Secondary Treatment

Secondary treatment focuses on biological carbon and nutrient removal from wastewater to comply with the effluent discharge limit. The secondary treatment process must meet increasingly stringent current and future water quality standards. In particular, existing treatment plants need to be retrofitted efficiently and economically in order to comply with the increasingly demanding water quality standards. 


Biological and Physical treatment in one reactor

The BBF process is an upflow biological filtration process utilizing specially designed floating EPP filter media. The patented EPP media has unique shape that optimizes the pore size to secure high concentrations of microorganisms, so that nitrogen and organic removal rate is high. Since biological treatment and physical filtration are carried out at the same time, the treated water quality is excellent even without a separate sedimentation tank.


Nitrification and Denitrification in one reactor

Nitrification, denitrification, nitrification/denitrification can be performed depending upon the method and location of the air supply. Thus, various process configurations can be achieved. When combined with existing treatment plants lacking HRT, BBF will perform nitrification while the existing treatment plant performs denitrification and removal of phosphorus.


for New facilities and retrofitting the old

bbf (new facilities)

bbf secondary new facility.png
  • Small footprint due to short HRT
  • No primary or secondary sedimentation basin necessary
  • o tertiary filtration required
  • Easily responds to hydraulic load fluctuations

bnr-bbf (retrofitting)

Current treatment plant (Phosphorus Removal, Denitrification) + BBF (Nitrification)

Current treatment plant (Phosphorus Removal, Denitrification) + BBF (Nitrification)

The heterotrophs (phosphorus and denitrifying microorganisms) and autotrophs (nitrifying microorganisms) can be operated in separate spaces with optimal SRT conditions. BBF can be adopted while the existing process is still in operation. If sludge sedimentation deteriorates during operation, it is possible to secure stable treated water quality through filtration of BBF.

BBF can be operated under nitrification, nitrification/denitrification modes, and is flexible with changes in regards to water quality and operating conditions.