阅读说明：本技术 一种污泥固化方法 (Sludge solidification method ) 是由 王翔 王廷亮 于 2018-08-20 设计创作，主要内容包括：本发明提供了一种污泥固化方法,包括以下步骤：称取高岭土和生石灰,预混合,得到高岭土和生石灰的混合料；将高岭土和生石灰的混合料加入到待固化的污泥中,进行低速预搅拌；接着,向待固化的污泥中添加硫酸亚铁和减水剂,进行中速搅拌；出料,最后进行养护,完成污泥固化。本发明利用生石灰和硫酸亚铁改变污泥的表观颜色,扩宽了固化处理后的污泥的适用性；高岭土和减水剂的配合使用能够有效降低固化处理后的污泥的碱性；合适种类的减水剂的使用,能够破坏污泥的微观结构,提高固化反应速度,同时提高养护前固化污泥的流动性,有利于简化并缩短工艺流程。因此,所述污泥固化方法具有广阔的应用前景。(The invention provides a sludge solidification method, which comprises the following steps: weighing kaolin and quicklime, and premixing to obtain a mixture of the kaolin and the quicklime; adding a mixture of kaolin and quicklime into the sludge to be solidified, and pre-stirring at a low speed; then, adding ferrous sulfate and a water reducing agent into the sludge to be solidified, and stirring at medium speed; discharging, and finally curing to finish sludge curing. The invention utilizes quicklime and ferrous sulfate to change the apparent color of the sludge, and widens the applicability of the sludge after solidification treatment; the alkalinity of the sludge after the solidification treatment can be effectively reduced by the matching use of the kaolin and the water reducing agent; the use of the proper water reducing agent can destroy the microstructure of the sludge, improve the curing reaction speed, improve the fluidity of the cured sludge before curing, and facilitate the simplification and shortening of the process flow. Therefore, the sludge solidification method has wide application prospect.)

1. The sludge solidification method is characterized by comprising the following steps:

the method comprises the following steps: weighing kaolin and quicklime, and premixing to obtain a mixture of the kaolin and the quicklime;

step two: adding a mixture of kaolin and quicklime into the sludge to be solidified, and pre-stirring at a low speed;

step three: then, adding ferrous sulfate and a water reducing agent into the sludge to be solidified, and stirring at medium speed;

step four: discharging, and finally curing to finish sludge curing.

2. The sludge solidification method according to claim 1, wherein in the first step, the addition amount of the kaolin is 8-10 g/100mL of sludge, and the addition amount of the quicklime is 3-5 g/100mL of sludge.

3. The sludge solidification method according to claim 1, wherein in the second step, the stirring speed of the low-speed pre-stirring is 20 to 30r/min, and the duration time is 8 to 12 min.

4. The sludge solidification method as claimed in claim 1, wherein in the third step, the addition amount of the ferrous sulfate is 8-12 ml of FeSO₄Solution/100 mL sludge, FeSO therein₄The concentration of the solution was 10 wt%.

5. The sludge solidification method according to claim 1, wherein in the third step, the water reducing agent is added in an amount of 0.3 to 0.5g/100mL of sludge.

6. The sludge solidification method as claimed in claim 5, wherein the water reducing agent is selected from any one of: sulfonated melamine resin, amino sulfonate high-efficiency water reducing agent, calcium lignosulfonate water reducing agent and naphthalene sulfonate formaldehyde condensate water reducing agent.

7. The sludge solidification method according to claim 1, wherein in the third step, the stirring speed of the medium-speed stirring is 90-120 r/min, and the duration time of the medium-speed stirring is 10-20 min.

8. The sludge solidification method according to claim 1, wherein in the fourth step, the curing conditions are: curing reaction is carried out for 24-48 h at normal temperature and normal pressure.

Technical Field

The invention relates to the technical field of sludge treatment, in particular to a sludge solidification method.

Background

Sewage plant sludge is a precipitate generated in a sewage treatment process of a sewage plant, has complex components, and is an aggregate of solid particles such as silt, fibers, animal and plant residues and the like mixed in domestic sewage and industrial and mining wastewater, coagulated floccules thereof, various colloids, organic matters, adsorbed metal elements, microorganisms, germs, ova and the like. The water content of the fertilizer is usually higher than 80%, and the fertilizer contains a large amount of organic matters, pathogenic bacteria, microorganisms and toxic and harmful substances, and is easy to decay and generate malodor during storage. At present, due to the special physical, chemical and biological properties of sludge, how to implement economic and effective treatment on sludge becomes one of the important problems of environmental engineering and environmental geotechnical engineering in China.

Because industrial sewage and domestic sewage in China are discharged in a mixed manner, the pollution of microorganisms such as heavy metals and viruses, organic pollutants and the like contained in the generated sludge is easily enriched in soil and plants, and the pollution harms human health if entering a food chain; in addition, the sludge leachate is easy to pollute a water body after entering an underground water layer, the possibility of generating dioxin exists in the sludge incineration disposal process, the sludge stacked for a long time is easy to decay and generates stink, and thus the proper treatment problem of the sludge is needed to be solved.

In the prior art, chinese patent CN103739186A discloses a method for modifying sludge, which adopts a sludge modifier to modify the sludge, wherein the sludge modifier is waste acid, waste alkali, and FeCl₃Medicament, calcium oxide additive and waste ash; the specific resistance of the sludge modified by the modification method is greatly reduced, and the dehydration performance is obviously improved; however, in this embodiment, since Fe is used³⁺Salt, so that the sludge has no reduction performance and no decolorization reaction, so that the color of the sludge is still black, and the sludge is obviously different from common soil; meanwhile, the components of the waste ash are complex, and the components of the modified sludge are more disordered, so that the application range of the modified sludge is limited to a great extent.

According to analysis, the existing sludge modification and solidification method has the following technical defects: the direct modification of the sludge is mostly carried out by adding quicklime, but the pH value of the sludge is too high, namely the alkalinity is too high due to too large addition amount of the quicklime, so the treated sludge can only be used for mixed landfill, and the application range of the sludge is greatly limited.

Disclosure of Invention

Aiming at various technical defects in the prior art, the invention aims to provide a sludge solidification method based on a soil reconstruction principle, which can effectively adjust the pH value of sludge, can be widely applied to different soil requirements and ensures that the treated sludge has extremely high similarity with common soil. The technical scheme provided by the invention not only meets the requirement of the environment, but also solves the problem of overhigh pH value of the soil, and reserves most useful organic matters in the sludge, so that the property of the organic matters is very close to that of natural soil, and the method is particularly suitable for harmless treatment of the sludge.

In order to achieve the purpose of the invention, the inventor provides the following technical scheme: a method of sludge solidification comprising the steps of:

the method comprises the following steps: weighing kaolin and quicklime, and premixing to obtain a mixture of the kaolin and the quicklime;

step two: adding a mixture of kaolin and quicklime into the sludge to be solidified, and pre-stirring at a low speed;

step three: then, adding ferrous sulfate and a water reducing agent into the sludge to be solidified, and stirring at medium speed;

step four: discharging, finally maintaining, and completing sludge solidification, namely completing sludge solidification based on the soil reconstruction principle.

Preferably, in the first step of the sludge solidification method, the addition amount of the kaolin is 8-10 g/100mL of sludge, and the addition amount of the quicklime is 3-5 g/100mL of sludge.

Preferably, in the second step of the sludge solidification method, the stirring speed of the low-speed pre-stirring is 20 to 30r/min, and the duration time is 8 to 12 min. The stirring speed as used herein refers to the speed of the stirrer.

Preferably, in the third step of the sludge solidification method, the addition amount of the ferrous sulfate is 8-12 ml of FeSO₄Solution/100 mL sludge, ofFeSO₄The concentration of the solution was 10 wt%.

Preferably, in the third step of the sludge solidification method, the addition amount of the water reducing agent is 0.3-0.5 g/100mL of sludge.

Further preferably, in the third step of the sludge solidification method, the water reducing agent is selected from any one of the following: sulfonated melamine resin, amino sulfonate high-efficiency water reducing agent, calcium lignosulfonate water reducing agent and naphthalene sulfonate formaldehyde condensate water reducing agent. On the basis, calcium lignosulfonate water reducing agent is more preferable.

Preferably, in the third step of the sludge solidification method, the stirring speed of the medium-speed stirring is 90 to 120r/min, and the duration time of the medium-speed stirring is 10 to 20 min.

Preferably, in the fourth step of the sludge solidification method, the curing conditions are as follows: curing reaction is carried out for 24-48 h at normal temperature and normal pressure.

It should be added that the soil reconstruction principle used in the above sludge solidification method is as follows:

firstly, after quicklime is added into sludge, the quicklime reacts violently with a large amount of water in the sludge to generate a large amount of heat and generate an alkaline environment; wherein, the high temperature brought by the heat can kill the microorganisms such as pathogenic bacteria, and the alkaline environment can inhibit the growth and the propagation of the microorganisms; wherein, the chemical reaction of the quicklime and the water is as follows:

CaO+H₂O→Ca(OH)₂+ Heat

Meanwhile, kaolin in water neutralizes Ca (OH)₂The reaction takes place, and both reaction rates are comparatively mild, under the pH value circumstances in the mud is reduced step by step, can effective control mud in the alkaline environment for basicity can not be too strong, thereby be favorable to going on of ferrous sulfate complex reduction reaction, and the kaolin concrete reaction is as follows:

SiO₂+Ca(OH)₂→CaSiO₃+H₂O

Al₂O₃+Ca(OH)₂+H₂O→Ca[Al(OH)₄]₂

then, after adding ferrous sulfate, the following reaction occurs:

Ca(OH)₂+FeSO₄→Fe(OH)₂+CaSO₄

Fe(OH)₂+H₂O+O₂→Fe(OH)₃

therefore, the ferrous sulfate accelerates the hydrolysis in the alkaline environment, and Fe is generated after the hydrolysis²⁺Ions are gradually increased, and Fe²⁺Ions are more suitable for decolorization and reduction, and can be adsorbed and removed by forming a polynuclear complex with a chromophoric group, and the reaction principle of the two is a complex-adsorption bridge mechanism. Meanwhile, the addition of the ferrous sulfate destroys the microstructure of the sludge and accelerates the hydration reaction of the quicklime.

And after the water reducing agent is added, because the water reducing agent molecules can be directionally adsorbed on the surfaces of the sludge particles and the CaO particles, the surfaces of the particles are provided with the same charge (usually negative charge), so that an electrostatic repulsion effect is generated, the particles are promoted to be mutually dispersed, a flocculation structure is damaged, and the wrapped part of water is released, therefore, the hydration reaction of the quicklime (CaO) is remarkably accelerated, and meanwhile, the fluidity of the initially solidified sludge can be effectively increased.

In summary, compared with the sludge modification method or the sludge solidification method in the prior art, the sludge solidification method provided by the invention has the following technical advantages: according to the invention, the kaolin, the quicklime, the ferrous sulfate and the water reducing agent are added in a combined manner, so that on one hand, the quicklime and the ferrous sulfate can be used for changing the apparent color of the sludge, the color of the sludge is closer to that of common soil, the applicability of the sludge after solidification is widened, and in other words, the application range of the sludge is wider; on the other hand, the kaolin and the water reducing agent are matched for use, so that the usage amount of the quicklime can be greatly reduced, the alkalinity of the solidified sludge is effectively reduced, and the applicability of the solidified sludge is enhanced from another angle; in addition, the use of the proper water reducing agent can destroy the microstructure of the sludge, thereby improving the solidification reaction speed of the sludge, improving the fluidity of the solidified sludge before maintenance, and being beneficial to simplifying and shortening the process flow. Therefore, the sludge solidification method has wide application prospect.

Drawings

FIG. 1 is a TN change curve graph in a simulated rainfall erosion test of the sludge solidified in examples 1 to 3 of the present invention;

FIG. 2 is a graph showing the TP change curve in a simulated rainfall erosion test of the sludge solidified in examples 1 to 3 of the present invention;

FIG. 3 is a graph showing COD change in a simulated rainfall erosion test of the sludge solidified in examples 1 to 3 of the present invention;

FIG. 4 is a photograph of sludge before solidification;

FIG. 5 is a photograph of a dried sample of sludge after solidification treatment according to the sludge solidification method of the present invention;

FIG. 6 is a photograph showing a site where sludge is solidified by the sludge solidifying method according to the present invention.

Detailed Description

The present invention will be further described with reference to specific embodiments, but the present invention is not limited to the following embodiments.

The sludge solidification method comprises the following steps: the method comprises the following steps: weighing kaolin and quicklime, and premixing to obtain a mixture of the kaolin and the quicklime; step two: adding a mixture of kaolin and quicklime into the sludge to be solidified, and pre-stirring at a low speed; step three: then, adding ferrous sulfate and a water reducing agent into the sludge to be solidified, and stirring at medium speed; step four: discharging, and finally curing to finish sludge curing.

In a preferred embodiment, in the first step, the addition amount of the kaolin is 8-10 g/100mL of sludge, and the addition amount of the quicklime is 3-5 g/100mL of sludge.

In a preferred embodiment, in the second step, the stirring speed of the low-speed pre-stirring is 20 to 30r/min, and the duration time is 8 to 12 min.

In a preferred embodiment, in the third step, the addition amount of the ferrous sulfate is 8-12 ml of FeSO₄Solutions of/100mL of sludge, FeSO therein₄The concentration of the solution was 10 wt%.

In a preferred embodiment, in the third step, the addition amount of the water reducing agent is 0.3-0.5 g/100mL of sludge.

In a further preferred embodiment, the water reducing agent is selected from any one of the following: sulfonated melamine resin, amino sulfonate high-efficiency water reducing agent, calcium lignosulfonate water reducing agent and naphthalene sulfonate formaldehyde condensate water reducing agent. In a still further preferred embodiment, the water reducer is a calcium lignosulfonate water reducer.

In a preferred embodiment, in the third step, the stirring speed of the medium-speed stirring is 90-120 r/min, and the duration time is 10-20 min.

In a preferred embodiment, in the fourth step, the curing conditions are as follows: curing reaction is carried out for 24-48 h at normal temperature and normal pressure.