Method for preparing fertilizer by utilizing sludge left after sewage treatment and kitchen garbage

Abstract

The invention relates to a method for preparing a fertilizer by utilizing sludge left after sewage treatment and kitchen garbage. The method comprises the following steps that 1, sludge from a sewage treatment plant is subject to ultrasonic wave radiation for 30-90 minutes, the sound energy density of ultrasonic waves is 0.5-3 w / mL; 2, the sludge obtained after ultrasonic wave radiation is mixed with the kitchen garbage and wood bits according to the volume ratio of 8 to 2 to 1; 3, the mixture obtained after ultrasonic wave radiation is piled on an open place, transverse water discharging bodies are laid on the surface of the sludge at intervals of preset heights, vertical water discharging bodies inserted into the sludge are arranged at intervals, and then earthworms are put on the surface of the sludge and are sequentially and upward piled, wherein the number of the earthworms put in per cubic meter of sludge is 3000-6000; 4, after 3-15 days, a layer of seal film is laid on the sludge after earthworm processing, then the seal film is connected with a vacuumizing apparatus, and vacuum preloading and solidification treatment is conducted on the sludge by using the vacuumizing apparatus. By adopting the method, the sludge obtained after urban municipal sewage treatment can be utilized and treated to obtain the organic fertilizer.

Description

technical field [0001] The invention relates to a method for making fertilizer from remaining sludge and kitchen waste after sewage treatment, and belongs to the technical field of sewage treatment. Background technique [0002] With the acceleration of urbanization, the rate of urban sewage treatment has increased year by year, and the output of sludge after urban sewage treatment has also increased sharply. The sludge not only contains a large number of harmful substances and pathogenic bacteria, but also contains rich nutrients such as nitrogen, phosphorus, potassium and organic matter. substance. [0003] Moisture content refers to the percentage of the water contained in the sludge to the total mass of the sludge. Moisture content is an important physical property of sludge. The higher the water content, the larger the volume it occupies, which is more unfavorable for transportation and treatment. The lower the water content, the smaller the volume it occupies, which i...

AI Technical Summary

Problems solved by technology

Moreover, because the sludge residue contains harmful substances such as heavy metals, it is now strictly prohibited by local governments to landfill it. Although it is dehydrated by chemical methods and then burned in a furnace or disposed of by a cement factory, the amount of digestion is far from meeting the production volume.

The cost of traditional sludge treatment and disposal processes is high, usually accounting for about 50-60% of the total operating cost of sewage treatment. The high cost of sludge treatment and disposal has brought huge economic pressure to sewage treatment plants

[0004] More than 80% of the water in the sludge of domestic sewage plants is crystalline water that is difficult to evaporate even if it is exposed to the sun. The required energy and capital investment is very large, and secondary pollution is inevitable