Method for jointly treating polluted sludge by electroosmosis and solidification

Abstract

The invention discloses a method for electro-osmosis solidification combined treatment of polluted sludge, which comprises the following steps: 1) fishing out the polluted sludge and filtering to remove water on the surface of the polluted sludge to obtain pretreated sludge; 2) filling the pretreated sludge into an electroosmosis device for electroosmosis treatment until the required water contentis reached; 3) taking out the electrode of the electroosmosis device, adding a curing agent into the treatment tank, and stirring to obtain solidified sludge. The above method is convenient to construct, and only requires a small amount of energy consumption and curing agent to achieve a good drainage consolidation effect.

Description

technical field [0001] The invention relates to the technical field of polluted sludge treatment, in particular to a method for electroosmotic solidification combined treatment of polluted sludge. Background technique [0002] Due to the unique geographical advantages of coastal countries, coastal cities, and areas with rich water resources such as rivers and rivers, the rapid economic development and the huge flow of people make commercial land and housing land very tight, but this brings land resources. In short supply. In order to alleviate this situation, there are sea reclamation projects all over the world, that is, sand and gravel are injected into the sea to make land or build artificial islands to increase land supply in the silted tidal flat section; however, the water content of marine silt is as high as 70wt%, and the rest is mostly sand, so the mud-water mixture blown up to the bank is in a fluid plastic state, and the formed blown fill foundation has extremely...

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Problems solved by technology

Among the above-mentioned consolidation techniques, the heap loading and vacuum preloading methods usually require loads to be applied on the site. However, due to the relatively low initial strength of marine silt, conventional equipment cannot be erected on the shore, which limits the reinforcement to a certain extent. The effect of permeable marine silt loading is general; the vacuum preloading method is to lay a horizontal drainage sand cushion in the reinforcement area and insert a vertical drainage body, then seal the sand cushion with a sealing film, and vacuumize the soil Negative pressure is generated to draw out the pore water in the soil to consolidate the soil. Such vacuuming usually requires the vacuum pump to work for 2 to 5 months to maintain the vacuum at 80 to 90kPa, so the construction takes a long time

[0004] Curing agent is a commonly used chemical consolidation method, but the higher the moisture content of polluted sludge, the more curing agent is needed. For marine sludge, if the curing agent is used directly for treatment, the general dosage will reach 10-15wt%. The volume of marine silt is huge, so the amount of curing agent required is huge. For example, 1 ton of marine silt is mixed with 100-150kg of traditional curing agent. Such a large amount will undoubtedly increase the cost

The existing electroosmotic method, also known as electrokinetic repair technology or electrochemical method, generally adds some external dopants, such as acids or complexes, which can reduce the adsorption between Zn, Pd, Cu and other heavy metal ions and soil particles. Then the heavy metal ions detached from the soil particles can complete the migration with electromigration. The characteristic of using electrokinetic restoration technology is that the early effect is very good, but as the concentration of heavy metal ions decreases in the later stage, the required energy consumption is higher. The effect becomes worse, so it takes a long time, the cost is high, and there is also the problem of secondary pollution caused by external admixtures

Moreover, the devices required by the current electric repair technology need to have the function of adding additional solution, and the equipment must be sealed so that the solution will not leak out; but the cost of outdoor construction devices is too high, so most of them can only be carried out indoors and cannot be used on a large scale. scale application

[0005] CN102704463B discloses a vacuum preloading-electroosmosis combined reinforcement method for silt foundations. First, vacuum preloading is carried out to extract pore water in the soft soil, so that the soft soil can be consolidated and compressed, and its strength improved. After a period of vacuuming, the reinforcement effect When it can no longer be improved, start electroosmosis at the same time to further discharge part of the free water and weakly bound water that cannot be discharged by simple vacuum preloading; but the above method only has a good reinforcement effect on ultra-soft silt foundations, and it is not suitable for rivers containing heavy metal ions. Sludge is not universal, especially for the stable solidification of heavy metal ions does not have a significant effect

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