Sewage treatment plant sludge treatment and disposal technologies mainly include:
1. Concentration and dehydration technology
Sludge thickening is to remove part of the water in the sludge by gravity or mechanical means to reduce the volume; sludge dewatering is to separate part of the interstitial water in the sludge by mechanical means to further reduce the volume. The methods of sludge concentration are mainly divided into gravity concentration, mechanical concentration and air flotation concentration. At present, gravity concentration and mechanical concentration are often used; dehydration mainly includes pressure filter dehydration, centrifugal dehydration and plate and frame filter press dehydration.
2. Anaerobic digestion technology
Anaerobic digestion is a very effective sludge treatment process that uses facultative bacteria and anaerobic bacteria to carry out anaerobic biochemical reactions, decomposes organic substances in sludge, produces biogas and other usable resources, and achieves sludge stabilization. For mesophilic anaerobic digestion and high temperature anaerobic digestion.
3. Aerobic fermentation technology
Usually refers to high temperature aerobic fermentation, which is a process of converting organic matter in sludge into stable humus through the biological metabolism of aerobic microorganisms.
4. Sludge thermal drying technology
The technology of removing water in sludge through heat transfer between sludge and heat medium. At present, the most widely used sludge drying technologies include fluidized bed drying, belt drying, paddle drying, horizontal rotary disk drying, vertical disc drying and spray drying. The sludge is dried to below 60% water content.
5. Lime stabilization technology
By adding a certain proportion of quicklime to the dewatered sludge and mixing it uniformly, the quicklime reacts with the moisture in the dewatered sludge to generate calcium hydroxide and calcium carbonate and release heat to achieve sterilization and inhibition of corrosion, dehydration, sludge The role of modification and granulation.
6. Other technologies
Sludge pyrolysis treatment technology refers to the technology that the organic matter in the sludge is heated to a certain temperature under anoxic conditions and cracked, and converted into fuel oil, gas, sludge carbon and water.
Sludge hydrothermal treatment technology is a technology that heats the sludge, hydrolyzes the viscous organic matter in the sludge under a certain temperature and pressure, destroys the colloidal structure of the sludge, and improves the dehydration performance and anaerobic digestion performance.