Printing and dyeing sludge landfill treatment

      Printing and dyeing sludge to be landfill treatment, sludge must meet the requirements of the landfill on its mechanical indicators: transverse shear strength >25 kPa, uniaxial pressure BBB> kPa.

In order to meet such requirements, the key lies in the way of conditioning and the choice of dehydrator before sludge dewatering.

At present, the commonly used domestic printing and dyeing sludge conditioning method is mainly chemical conditioning, its use method is to add chemical agents in the need of dehydration printing and dyeing sludge, mainly chemical coagulant, so that the sludge particles flocculation, improve its dehydration performance.

Adding chemical agents can be divided into inorganic agents and organic agents.

Inorganic chemicals are ferric salts and aluminum salts, such as ferric chloride, ferrous sulfate, ferric sulfate, aluminum sulfate, and sometimes other inorganic agents such as bentonite are used.

In addition to the use of inorganic chemicals in the conditioning process of printing and dyeing sludge, it is often necessary to adjust the hardness with lime.

In this way, inorganic agents and lime will form a skeleton in the sludge that can withstand high pressure and improve its structure, thus improving its mechanical properties.

Mechanochemical agents are mainly synthetic polymer chemicals such as polypropylene phthalamide, polyvinyl alcohol, polyethylene oxide. Different from inorganic agents, organic polymer chemicals will not produce additional solids in the sludge.

Inorganic chemical agents are cheaper to use, but in the process of use, some solid substances need to be added to assist conditioning, after conditioning, the volume of sludge will increase.

The use of organic chemicals is good, and does not increase the volume of sludge.

But the price is higher.

Generally, the appropriate conditioning method can be selected according to the size of the sewage treatment station and the volume of the printing and dyeing sludge.

When the scale is large, inorganic chemical agents can be used for conditioning.

The sludge after conditioning is usually dehydrated again, with the purpose of enriching solid substances and reducing the volume of sludge.

The commonly used dehydration methods are natural dehydration and mechanical dehydration, natural drying treatment needs to occupy a large geographical area, generally difficult to use.

At present, mechanical dehydration is commonly used, which is mainly divided into two categories: one is filtration dehydration machinery, and is divided into negative pressure filtration machinery, such as vacuum filter.

Positive pressure filtration machinery belt filter press, plate and frame filter press, sludge filtration and dehydration is to rely on the filtering medium, porous material, pressure difference on both sides as a driving force, so that the water forced through the filtering medium, the solid particles trapped in the medium, to achieve the purpose of dehydration.

The second type is the dehydration mechanical centrifugal dehydrator that produces artificial force field. Under the action of artificial force field, with the help of the density difference between solid and liquid, solid and liquid are separated.

After the dehydration of printing and dyeing sludge, because it contains a large number of heavy metal ions and other chemical agents, so it is not suitable for agriculture and land use, generally speaking, can only carry out sanitary landfill treatment, and sanitary landfill generally higher requirements.

Therefore, for printing and dyeing sludge, the treatment method is generally mixed with local municipal solid waste into sanitary landfill is a better choice.

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