Operating Advantages
- Smaller footprint. The solids separation tower is vertical vs. horizontal for DAF.
- Fewer moving parts. No skimmers and no pumps and compressors for dissolving air.
- Quieter operation as no air compressor or skimmer is required.
- No odor. Solids separation tower is totally enclosed with vents to the outside. This allows the use of gases other than air.
- Higher throughput capacity and more energy efficient. DAF requires recycling of some of the clean effluent, adding air under pressure then injecting it into the DAF influent in order to float the solids to the surface of the DAF, which reduces DAF capacity. In the case of AFS™, clean wastewater from the bottom of the tower is pumped through a Mazzei injector and back into the tower which allows for gas addition without a compressor and without compromising the hydraulic capacity of the tower.
- Easier to clean, especially compared to a DAF with a plate pack.
- AFS™ Separation Towers are made of more cost-efficient materials (Polyethylene) as opposed to DAF (Stainless Steel).
- DAF units are more expensive per unit of volume and are only available in limited sizes and limited flow rates, making it much more difficult to accommodate large fluctuations in flow. The separation towers and mix tanks for AFS are available in a wide range of sizes and operating capacities which makes the modular design of AFS more cost effective than DAF.
- Separation towers can be run in parallel for a single pass design, or in series for a 2 stage treatment design depending on the wastewater characteristics and the pollutants to be removed.
Performance Advantages
- AFS™ uses no polyacrylamides. Recovered solids do not have to go to landfill. Beneficial use is site specific. Composting trials were successfully completed in 2025. Proximate analysis of recovered solids data is available. Potential for re-use of the clean effluent.
- Removes more suspended solids, oil and grease, and some of the dissolved organic and inorganic solids better than DAF. Pilot trials in 2025 show successful removal of TKN, Total Phosphorous and most heavy metals. May also remove Ammonia-Nitrogen.
- The percent solids and recovery of the foamate can be increased by recycling a portion of the foamate back to the influent of the tower.
- Significantly reduces or eliminates bacteria without the use of toxic chemicals. DAF alone may not achieve the required bacteria limits even with a mixing zone allowance; a comparable DAF configuration would require an additional bacteria removal system.
- Works at a range of temperatures (as low as 0.5 deg. C.) and salinity (as high as 22 ppt).