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Method for removing heavy metals in excess sludge by bioleaching-similar Fenton oxidative coupling

A technology of biological leaching and excess sludge, which is applied in biological sludge treatment, oxidation treatment of sludge, chemical instruments and methods, etc., can solve the problems of difficult application, high operating cost of sludge treatment, and long biological leaching period. , to achieve the effect of short process flow, low content of toxic and harmful substances and pathogens in sludge, and good dewatering performance

Inactive Publication Date: 2010-11-24
BEIJING FORESTRY UNIVERSITY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] Sludge Fenton oxidation requires low pH to achieve good results, so it is first necessary to add inorganic acid to acidify the sludge, which makes the sludge treatment operation cost high
However, the cycle of bioleaching is relatively long, which brings certain difficulties to practical application.

Method used

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  • Method for removing heavy metals in excess sludge by bioleaching-similar Fenton oxidative coupling
  • Method for removing heavy metals in excess sludge by bioleaching-similar Fenton oxidative coupling

Examples

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Effect test

example 1

[0022] This process is used for batch treatment of sludge in the laboratory. The treated sludge is the residual sludge produced by the oxidation ditch process to treat urban domestic sewage. The main characteristics of the sludge are: pH, 6.83; total solid content, 14461mg / L; volatile solid content, 10048mg / L; copper content, 421mg / L kg dry sludge; zinc content, 1512mg / kg dry sludge; lead content, 177mg / kg dry sludge; cadmium content, 13.7mg / kg dry sludge; chromium content, 258mg / kg dry sludge: arsenic content, 2.3 mg / kg dry sludge; nickel content, 59.9mg / kg dry sludge. Specific processing steps refer to figure 1 :

[0023] (1) Sludge bioleaching inoculum cultivation: The inoculum cultivation and domestication process uses concentrated sludge with a solid content of 2% from the oxidation ditch process. Take 100mL of sludge in a 250mL Erlenmeyer flask, add 10g / L of S powder and 10g / L of FeSO 4 ·7H 2 O, shake culture at 180r / min at 28°C until the pH of the sludge drops belo...

Embodiment 2

[0029] This process is used to expand the pilot scale treatment of sludge. The treated sludge is A 2 The remaining concentrated sludge after treatment of urban domestic sewage by / O process, the main characteristics of the sludge are: pH, 7.10; total solid content, 25660mg / L; volatile solid content, 20185mg / L; copper content, 299mg / kg dry sludge ; Zinc content, 2108mg / kg dry sludge; Lead content, 87.7mg / kg dry sludge; Cadmium content, 5.7mg / kg dry sludge; Chromium content, 48.5mg / kg dry sludge; Nickel content, 47.4mg / kg kg of dry sludge. Specific processing steps refer to figure 1 :

[0030] (1) Sludge bioleaching inoculum culture: In 5L sludge with a solid content of 2.5%, add sulfur powder and FeSO at 10 and 20g / L respectively 4 ·7H 2 O is used as an energy source for leaching bacteria, air is blown from the bottom of the reactor at 0.5 L / (min·L sludge), and the domesticated sludge is cultivated at 28 °C and 180 r / min under agitation until the pH of the sludge drops to ...

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Abstract

The invention relates to a method for removing heavy metals in excess sludge by bioleaching-similar Fenton oxidative coupling and belongs to the technical field of sewage and sludge treatment. The method comprises the following steps of: culturing domesticated autochthonous bioleaching bacteria serving as inoculation liquid in the sludge under the condition that enough substrate is added; adding the inoculation liquid into the excess sludge and bioleaching the sludge under the condition that oxygen exists, stirring is performed and an appropriate amount of substrate is added until the pH of the sludge is between 2 and 3; allowing H2O2 to produce strong oxidizing free radicals and the like to oxidizing the sludge under the catalytic action of Fe<2+> and Fe<3+>; adding solution of Ca(OH)2 into the treated sludge and adjusting the pH of the sludge to be between 6 and 7; and dehydrating the treated sludge by a plate and frame filter pressing or centrifugal dehydration method to obtain the dehydrated sludge of which the water content is between 65 and 75 percent. After the sludge bioleaching-similar Fenton oxidative coupling is performed, the dissolution rates of cadmium, mercury, lead, chromium, arsenic, nickel, zinc and copper in the sludge are up to 50 to 65 percent, 50 to 70 percent, 15 to 35 percent, 55 to 70 percent, 70 to 80 percent, 65 to 80 percent, 60 to 85 percent and 60 to 80 percent respectively. The heavy metal content of the sludge is lower than the requirements of The Disposal of Sludge from Municipal Wastewater Treatment Plant: Control Standards for Agricultural Use of the State Criteria of the People's Republic of China (CJT309-2009) and The Disposal of Sewage Sludge from Municipal Wastewater Treatment Plant Sludge Quality for Afforestation in Gardens or Forests (GB / T 23486-2009).

Description

technical field [0001] The invention belongs to the technical field of sewage sludge treatment, adopts biological leaching-Fenton-like oxidation coupling to remove heavy metals in excess sludge, makes the treated sludge reach the standard of agricultural sludge or forestry sludge, and lays the foundation for subsequent resource utilization of sludge Base. Background technique [0002] With the development of the economy and the improvement of people's living standards, the public's requirements for environmental quality are increasing day by day. In order to prevent water pollution and improve the ecological environment, most cities in my country have built centralized domestic sewage treatment plants. The current sewage treatment technology transfers a large amount of pollutants in the sewage to the remaining sludge through microbial metabolism and other physical and chemical methods. The essence is the phase transfer of pollutants, and the water pollution problem is conve...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C02F11/02C02F11/06C02F11/12C02F101/20
Inventor 张盼月肖凌鹏张光明孙世昌
Owner BEIJING FORESTRY UNIVERSITY
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