Flocculation, air flotation, and sedimentation equipment 1

[Overview]

Dissolved air flotation technology has been widely used in water supply, drainage, and wastewater treatment in recent years. It can effectively remove light flocs that are difficult to precipitate in water. It has a large processing capacity, high efficiency, small footprint, and wide range of applications, and is widely used in wastewater treatment for petroleum, chemical, printing and dyeing, papermaking, oil refining, leather, steel, mechanical processing, starch, food, and other industries.

In recent years, air flotation technology has been widely used in water supply and drainage as well as wastewater treatment. It can effectively remove light flocs that are difficult to precipitate in wastewater.

1. Large processing capacity, high efficiency, and small footprint.

2. The process and equipment structure are simple, easy to use and maintain.

3. Can eliminate sludge swelling.

4. Aeration into the water during air flotation has a significant effect on removing surfactants and odors from the water. At the same time, aeration increases dissolved oxygen in the water, providing favorable conditions for subsequent treatment.

5. For water sources with low temperature, low turbidity, and high algae content, air flotation can achieve good results.

【 Working Principle 】

The pollutants in sewage are divided into dissolved organic matter and insoluble substances (i.e. SS). Dissolved organic matter can be converted into non soluble substances under certain conditions. One of the methods of sewage treatment is to add coagulants and flocculants to convert most of the dissolved organic matter into non soluble substances, and then remove all or most of the non soluble substances (i.e. SS) to achieve the purpose of purifying sewage. The main method of removing SS is to use air flotation.

After the chemical addition reaction, the sewage enters the mixing zone of air flotation and comes into contact with the released dissolved air water, causing the flocs to adhere to fine bubbles before entering the air flotation zone. Under the action of buoyancy, flocs float towards the water surface to form floating scum. The clear water in the lower layer flows through the collector to the clear water tank, and a part of it is refluxed for use as dissolved air. The remaining clear water flows out through the overflow port. After the floating slag on the surface of the air flotation tank accumulates to a certain thickness, it is scraped into the sludge tank of the air flotation machine by a scraper and discharged.

[Scope of Application]

1. Removal of various heavy metal ions (electroplating mixed wastewater treatment)

2. Oil water separation for refining and various types of oily wastewater

3. Oil and color removal from tannery wastewater

4. Separation of biofilm after biological treatment of various types of wastewater

5. Mud concentration (with a treatment capacity of 20-30% of the equipment's sewage treatment capacity)

6. Color removal treatment and impurity separation of printing and dyeing wastewater

7. Removal of algae in water supply engineering

8. Treatment of wastewater from sausage processing

1. Before installing the equipment, the foundation must be compacted. And use concrete mortar to elevate 100-150mm. It can also be installed overhead, but the foundation must be able to bear the weight of the equipment during operation.

2. After the equipment is in place, it needs to be adjusted horizontally.

3. The equipment needs to be equipped with a cleaning sewer, which can be dug into an open channel or directly connected to a regulating tank through a pipeline for flushing the air flotation tank and discharging the water.

4. The connecting pipeline between the sewage inlet and the reaction tank should be as short as possible to prevent the flocs from being damaged in the pipeline.

5. The clear water outlet can be connected to the sewer for discharge. If it needs to enter the next treatment process, it can be directly connected to the next treatment equipment.

6. The sludge outlet can be connected to the sludge tank or sludge treatment equipment.

7. The electrical box should generally be placed on the side of the escalator, and the environment should be clean and tidy.

A、 Before equipment debugging, the following preparations should be made:

1. Clean all the dirt and debris in the pool.

2. Lubricate parts such as water pumps and air compressors with oil.

3. Connect the power, start the water pump, and check if the direction of rotation is consistent with the direction indicated by the arrow. Start the air compressor manually and check if it is running normally. If any abnormal situation is found, promptly investigate the cause.

4. Press the foam scraper switch to move towards one end of the dissolved air system. After running to the end, under the action of the stroke collision block, the scraper moves in the opposite direction until it reaches the sludge tank. The stroke collision block flips up the scraper and presses the stop button to stop scraping.

B、 Trial operation:

1. Add water: Make the water level of the air flotation machine reach about 20-50MM from the upper edge of the sludge tank partition. The water level of the air flotation tank can be adjusted using a water collector.

2. Operation of dissolved gas system: Close all control valves, turn the electrical knob switch to the automatic position, start the water pump, and the air compressor will also enter the automatic working state. Then open the inlet valve, outlet valve, and control valve of the lifting water pump in sequence, and the pressure gauge pressure gradually increases, generally reaching 0.4-0.5MPA. At this point, open the outlet control valve of the dissolved air tank to release the dissolved air through the release device into the air flotation tank. A large number of fine bubbles appear in the air flotation tank, causing the clear water to turn milky white. The dissolved air system is normal, and the higher the dissolved air pressure, the higher the density of the released dissolved air bubbles. The gas in the dissolved gas system is provided by an air compressor. Due to the continuous removal of air from the tank by dissolved water, the air inside the tank gradually decreases and the water level rises. When the water level rises to a certain position, the float level gauge will control the operation of the air compressor to ensure sufficient air volume in the tank.

3. Air flotation operation: After the dissolved air system is running normally, the wastewater after the dosing reaction is sent to the air flotation mixing tank. The flow rate is initially reduced and gradually increases to the rated value after it returns to normal.

4. Dissolved water: Dissolved water is first treated with tap water as the reflux water, and then treated with clean water as the reflux water. If the amount of detergent in waste water is large and there are many foam, which will affect the flotation effect, clean water can be used all the time.

5. After the accumulation of floating slag to a certain thickness, start the foam scraper.

6. When the equipment is shut down, the sewage control valve should be closed first, then the sewage pump should be turned off, the foam should be scraped off, the foam scraper should be stopped, then the clean water valve should be opened, tap water should be introduced and run for 30 minutes, the dissolved air outlet and inlet control valve should be closed, and the clean water pump should be stopped.

【 Precautions and Daily Maintenance 】

1. The pressure gauge reading on the dissolved gas tank shall not exceed 0.6MPA.

2. Clean water pumps, air compressors, and foam blowers should be regularly lubricated with oil. Generally, air compressors should be lubricated every two months and replaced every six months.

3. The air flotation tank should be cleaned regularly depending on the amount of sediment.

4. The sewage entering the air flotation machine must be treated with chemicals, otherwise the effect will not be ideal.

5. Regularly check whether the safety valve on the dissolved gas tank is working reliably.

6. When the release device is blocked, the vacuum valve can be opened to open the release tongue, and it can be cleaned with clean water to flush the blockage. Then, the valve can be closed, which usually only needs to be opened for 10-20 seconds.