Method for improving dehydration performance of residual sludge by assisting oxidization of ferrate by utilizing ultrasonic waves

Abstract

The invention relates to a method for improving dehydration performance of residual sludge by assisting oxidization of ferrate by utilizing ultrasonic waves and belongs to the technical field of sludge processing. The method comprises the following steps of: introducing concentrated sludge into a conditioning tank, and adding dilute sulfuric acid or dilute nitric acid into the conditioning tank while stirring, so as to enable the pH of the sludge to be 2.5-3.5; adding potassium ferrite under the action of the ultrasonic waves, adding calcium hydroxide into the reacted sludge and carrying out stirring, and regulating the pH to 6-7, wherein the adding amount of the ferrate (namely the mass ratio of the ferrate to the residual sludge) is ((0.5-2)*10<3>):1, the ultrasonic frequency is 20-40 kHz, the energy density of sound of a dry basis is 1000-3000 KJ / kg, and the action time is 60-90 seconds; carrying out mechanical dehydration on the processed sludge by utilizing a belt press-filter or centrifugal dehydration method, so as to obtain the dehydrated sludge with the water content of 70-75%. According to the method disclosed by the invention, the filtering specific resistance of the sludge can be reduced, the solid content of a mud cake can be increased, the reaction efficiency can be improved, the reaction time can be shortened, the processing capacity can be improved, and the sludge treatment cost can be lowered.

Description

technical field [0001] The invention relates to a method for improving the dewatering performance of excess sludge by ultrasonic-assisted ferrate oxidation. The invention belongs to the field of sewage sludge treatment and specifically relates to the application of industrial solid waste. Background technique [0002] The activated sludge process is widely used in municipal sewage plants, and its operation produces a large amount of excess sludge. The cost of excess sludge treatment is expensive, accounting for about 25-50% of the entire sewage treatment cost, which brings huge pressure to the treatment and operation of sewage plants. The excess sludge has a high moisture content and a large volume, so it must be dehydrated to reduce its volume. my country's sludge treatment started relatively late. Generally, after concentration and mechanical dehydration, the dewatered sludge with a moisture content of more than 80% is directly sent to the landfill for sanitary landfill....

AI Technical Summary

Problems solved by technology

[0003] Sludge has a stable structure similar to colloid, and a large amount of bound water contained in sludge flocs is difficult to remove, resulting in high filtration specific resistance of sludge, poor dehydration performance, and very difficult dehydration

At present, the organic polymer flocculant widely used in sewage plants is polyacrylamide. Although its coagulation efficiency is good, its price is high, and its monomer is toxic, and the residue is not easy to be biodegraded, which is easy to cause secondary pollution.