Method for removing heavy metals from activated sludge

Abstract

A method for removing heavy metals from activated sludge is characterized in that through chemical catalytic hydrolysis and solid-liquid separation, the heavy metals exist in the filtrate; the filtrate is subjected to rough filtration pretreatment and ultrafiltration membrane separation in sequence; the permeate adopts adsorbent polyhumic acid to adsorb the heavy metals; the removal rate of the adsorbed heavy metals is higher than 95%; ultrasonic waves are used for desorption treatment; the heavy metals are in the state of hydroxide precipitation so as to be desorbed from the adsorbent in thedissolved state; the adsorbent is regenerated and reused; the heavy metal hydroxides are prepared for ferrite to recycle through recycling or harmless treatment, the process of harmless treatment is carried out through cement solidification and filling after stabilization; the concentrated solution of the ultrafiltration membrane and reverse osmosis membrane is subjected to vacuum evaporation andconcentration to produce fertilizers; the permeate of the reverse osmosis membrane is pure water which can be reused; the desorbed alkaline solution containing polyhumic acid is subjected to adsorbent recycling; and the regenerated acid liquid is recycled for acid blending, thus realizing zero emission of closed cycle. The method is conductive to environmental protection and resource recycling, simple in process, lower in cost and suitable for popularization and use.

Description

technical field [0001] The invention relates to a method for removing heavy metals, in particular to a method for removing heavy metals from activated sludge, and belongs to the technical field of organic solid waste resource treatment and comprehensive utilization. Background technique [0002] The existing treatment method for activated sludge with excessive heavy metals is the most traditional method of anaerobic digestion to produce biogas, and the reduced digested sludge is dried and dehydrated to a water content of less than 10% for incineration. The remainder is fly ash and slag containing excessive heavy metals, which are solidified with cement and landfilled. The organic components in the activated sludge are wasted in vain, the equipment investment is high, and the treatment cost is high. [0003] At present, there is another method in which the activated sludge is dried and dehydrated until the water content is less than or equal to 60% and directly landfilled. ...

AI Technical Summary

Problems solved by technology

[0007] The present invention aims to solve the above problems, overcome the waste of organic components in the activated sludge produced by anaerobic digestion, high equipment investment, and high processing costs; The ash and slag need secondary solidification and landfill treatment, and the process is complicated; and it overcomes the shortcomings of anaerobic high-temperature pyrolysis to produce charcoal, creosote, wood acetic acid, etc., which requires a relatively high equipment investment and high cost

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