Sand washing wastewater treatment

Sand washing wastewater treatment refers to the process of treating wastewater containing a large amount of silt, suspended matter and possibly a small amount of chemical additives generated during the sand washing process to achieve the recycling of wastewater, reduce environmental pollution and meet the requirements of environmental protection regulations. Sand washing wastewater is characterized by high concentration, large silt content and high suspended matter. If not properly treated, it will not only cause waste of water resources, but also cause serious pollution to the surrounding environment. The following are the basic steps and common equipment for sand washing wastewater treatment: Basic treatment process 1. Pretreatment and sedimentation: - Concentration tank/pre-sedimentation tank: Sand washing wastewater first enters the concentration tank or pre-sedimentation tank, and naturally settles by gravity. Large particles such as silt and sand are deposited at the bottom, and the upper clear liquid can be initially separated. This stage can reduce the load of subsequent treatment facilities and extend their service life. - Flocculant addition: In order to accelerate the separation of mud and water and improve the sedimentation effect, flocculants are usually added to the outlet of the pre-sedimentation tank to aggregate fine particles into larger flocs for further sedimentation. 2. Secondary sedimentation and deep separation: - Secondary sedimentation tank: The wastewater after flocculation treatment enters the secondary sedimentation tank, where the flocs continue to precipitate to form sludge, and the supernatant is further clarified. - Mud pump: The sludge at the bottom of the sedimentation tank is transported to the dewatering equipment through the mud pump. 3. Dewatering treatment: - Belt filter press: The mud undergoes gravity dehydration, pre-pressure dehydration, extrusion dehydration and other stages on the belt filter press, and finally forms a mud cake with extremely low moisture content. The mud cake can be directly drained, landfilled, or used for other resource utilization (such as greening backfill, brick making raw materials). - Other dehydration equipment: Depending on the specific process and site conditions, other types of dehydration equipment such as chamber filter presses and centrifugal dehydrators may be selected. 4. Clean water recovery and recycling: - Clean water tank: The clarified supernatant (i.e. treated clean water) obtained after the above treatment enters the clean water tank for storage, which can be recycled for sand washing operations, greatly reducing the consumption of fresh water sources. - Water quality monitoring: Regularly monitor the water quality of circulating water to ensure that it meets the sand washing process requirements and environmental protection standards. 5. Sludge disposal: - Drying yard: Some sludge may be naturally dried in the drying yard to further reduce the moisture content, and then transported to a designated location for landfill or other uses. - Direct dehydration and transportation: The mud cake formed by dehydration by equipment such as belt filter press can be directly transported to landfill or used for resource utilization due to its low moisture content. Equipment configuration and safeguard measures - Equipment backup: Sand washing wastewater treatment equipment is usually equipped with backup parts or backup systems to deal with sudden failures and ensure the continuity of construction or production. Manufacturers usually promise to complete maintenance response within a specified time (such as 24 hours). - Safety and compliance: The design and operation of the equipment should comply with relevant safety production standards and environmental protection regulations to ensure the safety of operators and the compliance of wastewater discharge. The system has a large processing capacity and a high purification and sand removal rate, and can effectively treat a large amount of sand washing wastewater. Comprehensive management and optimization - Monitoring and control: Use an automated control system to monitor various parameters in the sewage treatment process (such as flow, turbidity, pH value, dosage of reagents, etc.) in real time, and adjust the operating conditions based on feedback to ensure stable treatment effects. - Wastewater source control: Optimize the sand washing process, reduce the use of chemical additives in the sand washing process, and reduce the initial pollution load of wastewater. - Resource utilization: Encourage the use of treated mud cakes for land improvement, building material manufacturing, etc., to realize the resource utilization of waste, reduce disposal costs and comply with the concept of circular economy. In summary, sand washing wastewater treatment is a comprehensive process involving pretreatment, sedimentation, deep dehydration, clean water recovery and recycling, sludge disposal and other links. By reasonably selecting and combining various equipment and processes, it is ensured that sand washing wastewater is effectively treated, while maximizing resource utilization and minimizing environmental impact.