SAF ? Packaged Sewage Treatment Plant

Domestic Sewage Treatment Units
For 100 pe to 10,000 pe

Naston SAF (Submerged Aerated Filter) packages offer a robust, flexible process, that will require far less operation intervention that conventional activated sludge plants and out-perform traditional percolating filters.

Typical Applications

- First time treatment
- Small plant extensions
- Temporary capacity
- Sensitive or restricted locations
- Stainless Steel units up to 500 pe
- Modular Units may be retrofitted into existing tanks
- Effluent Quality to 20mg/l BOD, 30mg/l TSS, 5mg/l NH4-N

A range of technical and commercial advances borne out of 25 years of Naston wastewater treatment experience worldwide:

- Reliable compact units
- Removable media/diffuser module
- Fully enclosed design
- Easy installation and small footprint
- Low maintenance
- Minimal operator attendance
- High Energy efficiency
- Simple operation
- Security and flexibility
- Proven process design
- Rapid availability
- Odour and nuisance free
- Stainless Steel or concrete tank
- Naston Warranty

The Naston SAF Unit shown is the NS2 packaged SAF system, which is incorporated into a stainless steel tank.
The NS2 includes two biozones and an integral clarifier which houses the sludge recycle pump as shown.

The SAF Process

The submerged Aerated Filter (SAF) uses support media to retain a body of active biomass sufficient to reduce the sewage influent soluble BOD to the level desired for discharge.
The structured plastic media used in Naston SAF system provides an effective, tough yet light support media which offers a high surface area to volume ratio of 150 m?/m? and ample voidage to reduce blockages from biomass accumulation.

Air is fed in below the media to supply Oxygen for biological growth. The tubular diffusers used in the Naston SAF give good air dispersal, dislodging excess growth, keeping the media pathways clear of solids and providing an airlift effect, diverting the influent up through the media. This tubular diffuser design prevents occurrence of dead zones below the diffusers, reducing solids settlement and thereby avoiding mal-operation. Excess biomass entrained with the effluent is then removed in the humus settlement tank.

Removable Media/Diffuser Module
This unique Naston SAF feature allows easy access to the plastic media AND the attached fine bubble tubular diffusers, simplifying long term inspection and maintenance and preventing the need for plant shutdown during the removal and inspection period.

Enclosed operation
To ensure safety and reduce nuisance, Naston SAF packages are fully enclosed by lightweight and rigid plastic covers. This feature also obviates problems of surface pollution caused by fallen leaves for example.

Energy Efficiency and Low Maintenance
Standard Naston SAF packages have the benefit of durable stainless steel construction. With reliable and robust pump and air blower, standby equipment is not necessary, reducing costs and further simplifying maintenance.

Naston Guarantee
Naston Ltd will warrant the process performance and quality of the plant and equipment supplied. This warranty is valid for 18 months from the date of delivery.