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Method for removing heavy metal by pretreated sludge

A pretreatment and heavy metal technology, applied in the direction of sludge treatment, multi-stage water treatment, water/sewage treatment, etc., can solve the problems of poor economy, complicated process, low adsorption efficiency, etc., and achieve low operating cost, simple process, and easy operation and the effect of easy control

Inactive Publication Date: 2016-07-20
RES CENT FOR ECO ENVIRONMENTAL SCI THE CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] In order to overcome the disadvantages of low adsorption efficiency, poor economy and complex process in the above-mentioned traditional heavy metal adsorption method, the present invention provides a method for efficiently removing heavy metal ions in wastewater with simple process, simple operation and control, and low operating cost. The sludge produced by the sewage treatment plant is used to absorb the heavy metals in the precipitated wastewater, so that the sludge can be used as a resource while the sludge is harmlessly treated, and the cost of removing heavy metal pollution can be reduced, and the waste can be treated with waste.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0026] A method for removing heavy metals from pretreated sludge, the method comprising:

[0027] Step A, sludge pretreatment, release the organic substances in the sludge and form sludge solids;

[0028] Step B, mixing the pretreated sludge or its components with the heavy metal wastewater;

[0029] Step C, precipitation separation.

[0030] Further, step A includes

[0031] Step A1, the sludge concentration treatment of the sewage treatment plant, the retrieved sludge is allowed to settle freely for 6 hours to concentrate, and the sludge concentration is adjusted to 100g / L;

[0032] Step A2, pretreat the concentrated sludge. The sludge pretreatment methods include heat treatment, microwave treatment, ultrasonic treatment, acid-base treatment, high-voltage pulse electric field treatment, homogeneous treatment and mechanical crushing, and other methods that can dissolve the sludge. Any one or a combination of several cell treatment methods.

[0033] Further, the specific o...

Embodiment 2

[0038] The remaining sludge from the sewage treatment plant was concentrated by free precipitation, the sludge concentration was adjusted to 14g / L, the pH value of the sludge was adjusted to 13 with NaOH solution, heat treatment was carried out at 175°C for 70min, and then the sludge was heated at 8000r Centrifuge for 5min at 1 / min to separate the sludge solids from the supernatant, and finally mix the sludge supernatant with 30mg / LCu 2+ The solution was mixed 1:4 and kept shaking for 1h.

[0039] After removing the precipitate, Cu in the supernatant 2+ The concentration is 5.26mg / L, Cu 2+ The removal rate reached 82.5%.

Embodiment 3

[0041] The remaining sludge from the sewage treatment plant was centrifuged and concentrated, and the sludge concentration was adjusted to 200g / L. Ultrasonic treatment was performed with ultrasonic power of 1800W, frequency of 100kHz, and acoustic energy density of 1.0W / ml for 60 minutes. The sludge after ultrasonic treatment was mixed with 30mg / LPb 2+ The solution was mixed at a volume ratio of 1:10, and continuously oscillated and mixed for 1.5h, centrifuged at 5000r / min for 15min, the Pb in the supernatant 2+ The concentration is 1.48mg / L, Pb 2+ The removal rate reached 95.1%.

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Abstract

The invention relates to a method for removing heavy metal by pretreated sludge. The method mainly comprises three parts of pretreating sludge, mixing pretreated sludge or components thereof with a heavy metal wastewater solution, and performing precipitation separation. The method is operated through the following steps: firstly, concentrating sludge in a wastewater treatment plant, performing regulation until appropriate concentration is obtained, and then performing pretreatment; then, stirring and mixing the pretreated sludge or the components thereof with the heavy metal wastewater solution, and finally, performing precipitation separation. Appropriate pretreatment is adopted, so that organic matters in the sludge can be released out. The organic matters can be combined with heavy metal ions in the wastewater, so that precipitates are produced; pretreated solid sludge can adsorb the heavy metal ions in the solution all the same, and the heavy metal ions can be removed under two actions. The method disclosed by the invention is simple in technology, simple and convenient to operate and control, and low in running cost, and the purpose of treating waste with another waste is realized.

Description

technical field [0001] The invention belongs to sludge treatment technology, in particular to a method for removing heavy metals in waste water solution after pretreatment by utilizing surplus sludge of a sewage treatment plant. Background technique [0002] Excess sludge is a by-product produced in the process of sewage biological treatment. The sludge contains a large amount of organic waste, which can easily cause secondary pollution to the environment without treatment. With the acceleration of urbanization and industrialization in my country, the amount of urban sewage treatment has also increased significantly, and the surplus sludge produced after sewage treatment has also increased significantly. According to reports, in 2015, the sludge output of urban sewage treatment plants in my country (in terms of Moisture content 80%) reached 33.59 million tons, and it is still increasing. It is estimated that the sludge output will exceed 60 million tons by 2020. The tradition...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C02F1/28C02F9/02C02F11/00C02F11/12
CPCC02F1/281C02F1/28C02F1/38C02F1/52C02F9/00C02F11/00C02F11/12C02F11/127C02F2101/20C02F2101/203C02F2101/206C02F2101/22C02F2301/08
Inventor 肖本益翟世民郭雪松刘俊新
Owner RES CENT FOR ECO ENVIRONMENTAL SCI THE CHINESE ACAD OF SCI