The purification effect of dissolved air flotation in air flotation in sewage treatment is better th

Air flotation machine is a water treatment equipment that produces a large number of fine bubbles in the water by the dissolved air system, so that the air is attached to the suspended matter particles in the form of highly dispersed tiny bubbles, resulting in a state with a density less than that of water, and uses the principle of buoyancy to make it float on the water surface, so as to realize the solid-liquid separation. Air flotation machines are divided into super-efficient shallow air flotation machines, vortex concave air flotation machines, and advection air flotation machines. At present, it has applications in water supply, industrial wastewater and urban sewage treatment.

The advantages of air flotation machine are that its solid-liquid separation equipment has the characteristics of low investment, very small ground occupation, high degree of automation, and convenient operation and management. Weifang Tianyuan Environmental Protection Technology Co., Ltd. is a high-tech enterprise integrating the production and research and development of environmental protection equipment, and is now the cooperation base of Shandong Academy of Water Conservancy Sciences, and was designated as a key recommended enterprise by Shandong Provincial Environmental Protection Bureau in 2011. Advanced....

I've been exposed to it before, and it may not be so accurate, but it should make some sense, please refer to it.

Dissolved air flotation is mainly in the case of pressurization, the use of dissolved air pump to pump gas into the water, dissolved in water, and then released by depressurization, there is also a dissolved air tank or dissolved gas pipeline at the back end of the pump to assist the gas-liquid mixing effect, so the bubble particles in the water are very small and many, so the effect of flotation is good.

Inflatable air flotation may directly pass the air into the water, and the bubble particles at this time are large, so the flotation effect is not good.

It's an experience, hope.

There are many microbubbles in the dissolved gas method, which can be fully in contact with small magazines and adsorbed and float. The inflation method is mainly large bubbles, which are not easy to fully contact.

Nowadays, multiphase pumps are basically used for air flotation, which is quite convenient.

The working principle is that part of the treated wastewater circulates into the dissolved air tank, in the pressurized air state, the air is supersaturated and dissolved, and then mixed with the raw water added to the flocculant at the inlet of the air flotation tank, due to the decrease in pressure, the supersaturated air is released, forming tiny bubbles, which are quickly attached to the suspended solids and lift it to the surface of the air flotation tank.

As a result, a floating layer of sludge is formed, which is easily removed, and the heavier solids that settle at the bottom of the pond are also removed.

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 wastewater treatment in oil refining, papermaking, printing and dyeing and other industries.

Air flotation tank structure

In terms of appearance, it is mainly divided into two types of air flotation tanks: circular air flotation tanks and rectangular air flotation tanks;

The circular air flotation tank is called super shallow air flotation, which is the most advanced air flotation machine on the market, mainly using the shallow pool theory and zero velocity principle, and the efficient use of international advanced micro-oxidation technology and high-density ion bubble technology, which changes the surface tension of water, improves the dissolved oxygen in water on a large scale, adsorbs a large number of short-chain organic molecules and colored groups in water, and makes a technological breakthrough in COD that is difficult to degrade biochemically and physicochemically.

The rectangular air flotation tank is a traditional air flotation process, which is only used to inject a large number of bubbles into the water to make the granular suspended solids in the water float, and the static floating effect cannot be achieved during operation, and the stability of the water is generally poor.

Air flotation tank composition.

The air flotation tank is generally composed of three parts: a flocculation chamber, a bubble contact chamber and a 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, other ancillary facilities need to be combined with it, such as the pressure drop air flotation tank, which needs to be equipped with a pressure gas tank and a dissolved air release device.

Air flotation plays a role in separating pollutants in wastewater treatment.

The highly dispersed tiny bubbles are used as carriers to adhere to the pollutants in the wastewater, so that their buoyancy is greater than gravity and floating resistance, so that the pollutants float to the water surface and form foam, and then the foam is scraped off from the water surface with slag scraping equipment to achieve solid-liquid or liquid-liquid separation.

The necessary conditions for the air flotation process are: a large number of fine bubbles should be distributed in the treated wastewater, and the treated pollutants should be suspended, and the surface of the suspended particles should be hydrophobic and easy to adhere to the bubbles and float.

Air flotation equipment and sedimentation equipment are two commonly used process equipment in sewage treatment, and they have some differences in treatment principles and functions.

1.Air flotation equipment: Air flotation equipment uses the adhesion between air bubbles and suspended matter to achieve the separation of suspended solids.

In an air flotation tank, tiny bubbles are created by introducing air or other gases, and then these bubbles are brought into contact with suspended matter, causing them to attach to the bubbles, forming buoyancy, and floating to the upper part of the liquid surface. Finally, the float and sink are separated, and the floating matter (suspended solids) is removed from the liquid surface. Air flotation equipment is suitable for solid particles that are difficult to remove by precipitation, such as planktonic suspended solids, fats, and greases.

2.Sedimentation equipment: Sedimentation equipment is a process that uses gravity to make suspended substances ignite under static or fluid conditions due to the difference in sedimentation velocity to achieve solid-liquid separation.

In the sedimentation tank, the sewage gradually settles to the bottom of the sludge due to gravity by slowing down the flow rate or standing still, causing the suspended matter to gradually settle to the bottom of the sludge due to gravity, forming a sludge layer, and collecting clean water from above. The sedimentation equipment is suitable for granular skin fronts or large and dense suspended substances, such as sand, suspended particles, etc.

In general, the air flotation equipment is mainly suitable for the treatment of floating suspended solids and grease substances, and its separation effect is good. The sedimentation equipment is suitable for the treatment of suspended substances with large particles and has a high processing capacity. In practical application, according to the nature and treatment requirements of the wastewater, air flotation equipment, sedimentation equipment or a combination of the two can be selected according to the needs to achieve efficient sewage treatment.

In the air flotation treatment method, air is introduced into the wastewater and the tiny bubbles precipitated from the water are used as the carrier of pollutants. Emulsification in typically wastewater.

Oil, tiny suspended particles and other pollutant substances will adhere to the surface of the bubbles, and float to the water surface with the bubbles, and the purpose of separating impurities can be achieved by collecting bubbles or scums, so that the wastewater can be purified. From the principle of air flotation, it can be seen that the air flotation method is mainly used to treat emulsified oil or relative, which is difficult to settle or float naturally in wastewater.

Tiny suspended particulate matter with a density close to that of water.

According to the way of generating bubbles, the air flotation method can be mainly divided into three types: fine crushed air flotation, electrolytic air flotation, and pressure dissolved air flotation, and the advantages of pressure dissolved air flotation.

It is more widely used in practical engineering. The most widely used in pressure air flotation is the partial reflux dissolved gas type pressure dissolved air flotation method, which has been widely used because of its good effect.

fruit, and for the pollutants in the wastewater that can be treated by precipitation method, can often also achieve better removal effect; The residence time of air flotation tank is short, and the depth of the pool required is shallower than the sedimentation method, so the floor space is small; The moisture content of scum is low, generally at 96%.

Below, the volume of the same dry and heavy sludge produced by the sedimentation method is 2 10 times less, the sludge disposal process has been simplified, the sludge disposal cost has been saved, and the air float surface slag removal is more convenient than the sedimentation tank bottom sludge discharge; Air flotation has the effect of removing suspended solids.

In addition, can also play the role of pre-aeration, decolorization, reduce chemical oxygen demand, etc., effluent and scum all contain a certain amount of oxygen, is conducive to subsequent treatment, and sludge is not easy to spoil and deteriorate. However, the air flotation method requires a certain amount of energy consumption and the releaser used for it.

It is easy to block, and the scum of the air flotation tank installed outdoors is greatly affected by wind and rain.

The traditional use of air flotation is to remove oil in an emulsified state or fine suspended particulate impurities with a density close to that of water. Air flotation is also common.

As a supplementary treatment after the oily sewage is separated, it is a pretreatment before the secondary biological treatment. The solid particles in the sewage are very fine, and the density of the particles themselves and the floc formed by them is close to or lower than that of water, and it is difficult to achieve solid-liquid separation by precipitation method, and the air flotation method can be used. When land use is restricted or needs to be precipitated higher than gravity.

In the case of hydraulic load or solid load, air flotation can also be used instead of precipitation. In addition, air flotation can also be effectively used for the thickening of activated sludge.

Hello, air flotation machine is a kind of equipment to remove solid suspended solids (SS), grease and various gels in various industrial and municipal sewage. The equipment is widely used in oil refining, chemical industry, brewing, vegetable oil production and refining, slaughtering, electroplating, printing and dyeing and other industrial wastewater and municipal sewage treatment.

1. Process flow and principle of air flotation device.

1. The raw water enters the mixing reactor, and the agent (degreaser or coagulant) is added to the mixing reactor to form separable flocs;

2. The pretreated sewage enters the air flotation device, and the tiny bubbles (bubble diameter range 30 50um) released in the sewage and air-water mixture in the inlet chamber are mixed. These tiny bubbles adhere to the floc in the sewage, forming an air float with a specific gravity smaller than that of water. The air float rises to the water surface and condenses into oil (or scum), which is scraped to the oil (slag) tank by the oil (slag) scraper;

3. Heavy solid particles in the inlet chamber are precipitated here and discharged through the sand discharge valve, and the system requires the sand discharge valve to be opened regularly to keep the inlet chamber clean;

4. When the sewage enters the water distribution area of the air flotation device, the rapidly rising particles will float to the water surface; Once a particle touches the corrugated sloping plate, it can rise against the direction of the water flow under the action of buoyancy.

5. All heavy particles will sink, and the sinking particles will be collected by the bottom scraper and discharged by opening the mud discharge valve regularly.

2. Process flow chart of air flotation device:

Air flotation method: It can separate those fine particles with a particle density close to or less than water, which is suitable for the situation that the activated sludge floc is not easy to precipitate or is easy to expand, but it requires energy to produce fine bubbles, and the economic cost is high.

Precipitation method: It can separate those particles whose particle density is greater than that of water energy sedimentation, and the separation of solid and liquid generally does not require energy, but the general sedimentation tank covers a large area.

Advantages of air flotation method and precipitation method: dissolved oxygen in the water is increased during the air flotation process, and the scum contains oxygen, which is not easy to decay and is conducive to subsequent treatment; The surface load of the air flotation tank is high, the hydraulic retention time is short, the pool depth is shallow, and the volume is small; The scum has low moisture content and convenient slag discharge; When flocculant is added to treat wastewater, less dosage is required.

Disadvantages of air flotation method and sedimentation method: more power consumption, more electricity consumption per cubic meter of wastewater than precipitation method, and high operating costs; When the concentration of suspended solids in wastewater is high, the pressure reducing release is easy to clog and the management is complicated.

Disadvantages of air flotation: large power consumption.

Disadvantages of precipitation: the sedimentation effect is worse when the alum flower is lighter, and the area is larger than that of air flotation.

Regarding the issue of water treatment, you can also go to the environmental protection link to communicate with everyone.

It is suitable for water containing suspended solids and insoluble solid particles, and air flotation is a physical treatment method.