Treatment method of excess sludge of sewage treatment plant

Abstract

The invention provides a treatment method of excess sludge of a sewage treatment plant. The method comprises the following steps: (1) uniformly stirring and mixing sludge and chromium-containing sewage to prepare mixed slurry, introducing the obtained mixed slurry into an aeration tank provided with an ultrasonic generator probe; adding a treating agent A into the mixed slurry, stirring to enablethe treating agent A to be fully dispersed into the mixed slurry, then adjusting the pH of the mixed slurry to 3.0-3.5, adjusting the ultrasonic intensity to 0.40-0.45 W / mL, carrying out ultrasonic treatment for 2.5-3.5 min, and then carrying out stirring treatment; (2) adding a treating agent B into the treated mixed slurry, stirring, and then pumping the mixed slurry into a plate-and-frame filter press for dehydration treatment; (3) adding fluidized bed ash into the dewatered slurry, and uniformly stirring and mixing to obtain mud cake; and (4) smelting the obtained mud cake to obtain a metal alloy and slag. According to the method, the purpose of treating waste with waste is achieved, organic pollutants in the sludge can be efficiently removed, and recovery of heavy metal ions is achieved.

Description

technical field [0001] The invention relates to the field of sludge treatment, in particular to a method for treating excess sludge in a sewage treatment plant. Background technique [0002] Residual sludge in sewage treatment plants is the waste generated in sewage treatment. The residual sludge contains a large amount of organic matter, heavy metals and microorganisms. At present, the domestic treatment methods for residual sludge in sewage treatment plants mainly include: dry incineration, Solidified landfill road construction, coking treatment, solvent extraction, land farming, composting, etc. Although the existing sludge treatment process can realize the treatment of sludge to a certain extent, at the same time, these methods have some limitations. For example, toxic and harmful gases such as dioxin may be produced during the drying and incineration process, and cannot Thoroughly solve the pollution problem of heavy metals and other harmful substances contained in slu...

AI Technical Summary

Problems solved by technology

[0006] (1) Stir and mix the sludge and chromium-containing sewage at a volume ratio of 1:0.5-0.6 to obtain a mixed slurry, and then introduce the resulting mixed slurry into an aeration tank equipped with an ultrasonic generator probe, and pour into the mixed slurry Add treatment agent A to the mixture, stir to fully disperse treatment agent A into the mixed mud, then adjust the pH of the mixed mud to 3.0-3.5, turn on the ultrasonic generator, adjust the ultrasonic intensity to 0.40-0.45W / mL, and ultrasonic treatment to 2.5-3.5 min, and then stirred for 50-60min; the treatment agent A comprises: 8-10% cerium oxide and 90-92% ferric sulfite by mass percentage; the arrangement density of ultrasonic generator probes is 2 Set up a probe whose depth range is 50% of the effective water depth of the aeration tank; under certain pH conditions, after the added chromium-containing sewage is mixed with ferric sulfite and cerium oxide in treatment agent A, it can produce a large amount of sexual SO 4 ˙ - Free radicals, combined with a large number of OH free radicals generated by the ultrasonic process, can efficiently oxidize organic pollutants such as benzene series and phenols contained in sludge. Cerium oxide has the function of storing and releasing oxygen, and is used as a raw material for treatment agent A After being added to the mixed mud, it can release oxygen and increase the content of dissolved oxygen, which is beneficial to SO 4 ˙- The formation of free radicals, the ultrasonic process can also generate vibratory shearing force to achieve the purpose of destroying the microbial cell wall and release intracellular water, which is conducive to improving the dehydration efficiency of the sludge in the subsequent process; through ultrasonic and chromium-containing sewage-treatment agent The mutual cooperation and mutual coordination of the A system can not only solve the problem of high energy consumption in the simple use of ultrasound, but also realize "treatment of waste with waste", reduce treatment costs and improve economic benefits;