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Swirl concave air flotation machine

Vortex concave air flotation is the world's most patented water treatment equipment proposed by the US Department of Commerce and the Environmental Protection Agency, and it is also the export recommended technology of the US Department of Commerce and the Environmental Protection Agency.

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Swirl concave air flotation machine
  • Details
  • Vortex concave air flotation is the world's most patented water treatment equipment proposed by the US Department of Commerce and the Environmental Protection Agency, and it is also the export recommended technology of the US Department of Commerce and the Environmental Protection Agency.

      

    1 System structure and principle

    Cavitation Air Flotation (CAF, Cavitation Air Flotation) system is the world's most patented water treatment equipment, and it is also the export recommended technology of the US Department of Commerce and the Environmental Protection Agency. CAF is a system specially designed to remove grease, glue and solid suspended solids (SS) from industrial and municipal sewage. The entire air flotation system consists of five parts.

    The pretreated sewage flows into a small inflatable section equipped with a vortex-concave aerator. During the rise, the sewage is fully mixed with the micro-bubbles generated by the aerator through the inflatable section, and the aerator transfers the air on the water surface to the water through the exhaust duct. The working principle of the aerator is to use the high-speed rotation of the air dissipation impeller at the bottom of the air delivery pipe to form a vacuum area in the water. The air on the liquid surface is input into the water through the aerator to fill the vacuum, and the micro-bubbles are generated and spiraled. The ground rises to the water surface, and the oxygen in the air also dissolves into the water.

    Due to the density imbalance between the air-water mixture and the liquid, a vertical upward buoyancy is created, bringing the SS to the surface. During the floating process, micro-bubbles will attach to the SS, and after reaching the surface, the SS will rely on these bubbles to support and maintain the surface. The SS floating on the surface is intermittently removed by a chain scraper. The scraper moves along the entire liquid surface and pushes the SS from the inlet end of the air flotation tank to the sludge discharge pipe at the outlet end. There are horizontal screw thrusters in the sludge discharge pipe to send the collected sludge into the sludge collection tank. The purified sewage flows into the overflow tank and then flows to the biochemical treatment part.

    An open return pipe extends from the aeration section along the bottom of the air flotation tank. While micro-bubbles are generated, the vortex aeration machine creates a negative pressure area at the bottom of the pool with the return pipe. This negative pressure will cause the wastewater to flow back from the bottom of the pool to the aeration area and then back to the air flotation section. This process ensures that about 40% of the sewage is backflowed and the air flotation section can still work without water ingress.

    2 System advantages

    1. Save investment

    There is no pressure vessel, air compressor, circulating pump and other equipment for vortex concave air flotation, so the equipment investment is small.

    The equipment occupies a small area and reduces civil construction investment. The vortex-concave air flotation (CAF) equipment with Q = 200m3/h occupies an area of only 36.15m2.

    2. Low operating costs

    The system saves power consumption because there are no pressure vessels, air compressors, circulating pumps and other equipment. The energy consumption of the vortex-concave air flotation (CAF) system with Q = 200m3/h is only 5.435KW, while the energy consumption of the dissolved air flotation (DAF) system is as high as 65KW. The vortex-concave air flotation (CAF) system is very easy to operate, and there is no complicated equipment at all, so the manual operation and maintenance workload is very small, which reduces labor and maintenance costs.

    3. The treatment effect is remarkable

    The removal rate of petroleum and solid suspended solids (SS) exceeds 80%.

    The removal rate of BOD and COD can reach more than 60%. The removal rate of BOD and COD by dissolved air flotation (DAF) system can only reach about 35%.

    It can promote the oxidation of sulfides and reduce the sulfur content in sewage

    4. Simple operation

    The system is very easy to operate without complicated equipment; the whole system consists of only two mechanical parts, unlike the dissolved air flotation (DAF) system, which includes many necessary equipment such as pressure vessels, air compressors, and circulating pumps.

    3 Relative economic comparisons

    Economic comparison with dissolved air flotation (DAF) and dissipated air flotation (IAF)

    This comparison is based on 2000t/d, equipment without chemical feed, see Table 1.

    Processing method

    Equipment occupies an area/m2

    Energy consumption/KW

    Investment ratio

    DAF

    60

    22.4

    1.37

    IAF

    30

    10.0

    1.18

    CAF

    19.3

    2.6

    1.00

     

     

    Value of design parameters

    Residence time 15~ 20min.

    Surface load 5~ 10m3/(m2 · h).

    The working depth of the pool is not more than 2.0m, and the aspect ratio of the pool is not less than 4.

    Vortex concave air flotation equipment, introduction

    Vortex concave air flotation adopts the principle of combining mechanical aeration and chemical flocculation to treat various types of sewage with different water quality, which is an ideal physicochemical equipment for sewage. In some sewage treatment with light pollutant content, the treated water can be recycled or discharged up to the standard and combined with biochemical treatment technology, which can completely meet the standard treatment.

    The system is mainly used in the purification and treatment of industrial sewage in papermaking, chemical industry, printing and dyeing, food, beer, pharmaceutical, slaughtering and other industries.

    advantage

    1. Save investment, low energy consumption, automatic slag discharge without noise, and convenient operation and management.

    2. Mainly remove most of the insoluble COD and SS that can float (specific gravity is less than water) and SS that can sink (specific gravity is greater than water) in sewage.

    3. Compared with the traditional domestic pressurized dissolved air flotation system, dissolved air tanks, air compressors, high-pressure water pumps and other equipment are omitted, and the energy consumption is 1/8 to 1/10 of conventional air flotation.

    4. The system can remove grease, glue and fiber suspended solids in sewage, reduce BOD, COD, SS and other sewage loads, and can significantly improve the color of water quality.

    Operational characteristics

    The vortex-concave air flotation is an excellent innovation in sewage treatment technology and equipment. It has reasonable design, convenient operation and economical operation. It directly removes solid suspended solids from the wastewater and generates air flotation from the air. The vortex-concave aerator directly injects "microbubbles" into the sewage without dissolving air in advance, and then distributes the "microbubbles" evenly in the sewage through the air-dissipating impeller, so there will be no blockage during the entire operation process, and there is no need for pressure dissolving air, air compressors and circulating pumps and other equipment.

    The untreated sewage first enters the aeration shell gas section and is fully mixed with the micro-bubbles. The micro-bubbles bring the solid suspended solids to the water surface in the process of rising. The mud scraper moves along the liquid surface to scrape the suspended solids onto the metal plate of the inclined material, and then pushes it into the sludge discharge pipeline. There is a horizontal screw thruster in the sludge discharge pipeline to send the collected sludge into the sludge collector. The thruster and the scraper are driven by the same motor. The power is only 0.5 horsepower. After the sewage is purified, it will pass through the overflow tank under the inclined plate before discharge. The overflow tank is used to control the water level of the air flotation tank to ensure that the liquid in the tank does not flow into the sludge discharge pipe. The open pharyngeal flow pipe extends from the aeration section along the bottom of the air flotation tank. While generating micro-bubbles, the vortex aeration machine will extend in the pool with the return pipe. A negative pressure area is formed at the bottom of the pool, and this negative pressure effect will make the wastewater flow back from the bottom of the pool to the aeration area, and then back to the air flotation section. This process ensures that air flotation continues even with incoming flow.

    Equipment Specifications Reference

     

    Equipment model

    Flow rate (m/h)

    Pool length (m)

    Pool width (m)

    Depth (m)

    Total power (kw)

    RK-CAF-5

    5

    2.94

    0.

    1.23

    1.6

    RK-CAF-10

    10

    3.55

    1.23

    1.23

    1.6

    RK-CAF-15

    15

    4.1

    1.23

    1.23

    1.6

    RK-CAF-20

    20

    4.6

    1.23

    1.23

    1.6

    RK-CAF-25

    25

    5.1

    1.52

    1.83

    2.94

    RK-CAF-35

    35

    5.72

    1.52

    1.83

    2.94

    RK-CAF-50

    50

    6.33

    1.8

    1.83

    2.94

    RK-CAF-75

    75

    7.55

    2.41

    1.83

    2.94

    RK-CAF-100

    100

    8.77

    2.41

    1.83

    5.5

    RK-CAF-150

    150

    12.3

    2.41

    1.83

    5.5

    RK-CAF-175

    175

    14.5

    2.41

    1.83

    5.5

    RK-CAF-200

    200

    16.09

    2.41

    1.83

    7.7

    RK-CAF-320

    320

    16.09

    3.05

    1.83

    8.1

    RK-CAF-400

    400

    17.6

    3.5

    1.83

    10.3

    RK-CAF-500

    500

    21.62

    4.4

    1.83

    14.7

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