JPS58101800A - Dehydrating method for muddy material - Google Patents

Abstract

PURPOSE:To decrease moisture content down to levels at which self-burning is possible by granulating primarily dehydrated muddy materials to suitable grain sizes and sticking dehydration aids on the surfaces of granules then subjecting the granules to secondary dehydration. CONSTITUTION:Muddy materials contg. org. components are dehydrated by suitable dehydrators down to about <=82% moisture content. The primarily dehydrated materials are charged into a rotary cylindrical mixer or the like and are crushed; at the same time, the materials are granulated to suitable grain sizes. Thereafter >=1 kind among diatomaceous earth, slaked lime, calcium carbonate, incineration ashes, finely grained coal, sawdust, dry pulp and soil are added as dehydration aids at about 10-100wt% based on the dry weight of the original sludge solids, and are stuck on the surfaces of the granules. The secondary dehydration of the granular sludge materials is carried out with the above- described dehydrators, whereby the moisture is reduced down to <=60%.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for dewatering sewage sludge, a muddy water material with a high gold-containing water content.

Currently, the amount of water purification is increasing due to the improvement of water quality in public water bodies and the development and transformation of the industrial world, and as a result, the amount of sludge as a byproduct is steadily increasing. In general, the combustible content of organic sludge is cellulose type 1 [& indicates 3000 to 5
It has a calorific value of 0.00 (Ka &t/J9, organic content), which is comparable to that of coal.Despite this, more than 90% of the total amount of sludge generated in medical facilities ends up on the earth or in the ocean. They rely on dumping. However, because untreated sludge contains a large amount of water, is putrid, and produces a strong odor, there are restrictions on dumping it for environmental protection reasons, and land disposal sites in large cities and surrounding cities are now saturated. ing.

Therefore, with regard to the treatment and disposal of sludge materials, effective use and reuse have been advocated from the perspective of resource conservation, and one local government manufacturer has taken up the initiative, but there is still no definitive solution.

Conventionally, in order to dehydrate and solidify sludge containing organic components, some kind of steric agent is added to the sludge, and then gravity dehydration after dehydration 1. However, due to dehydration interference such as capillarity between water-containing powders and clogging of filter cloth, the water content after dehydration was in the 70 to 80% range, and various types of furnaces, including multi-stage furnaces, It was not possible to dehydrate the water to a point where it could self-combust in an incinerator. Dehydration of muddy substances to the point where they are self-combustible is also important from the perspective of resource conservation.

Here, the moisture content in the self-combustion range needs to be about 65% or less. For this reason, conventionally, muddy materials are dehydrated and solidified, followed by drying in the sun or by circulating combustion gas for the purpose of evaporating water. However, in the conventional method, sludge cake 1
It required 30 to 401 tons of external fuel per ton, was uneconomical, and had many problems in terms of equipment. The present invention solves the above-mentioned problems and provides a dewatering method that can reduce the moisture content until self-combustion is possible, and can dewater sludge material until it can generate more energy.

Therefore, the dehydration method of the present invention involves granulating the dehydrated slurry to an appropriate particle size, attaching a dehydration aid to the surface of the granules, and then subjecting the granules to secondary dehydration. It is characterized by making the ratio 60- or less.

In the preferred implementation of this @mei, secondary dehydration is performed under pressure to reduce the water content to 50% or less.

The present invention will be explained in detail step by step.

In the primary dewatering of the present invention, muddy materials containing organic components collected from waterways, rivers, and sedimentation ponds are processed into muddy materials using a dewatering machine such as gravity dehydration, tank air dehydration, centrifugal dehydration, belt press, or filter press. Keep the moisture content of materials below 82%
reduce. For example, if you use a belt press, 2 to 3
At an operating pressure of kg/ad, 75 due to gravity and squeezing action
It is possible to dehydrate up to a moisture content of 1. For a centrifugal dehydrator, g
ooo~5ooo The same (7
Dehydration is possible up to a moisture content of 5%. However, it is important to note that each dehydrator should be operated at an appropriate operating pressure.

However, unnecessarily increasing the operating pressure will promote the compaction of the sludge, which will make it impossible to drain the water, and will even lead to the opposite effect, such as clogging of the r-cloth.

The filth that has been primarily dehydrated in this way is put into a rotating cylindrical mixer, etc., and is crushed and granulated to an appropriate particle size.
Then, as a dewatering aid, one or more of diatomaceous earth, slaked coal, calcium carbonate, incinerated ash, pulverized coal, sawdust, dried pulp, and biomass is added to the dry weight of the original sludge solids at lO~10
It is added at 0'1 IDjll to form a layer of dehydration aid on the surface of the granules. Said dehydration aid! Of these, the incineration ash includes sewage treatment sludge ash, sewage treatment sludge ash, industrial wastewater treatment sludge ash, municipal waste incineration ash, industrial waste incineration ash, etc., which are relatively easy to obtain and have little industrial reuse value. It is desirable to use it. In particular, it is desirable to circulate and use a portion of the incineration ash produced by incinerating the dehydrated product produced by carrying out the present invention.

The granulation method is to use a mixer such as a rotary set, a screw set, or a vibrating mixer to mix the above-mentioned drying aid so that it does not sink into the sludge and rises up. The particle size after granulation should be less than the diameter zom, and it is particularly desirable that 70% or more of the particles by weight be distributed within the range of 1 to 10 g in diameter. As in the present invention, after sludge material is granulated to an appropriate particle size, a dewatering aid is formed on the surface of the granulated material. The action of this dehydration aid during squeezing
It is thought to prevent sludge substances from coming into direct contact with filters such as cloth.

This granular sludge material is again dehydrated (
By performing secondary water harvesting, the water content can be reduced to 60 shi or less, and the capacity can be reduced to 50% or less compared to the first one. In addition, this secondary dehydration is carried out by pressing, and by separating the initial pressure and pressurization into two-stage compression using bamboo, the water content is reduced to 50% or less and the volume is reduced to 611 Il or less. The initial pressure is preferably 3079/min or less, preferably 4; Lla to 25/m, and the time is desirably 2 minutes or less. Further, the main pressurization is carried out at a pressure of 60 to 100 & 9Z-value or 60 to 80 J9/1 for 1 to 3 minutes.

Next, the present invention will be explained in detail based on experimental examples.

Sludge containing organic matter precipitated in waterways, rivers, sedimentation ponds, etc. and having a water content of 98% is collected by a pump and fed to a belt press. At this time, the water content of the muddy material B was approximately 96%, as the water content decreased slightly during recovery. This muddy gk! 1 is subjected to primary dehydration using a belt press. Pressure dehydrates it into a disk shape with a thickness of 10m11 or less! The solid muddy substance O is taken out.

This solid mud material is crushed in a rotating cylindrical mixer.

During this period, each time the muddy material 0 is turned over in the mixer, it is divided into quarters and five bags and mixed with the incineration ash and transferred, resulting in a granular muddy material having a dry skin and a diameter of 5 sm or less.

This granular slurry @D is placed in a compression device for secondary dehydration, and the compression operation is performed by initially applying a pressure of zohg / (ill) for 1 minute.
Apply pressure for 2 minutes. Through this operation, the granular slurry becomes slurry with extremely low water content ◎ This slurry is further broken down by a crusher into solid slurry powder 1 ◎
This solidified mud powder 1 can be completely burned in an incinerator, and a part of the resulting incinerated ash can be used as an additive drying aid and circulated back to the above-mentioned main direction.

Note that the 96% water-containing muddy substance 1 may be formed into a 70% water-containing muddy substance B' using a filter press, and the amount of incineration ash added in the mixer may be set to 30% or less to facilitate compression dehydration. .

Next, the actual test results of this experiment will be explained.

Figure 1 shows the incineration ash added to the secondary dehydration cake when incineration ash was added as a dehydration aid, mixed and granulated, and secondary dehydration was carried out.
This shows the relationship between m and the water content of dehydrated sludge material.

From this figure, as shown by line 7a, when the water content before secondary dehydration is 98%, the water content after secondary dehydration is constant until the amount of dehydration aid added is 100% or more, and then it rapidly decreases. It stabilizes at around 10%. This moisture content was outside 40. Next, when the water content before the secondary dehydration was 80% (graph b), the water content after the secondary dehydration was 40% when the amount of the dehydration aid added was sO% or less. When the amount of dehydration aid is sO~50%, the water content after secondary dehydration is stable. Next, in the case of water content u1 before secondary dehydration (graph 0), the process is exactly the same as in the case of water content 80%, but with the addition of a
It can be seen that the moisture content can reach up to 40%.

As you can see from the above, the drying aid is 130% in both cases.
% or more, the water content will be 60% or less.

However, if the moisture content before the secondary dehydration is 98%, the moisture content cannot be reduced to less than 50% unless a drying aid of 10% or more is added. On the other hand, for 80% and 75% products, the water content can reach 40% by adding only 20% of the dehydration aid.

In this way, it is desirable to reduce the water content as much as possible during the first dehydration, but considering the capacity of a normal dehydrator,
%" or less is considered to be sufficient. With this water content, the dehydration aid can be attached to the surface of the granulated powder. If the water content is higher than this, the dehydration aid will be consumed during granulation. Many auxiliary agents are required.

Next, in this experiment, the initial sludge material, the state of the sludge material after the second dehydration, and the second dehydration have a water content of 98% and 175%, respectively.
, 30%. FIG. 2 shows a comparison of the weights of these. For example, if the total weight of sludge with a moisture content of 95I% was initially 1Jcg, after the primary dehydration, if the moisture content was 75%, the total weight would be 480g, which is approximately 480g, and after the secondary dehydration, even if 10ρ weight of dehydrating agent was added. At 30% moisture, the total weight decreases to 42g. Comparing the water content weight, the weight decreases to 9 BOg x 60g and 12g, respectively.

The sludge material secondary-dehydrated in this way has a water content of 50 to 60.
% or less, it becomes a solid state with no surface moisture and can be left as is! It becomes a yozu with a calorific value of OOO~2500Ko&A/kg.゛Next, Figure 1g3 (a) shows the granular muddy material before the next dehydration (
b) is an imagined organization diagram of the combustible mud material after secondary dehydration. (&) In the figure, the filth 1Iil includes sludge solids 12, pore water 13, capillary rising water 14, surface submerged water 15,
It is composed of internal water 16 and surrounding free water 17, and everything except the sludge solids is water. Of the above moisture, only internal water 16 exists inside the solid cedar component 1, and because of its strong bonding force and compressibility, it is difficult to mechanically dehydrate it. 13 water, 1 capillary rising water
4, surface-attached submersible material 15, etc.) can be relatively easily dehydrated by adding a dehydration aid or by mechanical dehydration. After the secondary dehydration, the sludge solids 12 and the sludge solids 12 are deformed into a flat shape, and the bound water other than the internal water 16 is almost completely removed, as shown in Figure (b). The reason why the above results are obtained is that the drying aid 18 added before the secondary dehydration adheres to the outer skin of the soiled material, and the surface layer water 15. The affinity of is weakened.

Then, the squeezing action was added, and the shell of the granular mud material was crushed, and at the same time, the solid sludge was crushed, leaving no place for escape. It is thought that this is because bound water is drained to the outside through the main body between grains.

Finally, FIG. 4 shows the moisture content of sludge materials in the conventional dewatering method and the dewatering method according to the present invention, and the thermal characteristics in each water content state. As shown in this figure, in the current multistage furnace, in order to dry the sludge material to the self-combustion range, 30 to 40 tons of external combustion fuel is consumed per sludge n. Therefore, attempts have been made to increase the level of self-combustion in various incinerators, but it is difficult to create incinerators that can self-combust when the water content is 65% or more. By the dehydration method of the present invention, the moisture content of sludge is reduced to 60 hiss or less, preferably 0% or less, so it is now possible not only to burn the sludge as it is, but also to create energy. As explained above, the invention has succeeded in reducing the water content to a point where self-combustion is possible without wasting the high thermal properties of sludge material containing organic components, and in addition, the volume of sludge material after dewatering has been reduced. 5 I was able to reduce the volume to below I11. It is also possible to use the heat from combustion and convert it into useful energy such as power generation. As described above, the present invention is a very effective method for dewatering sludge materials in these days when the effective use and reuse of industrial waste is becoming more and more popular in terms of resource conservation.

[Brief explanation of the drawing]

Figure 1 shows the relationship between the amount of incinerated ash added and the moisture content of dehydrated sludge material, and Figure 2 shows the relationship between the amount of added incinerated ash and the moisture content of dehydrated sludge material. A diagram showing the weight ratio, Figure 3 is an imagined set of sludge materials before dewatering and after secondary dewatering 1lii
Figure i and Figure 4 (1) are diagrams showing the moisture content of sludge materials in the conventional dehydration method and the dehydration method according to the present invention, as well as the thermal characteristics in each water content state. l: sludge substance, 12 = sludge solid, 13: pore water, 14
Capillary rising water, 15: Surface submersion, 16: Internal water, 17:
Free water, 18: drying aid. <2 Agent 1) Hisashi Naka -(,5″, i;1.i゛・No.-
ㅅProcedural amendment (voluntary) 11j (□151゜9..20,. 1° ”°゛1 ′I) ′□ 1″゛ If the method of dehydrating muddy substances Ura II is used, l1111;lii 'l'f + ：'l excited i 1
yl (... Higashi 5; C Toriyo 111-ku Marunouchi 2-chome 1
No. 11, 2, H, 508, UL'C Co., Ltd.
1st 2nd; -1l : i, ', v, genus is within admission 11
Tsuzume Tokyo 28th-4612 Sode IF, '1 k.
[Detailed description of the invention in the description. Contents of the amendment The content of the "detailed description of the invention" shall be amended as per Europe. L page 9, line 6, hard cedar muddy powder r with z 9 sada) line to 8 lines as a dehydration aid for addition 3 10 sada line 6 3
4 outside 40 with 0% or less 10i [11 lines
All include dehydration aids &NII'% row Add all dehydration aids of 15% or more & zg 4 rows Others (between-
], Line 11, 9 Add the weight of 10 g of dehydration aid & Line 1396 Water content of sludge is 4Jd60 or more
Up

Claims (1)

[Scope of Claims] L In the dehydration of muddy materials, the dehydrated muddy materials are granulated to an appropriate particle size, a dehydration aid is applied to the surface of the granulated material for a length of 9 m, and the granulated material is further granulated. 1. A method for dehydrating muddy materials, which comprises reducing the water content to 60% or less by subjecting the material to secondary dehydration. 2. A method for dehydrating a muddy material according to claim 1, characterized in that the secondary dehydration is performed under pressure to reduce the water content to 50% or less. & In claim 1 or 2, the moisture content of the muddy substance is reduced to 8! ! A method for dehydrating muddy substances characterized by reducing the water to z or less. 4. In claims 1 to 3, the dehydration aids include siliceous earth, slaked lime, calcium carbonate incineration ash, pulverized coal, ±(, blue powder, sawdust, dry pulp, Lm
A method for dehydrating muddy substances characterized by using the above method. 4. A method for dewatering muddy substances as set forth in claim 4, characterized in that incineration ash is used. 6 In claim 1, incineration ash includes sewage treatment, sludge ash, (urine treatment sludge ash, industrial wastewater treatment sludge ash,
A method for dewatering muddy substances, characterized by using either municipal waste incineration ash, industrial waste incineration ash, or a mixture thereof. 7. In claim 1, the amount of dewatering aid added is 10 to 100% of the dry weight of the original sludge material! #Dehydration method for muddy substances that turn into mold. (a) A method for dewatering a slurry material according to claim 1, characterized in that the particle diameter after granulation is less than or equal to gosat. 9. In claim 8, 1! A method for dewatering muddy substances characterized by a distribution of particles of 70% or more in terms of quantity. 1α Claim 2 is characterized in that the pressurization method is direct pressurization or indirect pressurization using either vertical evacuation or a 1i# type dehydrator, and two-stage squeezing is performed in which pressurization is applied after initial pressure. Method for dewatering muddy substances. IL In claim 2, the initial pressure is 30/- or less for 2 minutes or less, and the pressurization is bO
10019/am” for 1 to 3 minutes.