EfloSAF - Submerged Aerated Filter - Sewage Treatment Plant

The EfloSAF Submerged Aerated Filter or SAF,  is a very compact, robust and trouble free process ideally suited to package type plants for communities and labour camps.  The process employs a structured,  support media and this forms an ideal place for the biomass to attach itself.  The waste water then passes through the matrix where the biomass consume the organic matter.  


Download the Brochure here   EfloSAF Brochure Ver 1.20

SAF Submerged Aerated Filter packaged sewage treatment plant

EfloSAF 1000 - ECS at International City, Dubai, 1000 m3/Day - Prefabricated Steel Tank Work


The media a non clogging structure, fixed in place and with a very high surface area for the volume it occupies.   It sits submerged in the biozone.   The water passes through the cross fluted media in a very precise manner, flowing through every part ensuring excellent contact with the biomass.


Air in introduced underneath and the media ensures very high oxygen transfer rates, allowing for small air blowers and reduced running costs. After the biozone a standard settlement tank is used to clarify the water of any biomass that has detached itself from the support matrix.  The is no requirement for a sludge recirculation system.


SAF Submerged Aerated Filter packaged sewage treatment plant

EfloSAF Biozone Support Media 


SAF Submerged Aerated Filter packaged sewage treatment plant

EfloSAF Biozone Support Media - Enlarged view showing high specific surface area to support biomass growth in the biozone


EfloSAF Biozone Flow Pattern - Cross section schematic showing the water flow pattern within the biozone.  The careful placement of the air sparge pipes deliver diffused air with a very high oxygen transfer efficiency, close to fine bubble air diffusion.   Above the air sparge pipes, the water flow is ‘air-lifted’ and then allowed to gravitate down, causing a circular, fully mixed flow within the biozone.

The water flow pattern provide excellent contact between the water and its nutrients and the biomass attached to the media.   A further benefit is a very long sludge age, partial de-nitrification, low sludge production and low energy consumption.


The plant does not need constant operator attention and is happy to run in automatic mode for extended periods. 

SAF Submerged Aerated Filter packaged sewage treatment plant


EfloSAF plants deliver a very high quality of effluent to meet the highest standards specified, including a fully nitrified TSE.


The EfloSAF attached growth technology can be added to existing plants to upgrade the final effluent, in particular for plants suffering high ammonia levels in their effluent.   Often the EfloSAF Biozone, dedicated to ammonia removal is sufficient but in other cases a further settlement tank will be needed.


For complete de-nitrification the Eflo submerged, attached growth technology used in the EfloSAF is modified to an anaerobic process call the EfloSNAF ( Submerged Non Aerobic Filter).   With hydraulic circulation, nutrient and alkalinity dosing, the effluent can be fully de-nitrified in cases where nitrates would be unacceptable in the receiving waters.  


Eflo have standardised EfloSAF plants which are ISO Container sized for easy, world-wide shipping.    The capacities of these standardised plants are :

50 m3 per day up to 1000 m3 per day all with tertiary treatment giving an effluent quality of 10 mg/l BOD and 10 mg/l suspended solids.    These can serve 250 persons  - 5,000 persons.


Larger sizes are individually sized and manufactured up to municipal sized plants with either steel fabricated tanks or locally constructed concrete tanks.


The EfloSAF process is ideal for upgrading and increasing the capacity of existing treatment works by utilising the tank work in place.    Below is a photo of an old activated sludge plant having it’s aeration tank upgraded with Modular EfloSAF technology.   All prefabricated and factory tested for rapid installation and minimal disruption.    


EfloSAF plants are often in stock for immediate despatch worldwide.    




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