Eco SAF ™

The above or below-ground installed Eco-SAF Wastewater treatment system is based on proven biological Submerged Aerated Filter (SAF) technology and has been manufactured by us since 1996.

The Eco-SAF was originally designed as a secondary biological treatment for domestic sewage to an accepted standard where mains drainage (into the foul sewer) was unavailable. However, we have developed further a high treatment system for advanced ammonium removal, total N (nitrogen) removal, and to treat a wide variety of Industrial and Trade effluent COD levels. Additional equipment can be added to remove phosphorus.

To meet stringent environmental discharge consent standards, Eco-SAF systems are available to treat the equivalent of 50pe to 1000pe, which is scalable to accommodate a growing population of up to 10,000pe. In addition, primary/Balance and Humus settlement tanks (Integral or separate tanks depending on overall system size) are available as part of a complete three-stage packaged wastewater treatment system.

As part of our ongoing development of the Eco-SAF, it is now available in a modular design. Each cell is contained within a structural ‘exoskeleton’ frame, which, when connected in series, can provide a true modular large-scale SAF plant. Rapid deployment and requiring minimum site installation are available on a purchase-or-hire basis.

The Eco-SAF does not use chemicals in the treatment process and will safely discharge wastewater into the local environment where extra importance is required, typically nature reserves, fisheries etc. or for any sensitive locations.

Why you should choose an Eco-SAF:

Robust process:

  • We are not just an off-the-shelf Tank manufacturer who has seen the opportunity to convert a standard tank design to accept the SAF process. Rather we are proven and experienced Wastewater Engineers who listen to our customers and continually develop the Eco-SAF to suit their needs.
  • High-quality components, including Blowers, pumps, media and diffusers, provide the module’s reliability.
  • Available in Carbon steel which is blast cleaned to quality SA2.5followed by three coats of 2-pack high-quality industrial paint internal and external (or to WIMES specification). Optional grade 304, 316 or duplex Stainless Steel modules.
  • All submerged Aeration pipework is manufactured in corrosion-resistant stainless steel.
  • We include aerated cells plus anoxic and anaerobic zones in each module to optimise performance, depending on the application.
  • A unique flow balancing system ensures no shock loads and optimises retention time in the biological cells.
  • High-level gravity by-pass system will activate power failure to safeguard against pollution incidents.
  • Modular design allows for additional future growth.
  • Configured to eliminate the risk of process shortcuts and dead zones.
  • Separate GRP weatherproof Controls and blower housing.
  • The immediate effect on BOD reduction, the system can be 100% effective within 4 weeks of the start-up.
  • Designed to operate efficiently based on seasonal variations in loadings often experienced by hotels, caravan parks, chalet parks and cafes.
  • Designed and manufactured in-house to ISO 9000 quality and with all the relevant Welder qualifications.

Low maintenance:

  • No internal mechanical or electrical moving parts within the tank.
  • All aeration diffusers can be isolated and removed without shutting down or draining the process.

Energy efficiency:

  • Duty-standby blower arrangement provides process air; the secondary blower provides other diffusers/media scour when required, reducing energy use.
  • Variable speed blower drive controls to optimise power usage and blower maintenance.
  • DO Probes to control dissolved oxygen and reduce energy use and blower maintenance.

Ease of installation:

    • Both above or below ground or a partially submerged option minimise civil site requirements and, depending on the site requirements, will have the option of not impeding on the landscape.
    • The modular design ensured no restriction to the pipework.


    • Compliance with Environment Agency guidelines and Building Regulations.
    • Designed following the guidelines for Wastewater Treatment Plants in BS EN 12255.
    • Use British Water’s code of practice – Flows & Loads

Why Rectangular Tanks and not Circular Tanks?

The main function of a properly designed SAF is to provide a controlled environment and a concentration of nutrients (dissolved oxygen, mainly) sufficient to achieve optimum growth of the microbe population in the process. In addition, the rectangular design of the Eco-SAF ensures that the removal rate of organic contaminants is significantly improved compared to a circular (or Hopper) designed SAF. Why?

      • We can utilise the full available width of the bio-cell to install the most efficient fine bubble diffused aeration. This ensures no dead zones or unaerated zones (bubbles naturally want to travel up, not sideways!!)
      • Significantly more interaction between the oxygen-rich wastewater and the contact media.
      • The optimum fill rate of media can be achieved in a smaller footprint.
      • Oxygen transfer (AOR) is more efficient as the bubbles travel further in a rectangular tank.
      • More sludge retention, increasing the period between de-sludging requirements.
      • A smaller overall footprint is required for a complete eco-SAF system.
      • Typical comparisons per linear metre between a rectangular tank (2.5m x 2.5m) and a circular tank (2.5m diameter) are:
        Aeration capacity: +45% ~ Media capacity: +60% ~ Sludge capacity: +70%

The Eco-SAF can be configured for the following applications:

Secondary: Eco-SAF
      • For settled wastewater after primary settlement. Carbonaceous and nitrifying applications.
Tertiary: Eco-SAF
      • For polishing liquor from existing biological treatment where further BOD or nitrification is required to meet consent.
Ammonia reduction: Eco-N-SAF (A)

A nitrifying SAF where applications when the carbonaceous BOD has already been removed, however, full nitrification is required. In addition, further nitrate as nitrogen gas is removed by allowing denitrification bacteria to operate in anoxic conditions.

Total N removal: Eco-N-SAF (N)

Enhanced biological uptake in combination with a standard aerated process encourages luxury uptake to establish a population of microorganisms with the ability to store phosphate beyond their normal metabolic requirements. For applications that require secondary carbonaceous, nitrifying and de-nitrifying treatment.

Design options:

      • Duty/Standby blowers with automatic changeover to ensure uninterrupted air supply.
      • Energy saving variable speed drive blower controls.
      • Dissolved oxygen metering system.
      • Lamella Clarifier design for final settlement.
      • GMS Telemetry for remote monitoring of the system.
      • Galvanised access steelwork.
      • Mechanical or manual inlet screening system.
      • Pump chambers.
      • Dosing system for phosphate control.
      • Visual and audible alarms for mechanical failure and loss of air pressure.
      • Trace heating and lagging to exposed pipework and valves.

Typical uses for the Eco-SAF system:

Municipal and Commercial:
      • Villages and rural communities
      • Hotels, restaurants and public houses
      • Housing developments
      • Leisure facilities include golf courses, fishing lakes, Theme parks, stately homes etc.
      • Camping and Caravan sites
      • Utility WwTW
      • Schools, colleges and training centres
      • Care homes and retirement villages
      • Commercial buildings and offices
      • Motorway services
      • Garden centres
Industrial Trade Effluents:
      • Abattoirs, meat and Poultry processing
      • Vegetable processing
      • Baking and confectionery, readymade meals etc.
      • Dairy including milk, cream, yoghurts and cheese processing plant
      • Brewery, winery and soft drink manufacturers
      • Animal waste such as stables and kennels
      • Farmers auction mart run-off
      • Paper and pulp industry
      • Fish processing
      • Pharmaceuticals
      • Waste recycling centres

Eco-SAF new 18-05-18

Lamella Clarifier New Logo