JPH10337575A - Coagulant for sludge treatment and sludge treating method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a sludge coagulating flock of a good dehydrating property by forming quickly the sludge coagulation flock even for any sludge by a method wherein rock burnt powder, inorganic calcium compound, inorganic magnesium compound, and inorganic sodium compound are contained by respective specific amounts. SOLUTION: A sludge treating coagulant contains respective constituents of 100 pts.wt. of rock burnt powder, 80 to 120 pts.wt. of inorganic calcium compound, 80 to 120 pts.wt. of inorganic magnesium compound, and 80 to 120 pts.wt. of inorganic sodium compound. Then, a coagulation stirrer 2 adds the coagulant for sludge to water to be treated containing excess sludge or the like introduced into a treating tank 10, and generates a sludge coagulation flock by stirring the water to be treated with a stirring mechanism 16 executing aeration in the water to be treated from an air discharge pipe 14. A coagulation flock separator 4 makes effluent containing the sludge coagulation flock flow down on a screen 24 from a treating water exhaust pipe 18, and separates the sludge coagulation flock 30.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a powdery flocculant for treating sludge used in treating water containing sludge such as excess sludge, and a method of treating sludge using the flocculant.

[0002]

2. Description of the Related Art Conventionally, typical coagulants used in treating water containing sludge include aluminum compounds such as polyaluminum chloride (PAC) and aluminum sulfate (sulfate band), and ferric chloride. And iron salts such as ferric polysulfate and various polymer flocculants.

[0003]

However, when the coagulation and stirring treatment of the water containing the sludge is performed using the conventional coagulant as described above, it takes a long time to form the coagulated floc.
The dewatering property of the obtained sludge flocculated floc is poor, and it takes time to dewater the sludge flocculated floc. In addition, there are sludges that cannot be treated with the conventional flocculants.

The present invention has been made in view of the above circumstances, and by adding sludge to water containing sludge in the flocculation and stirring step, any sludge can quickly form sludge flocculated flocs and can be dewatered. It is an object of the present invention to provide a flocculant for sludge treatment capable of obtaining a sludge flocculation floc having good properties, and thus improving the efficiency of the flocculation stirring step and the dewatering step.

[0005]

The present invention provides a coagulant for sludge treatment, which comprises the following components (A) to (D) in order to achieve the above object. (A) Rock fired powder 100 parts by weight (B) Inorganic calcium compound 80 to 120 parts by weight (C) Inorganic magnesium compound 80 to 120 parts by weight (D) Inorganic sodium compound 80 to 120 parts by weight

The present invention also relates to the above components (A) to (D)
And a coagulant for sludge treatment further comprising the following components (E) and (F). (E) anionic polymer coagulant 20 to 60 parts by weight (F) cationic polymer coagulant 40 to 80 parts by weight

[0007] The present invention further relates to the above components (A) to
Provided is a sludge treatment flocculant which further contains the following components (E) and (G) in addition to (D). (E) anionic polymer coagulant 20 to 60 parts by weight (G) nonionic polymer coagulant 40 to 80 parts by weight

Hereinafter, each component will be described. Component (A) Since the fired rock powder of the component (A) has pores having a large surface area, the pores have a function of improving the dewatering property of the flocculated floc, and a function of reducing the smell of the floc floc. . The type of the fired rock powder is not limited, and for example, one or more fired powders selected from perlite pearlite, obsidian, montmorillonite-based acid clay, and zeolite can be used. Further, the particle size of the fired rock powder is preferably set to 50 to 100 mesh. The component (A) can be obtained, for example, by firing the above-mentioned powdered material in a firing furnace at 800 to 1000 ° C. for about 20 to 40 minutes. At this time, if necessary
A pore-forming agent such as, for example, addicarbonamide can be added to the above raw materials.

Component (B) The inorganic calcium compound as the component (B) suppresses the termination of the agglutination reaction due to excessive sulfate ions in the water to be treated when a sulfate is used in combination. In addition, it has a coagulation effect on protein components in sludge and has an entry guide function on dewatered sludge. The type of the inorganic calcium compound is not limited, but for example, calcium hydroxide or calcium chloride can be used. The amount of the inorganic calcium compound is 80 to 120 parts by weight, preferably 90 to 110 parts by weight, per 100 parts by weight of the component (A). Further, the particle size of the inorganic calcium compound is 13
It is preferable to set it to 0 to 180 mesh.

Component (C) The inorganic magnesium compound (C) generates an ionic surfactant by a hydration reaction, neutralizes the charge of the particles, and exhibits an aggregation effect and a hydrophobic effect. In addition, the thickness of the colloidal charged double layer is reduced so that the particles are attracted to each other so that the coagulation can be carried out well. In addition, it has a function of coagulating proteins in sludge and a function of neutralizing sulfate ions. Although the kind of the inorganic magnesium compound is not limited, for example, magnesium sulfate, magnesium hydroxide or magnesium chloride can be used. The amount of the inorganic magnesium compound is 80 to 120 with respect to 100 parts by weight of the component (A).
Parts by weight, preferably 90 to 110 parts by weight. Further, the particle size of the inorganic magnesium compound is preferably 30 to 50 mesh.

(D) Component The inorganic sodium compound of the component (D) generates an ionic surfactant by a hydration reaction, neutralizes the charge of the particles, and exhibits an aggregation effect and a hydrophobic effect. In addition, the thickness of the colloidal charged double layer is reduced so that the particles are attracted to each other so that the coagulation can be carried out well. In addition, it has a function of coagulating proteins in sludge and a function of neutralizing sulfate ions. Although the kind of the inorganic sodium compound is not limited, for example, sodium sulfate or sodium hydroxide can be used. The amount of the inorganic sodium compound is 80 to 120 parts by weight, preferably 90 to 11 parts by weight, per 100 parts by weight of the component (A).
0 parts by weight. Further, the particle size of the inorganic sodium compound is preferably 40 to 60 mesh.

Component (E) The anionic polymer coagulant (E) causes a strong coagulation reaction particularly in an acidic region. Further, it is electrostatically attracted to colloidal particles having a positive charge such as metal hydroxide, and causes aggregation and crosslinking to occur. In addition, it has the best capacity for treating large particles such as excess sludge and fish processing wastewater. The type of the anionic polymer flocculant is not limited, but for example, sodium polyacrylate can be used. In addition, the compounding amount of the anionic polymer flocculant,
20 to 60 parts by weight, preferably 30 to 50 parts by weight, per 100 parts by weight of component (A). Further, the particle size of the anionic polymer flocculant is preferably 100 to 150 mesh.

Component (F) The cationic polymer flocculant of component (F) is effective for turbidity and decolorization, and concentrates and dewaters sludge from wastewater containing a large amount of organic colloid particles, for example, dyeing wastewater and food processing wastewater. It is effective in improving the performance. The reason is that not only the aggregation by the charge neutralization of the colloid particles, but also the reaction with the negatively charged dissolved substance to generate an insoluble salt, which has both functions of charge neutralization and flocking. The type of the cationic polymer flocculant is not limited, but it is preferable to use, for example, a high molecular weight, low viscosity one. The amount of the cationic polymer flocculant is 40 to 80 parts by weight, preferably 50 to 70 parts by weight, per 100 parts by weight of the component (A). Further, the particle size of the cationic polymer coagulant is preferably set to 100 to 150 mesh.

Component (G) The nonionic polymer flocculant of the component (G) has the following characteristics as compared with the anionic polymer flocculant. That is, the pH of the water to be treated is less affected by the salts contained in the water to be treated, and the coagulation effect is inferior to that of the anionic polymer flocculant in the neutral and alkaline regions, but is superior in the acidic region. It has features such as high strength and optimal for treating paper pulp wastewater. The type of the nonionic polymer flocculant is not limited, but it is preferable to use, for example, a high molecular weight, low viscosity one. The amount of the nonionic polymer flocculant is 40 to 80 parts by weight, preferably 50 to 70 parts by weight, per 100 parts by weight of the component (A).
Parts by weight. Further, the particle size of the nonionic polymer flocculant is preferably 100 to 150 mesh.

Method for Using Coagulant for Sludge Treatment The coagulant for sludge treatment of the present invention is added to the water to be treated in the coagulation and stirring step. In this case, p
It is appropriate to adjust H to the acidic side, particularly to about pH 5 to 6. The amount of the coagulant for sludge treatment of the present invention added to the water to be treated is about 0.5 to 2 g per liter of the water to be treated. Further, the stirring time in the coagulation stirring step is 10
It is appropriate to set it to about 20 minutes.

When the coagulant for sludge treatment of the present invention is used, if necessary, a liquid treatment agent containing aluminum salt as a main component and sodium salt, magnesium salt and iron salt as an auxiliary agent may be used. Thereby, it is possible to further speed up the generation of the sludge flocculated floc and to improve the dewatering property of the sludge flocculated floc. More specifically, examples of such an auxiliary include a liquid treating agent containing aluminum sulfate, ferric polysulfate, ferric chloride, magnesium chloride and sodium hydroxide.

Apparatus The apparatus for performing the coagulation and sedimentation treatment using the coagulant for sludge treatment of the present invention is not particularly limited. However, the coagulant is added to the water to be treated containing sludge, and the water to be treated is stirred while performing aeration. A flocculating stirrer that generates flocculated floc by performing the process, and a metal porous screen having a large number of through-holes disposed partially or entirely in an inclined manner. The sludge treatment apparatus having an agglomeration floc separating apparatus for separating coagulated floc on the porous screen and separating water under the porous screen through the through-holes can be used particularly preferably. .

That is, in the conventional sludge treatment apparatus, the sludge flocculated floc and water are separated by using a cloth filter cloth as a filter medium. In this conventional apparatus, the filter cloth is easily damaged, and it is often necessary to replace the filter cloth. However, in the agglomerated floc separation apparatus, since a metal porous screen is used as a filter medium, there is no need to replace the filter medium. Therefore, in the sludge treatment device using the flocculated floc separation device, sludge flocculent flocs can be continuously and efficiently removed, and
The operation cost can be reduced by eliminating the need to replace the filter medium. In addition, when the flocculant for sludge treatment of the present invention is used, sludge flocculants having good dehydration properties can be obtained, so that the flocculated floc separating device can easily separate sludge flocculants from water.

In this case, it is preferable that the sludge treatment apparatus is configured such that the effluent of the flocculation stirrer is introduced onto the porous screen of the flocculation floc separator by using the water pressure of the effluent. As a result, the device can be operated without using extra power, and the operation cost of the device can be further reduced.

[0020]

FIG. 1 is a schematic diagram showing an example of a sludge treatment apparatus for performing sludge treatment using the flocculant for sludge treatment of the present invention. In the apparatus shown in FIG. 1, reference numeral 2 denotes an aggregating stirring device, and 4 denotes an aggregating floc separating device.

In the coagulation stirrer 2, 10 is a treatment tank,
Reference numeral 12 denotes a blower (baffle plate) vertically disposed on the inner wall of the treatment tank 10, reference numeral 14 denotes an air discharge pipe for performing aeration, reference numeral 16 denotes a stirring mechanism, and reference numeral 18 denotes a treated water discharge pipe. The air discharge pipe 14 is provided along the blower 12.

The coagulation / stirring apparatus 2 of this embodiment adds a coagulant to the water to be treated containing sludge such as excess sludge introduced into the treatment tank 10, and aerates the water to be treated from the air discharge pipe 14. The agitation mechanism 16 stirs the water to be treated to generate sludge flocculated flocs.

As shown in FIG. 2, the flocculating floc separating device 4 has a depressurizing plate 19 inside, and a depressurizing tank 20 connected to the treated water discharge pipe 18 of the flocculating and stirring device 2;
2 and four porous screens 24 having a large number of through-holes and arranged in the separation tank 22 in an inclined state.
As shown in FIG. 3, the porous screen 24 has a plurality of stainless steel wires (wedge wires) 26 having a substantially inverted triangular cross section arranged in parallel in a square stainless steel frame. This is a so-called wedge wire screen in which divergent slits (through holes) 28 are formed, the intervals of which increase as the distance from the screen increases. The size of the through-hole can be set as appropriate,
Usually, the interval between the wires 26 at the upper end is 0.3 mm
Use something of the order.

The flocculated floc separating device 4 of the present embodiment comprises a flocculated stirring device 2 including sludge flocculated flocs from a treated water discharge pipe 18.
Effluent is introduced into the decompression tank 20 by its water pressure,
Here, after the pressure is reduced, the water is introduced into the porous screen 24 and flows down on the screen 24, thereby separating the sludge flocculated floc 30 on the porous screen 24 and simultaneously passing through the through-hole 28. 2
4 separates water 31 from the lower side, and discharges the water 31 from a treated water discharge pipe 34 connected to the lower part of the separation tank 22. Further, the sludge flocculants separated on the porous screen 24 can be collected and subjected to appropriate treatment such as screw dewatering and press dewatering.

The sludge treatment apparatus of the present embodiment efficiently forms sludge flocculated flocs by performing aeration in the flocculating and stirring apparatus 2, and forms sludge flocculated flocs contained in the effluent of the flocculating and stirring apparatus 2 by the flocculated floc separating apparatus 4. , Sludge treatment can be performed almost continuously and efficiently. Further, the coagulation stirring device 2 and the coagulation floc separation device 4
By setting the upper and lower positional relations, the effluent of the flocculation / stirring device 2 is introduced onto the porous screen 24 of the flocculation floc separating device 4 by using its water pressure, so that the operation cost of the device can be reduced.

When the sludge treatment is performed by the above-mentioned sludge treatment apparatus using the sludge treatment flocculant of the present invention, the sludge treatment flocculant of the present invention is added to the water to be treated in the flocculation stirring apparatus to perform the flocculation stirring treatment. This makes it possible to quickly form sludge flocculated flocs of any kind of sludge, and to obtain sludge flocculated flocs having good dewatering properties. This floc can be easily separated by the subsequent flocculated floc separating device.

[0027]

EXAMPLES Coagulants 1 and 2 for treating sludge of the present invention having the following compositions:
Was manufactured respectively. In this case, all the raw materials were put in a powder mixer and stirred for about 10 minutes. The perlite pearlite fired powder was manufactured by firing 100-mesh perlite pearlite powder at 900 ° C. for 30 minutes.

Coagulant for sludge treatment 1 Pearlite pearlite fired powder 500 g Calcium chloride 500 g Magnesium sulfate 500 g Sodium sulfate 500 g Sodium polyacrylate 200 g Cationic polymer coagulant 300 g

Coagulant for sludge treatment 2 Pearlite pearlite fired powder 500 g Calcium chloride 500 g Magnesium sulfate 500 g Sodium sulfate 500 g Sodium polyacrylate 200 g Nonionic polymer coagulant 300 g

Sludge treatment was performed using the sludge treatment flocculants 1 and 2 by the sludge treatment apparatus shown in FIG. In this case, the coagulant 1 or 2 of the present invention for sludge treatment was added to the water to be treated by the coagulation stirrer 2. As a result, the coagulation stirrer 2
, A flocculated floc with good dewatering property was quickly formed. This floc could be easily removed by the subsequent flocculated floc separating device.

[0031]

The coagulant for treating sludge of the present invention can quickly form sludge flocculated flocs of any sludge and can obtain sludge flocculated flocks with good dewatering properties. Therefore, by using the flocculant for sludge treatment of the present invention, it is possible to increase the efficiency of the flocculation stirring step and the dewatering step.

[Brief description of the drawings]

FIG. 1 is a schematic view showing an example of a sludge treatment apparatus for performing sludge treatment using the flocculant for sludge treatment of the present invention.

FIG. 2 is a perspective view showing a flocculated floc separating device of the wastewater treatment device of FIG. 1;

FIG. 3 is an enlarged cross-sectional view showing a perforated screen used for the flocculated floc separating apparatus of FIG. 2;

[Explanation of symbols]

 2 Coagulation stirrer 4 Coagulation floc separator 14 Air discharge pipe 16 Stirring mechanism 24 Porous screen 28 Through-hole

Continued on the front page (51) Int.Cl. ⁶ Identification code FI C02F 11/14 ZAB C02F 11/14 ZABB

Claims (6)

[Claims] 1. A flocculant for sludge treatment, comprising the following components (A) to (D). (A) Rock fired powder 100 parts by weight (B) Inorganic calcium compound 80 to 120 parts by weight (C) Inorganic magnesium compound 80 to 120 parts by weight (D) Inorganic sodium compound 80 to 120 parts by weight 2. The flocculant for sludge treatment according to claim 1, further comprising the following components (E) and (F). (E) anionic polymer coagulant 20 to 60 parts by weight (F) cationic polymer coagulant 40 to 80 parts by weight 3. The flocculant for sludge treatment according to claim 1, further comprising the following components (E) and (G). (E) anionic polymer coagulant 20 to 60 parts by weight (G) nonionic polymer coagulant 40 to 80 parts by weight 4. The fired powder of rock (A) is one or more fired powders selected from perlite pearlite, obsidian, montmorillonite acid clay and zeolite, and (B)
The inorganic calcium compound is calcium hydroxide or calcium chloride, (C) the inorganic magnesium compound is magnesium sulfate, magnesium hydroxide or magnesium chloride, and (D) the inorganic sodium compound is sodium sulfate or sodium hydroxide. 4. The flocculant for sludge treatment according to 2 or 3. 5. The flocculant for sludge treatment according to claim 2, wherein (E) the anionic polymer flocculant is sodium polyacrylate. 6. A coagulation / stirring device for generating coagulated flocs by stirring a water to be treated while adding an aggregating agent to the water to be treated containing sludge and performing aeration, and a part or whole of the device is arranged to be inclined. By providing a metal porous screen having a large number of through-holes, by flowing down the effluent of the coagulation stirring device on this porous screen,
Using a sludge treatment device having a flocculation floc separating device for separating water on the lower side of the porous screen through the through holes while separating flocculated floc on the porous screen, wherein the water to be treated in the flocculation stirring device is used. A sludge treatment method comprising adding the coagulant for sludge treatment according to any one of 1 to 5 to perform sludge treatment.