JPS5919600A - Apparatus for flotation of sludge - Google Patents

Abstract

PURPOSE:To increase the amount of fine gas bubbles formed during electrolysis, by providing a cell for the electrolysis of sludge, a power source, a tank for the treatment of flocs in floating sludge and a means for separately supplying sludge and an electrolytic solution to be electrolyzed to a space between electrodes. CONSTITUTION:Fine gas bubbles are efficiently formed by the electrolysis of an electrolytic solution supplied through an inlet 11 for the inflow of an electrolytic solution provided below electrodes 4, so that flocs in sludge supplied through an inlet 1 for the inflow of sludge are let float up by said fine gas bubbles and stay on the surfaces in an electrolytic cell 12 and a separation tank 7. This floating sludge is scratched off by a sludge scraper 6 and dropped into a concn. sludge tank 8. The separated water from which the flocs have been removed is circulated through an outflow device 9 and a device 10 for regulating a water level and then drained or recovered. The separated water recovered through a water intake 16 for separated water is mixed with alkali or the like charged from a hopper 15 in a tank 13 for supplying an electrolytic solution and then supplied through an injection opening 11 to the electrolytic cell 2.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a sludge flotation treatment device that floats sludge using microbubbles generated by electrolysis.

A conventional device of this type is shown in FIG.

In the figure, (1) is the sludge inlet, (2; is the partition plate (3)
), (4) is an electrode provided at the bottom of this electrolytic cell, (5) is a DC power source for applying voltage between these electrodes, and (6) is separated by a partition plate (3). Separation tank (sludge scraper installed at the top of the electrolytic tank (2; Next is the water level regulator.

Next, the operation will be explained.

The sludge supplied from the sludge inlet (1) to the lower part of the electrode (4) rises between the electrodes and flows into the electrolytic tank (2) and then into the separation tank (
Enter the room. Water level of separation tank (7) and electrolytic tank (2;
Since the sludge level (sludge level) is adjusted by the water level regulator α1, the water levels in the electrolytic tank (2; and separation tank (7)) are kept constant. .

The separated water is discharged from the separation tank (7) through the water level regulator 00 from the outlet path (9).

When the power switch is turned on and current is applied when there is a sludge flow as described above, microbubbles are generated from each electrode. The generated air bubbles contact the flocs (F) in the sludge and float to the surface.
Remains on the surface of the electrolytic cell and separation tank. The accumulated sludge is scraped off by a sludge scraper (6) and falls into a thickened sludge tank (8). On the other hand, the separated water from which the flocs in the sludge were removed is 9
From the separated water outflow channel (9).

It passes through the water level regulator α1 and is collected or discharged as nine separated water.

The ratio of the amount of air bubbles to the solid content of the floc above is 10 to 30.
The value of (l-gas/XgDs) is good.

Although this is known, the relationship between bubble generation and electrolytic current will be described below.

As already known, when heavy pressure is applied between insoluble electrodes placed in water containing an electrolyte.

Microbubbles are generated in response to the current. Let me show you this simply.

Anode reaction Z OH-> H20-j702 +
2 e cathode reaction ZH20-t-Ze-)H2+Z
OH-total reaction H20→H2+-, -02 side reaction Cl'+ Z OH-→(: lO+H20
+Z e or more, mainly hydrogen and oxygen are generated, the amount of which is 675m/A-Hteal at 20℃.

The voltage required to obtain this current (directly) is E=1.23
+KR+EC! (EC+ER)'e overvoltage and (
-KR is determined by the path between the electrodes and the electrical conductivity of water containing electrolyte. In order to reduce ERy, the path between the electrodes may be made smaller, the electrical conductivity may be increased, or the number of electrodes may be increased by 7.

Conventional flotation treatment equipment is configured as described above, and when processing biologically produced sludge such as sewage activated sludge without flotation, its electrical conductivity is -low, so it increases the efficiency of flotation concentration. Therefore, it is necessary to increase the voltage applied between the electrodes. In order to increase efficiency under the same voltage, it had many drawbacks, such as the need to shorten the path between the electrodes (this would cause sludge to get entangled with the electrodes and cause failures, so the number of electrodes had to be increased).

This invention was made in order to eliminate the drawbacks of the conventional ones as described above, and it increases the amount of microbubbles generated during electrolysis by supplying an electrolytic solution between the electrodes built into the electrolytic cell. The object of the present invention is to provide a sludge flotation treatment device that can efficiently float sludge.

An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 2, (1) to Cl are exactly the same as those in the conventional device. (11) is an electrolytic solution injection port for supplying electrolytic solution between the electrodes, θ2 is an electrolytic solution supply pump for supplying electrolytic solution from the electrolytic solution supply tank 0 to the electrolytic solution injection port (Ill), (14) ) is a stirrer, (19
is a hopper for replenishing acid or alkali to the electrolytic solution supply tank 0, and αQ is a separated water intake.

Next, the operation of an apparatus according to an embodiment of the present invention will be explained.

Microbubbles are efficiently generated by electrolysis of the electrolytic solution supplied from the electrolytic solution inlet Ql) provided at the bottom of the electrode (4). The sludge inlet (
The flocs in the sludge supplied from 1) are floated by the microbubbles and remain on the surfaces of the electrolytic cell (2) and the separation tank (7). In the example, the gas-solid ratio is 12 (l!-gas/kg, Ds) + separation tank (if the residence time of sludge floated by force is 100 minutes, the supplied sludge concentration is 0.74%)
A thickened sludge concentration of 400% was obtained.

The floating sludge is scraped off by a sludge scraper (6) and falls into a thickened sludge tank (8).

On the other hand, the separated water from which flocs have been removed is sent to the separated water outlet (9
), the separated water is discharged or collected via the water level regulator α (lI. The separated water is collected from the separated water intake port 06), and an alkali or acid is added from the hopper 09 in the electrolytic solution supply tank 0 tank, and the separated water is charged with electricity. After the conductivity is adjusted.

The electrolytic solution is supplied to the electrolytic cell (2) from the electrolytic solution inlet (11). In the example, 1 me sludge was supplied at a rate of sm3/H, whereas the electrolyte solution was 6 to 7 mB (17001 with sodium hydroxide) 1) I11 added) i
It was fed at a rate of 1 l/h. Electrolytic and gaseous decomposition (in pronation, the electrolytic solution supplied between the electrodes (4) from the electrolytic solution inlet (II) is electrolytically and gaseously decomposed to generate microbubbles mainly composed of hydrogen and oxygen. However, the microbubbles rise together with the sludge supplied to the upper part between the electrodes, and the electrolytic solution is supplied between the electrodes in an amount that compensates for the decrease in electrolytic solution due to quantitative microbubbles generation. Electrolysis of the electrolytic solution is carried out efficiently without being caught between the electrodes.
).

In the above example, the electrolysis power when no electrolytic solution is used is 3
It was 75 KWH/DSt, but when electrolytic solution A was used at °C, it became 81 KWH/Dst. KWHX here
θt is electrolysis power per ton of sludge solid content.

In the above example, an alkali and separated water were used to make the electrolytic solution 7, but the same effect can be obtained by using acids and salts alone, and tertiary treated water instead of separated water. Also, although the 9-separation water intake port Oe is provided after the water level regulator 0Q, the same effect can be obtained even if it is provided in the 7-separation tank (7).

As mentioned above, according to this invention, since the electrolyte solution is supplied between the electrodes in the tank, the amount of microbubbles generated during electrolysis increases, and the sludge is efficiently treated. be able to.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view schematically showing a conventional sludge flotation treatment device;
FIG. 2 is a schematic WT view of a sludge flotation treatment apparatus according to an embodiment of the present invention. In the figure, (1) is sludge flow 1 population, (2; is electrolytic tank, (4)
is an electrode. (5) is the power supply, 01) is the electrolytic solution supply port, (la is the electrolytic solution supply pump, 0 is the electrolytic solution supply tank, (14)
h', stirrer, 09 is Honba+' (161 is separated water intake, (F) is floc. In Figure 9, the same reference numerals indicate the same or equivalent parts. Agent Nobu Kuzuno - T, Rei”, amendment, (spontaneous) 21 Name of the invention Sludge flotation treatment device - Location East 5: t” 1-12 Marunouchi 2-chome, 111-ku, Miyako Nanadai, 3 scenes in total (6, (601) Mitsubishi Electric (Iku Co., Ltd. t1゜Representative h) Piece 1111 8
Part 4, agent address: Heavy Industries; 11th ward, 90-nai 2-cho, 112ff? 3>N5 Subject of amendment (1) Detailed explanation of the invention in the specification. (2) Drawings. 6. Contents of the amendment (1) In the 2nd, 3rd, and 5th lines of page 4 of the specification, the ``zo-ko'' (J) is corrected to ``20H-''. (2) Page 4 of the specification "2" in the 3rd and 5th rows respectively.
Correct "θ" to "2e". (3) On the 4th page, line 3, replace “ZH20” with “
2H20” is corrected. (4) Replace Kr+msJ on page 6, line 15 with r.
1ms/(7)”. (5) On page 6, line 16, 16-7m, eJ is corrected to 16-7mday/cm, J. (6) Figures 1 and 2 of the drawings will be corrected as shown in the attached sheet. 7. List of attached documents (++ Drawings (Fig. 1, Fig. 2) At least 1 copy

Claims (1)

[Scope of Claims] (+1) An electrolytic cell having an electrode for electrolyzing sludge, a power source for applying voltage to the electrode, and flocs in the sludge floated by microbubbles generated by electrolysis at the electrode. A sludge flotation treatment device equipped with a treatment tank for treating the sludge, and a means for supplying an electrolytic solution for electrolyzing the sludge between the electrodes separately from the sludge. The sludge flotation treatment device according to claim 1, characterized in that it is provided on the upper part. (3) The sludge flotation treatment device according to claim 1, characterized in that an acid or alkaline aqueous solution is used as the electrolytic solution. The sludge flotation treatment device according to claim 2. (4) Claims 1 to 3, characterized in that separated water obtained from sludge is used as a solvent for the electrolytic solution.
1. The sludge flotation treatment device according to any one of the items.