Dear Safie,

The best way to achieve the numbers you indicated is to purchase membrane bioreactor (MBR):

In a conventional wastewater treatment plant, the secondary clarifier limits the solids concentration in the aeration tank. Typical mixed liquor suspended solids (MLSS) concentrations are 1,500 mg/l to 5,000 mg/l. The MBR replaces secondary clarification in a conventional wastewater treatment plant.

MBRs separate biologically treated effluent from the mixed liquor utilizing membranes to perform the separation. The membranes allow the purified water to pass through the pores (filtrate), while creating a complete barrier to the passage of any solid greater than 0.4 microns, which includes almost all bacteria and suspended solids. In an MBR, the membranes create a solids barrier and therefore the process is not subject to gravity settling solids limitations, as in conventional clarifiers. MBRs are limited instead by the fluid dynamics of high solids mixed liquor, and the effect on oxygen transfer. Typical MLSS concentrations in MBR systems are 10,000 mg/l to 12,000 mg/l.

For more on this topic, please use the following link:

https://encrypted.google.com/search?newwindow=1&q=related:https://www.gewater.com/kcpguest/documents/Technical%2520Papers_Cust/Americas/English/TP1037EN.pdf+to+increase+MLSS+in+aeration+tank+from+5000+mg/l+to+12000+mg/l&tbo=1&sa=X&ved=0ahUKEwjKgKy1h-nNAhUHyRQKHeVDCSMQHwghMAA

Hoping this will be helpful,

Rafik

Dear Safie,

I agree with Rafik's answer. Another option is to use degasification of mixed liquor in vacuum conditions between the bioreactor and secondary clarifiers. This way you can reach MLSS concentrations betweem 6000 & 9000 mg/l. Anyhow without a major investment it is close to impossible to achive 12 000 mg/l in a traditional activated sludge system.

Best regards, Jan

I agree with the previous colleagues regarding to use membrane bioreactors in orde to achieve high concentrations of biomass on the reactor itself. However, clogging should be closely evaluated because on or in the membrane there is a accumulation of biomass.

Best wishes

Luis Cumbal

 Dear Safie,

Salam,

In addition to the Membrane Bioreactors which are really high-efficient, you can use innovative biotechnological-based processes like bio-augmentation as well. In these processes, you can add some types of microorganisms with high growth rate. Of course with this method, reaching to 12000 mg/L of MLSS seems a little ambitious but I think the MLSS will  increase dramatically compared with alone activated sludge. And you should take care of competition between native microorganisms and alien ones.

Good luck.

Mehran

Dear Madam,

You can increased by increasing retention time of the waste water, increasing also the quantity of  substrate for microbial utilization.

thank you so much Mr Tesseme

Respected seniors,

I am currently working on a wastewater treatment plant.

I am stuck in some problem at the aeration tank as its sv is increasing while the mlss is relatively low. This gives an SVI of near about 200 and is very high.

Need some suggestions related to this issue that how we can cover this?

Dear Safie,

You can increase MLSS by concentrating the liquid with maximum part of cow dung slurry and small amount of water in the mixture which can be utilized as feed. Second thing is to add specific microbes with the cow dung slurry which may enhance the concentration of solids in the effluent..

You can reach an effect similar to having af MLSS of 12 g/L by converting from activated sludge to suspended biofilm system, MBBR. The biofilm is retained in the aeration tank and thus one can achieve higher biomass density.

MLSS can be increased by adding part of cow dung slurry.

Macro nutrients ,Micronutrients which supports the microbial growth may be added.

adjust ph , tem, food , and return sludge 100% it will accur very soon

By providing micronutrients.

How to control the brown colour foaming in aeration tank...?

Some cow dung slurry and little amount of sugar and aerate for fast growing MLSS