Setfords SAF Effluent Treatment
Setfords Submerged Aerated Filter (SAF) units can be supplied in a range of configurations for both Municipal and Industrial treatment applications.
Our SAF units utilise a biological treatment. It is simple to operate, robust in performance, and capable of producing a high quality treated effluent delivering typical effluent quality after downstream humus settlement: 10mg/l BOD, 30mg/l SS, 3mg/l Amm. Our SAFs are available in various sizes ranging from 100 population equivalent to 1,500 population equivalent, all in a single stainless steel tank divided into compartments
From our standard SAF range to super energy efficient PLC controlled I-SAF’s, to Anoxic SAF’s, Lamella Settlement Tanks and a range of pre and post treatment options, Setfords Technology offers the optimised solution to wide variety of waste stream profiles.



Setfords SAF Highlights
SAF’s also available in reinforced concrete cells to expand SAF opportunities from the low thousands population to around 10,000 population.
Very high density of air diffusers resulting in effective treatment across the full surface area of media.
Requirement for SAF desludging has been designed out.
Stainless steel construction with extending life span.
1,500 pe SAF unit available in a single tank.
Biological Wastewater Treatment
SAF is an efficient biological treatment process used to treat wastewater with high level of BOD, COD Nitrogen and high levels suspended solids.
In a Setfords SAF each compartment is filled with rigid structured Pvc media. These modern, high rate filter plastic media use naturally occurring bacteria to reduce both energy consumption ans carbon footprint.
Our SAFs can remove over 90% of COD and BOD pollutants, making SAF amongst the most universally effective solution for remedial water and waste water treatment solution for municipal and industrial effluent types.
Correct specification is crucial to both energy efficiency and operational reliability of a biological wastewater treatment solution. At Setfords we offer a comprehensive range of project scoping services, pilot treatability studies and test unit hire to ensure that our customers’ get the most effective solution to their specific requirements.
Reduced Downtime
Reduced Energy Consumption
Improved Flow Rate Management
Improved Toxicity & shock load Resilience
Reduced sludge production
EXTENDED ROI
Plastic Media Trickling Filter System Performance
%
Typical BOD & Ammonia Removal Rates
Plastic Media Trickling Filter System Performance
%
Mean Energy Saving over Activated Sludge
Setfords’ SAF System Specification

Setfords have been designing and building SAF systems since 1993, assisting Water Companies in the development of their SAF specifications and design standards.
Our extensive experience – combined with a comprehensive range of project scoping, consultancy and pilot studies services – ensure our syetems are designed to optimise our customers’ systems performance, extend RIO and minimise downtime.
At Setfords we deploy fine bubble membrane diffusers mounted on a removable stainless steel manifold assembly underneath the media.
The effluent passes through the media which provides a high surface area for the natural biomass to grow on.
Sufficient air is passed through the air diffusers by means of air blowers into the structured media. This not only provides oxygen for the biomass but, in addition, it scours off surplus biomass from the media, removing the need for pumped backwashing of the plant.
The SAF effluent then passes into humus tanks, with the settled SAF sludge normally being pumped back to the primary settlement tanks.
The air diffusers only require replacing every 7 years or so, and there are no moving parts in the SAF cells.
We supply a walk in GRP kiosk housing duty / standby side channel air blowers and a control panel.


Sufficient air is passed through the air diffusers by means of air blowers into the structured media. This not only provides oxygen for the biomass but, also, it scours off surplus biomass from the media, removing the need for pumped backwashing of the plant.
The SAF effluent then passes into humus tanks, with the settled SAF sludge normally being pumped back to the primary settlement tanks.
The air diffusers only require replacing every 7 years or so, and there are no moving parts in the SAF cells.
We supply a walk in GRP kiosk housing duty / standby side channel air blowers and a control panel.

For larger SAF installations we provide positive displacement air blowers mounted in their own weatherproof acoustic enclosures.
All tanks & pipework are manufactured in stainless steel delivering maintenance free & long asset life.
With no moving parts in the SAF compartments, all our SAF’s are extremely robiust and have very low maintenance requirements.
Our systems are also simple to operate., with no operational involvement required other than visual checks.
SAF technology also ensure that Setfords SAF’s are robust in performance and have the ability to accept shock loads. .
Model |
Pe |
Height |
Width |
Length |
Power |
ST 100 |
100 |
2.7m |
1.7m |
1.7m |
1.5kW |
ST 300 |
300 |
2.7m |
1.7m |
4.7m |
3.0kW |
ST 500 |
500 |
3.0m |
2.0m |
5.6m |
4.0kW |
ST 750 |
750 |
3.0m |
2.0m |
7.4m |
5.5kW |
ST 1000 |
1000 |
3.3m |
2.3m |
8.6m |
7.5kW |
ST 1400 |
1400 |
3.3m |
2.7m |
10.2m |
11.0kW |
Energy Efficient I-SAF Systems
To reduce energy consumption and operational costs, we offer an Intelligent SAF unit (I-SAF) which reduces power consumption by around 50%. A Setfords I-SAF is identical in every respect to one of our standard SAF units but has intelligent control and monitoring devices linked to a PLC. I-SAF is available in the following specifications:
- Gold – Dissolved oxygen control, variable speed blowers, PLC monitoring, timed air scour cycle
- Silver– 4-20mA output from inlet flow recorder linked to PLC monitoring, variable speed blowers, timed air scour cycle
- Bronze – Stepped increase and decrease from variable speed blowers based on historical flow data, PLC monitoring, timed air scour cycle.
%
Typical I-SAF Energy Saving
Anoxic SAF System

Used to remove Nitrogen and facilitate alkalinity recovery, Denitrification is a process where nitrate (NO3) is converted to Nitrogen (N2) primarily by means of heterotrophic bacteria.
Denitrifying microbes require a very low oxygen concentration of no greater than 0.5ppm, as well as organic C for energy.
Denitrification generally proceeds through some combination of the following intermediate forms:
NO3− → NO2− → NO + N2O → N2
The complete denitrification process can be expressed as a redox reaction:
2 NO3− + 10 e− + 12 H+ → N2 + 6 H2O
Air, required for occasional media scouring enters all three SAF cells. The air is controlled by means of a timer with adjustable frequency & duration.
Air scour is used sparingly, as the dissolved oxygen levels in the Anoxic SAF cells need to be maintained at a level no higher than 0.5mg/l. Default setting is daily for 10 mins at midnight.
Anoxic SAF Process

Lamella Plate Settlement Tanks

We design and manufacture a range of Lamella Plate Settlement Tanks that we use in conjunction with our SAF units to create a complete wastewater treatment system.
These units are available for hire and for purchase, should you only require a solids sedimentation system.
Meeting the Effluent Challenge
Whether you are looking to optimise the performance and or commissioning a new facility to meet the increasingly stringent discharge compliance standards, Setfords Technology’s can provide a treatment system that delivers:



To assess how a Setfords SAF system could reduce the cost of your wastewater treatment either call us on on (0)1359 243500 or click on the link below and complete the form and one of our expert engineers will help scope and price your project.

Setfords Technology Ltd
Surrey Office
Crowthorne, Furzen Lane,
Ellens Green, Horsham,
Surrey RH12 3AR
Switchboard: +44 (0) 1761 348011
Mobile: +44 (0) 7505 103146
enquiries@setfordstechnology.com
Company number 7715931
Registered Address
30 Chancery House, St Johns Road,
Woking, Surrey,
GU21 7SA, UK