The Ellis Dissolved Air Flotation (DAF) system is a time-tested technology that has been installed in hundreds of locations. The first generation of the Ellis DAF was manufactured and installed in 1973 in Chicago. During the past six decades Ellis engineers have made continuous improvements optimizing air bubble generation, rapid rise flotation rates, and adjusting surface area to meet performance goals. Ellis currently provides three different DAF designs to meet the challenges of our customer’s wastewater and achieve their goals. We offer Rectangular DAFs, Square DAFs, and Compact DAFs. Our basic designs provide the solutions based on pollutant loadings and allocated space.
The Ellis DAF surface skimmer design is unique on our systems to maximize solids removal and minimize water in the sludge. The design of the surface skimmer minimizes excessive wear and tear on the skimmer assembly operating in a Ferris wheel motion. This design minimizes wear and tear on the chain links, gears and motor.
Each DAF is shipped prewired and ready for operation. Once power is connected to controls, all the customer has to do is bring the wastewater feed and chemicals into the system and the separation process begins.
DAFs efficiently remove fats, oils, and greases (FOG) and suspended solids (TSS) from the wastewater. It is also capable of reducing insoluble biological oxygen demand (BOD) and chemical oxygen demand (COD). FOG and TSS removal rates in excess of 95% are common. Some installations report as much as a 99% reduction.
HOW IT WORKS
- Chemically pretreated wastewater enters the DAF flotation cell. Chemical pretreatment is used to break emulsified wastestreams so that the particulates can floc together to form a surface sludge blanket. Chemical pretreatment varies for every application.
- Ellis DAF units use optimally designed microbubble generator pumps. These microbubbles rapidly float the floc particles to form the surface sludge blanket onto the surface of the flotation cell.
- The floating solids are skimmed towards the front of the DAF and collected in a solids chamber. The effluent flows to the back side of the DAF under a baffle and into a separate liquid effluent chamber before leaving the unit.
DAF Optional Equipment
- Materials of Construction –304 and 316 Stainless Steel
- Chemical Reaction Tanks – Carbon Steel or Stainless Steel Design
- Tube Flocculator, PVC or Stainless Steel Design
- Wastewater FlowMeter
- Pumping package –Including Inlet, Outlet, &Sludge Removal Pumps and VFDs
- Solids Removal Auger
- Walkways and Guard Rails, Stairways or Ladders
- pH, Turbidity, Temperature, or Conductivity Monitoring Systems
- Freeze Protection–Thermal Heating and Extra Insulation.
- Effluent Weir Tanks–Final pH Adjustment and Flow Transfer to the Sewer.