At present, sand and gravel aggregates are the main building materials for structures such as concrete and masonry in water conservancy projects. However, the existing sand and gravel aggregates are washed through ordinary sand washing equipment, which cannot achieve a good separation of sand and gravel aggregates. The effect is poor. Need to go through many times of sand washing, the efficiency of sand washing is slow, and in the sand washing process, the wastewater generated in the sand washing process of the sand washing machine is directly discharged, which causes environmental pollution.

Sand washing wastewater treatment steps

To solve the technical problem of environmental pollution caused by the existing sand washing process of sand and gravel aggregates, LZZG provides an effective sand washing wastewater treatment process, which in turn includes the following steps.

1. Sand washing: Obtain a mixture of sand and gravel aggregate and mud water.

2. One-time separation: Separate the mixture obtained in step 1 to obtain a mixture of fine sand and fine mud and sand and gravel aggregates, and pass the separated sand and gravel aggregates through a dewatering screen for dehydration treatment.

3. Secondary separation: Separate the mixture of fine sand and fine sludge after separation in step two to obtain fine sand and sludge, and pass the separated fine sand through a dewatering screen for dewatering treatment to separate the treated sludge The solid content is 7-30%.

4. Concentration treatment: The sludge after the separation treatment in step three is pretreated and concentrated by adding flocculants in sequence, and the solid content of the sludge after pretreatment with flocculants is 30-40%. The solid content in the mud is not less than 50%.

5. Buffer treatment: the sludge after the thickening treatment in step 4 is buffered through the buffer tank, and the concentrated overflow water after the thickening treatment in step 4 is recovered for the acquisition of the mixture in step 1.

6. Three separations: the sludge after the buffer treatment in step 5 is separated and treated to obtain water and sludge.

7. Recycling: The water separated in step 6 is filtered through a filter box and then recycled through a clean water tank. The sludge separated in step 6 is discharged through a forklift.

Advantages of the process

1. Sequentially through sand washing, primary separation, secondary separation, concentration treatment, buffer treatment, tertiary separation, and recycling treatment of sand washing wastewater treatment process, the rapid separation of sand and water can be achieved through multiple separations, which can not only improve sand Separation efficiency from water and zero discharge of wastewater after sand washing, thereby realizing the efficiency of energy-saving and emission reduction. The buffer treatment can be buffered according to different sand and gravel aggregates to meet different sand washing requirements and the overall treatment process is simple, easy to operate with high sand washing efficiency.

2. The sand and gravel aggregate is washed with water and then sieved by a sieving machine to obtain a mixture of sand aggregate and mud water. The sieving machine can effectively remove other impurities in the sand and gravel aggregate and improve the aggregate and The quality of mud water is conducive to subsequent treatment and can realize water recycling and save water resources.

3. The spiral sand washer realizes the separation of fine sand and sludge. The spiral sand washer has the advantages of low power consumption, high cleanliness, overall cleaning, good dewatering effect, and stable fine sand and sludge during the separation process.

4. Through the pump, the mixture of fine sand and fine mud can be quickly transported to the cyclone, which improves the transportation efficiency, and through the centrifugal sedimentation principle of the cyclone, the separation of fine sand and fine mud can be quickly achieved.

5. The flocculant is added to the thickening tank through the flocculant supply box, which can realize the effective mixing of the flocculant and the sludge. Improve the efficiency of concentration, and the flocculant can remove the suspended solids in the wastewater, to achieve the purpose of water treatment, thereby realizing the recycling of water and reducing the discharge of wastewater.

6. Set the thickening tanks into two groups, which can realize two thickening treatments of sludge, and can stably and reliably ensure that the solid content in the thickened sludge is not less than 50%.

7. Set the thickening tank into a tank body and a feed pipe. The sludge is fed through the feed pipe, and the conical baffle is used to slow down the sludge falling speed, to avoid the sludge from being in the tank after being fed. Disperse, improve the quality of concentration.

8. Realize the unified recovery treatment of concentrated overflow water through the collection box, avoid the waste of concentrated overflow water, and control the flow of the return pipe through the flow valve, which can supply water according to different weights of gravel aggregates, reducing the step one Add the weight of water, thereby saving costs. The recycling of resources has been realized, and the efficiency of energy-saving and emission reduction has been realized.

9. The sludge is separated by a membrane filter press, which can effectively and quickly separate water and sludge, and can ensure that the moisture content of the separated sludge cake is less than 30%. It is conducive to the rapid realization of a dry pile of sludge filter cake.