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Method for treating sludge heavy metal

A heavy metal and sludge technology, applied in sludge treatment, chemical instruments and methods, water/sludge/sewage treatment, etc., can solve the problems of removing a lot of financial resources, refractory treatment, secondary pollution, etc., so as to facilitate popularization and application, The effect of simple operation and low cost

Inactive Publication Date: 2007-10-03
重庆市天境生态环境有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The disadvantages of chemical methods, biological methods, phytoremediation methods and incineration methods are that the removal of heavy metals from sludge not only requires a lot of financial and material resources, but it is obviously impractical to adopt this method in the face of hundreds of tons of sludge per year. And those plants that have absorbed and enriched heavy metals are also difficult to further process, and may cause secondary pollution problems; some studies have used fly ash to directly passivate heavy metals in sludge, although test results show that adding 10% to 20 % fly ash can significantly reduce the available content of zinc (Zn), copper (Cu), manganese (Mn) and lead (Pb) in the sludge, and its form changes from an unstable state to a stable state, but When the sludge and soil are applied at a volume ratio of 1:5, it will not affect the biological and environmental effects of the sludge
Moreover, this method uses the strong alkalinity of fly ash to make the heavy metals in the sludge form alkaline precipitates, which will dissolve when they encounter acid, and then lose the solidification and stability to cause secondary pollution, especially for Chongqing, where acid rain is more serious. is not feasible

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0020] The specific steps of a method for treating sludge heavy metals are as follows:

[0021] (1) Preparation of lime modified fly ash adsorbent

[0022] According to the ratio of lime:fly ash weight ratio of 1:5.7, lime and fly ash are added into the high-speed mixer and mixed evenly, then the mixture is put into the roasting furnace for roasting, the roasting temperature is 950°C, after roasting for 2.5 hours , and then the material is taken out and cooled, and finally ground to prepare a specific surface area of ​​850m 2 / kg of modified fly ash adsorbent.

[0023] (2) Treatment of sludge

[0024] After the step (1) is completed, add the lime-modified fly ash adsorbent prepared in the step (1) to the dewatered municipal sludge that has passed through a 10-mesh sieve, stir and mix evenly, and use the constant weight method at a temperature of 30°C Passivate for 10 days under the condition of maintaining moisture content of 35%. Wherein the weight percentage of adsorbent...

Embodiment 2

[0026] The specific steps of a method for treating sludge heavy metals are as follows:

[0027] (1) Preparation of lime modified fly ash adsorbent

[0028] According to the weight ratio of lime: fly ash is 1:14, put lime and fly ash into the high-speed mixer and mix evenly, then put the mixture into the roasting furnace for roasting, the roasting temperature is 1000°C, after roasting for 3 hours , and then the material is taken out and cooled, and finally ground to prepare a specific surface area of ​​1000m 2 / kg modified fly ash adsorbent.

[0029] (2) Treatment of sludge

[0030] After the step (1) is completed, add the lime-modified fly ash adsorbent prepared in the step (1) to the dewatered municipal sludge passing through a 10-mesh sieve, stir and mix evenly, and use the constant weight method at a temperature of 42°C to Under the condition of maintaining moisture content of 40%, passivation for 14 days. Wherein the weight percentage of adsorbent: dewatered sludge is ...

Embodiment 3

[0032] The specific steps of a method for treating sludge heavy metals are as follows:

[0033] (1) Preparation of lime modified fly ash adsorbent

[0034] According to the weight ratio of lime: fly ash is 1:19, put lime and fly ash into the high-speed mixer and mix evenly, then put the mixture into the roasting furnace for roasting, the roasting temperature is 1050°C, after roasting for 3.5 hours , and then the material is taken out and cooled, and finally ground to prepare a specific surface area of ​​1050m 2 / kg of modified fly ash adsorbent.

[0035] (2) Treatment of sludge

[0036] After the step (1) is completed, add the lime-modified fly ash adsorbent prepared in the step (1) to the dewatered municipal sludge passing through a 10-mesh sieve, stir and mix evenly, and use the constant weight method at a temperature of 58°C to Passivate for 15 days under the condition of maintaining moisture content of 45%. Wherein the weight percentage of adsorbent: dewatered sludge i...

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Abstract

A process for treating the heavy metals in sludge, especially the Zn and Cu in city sludge features that the lime modified powdered coal ash is used to passivate the Zn and Cu in the dewatered city sludge. Its passivated rate is more than 85% for Cu and more than 70% for Zn.

Description

1. Technical field [0001] The invention belongs to the technical field of treating heavy metals in sludge, in particular to a method for treating urban sludge with high zinc and copper content. 2. Background technology [0002] The disposal and utilization of sludge has attracted more and more attention. Since sludge is rich in nitrogen, phosphorus, potassium and organic matter, it is a good plant nutrient raw material and soil physical property improver. It is a good choice for agriculture and landscaping. This is the most economically feasible and promising disposal method, which is highly valued by countries all over the world. However, the utilization rate of sludge in various countries in the world is not high at present, such as the United Kingdom, Switzerland, and the Netherlands, which are only 40% to 50%. The important reason is that the heavy metal content in the sludge exceeds the standard. However, the heavy metal content in the sludge produced by my country's ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C02F11/00C02F101/20
Inventor 郑怀礼王白雪唐鸣放谭铭卓吴幼全
Owner 重庆市天境生态环境有限公司
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