（1）Superifical DAF introduction
Our Gongyuan GQF Type Superficial DAF is an advanced quick-speed flotation system integrated with flocculation, flotation, skimming and mud scrapping. Based on the traditional flotation theory, we also use the “shallow theory” and “principle of zero speed” successfully. Thus our superficial air flotation is widely applied in waterworks removing alga, varec and other turbic water from nature lake and river; Industrial sewage treatment projects such as petro-chemical, textile, printing and dyeing, electroplating, tanning, food industry and other fields; Recycling useful material in sewage like fibre recovery on paper& pulp industry
※Shallow effective water depth: 750mm~950mm
※Short hydraulic retention time: 5~10min
※Large purification capacity, namely high surface load
※Small footprint, light unit load, all prefabricated assembly, overhead installation or multi-layer combination mounting
※Low cost of installation and maintenance, easy to clean
※High purification degree, algae and other suspended solids removal rate over 90%, thickened sludge concentration can reach 35%
※Our superficial DAF will use GFA Type dissolved air system with its ingenious structure. The GFA dissolved air system has the strong anti-clogging ability.
（3）Structure and its working principle
Air-floated separation technology is a very good way of purifying water from suspend solid by releasing pressed saturated air water to make its generated air micro bubble contacting with suspended floc fully, which will form flotation sludge to be scrapped out of water by its scrapper .
Our device is an advanced quick-speed floatation system with all flocculation , floatation, skimming , mud scrapping together under successful use of the "shallow theory" and the "principle of zero speed" to gain high efficiency.
In order to make up shortcomings of the traditional unit, we design raw water inlet and purified water outlet as movable to save bubble floating time of raw water, namely, while raw water is flowing into the tank, the pool pipe water flow opposite way to make raw water in the pool nearly in static condition , by this way, the bubble can float to the surface quickly like SS flotation speed (4-10 minutes) , meanwhile , the purified water can be drained out when its pipe move here. Due to its compact round design with inlet and outlet pipes installed on rotating rack to generate centripetal moving with nearly zero speed , which will make the suspended solid fast floats on original water surface and then been purified within 3 minutes .
This equipment is cylindrical and compact in structure, including flotation tank, rotating water distributor, dissolved air release system, rotating rack, water collection device, scum skimmer, dissolved air system, reflux pipe, electric cabinet and etc. Inlet, outlet and sludge discharge outlet are all installed on the rotating area where water distributor, water collection device, dissolved air release system are connected to frame closely, rotating around the flotation tank center.This device provides module integrated equipment assembly by adopting both centralized and decentralized control system to realize the best operating condition.
（4）Process flow diagram