Denitrifying submerged aerated filter (DSAF)

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With reliable and cost-effective energy efficient blowers, the Rewatec DSAF range provides a robust and efficient long-term solution for larger projects where nitrogen removal is required.

Denitrifying Submerged Aerated Filter
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Built to last

Leak-proof design.
Robust and durable GRP shells.
Ribbed sidewalls for added strength.

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Smart Investment

Excellent performance to cost ratio.
Energy efficient blowers. 
Low maintenance costs.

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Tailored solutions

Pre-engineered or bespoke designs.
Single or multi-stream plants.
Above or below ground installations.

What is a denitrifying submerged aerated filter?  

The DSAF process uses individual cells within the tank which are arranged in series, the wastewater flows through each chamber in sequence. Each cell contains a media on which biomass forms, and a fine bubble diffuser system feeds oxygen from blowers in the control kiosk to promote the growth of the biomass.  

DSAF sewage treatment plant


Denitrification is the process whereby nitrogen is removed from water. Denitrification treats water to reduce its nitrate-nitrogen content to potable levels. 


Example applications

  • hotels and inns
  • leisure facilities 
  • camping and caravan sites
  • schools
  • office buildings 
  • industrial sites

Adaptable to suit your needs

The Rewatec DSAF sewage treatment plant comes in four variations, dependent upon population size and application parameters.  

Denitrifying Submerged Aerated Filter Operation
  • single tank 
  • semi modular tank (two tank system)  
  • modular (three tank system)  
  • multi stream systems (bespoke application design)  

How does the DSAF work?

The Rewatec DSAF sewage treatment plants form three treatment stages; primary settlement, biological treatment (biozone) and humus settlement. Flow through all of the treatment stages from inlet to outlet occurs through gravity and integral airlift.

A blower sends air to the bottom of the bed to provide oxygen for the biomass to support the oxidation process. The air stream promotes both efficient mixing of the effluent and disturbance of any excess solids from the filter medium. The denitrification process also significantly reduces the nitrogen levels within the final effluent. 



Rewatec DSAF maintenance 

We have a network of local service partners to maximise the life of your Rewatec DSAF system and to provide you with years of reliable operation.  

We stand by our products

Rewatec 20 year warranty

For over 50 years, we have proudly developed sustainable and long-lasting products that make a real difference for our customers, our professional partners, and above all, our planet. 

Our experience in the industry allows us to give you a complete 20-year warranty for our Rewatec DSAF sewage treatment plants and a 12-month warranty for our kiosks. 


Training programmes

​​​​​​At Premier Tech we provide a full range of training programmes to fully meet the requirements of our professional partners. If you require product functionality guidance or a more detailed training course for installations, we can provide a solution to meet your needs. 

Contact us for more information

Available products

We offer a complete range of Rewatec DSAF products to meet your needs. From 30PE to 600+PE, wherever your site, whatever the regulations, we have the right sewage treatment plant to transform any challenge into a tailor-made solution. 

Free quote

We are here to help. Request a quote today and our team of experts will be in touch. 

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