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Method for simultaneously stabilizing heavy metals and deeply dewatering municipal sludge for municipal sludge

A technology for dewatering municipal sludge and sludge, applied in chemical instruments and methods, water/sludge/sewage treatment, sludge treatment, etc., can solve problems such as long treatment cycle, reduced leaching rate, and limited resource utilization

Inactive Publication Date: 2013-05-01
上海环境保护有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The solidification technology of heavy metals in sludge mainly involves cement solidification method, lime solidification method, thermoplastic solidification method, vitrification technology, self-cementation solidification technology, etc., but these methods have the following defects: (1) The pollution is greatly changed. The structure of the sludge hardens or increases the volume of the sludge, which limits the subsequent utilization of resources; (2) the partial solidification method is expensive, complicated to operate, and difficult to popularize and apply
[0009] CN1544366A discloses a method for treating heavy metals in sludge, which uses sulfide and lime as fixatives to stabilize heavy metals and reduce their leaching rate
[0028] As mentioned above, although effective methods for stabilizing heavy metals and reducing water content have been developed so far, these methods also have certain shortcomings, such as cumbersome operation, long treatment cycle, large energy consumption, and high cost. , difficult to promote, etc., especially for heavy metal stabilization and sludge dewatering, there is still no technical means that can achieve these two goals at the same time and is easy to operate

Method used

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  • Method for simultaneously stabilizing heavy metals and deeply dewatering municipal sludge for municipal sludge
  • Method for simultaneously stabilizing heavy metals and deeply dewatering municipal sludge for municipal sludge
  • Method for simultaneously stabilizing heavy metals and deeply dewatering municipal sludge for municipal sludge

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0068] Example 1: Stability determination and speciation determination of heavy metals in dewatered sludge

[0069] Take the sludge from a sewage treatment plant in Shanghai, the water content is 81%, and the heavy metal content is as follows:

[0070]

[0071] Four parts of the same weight of the above sludge were taken as sample 1, sample 2, sample 3 and sample 4 respectively.

[0072] According to the above-mentioned steps (1) and (2) in the method of the present invention, in percentage by weight, add successively in sample 1 the ferrous sulfate heptahydrate that is 10% of sludge dry weight and the ferrous sulfate that is 5% of sludge dry weight lime (calcium hydroxide).

[0073] According to the above-mentioned steps (1)-(3) in the method of the present invention, in percentage by weight, add successively in sample 2 the ferrous sulfate heptahydrate that is 10% of sludge dry weight, be the ferrous sulfate heptahydrate of 5% of sludge dry weight Calcium hydroxide and ...

Embodiment 2-3

[0094] Embodiment 2-3: Stability determination and speciation determination of heavy metals in dewatered sludge

[0095] Except that the order of adding sample 4 is changed to add successively the ferrous sulfate heptahydrate which is 10% of the dry weight of the sludge, the calcium hydroxide which is 5% of the dry weight of the sludge, and the fluorophosphorus ash which is 2.5% of the dry weight of the sludge. stone and the clay mineral (corresponding embodiment 2) that is 2.5% of sludge dry weight, and change to add successively the ferrous sulfate heptahydrate that is sludge dry weight 10%, the calcium hydroxide that is sludge dry weight 5% In addition to the homogeneous mixture (corresponding to Example 3) obtained by mixing the clay minerals of 2.5% of the sludge dry weight with the fluorapatite of the sludge dry weight of 2.5%, carried out respectively in the same manner as in Example 1 Examples 2 and 3, and carried out heavy metal leaching test and speciation distribut...

Embodiment 4

[0097] Example 4: Stability determination and speciation determination of heavy metals in dewatered sludge

[0098] In addition to adding various components accounting for the following percentages of sludge dry weight in the following samples, and the kaolinite added therein has a Blaine specific surface area of ​​3000cm 2 / g, particle size is 400 orders, and the particle size of fluoroapatite is outside 400 orders, has carried out heavy metal leaching test and shape distribution determination in the same manner as embodiment 1:

[0099] Sample 1: 15% ferrous sulfate heptahydrate + 7.5% lime;

[0100] Sample 2: 15% ferrous sulfate heptahydrate + 7.5% lime + 10% kaolinite;

[0101] Sample 3: 15% ferrous sulfate heptahydrate + 7.5% lime + 10% fluorapatite;

[0102] Sample 4: 15% ferrous sulfate heptahydrate + 7.5% lime + 5% kaolinite + 5% fluorapatite.

[0103] The stability results are shown in Table 2 below.

[0104] Table 2. Heavy metal leaching concentrations before a...

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Abstract

The invention relates to a method for simultaneously stabilizing heavy metals and deeply dewatering municipal sludge for municipal sludge. The method comprises the step of: adding a certain amount of ferrite, lime, clay minerals and / or apatite in municipal sludge. Form of heavy metals in municipal sludge treated by the method is transformed to a stable state, so that the leaching concentration of heavy metal pollutants is reduced, and the heavy metal pollutants can be quickly and effectively sealed and stored stably. Meanwhile, the municipal sludge can be conditioned, so the dewatering performance is remarkably improved, the dewatering efficiency of sludge is extremely improved, and the moisture content is reduced for convenience of subsequent treatment and reduction of cost. The method is an efficient and novel treatment method which can obtain a good economic benefit.

Description

technical field [0001] The invention relates to a method for harmless treatment of solid waste pollution, in particular to a method for simultaneously realizing heavy metal stabilization and deep dehydration of urban sludge, and belongs to the fields of sludge treatment and environmental protection. Background technique [0002] Municipal sludge is the inevitable product of the biological process of secondary sewage treatment plants. With the acceleration of urbanization in my country and the improvement of centralized sewage treatment rate, the annual sludge output of sewage plants in my country is increasing day by day. According to statistics, by the end of 2010, my country's sewage The annual output of the treatment plant is about 21 million tons of sludge with 80% water content, and the annual output of sludge will increase at an accelerated rate in the future. [0003] The harmlessness and reduction of sludge are important principles of sludge treatment and disposal. Ho...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C02F11/00C02F11/14
Inventor 付融冰王旌徐珍
Owner 上海环境保护有限公司
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