EfloCT- Extended Aeration - Sewage Treatment Plant

EFLO CT is a biological treatment plant based on extended aeration.   The CT stands for Constant Transfer.  This was one of the earliest treatment plant designs made by Eflo and they were exported to many countries from the early 1970s.


Click here to download the EfloCT Extended Aeration Brochure  Ver 1.4


All waste water treatment plants receive varying flow rates, generally in several peaks during the day and the night time flows being low.     The plant design must cater for these peaks which may be 3 - 6 times the average flow rate.     This means much of the plant has to be designed for the peak flow rather than the average flow, meaning bigger aeration tanks and a bigger settlement tanks.


Eflo CT New Brochure pic 2.jpg


By fixing the flow rate from the Aeration Tank to the Settlement Tank, it means the Settlement Tank can be designed and sized on the fixed flow rate - or the Constant Transfer Rate, the CTR.    If the CTR is set at a little over the average flow rate, then the size of the Settlement Tank becomes smaller and more economical.   Eflo invented the Constant Transfer concept.


Extended Aeration Packaged Sewage Treatment Plant

Eflo located their screens as part of the Constant Transfer Unit.   In this way, the screenings collected are washed and biologically scrubbed in the aeration tank.    The screenings are in a more acceptable state for handling and disposal.

By using a fixed CTR, at times of low inflow to the plant, the Aeration Tank water level will fall, creating a huge capacity for the next peak inflow.  By careful design, the Aeration Tank can become a very effective "balancing tank”.


The EfloCT extended aeration process is a well proven,  remarkably simple, stable and robust.  The EfloCT can be shipped in complete knock-down form and quickly erected on the simplest of foundations.    The capacities are from 100 m3 per day upwards to municipal sized plants. 


The EFLO CT is also used for industrial waste water. Examples include food processing, slaughter houses, & agriculture.

The EFLO CT can be installed above or below ground, using pre fabricated steel tanks or locally build concrete tanks.

Extended Aeration Packaged Sewage Treatment Plant



Link back to Sewage Treatment

©  Eflo International Ltd -  Est 1972                                                             Site map                                                                            Updated:   7th Dec 2016