Municipal Wastewater

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.

Selection of sewage treatment process is affected by discharge standards, raw wastewater quality, and local (site) constraints. Tomorrow Water does not provide a simple unit technology but a well-balanced process after considering the various constraints of the site and the needs of clients. 

In particular, existing treatment plants need to be retrofitted efficiently and economically in order to comply with the increasingly demanding water quality standards. 

  • Small footprint due to short HRT

  • No primary or secondary sedimentation basin necessary

  • No tertiary filtration required

  • Easily responds to hydraulic load fluctuations


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.

Since the BBF process is a submerged attached growth process, it is suitable for sewage with relatively low concentration and high fluctuating flow rate. It is possible to construct a compact structure when the existing plant has limited space for expansions. BBF can perform stable nitrification even at low temperature, making it a suitable process for areas where there is concern for decreased efficiency due to cold temperatures.

Secondary for New Facilities