JPS6082199A - Method and device for dehydrating sludge - Google Patents

Abstract

PURPOSE:To form secure flocs and to permit easy dehydration by adding a cationic high polymer flocculating agent to waste water sludge to flocculate and thicken the sludge then forcing the sludge into the hermetic filter chamber of a filter press by a press-fit pump and dehydrating the cake. CONSTITUTION:A cationic high polymer flocculating agent having 10<4>-150X 10<4>mol.wt. is added to waste water sludge such as sewer or the like at 0.5-5% by weight in terms of the dry solid matter in the sludge to flocculate and thicken the sludge. The flocculated sludge is press fitted into the hermetic filter chamber of a filter press by a press-fit pump and is dehydrated. The filter press of, for example, the type in which the hermetic filter chambers 2 formed between many juxtaposed filter plates 1 are opened by each sheet upon completion of filtration and dehydration and the cake is stripped and discharged is used. The sludge is press fitted into the filter press under 3-7kg/cm<2> press-fitting pressure and is then compressed and dehydrated under 10-40kg/cm<2> compressing pressure.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for dewatering Nj mud such as sewage, and improvements to F2 and Q used for the dewatering. Conventionally, in order to dehydrate sludge such as sewage, a vacuum dewatering machine that uses vacuum negative pressure, and a VC between a large number of rolls is used as the equipment.
P mountain of Swallow tJ is stretched (]1, pressure force of roll and r
Belt press using P fli glue long sword, P plate and f
A sealed transient chamber is formed with a P frame, and fl is added to the filtration chamber.
A filter press or the like that press-fits mud and dehydrates it using F4 is often used. When sludge is dehydrated using Toru et al.'s dewatering machine, the sludge is treated in advance to suit the dewatering operation of each machine, and an appropriate amount of filtration (dewatering) aid is added. For example, if the vacuum drum has an endless fP if
In a vacuum dehydrator of the type where f is multiplied and rotated, sludge is coagulated by adding slaked lime or sludge, and the vacuum drum is immersed in the sludge M times, and the sludge is immersed in the sludge for 1 K times. Sludge is layered under suction to separate moisture. However, in this vacuum dehydrator, a strong floc is required so that the floc that is attracted and layered around the drum does not collapse when the drum is removed from the water. For this reason, in conventional vacuum dehydrators, it is necessary to add slaked lime and iron chloride as flocculating agents to create strong flocs. Since m is large and large, the dehydrated cake base increases, and when disposing of the cake after 11 days, it is difficult to obtain a dumping place, and problems such as alkali content leaching even after dumping are inevitable. Moreover, the water content of the dehydrated cake in a vacuum dehydrator is up to 80%, and auxiliary fuel is required to incinerate it, making it uneconomical. Next, the belt bracelet mentioned in 11.
i (, i4
L/L sludge was supplied, and after gravity dewatering on (1'fli), the sludge was subjected to shear force JP method y4 by passing it between rolls arranged in a chisel pattern or between opposing rolls. The pressure in the directions 〃1 and 1 is applied to the horns 11 and j8 water/).After dehydrating the sludge with this belt press in the Kabuto force dewatering zone, it is used as a jarring roll or as 1uJ.
Pressure with a roll? C. The flocs do not need to be so strong, so lime is not used as a flocculant, and an organic polymer klk agent is used, which requires only a small ridge. However, with this belt press, 1. The red sludge in the Ik Nagali water zone is transmitted in a state of being pinched in piles up and down, and is sent to the side in one pile, and is automatically pressed by jarring rolls and opposing rolls VC. It's Ruri,
Run to the side, if'' (J is here from 1J,
+I't+ Pressurize with the upper blade. Ma1ko,
Since jarring rolls and opposing rolls must apply pressure while running on one surface and twisting, it is mechanically difficult to achieve 1-level pressure with surface pressure. Therefore, even with the conventional belt press, the amount of dehydrated cake was small due to the use of polymer coagulation, but the moisture content of the cake after dewatering could reach up to 70%.

Next, compared to these vacuum dehydrators and belt presses, filter presses pressurize the sludge in a sealed filtration chamber, so they can pressurize several times as much as vacuum dehydrators and belt presses. However, the water in the 70 volumes of flocculated sludge is
It is not possible to separate the particles by applying pressure alone, but if too much pressure is applied, the particles are pushed into the first row of holes, making it impossible to filter.

Therefore, conventional filter presses add slaked lime, iron chloride, etc. to sludge to form strong flocs that can withstand high pressure and perform dewatering.
A water-containing cake of about f6 was obtained. However, in this case as well, slaked lime was necessary to form a hard floc, and this JL increased the amount of dehydrated cake, making it difficult to dispose of the cake after φ.

This invention was made in view of the conventional dehydration problems KM as mentioned above. First, the inventors discovered that in order to dive through a highly dehydrated cake, the fL floc that can be pressurized at high pressure was i9, and then As a dehydrator that can apply high pressure, we focused on the fact that the filter press was suitable for J' sewing, and as a result of repeated tests, we succeeded in forming a firm flock, and this is the new filter. By pressurizing dehydration using a press, we succeeded in producing a dehydrated cake of 11 [1;

Hereinafter, this invention will be explained in detail with examples. i-length is necessarily fixed time.
The point is that a strong floc was formed by using the polymer flocculant of Floodwall Molecule-Han and adding it to sewage sludge. To dehydrate the tsuku, filter it to the point using a sealed filter straw in a filter press. That is, d'', IH indicates the molecule sk of the polymer flocculant using the water reflow method for sludge according to the present invention, and this Table 1 shows the polymer flocculant C shown in Table 1. 7+S 41 times a day, it can form a strong floc, and the dehydration ability with a filter press is guaranteed to be 7C.(For examples showing the effect, see 1%.) According to Table 1 from 1 company, the polymer coagulation side number, which has been found to be effective in floc formation, has cationic properties,
In particular, those that have been found to have a remarkable effect are
It is necessary for ten thousand things. r61, 4g19AB with a molecular weight of 10,000
, O, molecule yiso million q+ll M G's house,
Although it is also effective against sludge in other places, in the practical test described below, the young fruit was inferior to the polymer flocculant of Song Tei J (A-F).

Next, the second column shows the cake moisture when sludge in various places is dehydrated using the above-mentioned polymer flocculant,
The numbers in the notes column are obtained by adding the same panmolecular ridge cutting to the sludge in the same place and using a belt press (refer to 7371'6+).
Remove moisture from the dehydrated cake using a 7F table.
The sludge injection pressure is 5 to 8, and the squeezing pressure is 15'1-8.
The belt press used for comparison had a general outline as shown in FIG. 7, and the V fabric tension was approximately 4). As is clear from Table 2, the dewatering of sewage sludge using a filter press + C, which was used in the conventional product (1), has been reduced to zero. It is 10% superior to that dehydrated with a belt press.Also, according to the ?J!2 table, even among the flocculants belonging to the low molecular weight, Ili, F whose molecules
It has been shown that the coagulant t;a1 has a remarkable effect on sludge at the place of death.

The above is about the relationship between the molecular weight of the polymer flocculant added and the moisture content of the dehydrated cake.Next, Table S3 shows the results of testing the relationship between the addition rate of the flocculant and the moisture content of the cake. There is little to show.

It can be considered that the more flocculant added during the third period, the more the cake moisture can be lowered. ]111, the flocculant in Table 3 is a polymer flocculant A (tentative name) with a molecular weight of 10,000, but other flocculants with different molecular weights, such as polymer flocculants with a molecular weight of 500,000 to 70,000 ( Tentative name 11i, F
) was confirmed to show the same area.

Regarding addition of 2, iJ B B (ratio to solids in sludge) 1.5% or less and ss 3% or more ('c
However, since the dehydration effect is poor at ss addition of 10.5% or less, and from the economical point of view, ss addition of 883% or more was omitted.

Next, regarding the pressurized pressure in the gap for pressurized dewatering, Table 4 shows:
Table 4 shows the test results of the squeezing pressure in the filter press and the water content of the dehydrated cake. According to this Table 4, the higher the squeezing pressure, the more the cake water content can be reduced. On this point, the fourth
At the filtration pressure (squeezing pressure) of 15Alj as shown in the table,
A filter press is the most suitable dehydrator that can process a small amount of sludge. : Must be +M.-Ma) This is the condition water pc l'+'i L using this polymer flocculant.
On the way to get rid of it, I noticed CQI A, that is, Cakeno during dehydration! I mimo, cake water content, (・1 i[i
It turns out that the i factor is important. 955 table 1
Yo, -) With iL's pressure! If submerged, K, t, -
This shows the relationship between 19 of the cake and moisture content.
・If it is deep, a thick cake will be formed into a shape. The reason for this is that when the /I' chamber is shallow, the thickness of the cake due to the IE]'++ pressure is, for example, up to 5ff if the chamber is 8 m deep. squeezed,
If the moisture inside is sufficiently squeezed out, but the pores are deep, it is assumed that even with high squeezing pressure, the moisture inside the rig cannot be squeezed out sufficiently. Incidentally, if the depth of the filtration chamber is 14 mm and the pressure is 15 mm or more, the cake depth will be approximately IQ mm.

Judging from this, it is thought that even if one squeeze is performed at 30'%d, the maximum depth of the filtration chamber can be reached at 20 mm. The cake thickness at this time is estimated to be 13) degree of fraud.

Above, we have explained the a'A rill used in this invention, its small horn, dewatering pressure, etc., but these factors that affect the water content of the dehydrated cake, 2, 6 independently affect the water content of sludge. In many cases, these tJ factors interact with each other in relation to each other. , the filtration performance of one single board was I grade 2+J/T- Sewage sludge was dehydrated using a practical filter press, arbitrary PM was removed, and the water content distribution of the dehydrated cake was shown. The numbers in the circle indicate the area where the cake was located.

In addition, the dehydration problem occurred in the following cases.

Injection time of sludge into the P chamber: 8 minutes for 111 hours of compression after 8 minutes Injection pressure: 5 - Squeezing pressure: 15 Molecular weight of soil-added polymer flocculant: 700,000 (01J code F) Addition rate of flocculant: 88 2% Sludge concentration 4.05% (W/V) Sludge properties M treatment plant Digested sludge Table 6 ■ 4-5 59.5 ■ 4-66L8 ■ 6-10 61i6 ■ 4-760.5 ■ 6-10 - Comparing this result with the result obtained by the above-mentioned Nori-7 test machine, it is clear that the leaf test machine is far superior to the water test machine, and we can expect a further dehydration effect when it is put into practical use. l
In addition, when comparing these results with the test results of the practical belt press described in the details column of Table 2 above, it was found that there was a difference of more than 10% in the moisture content of the dehydrated cake compared to other vacuum dehydrators and There is no need to explain that there is an even more significant difference when compared to a centrifugal dehydrator, and it goes without saying that it has an excellent dehydrating effect9. 17i1, the low molecular weight flocculant used in the present invention cannot be used in conventional belt fullless systems.1J
Since I was having trouble with this, I used the conventionally used molecule thIt6o.

More than 10,000 molecular aggregates were used. Moreover, even if A dehydration occurs, the present invention K 1i! ! The low molecular weight drug I used was very rare, and I had a rare case of rhf syndrome.

:、sノ、The filter press used in the above tests was a leaf test machine and a filter press (not shown in Figures 1 to 3).
A traveling type single filter press was used, but judging from the test results mentioned above, it is limited to this type.
Sealed filtration chamber 1'i as shown in Figures to Figure 6: ;rr
If a filter press having a structure capable of passing through high pressure V1 is used, a similar effect will be obtained at 44F. That is, what is shown in FIG. 4 is a large number of parallel t+":
After completing the R filtration and dehydration of the sealed filtration filter 2 which had accumulated a lot of Ji in a temporary period of time, we performed a formal ritual in which one piece of 1U was opened and the cake was peeled off and discharged. ” 11 shi-shaped fP 11j 3 zigzag-shaped V (a + stretched, each n] & cake formed between 57
The one shown in Figure 6 is one that opens all the furnace plates at once and allows the furnace cloth 3 to move. Since the P plate of the type shown is installed horizontally, it is generally called a vertical type.As shown above, regardless of the type of filter press, the airtightness P ]i→φ is 911+ and , lJj excessive dehydration is possible at high pressure.] They have two things in common.

In summary, this invention has succeeded in flocculating sludge and forming a strong floc using a special 116-molecule collector, and has succeeded in coagulating sludge to form a strong floc. The flocculating agent was used to successfully dewater the flocculated sludge.In a sealed-filter chamber using a filter press, high pressure ZJJ filtration becomes Compared to the pressurized 1j-1 filter, it is much lower than the average pressure, and compared to the conventionally used slaked lime and iron chloride, there is an extremely low level of 7JII. Even when disposing of the cake after 91, the various salmon costs will be reduced by r + lj to 1] and 1d will be calculated.

[Brief explanation of the drawing]

1st i/! , l shows a side view of a filter press similar to 11α used for summer use in this invention, and Fig. 582 and Fig. 3 are:
Figure 1 is a longitudinal cross-sectional side view to explain the structure of the extending plate, and Figure 1 is a schematic side view of each mallet filter press. Figure 7 is a 4i1 side view of the belt press.
4 is shown in a schematic side view to explain the appearance. Code explanation 1, 枦板 2. Filtration chamber 3. F cloth o 2 I germ spear φ picture spear 9 figures 6 x

Claims (1)

[Scope of Claims] (1) When dewatering wastewater sludge such as sewage, first, a cationic polymer flocculant is added to the wastewater sludge to collect and concentrate it, and then it is pumped into a filter press using a pressure pump. A sludge dewatering method that involves pressurizing the sludge into a sealed filtration chamber. (2) The molecular weight of the polymer flocculant is 10' to 150X
If' is 10', preferably 105 to 7X1θ5
A method for dewatering sludge according to claim t11. (3) The sludge according to claim (1), wherein the amount of the polymer flocculation agent 1j added is 0.5 to 5% in -t-JJk ratio with respect to the dry solids in the sludge. Dehydration method. +41 The sludge before adding the above polymer flocculant is 1~
5. A method for dewatering sludge according to claim No. fil no. (5) A patent claim characterized in that when the sludge is forced into the filter press, the sludge is first injected and dehydrated at a pressure of 3 to 7, and then dehydrated by compression at a pressure of 10 to 40. View No. (method for dewatering sludge according to item 11). (6) A patent claim characterized in that in supplying the flocculated sludge to the closed filtration chamber and dewatering it, the sludge is pressurized at a pressure of 10 to 30 to dehydrate the sludge. (7) The depth of the B5 chamber of the filter press for dewatering the a-shrunken sludge according to claim 11 is 5.
1. A sludge dewatering device characterized in that a sludge dewatering device is provided with a diaphragm at least on the negative side of the filtration chamber. (8) The filtration γ of the upper Ie filter press is
A sludge dewatering device according to claim 7, wherein the sludge dewatering device is constructed of a frame and a F. (9) The dewatering apparatus of γsd et al. according to claim (7), wherein the filtration chamber of the filter press is provided horizontally. sq II+f Claim as stated in Clause (7) above, in which the P city provided in the above-mentioned filtration chamber is allowed to run independently in each ff'J room. Sludge dewatering equipment. (111 above ife Patent claim in which the P cloth provided in the filtration chamber is in a long, endless shape, and is provided at the nth position so that it can run on the plate surface of the valley i + j. A sludge dewatering device according to item (7) of the scope of the present invention.
The sludge dewatering device described in section 7).