Treatment method for removing and recycling heavy metals in wastewater sludge based on biological sulfur circulation

A technology of wastewater sludge and treatment method, which is applied in biological sludge treatment, biological water/sewage treatment, water/sludge/sewage treatment, etc., can solve the problems of high cost, complicated operation, secondary pollution, etc. The effect of low consumption cost, less consumption and saving processing cost

Active Publication Date: 2021-05-11
NANJING AGRICULTURAL UNIVERSITY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The method in this application extracts heavy metals through metal-selective extraction reagents, which is not only expensive, cumbersome to operate, but also easily causes secondary pollution

Method used

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  • Treatment method for removing and recycling heavy metals in wastewater sludge based on biological sulfur circulation
  • Treatment method for removing and recycling heavy metals in wastewater sludge based on biological sulfur circulation
  • Treatment method for removing and recycling heavy metals in wastewater sludge based on biological sulfur circulation

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0045] In this example, the biosulfur cycle is used to remove and recover heavy metals from wastewater sludge containing various heavy metal elements.

[0046] The sample was collected from the sludge thickening tank of a sewage treatment plant in an industrial park in Jiangsu. The solid content of the sludge was 3.2%. The basic properties are shown in Table 1. Compared with the sludge agricultural pollutant control standard (GB4284-84), the content of heavy metals such as Zn, Cu, Cd and Ni in the sludge exceeds the standard by 2-6.5 times.

[0047] Table 1 Basic properties of sludge

[0048]

[0049] The present embodiment is aimed at the treatment of above-mentioned sludge, and flow chart is as follows figure 1 shown, including the following steps:

[0050] Biological sulfur elemental oxidation stage (sulfur pellets): Add sludge with a solid content of 3.2% and 8.0g / L sulfur pellets to the biological sulfur oxidation reactor, blow and aerate for 10 days at 25°C, and the...

Embodiment 2

[0070] This embodiment is the removal and recovery of only a single high-concentration heavy metal Cu in the wastewater sludge of copper electroplating by biological sulfur circulation.

[0071]The sample is electroplating sludge from a wastewater treatment plant in an electroplating industrial park in Shandong. The solid content of the sludge is about 30%, and the pH is 6.8. The sludge mainly contains copper, and the total copper content is 10280mg / kg.

[0072] The treatment method for the removal and recovery of heavy metals in the sludge based on the biosulfur cycle of this embodiment includes the following steps:

[0073] Biological sulfur elemental oxidation stage (sulfur flakes): Add electroplating sludge with a solid content of 3% diluted with tap water and 12.0g / L sulfur flakes into the biological sulfur oxidation reactor, stir evenly and aerate for 5 days at 20°C , the pH of the sludge was reduced to 3, and the remaining sulfur flakes in the reactor were taken out, wa...

Embodiment 3

[0077] This embodiment is the removal and recovery of only a single high-concentration heavy metal Cu in the wastewater sludge of copper electroplating by biological sulfur circulation.

[0078] The sample is the same copper electroplating sludge as in Example 2. The treatment method for the removal and recovery of heavy metals in the sludge based on the biosulfur cycle of this embodiment includes the following steps:

[0079] Biological sulfur elemental oxidation stage (sulfur pellets + sulfur flakes): Add electroplating sludge with a solid content of 10% diluted with tap water, 5g / L sulfur pellets and 5g / L sulfur flakes to the biosulfur oxidation reactor at 35°C Down, stirred evenly and aerated for 15 days, the pH of the sludge dropped to 2.2, and the remaining sulfur balls and sulfur flakes in the reactor were taken out, washed with tap water and set aside.

[0080] Dehydration stage: 50% (v / v) of the sludge in the reactor is retained, and the rest of the sludge is dehydra...

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Abstract

The invention belongs to the technical field of sludge harmlessness and recycling, and discloses a treatment method for removing and recycling heavy metals in wastewater sludge based on biological sulfur circulation. The method comprises the following steps: 1) adding granular elemental sulfur S0 into sludge for treatment, and taking out the granular elemental sulfur S0 from the sludge when the pH value of the sludge is 2.0-3.0; 2) removing heavy metals from a sludge solid phase through sludge dewatering, and simultaneously generating acidic wastewater containing heavy metal ions; and 3) adding the residual granular elemental sulfur S0 and an electron donor into the acidic wastewater, treating for a period of time to generate metal sulfide, increasing the pH value of the wastewater, recovering the metal sulfide through natural sedimentation, and discharging supernate reaching the standard. According to the method, two exactly opposite biotransformation processes of sulfur oxidation and sulfur reduction are coupled and linked, so that the purpose of removing and recovering the heavy metals from the sludge is achieved, and closed-loop circulation and near-zero emission of the heavy metals in the whole treatment link are realized.

Description

technical field [0001] The invention belongs to the technical field of sludge harmlessness and resource utilization, and in particular relates to a treatment method for removing and recovering heavy metals in waste water sludge based on biological sulfur circulation. Background technique [0002] The sludge discharged from the sewage treatment plant accumulates 50%-80% of the heavy metals in the sewage. In some towns and industrial parks where a large amount of industrial wastewater is mixed (such as: mechanical production, semiconductor processing and metal surface treatment), the sewage plant sludge The content of Zn, Cu, Pb, Cr, Ni and other heavy metals can be as high as several hundred to several thousand mg / kg. In recent years, environmental hazards and social impacts caused by non-standard disposal of sludge containing heavy metals have been frequently reported. Removing or recovering high-concentration heavy (precious) metals in these sludges is of great significanc...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C02F11/02C02F3/34C02F3/28C02F101/20
CPCC02F11/02C02F3/345C02F3/28C02F2101/20
Inventor 方迪周立祥
Owner NANJING AGRICULTURAL UNIVERSITY
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