentioned points are critical factors.

Your open details perhaps can bring forth inputs to the solution discussion.

If you need to increase dissolved oxygen level, I don't think liquid O2 is the way to go. Think about the goldfish in your fish tank - you don't add liquid O2; you use a bubbler pushing a lot of little air bubbles into the water. Suggest you try a larger "bubbler" to increase dissolved O2 in the "water". And you want lots of little bubbles, not a few big ones so there is more overall surface area to allow the O2 to dissolve into the water.

There's not enough information presented to make any determination.

Complete Mix or Plug Flow Activated Sludge process?

F/M ratio? Nitrogen and Phosp. Concentrations? Are you sure that your microbes are getting enough nutrients?

Return Activated Sludge Return Ratio and rate from the Secondary Clarifier?

Type of aeration disc? Fine or coarse bubblers? Have they been lifted and cleaned of any clogging recently? Induced air rates?

What does the biomass look like under the microscope? Has anyone done this yet?

Is there any evidence of high constituent concentrations such as heavy metals and/or chemicals in the waste stream that would case such a disruption?

MLSS? MLVSS? VSS?

DO values?

Mean Cell Residence times?

I could go on and on with questions....