Sludge treatment is a process of stabilizing and reducing sludge, generally including thickening, dehydration, stabilization (anaerobic digestion, aerobic digestion, composting), drying and incineration. Sludge thickening, dewatering and drying mainly reduce the water content of sludge, but the dry solids do not change; Sludge stabilization is mainly due to decomposition and reduction of the amount of organic matter in dry solids, with little change in water content; Sludge incineration is to completely eliminate organic matter, combustible matter and water, which is the most thorough stabilization and reduction.
Sludge thickening: sludge thickening is mainly to remove the interstitial water between sludge particles. After thickening, the moisture content of sludge is 95% – 98%, and the sludge can still maintain its fluid characteristics. In the past, some sewage treatment plants in the world often used gravity thickener for sludge thickening, taking into account sludge homogenization and regulation, with low power consumption, no drug consumption and low operation cost; However, with the improvement of the requirements of nitrogen and phosphorus removal, the gravity concentration time is long and phosphorus is easy to release. The supernatant of gravity concentration tank returns to the influent, which increases the phosphorus load of sewage treatment. Therefore, most of the newly built sewage treatment plants adopt mechanical concentration. Some small sewage treatment plants adopt more simple concentration and dehydration integrated machine.
Sludge mechanical dewatering: sludge mechanical dewatering is mainly to remove the capillary water between the sludge particles. The moisture content of sludge after mechanical dewatering is 65% – 80%, which is in the shape of sludge cake.
In the past, mechanical dewatering equipment mainly included belt filter press, plate and frame filter press and sludge thickener. The belt filter press has low power consumption, low moisture content of filter cake, strong adaptability, good sealing performance, large treatment capacity and small land occupation. In the past, most sewage treatment plants used centrifuges, belt filter presses and plate and frame filter presses, while small sewage treatment plants generally used all-in-one thickening and dewatering machines. The box filter press is commonly used now, so the cost of sludge treatment is low. This series of sludge thickening and dewatering equipment is mainly a patented product developed and produced by ldhb. It has unique technology and is an ideal equipment for sludge dewatering.