Shallow air flotation.
A shallow-tank dissolved air flotation unit that separates suspended solids and oil in a short retention time, used as pretreatment ahead of a biological stage.
What shallow air flotation does
Dissolved air flotation separates solids that settle too slowly or float instead of sinking. Air is dissolved into a recycle stream under pressure; when that stream is released into the tank the pressure drops, the air comes out as a dense cloud of fine bubbles, and the bubbles attach to suspended solids, oil and grease and lift them to the surface, where a skimmer takes them off as float. What does not float is settled out at the bottom and drawn off as sludge. The shallow design does this in a tank whose effective water depth is much lower than a conventional unit, which cuts the retention time to a few minutes and raises the surface loading rate the tank can carry. It suits high-density sewage, and it is normally used as pretreatment: it takes the suspended solids and oil out ahead of a biological stage, so the biology behind it sees a steadier and cleaner feed.
Factory footage
CXQF super-efficiency shallow air flotation
The CXQF unit is a shallow-tank dissolved air flotation plant. The tank is built as a round shallow basin with the influent, the dissolved-air release, the skimmed float collection and the sludge discharge arranged around it; the water level and the skimming depth are both adjustable, which lets the unit be trimmed to the float that is actually being produced. The shallow tank keeps the float easy to collect and the retention time short, and the floor that does not float is collected separately. The unit is built as one item so that it can be installed on a prepared foundation, and the tank material and scraper arrangement are chosen against the water being treated.
| Model | Capacity (m³/d) | Diameter (mm) | Total disc height (mm) |
|---|---|---|---|
| CXQF series | [to be confirmed with factory] | [to be confirmed with factory] | [to be confirmed with factory] |
The CXQF model range and its capacities, diameters and disc heights are being confirmed with the factory. The table is published once those figures are verified; final dimensions and weights are then confirmed against the site conditions and the actual build.
Saturator, release and skimming equipment
A dissolved air flotation unit is only as good as the bubbles it makes. A pump charges air into the saturator vessel under pressure, the air dissolves into the recycle water, and the release device spreads that water across the tank so the bubbles form where the solids are. The saturator, the recycle pump and the air compressor are the parts that set how much air the unit can deliver, and they are selected together with the tank area so that the surface loading rate and the air-to-solids ratio suit the water. The skimming arrangement then has to take the float off at the rate it is produced without drawing water with it, which is what the adjustable skimming depth is for.
Applications
Suspended solids removal
Taking suspended solids out of industrial and domestic sewage ahead of further treatment.
Oil and grease removal
Separating oil, grease and light float from process wastewater.
Pretreatment ahead of biological treatment
Reducing the solids load reaching a biological stage so it sees a steadier feed.
Paper making and wastepaper recovery
Recovering fibre and clarifying process water in paper mills.
Dyeing, painting and chemical plants
Clarifying wastewater from dyeing, painting and chemical production.
Food processing and brewing
Removing solids and float from food processing and brewing wastewater.
Water works
Pretreatment duty ahead of further treatment in water works.
Delivery
Units are assembled and tested at our factory before shipment, then shipped with export documentation. Loading arrangement and delivery schedule: [to be confirmed with factory].
