Daf System For Water Treatment

The DAF (Dissolved Air Flotation) system for water treatment is a highly efficient sewage treatment equipment. It dissolves gas into water and releases it to form fine bubbles, which attach to suspended matter and bring it to the surface of the water by buoyancy, thus achieving solid-liquid separation. This equipment is widely used in industrial wastewater treatment, such as in papermaking, printing and dyeing, electroplating, and other industries. It can effectively remove suspended matter, grease, and glue from sewage, with advantages including high treatment efficiency, a small footprint, and ease of operation.

The DAF system utilizes the different solubilities of water under varying pressures to generate microbubbles in water under pressurized or negative pressure conditions. This replaces traditional air-inducing equipment, which introduces air into the water. These microbubbles fully contact the suspended matter in the sewage and adsorb onto the flocculated suspended matter during the slow rise process. This decreases the density of the matter, causing it to float to the water surface, thereby achieving the removal of suspended matter and pollutants.

Air flotation primarily serves the role of solid-liquid separation (while also reducing COD, BOD, chromaticity, etc.). It uses the microbubbles in the dissolved air water generated by the dissolved air system to bond with the suspended flocs in the water. The suspended matter rises to the water surface with the microbubbles, forming scum, and thus removing the suspended flocs from the water.

Clean water passes through the jet suction device. Under a certain working pressure, air is dissolved into the water to the maximum extent. It is then released through rapid decompression to form small bubbles with a diameter of about 30 µm to 50 µm.

Flocculants such as PAC (Poly Aluminium Chloride) or PAM (Polyacrylamide) are added to the raw water (PAC dosage is 400-1000 mg/L, and PAM is approximately one-fifth of the PAC dosage). An effective flocculation reaction occurs for 3 to 15 minutes. The exact period, dosage, and flocculation effect must be determined through experimentation. After the flocculation reaction, the raw water enters the contact zone. In the contact zone, the microbubbles and flocs in the raw water bond with each other and move together into the separation zone. Under the action of the buoyancy of the bubbles, the flocs and bubbles rise to the liquid surface, forming scum. The floating scum is scraped into the sludge area by the scraper. The clean water in the lower layer flows to the clean water tank through the water collection pipe. After treatment, part of the clean water flows back into the dissolved air system, and the other part is discharged.

Air flotation equipment is used in electroplating, printing and dyeing, food processing, oil refining, wastewater grease removal, chemical industry, papermaking wastewater treatment, and drinking water purification. The air flotation system combines the flotation tank, dosing equipment, dissolved air tank, dissolved air pump, and air compressor into one integrated unit.

This integration shortens installation time and reduces the workload. It occupies a small area, is easy to operate, and does not require a foundation. Users only need to connect the sewage with an adjusted pH value to the inlet and outlet pipes. Once calibrated, it operates normally without the need for special personnel management, essentially running in an automatic, unmanned mode.