6mm AutoScreen

RawSewage

InletPumping

Station

Biozone

ConstantTransfer

Air Blowers

E�uent to TertiaryTreatment Filters

WasteSludge Final

DisinfectionTank

EFLO Submerged Aerated Filter

EFLOSAF

E�o International Ltd, the UK designer and of wastewater treatment technolo-gies, o�er innovative treatment solutions.

E�o has designed & installed treatment plants in the Middle East, Africa, Carib-bean the Indian Ocean islands over a period of more than 30 years.

As well as the E�oSAF, biological sewage treatment plants, E�o o�ers a range of other waste water treatment products for both sewage, industrial waste water & water re-use.

E�o is part of the Concorde Corodex Group of companies and through this group can o�er bespoke, potable, water treatment plants including River Water Treatment and Seawater Reverse Osmo-sis. Water treatment plants for small communities to large towns.

E�oSAF is “Fixed Film” or “Attached Growth” technology using a submerged aerated bio�lter.

The ‘heart’ of the system is a structured and rigid HDPE media with a very high speci�c surface area. This allows for high concentra-tions of attached biomass to be maintained in the Biozone.

The unique �ow patterns within the media ensure high rates of biological oxidation with relatively low retention time. The media ensures air bubble retention is prolonged and allows for excep-tionally high oxygen transfer rates with low energy consumption.

There are few moving parts within the plant allowing for low maintenance and low operator demands. Due to the gentle but fully mixed environment within the Biozone, the biomass is allowed to grow to a long sludge age before being “sloughed” from the media. This produces excellent e�uent with good nitri�cation and low levels of waste sludge production.

E�oSAF plants are either pre fabricated steel tank package type or fore larger projects use insitu concrete tanks. Existing treatment plants can be upgraded for capacity and e�uent quality by adopting E�oSAF E�oSAF can also be used as a polishing process to improve nitri�cation of an existing e�uent stream

E�oSAF Package SewageTreatment Plant

E�oSAF HDPE Biomass SupportMedia showing ‘Zig Zag’ pattern

E�oSAF “Sloughing” Process

This is a continuous process of biomass growth, followed biomass detachment. The detachment occurs shortly after an anaerobic layer forms at the support media surface. This anaerobic layer forms when the biomass thickness prevent air di�usion the full depth of biomass. The polysaccharides �rmly “gluing” the biomass to the media reduce and the nitrogen bubbles, along with the aeration bubble, “slough” chunks of biomass from the media surface. New biomass rapidly grows and the process continues.

E�oSAF Support Media and Process

The E�oSAF operates with a retention time of between 4 - 6 hours in the Biozone. This requires a very high concentration of biomass (MLVSS). The biomass is delicate and must be provided with a gentle environment to thrive. The E�oSAF provides just these conditions.

The “Sloughing” diagram shows how the biomass can grow fully to a thickness whereby an anaerobic layer is formed at the surface of the support media. The “sloughed” biomass is further assisted by the action of the aeration bubbles passing over the surface of the biomass. This “sloughed” biomass is collected in the settlement tank, where it settles very easily. Because the biomass is correctly �xed in the biozone, sludge return pumping is required in the E�oSAF

The E�oSAF provides a highly e�cient process for oxidation of BOD and where required, very high levels of nitri�cation.

The E�oSAF is a “Fixed Film” or “Attached Growth” process and is a direct derivative of the well known and extensively used trickling �lters but with a vastly reduced footprint due to the much higher e�ciency. The E�oSAF uses Medium Bubble air di�users. These are located at speci�c points below the biomass support media. The presence of the media above the air di�users provides exceptionally good oxygen transfer e�ciencies,in line with the best �ne bubble air di�users. The support media allows for long bubble retention times due to the “zig zag” route through the media. The high oxygen transfer e�ciency reduces the size of the air blowers and with large power savings.

Other �xed �lm processes are available, such as the moving bed bioreactor (MBBR). This is a derivative of “Suspended Growth” Activated Sludge process. The “Random Media” is used to partially �ll the aeration tank, providing the necessary surfaces for the biomass to attach too. However, ONLY coarse bubble aeration can be used as complete mixing of the aeration tank is essential. Not only is this very energy hungry but the aggressive mixing disrupts the proper growth of the biomass, causing it to detach too early and be discharged from the aeration tank.

The very high biomass concentration in the small MBBR aeration tanks can then cause failure of the downstream settlement tank, necessitating the use of DAF (Dissolved Air Floatation) for clari�cation. Due to the high concentration of biomass in suspension, sludge return pumping is required and this must be correctly controlled by the operator.

2000 m3/d E�oSAF for Atlantis Hotel, Dubai with on site sludge dewatering

E�oSAF for Ministry of Public WorksKuwait. 300 m3/d. TSE < 10 mg/l BOD, SS

< 10 mg/l, HN3-N < 5 mg/l

E�oSAF for International City, Dubai. 1000 m3/d. TSE < 10 mg/l BOD, SS < 10 mg/l, HN3-N < 5 mg/l

E�oSAF for Ammonia Reduction.Rusper WWTP, Thames Water, UK.Treatment of TSE with 30 mg/lNH4 to < 3 mg/l.

EFLO

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EFLO INTERNATIONAL LTD.The Colin Sanders Innovation Centre,Mewburn Rd., Banbury, OX16 9PA, UKTel + 44 (0) 1295 817623Fax + 44 (0) 872 115 6890Email: info@eflo.comwww.eflo.com