The first chapter, the process plan air flotation tank is generally composed of three parts: flocculation chamber, bubble contact chamber and separation chamber. It has the functions of completing the formation and growth of flocculation in water, the adhesion and trapping of microbubbles to flocs, and the separation of floc particles and water. In addition to the air flotation tank itself, there are still other ancillary facilities to be combined with it, such as the pressure drop air flotation tank, which needs to be equipped with pressure gas tank and dissolved air release device and other devices.
Air flotation mainly plays the role of solid-liquid separation (at the same time, it can reduce COD, BOD, color, oil, etc.). Flocculant PAC or PAM is added to the raw water, and after an effective flocculation reaction, the raw water enters the combined air flotation contact zone. In the contact zone, the microbubbles in the dissolved air water and the floc in the raw water are bonded to each other and enter the separation zone together, and under the action of bubble buoyancy, the floc and the bubble rise to the liquid level together to form scum. The scum is scraped to the sludge area by the foam scraping device. The clean water from the lower layer flows to the clear water pool through the water collection pipe. Part of the clean water is returned for use in the dissolved gas system, and the other part is discharged. The reflux clean water passes through the jet suction device, and under a certain working pressure, the air is dissolved into the water to the maximum extent to become dissolved air water, and the dissolved air water is released in the air flotation contact area through the rapid depressurization of the release device to form a microbubble with a diameter of about 15-30um. The microbubbles can then be bonded to each other with the floc in the raw water.
Air flotation technology is an excellent technological innovation of sewage treatment equipment, with reasonable design, convenient operation and economical operation, especially for the treatment of oily wastewater. The pressure vessel directly injects the "microbubbles" into the sewage without dissolving the gas in advance, and then evenly distributes the "microbubbles" in the sewage through the dispersed impeller, so there will be no blockage in the whole operation process.
The air flotation tank has been widely used in the water supply purification treatment with low raw water turbidity, algae, low temperature, high color and low dissolved oxygen, and is also widely used in the wastewater treatment of various industries such as food, oil refining, papermaking, printing and dyeing.
Chapter 2 Main construction contents2.1. Supporting equipment for air flotation device:
1) 2 sets of mixers, 22kw；
2) 1 air compressor, rated air capacity 06m3/min；
3) 1 set of dissolved gas tank, 06m3，0.6mpa；
4) 1 set of reflux pump, q=10m3 h, h=40m, n=40kw, pipeline pump;
5) 1 set of slag scraper, b=20m, chain type, material carbon steel anti-corrosion;
2.2. 3 sets of demulsifier dosing devices have been added to the dosing device, including: 3 dissolving boxes with a volume of 1500L and PE material3 dosing pumps, q=150l h, p=06mpa, 3 sets of mixers 11kw。
2.3. The control system has added 1 set of air flotation system control cabinet, CHINT components, and manual integration.