JP2007301458A - Treatment method of sludge, and fertilizer obtained by the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a treatment method of sludge usefully utilizing the sludge, particularly dredging sludge and blue powder sludge, and a fertilizer obtained by the treatment method. <P>SOLUTION: The sludge is loaded with a flocculant containing at least the following component and weight ratio, agitated and mixed, and separated into a condensate having water and a sludge content as a main component. The flocculant contains silicon dioxide of 15.0 to 35.0 pts.wt., aluminum oxide of 20.0 to 40.0 pts.wt., ferric oxide of 1.0 to 10.0 pts.wt., calcium oxide of 20.0 to 40.0 pts.wt., sodium oxide of 1.0 to 5.0 pts.wt., potassium oxide of 0.1 to 1.2 pts.wt., magnesium oxide of 0.3 to 1.8 pts.wt., phosphoric acid of 0.8 to 2.5 pts.wt., and titanium oxide of 0.01 to 2.0 pts.wt. The sludge is preferably the dredging sludge and the blue powder sludge. The blue powder sludge is preferably obtained by electrolyzing water to be treated containing a blue powder. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

The present invention relates to a method for treating sludge such as straw sludge and blue powder sludge, and a fertilizer obtained by the method.

The present inventors have developed a method for producing sand by adding a flocculant to sludge (Patent Document 1). This method is a method for producing sand and is not used for fertilizers.
Sludge, for example, sludge, contains nutrients such as plant leaves. If this can be used as fertilizer, it contributes to effective use of sludge. In addition, blue powder is a small freshwater algae that grows in lakes such as ponds and swamps and turns the water green, but if such blue powder contains a large amount of nutrients and can be used as a fertilizer, This is significant in conjunction with the purification of lake water.

As a method for treating blue powder, conventionally, a treatment method using microorganisms is known. This method is a method in which a microorganism having an ability to decompose blue powder is introduced into a liquid to be treated containing blue powder, and the blue powder is decomposed. However, the process takes a long time and is not efficient.
By the way, this inventor has already developed the water purification apparatus which applies a high frequency alternating voltage and a DC voltage simultaneously and purifies water as a purification method of to-be-treated water (patent document 2). It has been desired to efficiently separate blue powder and water from a liquid to be treated containing blue powder using such a processing apparatus.
Japanese Patent Application No. 2005-259424 JP 2004-130294 A

Accordingly, an object of the present invention is to provide a method for treating sludge that contributes to the effective use of sludge, in particular, sludge and blue powder sludge, and a fertilizer obtained by the method.

In order to solve the above-mentioned problems, the sludge treatment method according to the present invention comprises adding a flocculant containing at least the following components in the following weight ratio to the sludge, stirring and mixing, and agglomerates mainly composed of water and mud: It is characterized by being separated.
Silicon dioxide 15.0-35.0 parts by weight, aluminum oxide 20.0-40.0 parts by weight, ferric oxide 1.0-10.0 parts by weight, calcium oxide 20.0-40.0 parts by weight, Sodium oxide 1.0-5.0 parts by weight, potassium oxide 0.1-1.2 parts by weight, magnesium oxide 0.3-1.8 parts by weight, phosphoric acid 0.8-2.5 parts by weight, titanium oxide 0.01 to 2.0 parts by weight.
Here, it is good to use dredged sludge as sludge.
The sludge is blue powder sludge, and the blue powder sludge may be obtained by electrolyzing a liquid to be treated containing blue powder.
Here, in the electrolysis treatment, three or more electrodes are arranged in a water tank containing the liquid to be treated, a high-frequency alternating voltage is applied between at least two of the electrodes, and at least two or more of the electrodes. A DC voltage may be applied between the electrodes at the same time.
Further, an aluminum electrode may be used as the electrode.
Further, the fertilizer according to the present invention is composed of an aggregate mainly composed of (separated) mud obtained by the above-described sludge treatment method.

According to the sludge treatment method of the present invention, a flocculant having a predetermined composition is added to the sludge and mixed by stirring to separate water and agglomerates mainly composed of mud. It is possible to separate a large amount of sludge contained in a large amount into water and an aggregate having a low water content. The obtained agglomerates have a low moisture content (about 30 to 60%) and are in a state close to earth and sand, so that they are easy to carry on a truck or the like, are easy to handle, and can be used effectively.
When dredged sludge is used as sludge, dredged sludge contains nutrients, and thus the obtained agglomerates also contain nutrients and can be used effectively as fertilizers.
The sludge is a blue powder sludge. If the blue powder sludge is a blue powder sludge obtained by electrolyzing a liquid to be treated containing blue powder, the blue powder contains a large amount of nutrients. Therefore, the aggregate obtained from the blue powder sludge can be effectively used as a fertilizer.
According to the electrolysis treatment, the treatment can be performed in a short time, and the blue powder sludge can be obtained efficiently. Here, in the electrolysis treatment, three or more electrodes are arranged in the water tank, a high-frequency AC voltage is applied between at least two of the electrodes, and a DC voltage is applied between at least two of the electrodes. If applied simultaneously, electrolysis can be performed more efficiently due to the synergistic effect of electrolysis using alternating voltage and electrolysis using direct current voltage.
Further, when an aluminum electrode is used as an electrode, it can be cleanly separated into transparent water and blue powder, and the liquid to be treated containing blue powder can be purified sufficiently and efficiently.
This method capable of sufficiently and efficiently purifying dirty water containing blue powder is extremely effective as a purification method for lakes and marshes in which a large amount of blue powder is generated, and is an unprecedented and innovative treatment method.

The best mode for carrying out the present invention will be specifically described below with reference to the drawings. FIG. 1 is a schematic view of an electrolysis treatment apparatus, FIG. 2 is a schematic view of an electrolysis treatment apparatus according to another example, and FIG. 3 is a schematic view showing a state before and after electrolysis of a liquid to be treated contained in a beaker.

The sludge treatment method according to the present invention comprises adding a flocculant having a predetermined composition to the sludge, stirring and mixing, and separating into agglomerates mainly composed of water and mud.
As the sludge, straw sludge or blue powder sludge is preferable. The sludge and blue powder sludge contain nutrients made of organic matter, and the aggregates obtained from such sludge also contain nutrients, so that they can be effectively used as fertilizers.

The flocculant used in the present invention contains at least the following components in the following weight ratio. Silicon dioxide 15.0-35.0 parts by weight, aluminum oxide 20.0-40.0 parts by weight, ferric oxide 1.0-10.0 parts by weight, calcium oxide 20.0-40.0 parts by weight, Sodium oxide 1.0-5.0 parts by weight, potassium oxide 0.1-1.2 parts by weight, magnesium oxide 0.3-1.8 parts by weight, phosphoric acid 0.8-2.5 parts by weight, titanium oxide 0.01 to 2.0 parts by weight.

More preferably, at least the following components are contained in the following weight ratio.
20.0-30.0 parts by weight of silicon dioxide, 25.0-35.0 parts by weight of aluminum oxide, 2.0-7.0 parts by weight of ferric oxide, 25.0-40.0 parts by weight of calcium oxide, Sodium oxide 1.0-3.0 parts by weight, potassium oxide 0.5-1.2 parts by weight, magnesium oxide 0.5-1.5 parts by weight, phosphoric acid 1.0-2.0 parts by weight, titanium oxide 0.05 to 1.0 part by weight.

The flocculant having such a composition has a moisture adjustment function (hydrophobic function) for hydrophobizing and agglomerating the mud contained in the sludge, that is, adjusting the amount of water (moisture content) retained by the mud as a solid content. In addition, the agglomerated mud content (solid content) is imparted with an appropriate hydrophilicity, and has a coagulation function for causing hard crystallization by residual moisture and a curing acceleration function for promoting the curing of the coagulated mud.

Since the flocculant used in the present invention has such a function, sludge can be efficiently aggregated in a short time. The obtained aggregate is easy to handle and transport in a state close to earth and sand.
Further, the flocculant used in the present invention is almost in the neutral range even when dispersed in water, and does not change the pH of the separated water. Is also unnecessary.

The amount of the flocculant added to the sludge is 5 to 20 parts by weight of the flocculant with respect to 100 parts by weight of the sludge (water content 80 to 300%). The addition amount of the flocculant is appropriately changed within the above range according to the kind of sludge and the water content. The water content of the obtained aggregate is about 30 to 60%. Although the agglomerates thus obtained contain water, they can be transported by loading them on the truck bed in a solid state rather than a crumbly state.

浚 渫 Sludge and blue powder sludge contain nutrients such as organic matter, so the agglomerates obtained from such sludge also contain nutrients, which can be used as fertilizer for effective use of sludge. To contribute.

FIG. 1 shows an electrolysis apparatus for a liquid to be processed containing blue powder. A liquid 2 is stored in a water tank 1, and a first electrode 3a, a second electrode 3b, and a second electrode are stored in the water tank 1. Three electrodes including three electrodes 3c are arranged. A high frequency AC voltage is supplied from the AC high frequency power source 4 between the first electrode 3a and the second electrode 3b, and a DC power source is provided between the third electrode 3c and the first electrode 3a and between the third electrode 3c and the second electrode 3b. A DC voltage from 5 is applied simultaneously. Thereby, a direct current and an alternating current simultaneously flow between the respective electrodes, the liquid 2 to be treated in the water tank 1 is electrolyzed, and the blue powder floats upward and is separated from the water. In FIG. 1, reference numeral 6 denotes a switch.

Here, it is preferable to perform the electrolysis treatment under a high frequency of 60 to 250 kHz with a voltage of 30 to 110 V and a direct current with a voltage of 30 to 150 V. In addition, as the electrodes 3a, 3b, 3c, various conductive materials such as titanium, aluminum, platinum, stainless steel, iron, graphite, etc. can be used, but the electrolysis treatment of the liquid to be treated containing blue powder. In particular, aluminum is preferable.

FIG. 2 shows an electrolysis apparatus according to another example, in which a liquid 2 to be treated is accommodated in a water tank 1, two AC high frequency power supplies 14 a and 14 b and one DC power supply 15 are provided. Four electrodes including a first electrode 13a, a second electrode 13b, a third electrode 13c, and a fourth electrode 13d are disposed therein. Among these, between the first electrode 13a and the second electrode 13b, and between the third electrode 13c and the fourth electrode 13d, a high-frequency AC voltage is supplied from the AC high-frequency power sources 14a and 14b, between the third electrode 13c and the first electrode 13a, A DC voltage is simultaneously applied from the DC power source 15 between the third electrode 13c and the second electrode 13b, between the fourth electrode 13d and the first electrode 13a, and between the fourth electrode 13d and the second electrode 13b. The AC frequency, voltage, DC voltage, electrode, etc. are the same as described above.

Electrolytic treatment experiment of liquid to be treated containing blue powder An electrolysis treatment experiment of liquid to be treated 2 containing blue powder was performed using the electrolysis treatment apparatus shown in FIG. Specifically, 1 liter of a liquid to be treated 2 containing blue powder (collected from Yatsukiri-bori Pond in Kakegawa City) is placed in a 1 liter beaker (water tank 1), and the first electrode 3a, the second electrode 3b, An aluminum electrode is used for both the third electrode 3c, a high-frequency AC voltage of 105 kHz and 60.5 V is applied between the first electrode 3a and the second electrode 3b, the third electrode 3c and the first electrode 3a, and the third electrode 3c and the second electrode 3b. The liquid to be treated 2 was electrolyzed by simultaneously applying a DC voltage of 102 V between the two electrodes 3b. At this time, the AC side current was 3.4 A, and the DC side current was 7.9 A.
By performing such electrolysis treatment for 3 minutes, the liquid 2 to be treated (FIG. 3 (a)), which was initially green in the beaker, could be separated from the transparent water 8 as the blue powder 7 floated upward ( FIG. 3 (b)). Thus, the blue powder 7 that floated upward was collected and used as the blue powder sludge in Example 2 described later.
In addition, although it experimented using electrodes, such as titanium, platinum, stainless steel, and iron, as for an electrode, all are transparent in water, it does not reach transparency, and separation is inadequate, and when an aluminum electrode is used, it is transparent. It was cleanly separated into water and blue powder.

150 kg of flocculant was added to 1000 kg of sludge having a water content of about 200%, and the mixture was stirred and mixed with a multi-shaft mixer, and separated into aggregates and water having a water content of about 50%. The obtained agglomerates were easy to handle in a state close to earth and sand, and could be carried on a truck bed.
The composition of the flocculant used was 22.0 parts by weight of silicon dioxide, 30.0 parts by weight of aluminum oxide, 4.0 parts by weight of ferric oxide, 32.0 parts by weight of calcium oxide, 1.6 parts by weight of sodium oxide, It was 0.8 parts by weight of potassium oxide, 1.0 part by weight of magnesium oxide, 1.5 parts by weight of phosphoric acid, 0.1 part by weight of titanium oxide, and 7.0 parts by weight of other components.

100 g of a flocculant was added to 1 kg of blue powder sludge having a water content of about 200%, and the mixture was stirred and mixed to separate the agglomerate having a water content of about 50% and water. The obtained agglomerates were easy to handle in a state close to earth and sand, and could be carried on a truck bed. The composition of the flocculant used is the same as that used in Example 1.

Schematic of an electrolysis processing apparatus. The schematic of the electrolysis processing apparatus by another example. Schematic which shows the mode before and behind electrolysis of the to-be-processed liquid accommodated in the beaker.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Water tank 2 Liquid to be processed 3a, 13a 1st electrode 3b, 13b 2nd electrode 3c, 13c 3rd electrode 13d 4th electrode 4, 14a, 14b AC high frequency power supply 5,15 DC power supply 6,16 Switch 7 Blue powder 8 Transparent Water

Claims (6)

A method for treating sludge, characterized in that a flocculant containing at least the following components in the following weight ratio is added to sludge and mixed by stirring to separate into water and agglomerates mainly composed of mud.
Silicon dioxide 15.0-35.0 parts by weight, aluminum oxide 20.0-40.0 parts by weight, ferric oxide 1.0-10.0 parts by weight, calcium oxide 20.0-40.0 parts by weight, Sodium oxide 1.0-5.0 parts by weight, potassium oxide 0.1-1.2 parts by weight, magnesium oxide 0.3-1.8 parts by weight, phosphoric acid 0.8-2.5 parts by weight, titanium oxide 0.01 to 2.0 parts by weight. The sludge treatment method according to claim 1, wherein the sludge is dredged sludge. The sludge treatment method according to claim 1, wherein the sludge is blue powder sludge, and the blue powder sludge is obtained by electrolyzing a liquid to be treated containing blue powder. In the electrolysis treatment, three or more electrodes are arranged in a water tank containing a liquid to be treated, a high-frequency alternating voltage is applied between at least two of the electrodes, and a high-frequency alternating voltage is applied between at least two of the electrodes. The method for treating sludge according to claim 3, wherein a direct current voltage is applied simultaneously. The sludge treatment method according to claim 4, wherein the electrode is an aluminum electrode. The fertilizer which consists of the aggregate which has as a main component the mud obtained by the processing method of the sludge of any one of Claim 2 thru | or 5.

Images