JPS60222118A - Dehydrating treatment of organic sludge - Google Patents

Abstract

PURPOSE:To treat dispose dehydration resistant sludge with the economized resources and energy and to solve part of problems with the treatment of waste by using the waste paper which is made into a slurry by the org. slurry itself as a dehydrating assistant. CONSTITUTION:Part 2 of waste activated sludge 1 and waste paper 3 are supplied to a hydropulper 4 and the waste paper 3 is broken and loosened by the powerful stirring and shearing applied from a stirrer 5 to form a mixed slurry 6 in the stage of dehydrating waste activated sludge 1. The mixed slurry 6 of the slurried sludge 2 and paper 3 is added to the balance 7 of the sludge 1 and further a high polymer flocculating agent 8 is injected therto and thereafter flocs are formed in a flocculating and intimate mixing tank 9. The flocs are dehydrated by a dehydrator 10 such as a screw press and dehydrated cake 11 having 50-60% moisture content is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for dewatering organic sludge generated in the treatment of organic sewage such as sewage, human waste, and various industrial wastewater.

[Conventional technology]

Dewatering operations are essential to treat and dispose of organic sludge generated during the treatment of organic wastewater such as sewage, human waste, and various industrial wastewaters. Conventionally, the most common method for dewatering organic sludge is to add a cationic polymer, or a combination of a cationic polymer and an anionic polymer, to organic sludge as a macromolecular flocculant, and then flocculate the organic sludge using a belt press, centrifugal dehydrator, Dewatering methods using various dehydrators such as filter presses and screw presses have been adopted.

However, such conventional methods cannot handle sludge that is extremely difficult to thicken and dewater, such as surplus activated sludge.
Dehydrated cakes with a moisture content of 80% or higher are often only available, and they must be landfilled, composted, dried, or
When performing incineration.

Handling, generation amount, fuel efficiency, etc. are very important issues.

[Problem that the invention seeks to solve]

The present invention is capable of processing and disposing of organic sludge, especially separated aqueous sludge such as surplus activated sludge, in an extremely resource-saving and energy-saving manner, and also aims to partially solve the problem of vehicle disposal. .

[Means for solving problems]

The present invention supplies a part of the organic sludge to be dewatered and waste paper to a hydropulper, dissociates the waste paper and converts it into a slurry, and adds the slurry and a polymer flocculant to the remaining part of the organic sludge. Folk refers to the process of agglomerating the water and then dehydrating it.

[For production]

An embodiment of the present invention will be described with reference to the drawings.
For example, when dewatering surplus activated sludge 1 discharged in activated sludge treatment of sewage, a part 2 of surplus activated sludge and waste paper 3 such as old newspapers, old magazines, and other unnecessary documents discharged from homes, offices, factories, etc. is supplied to the hydropulper 4, and the waste paper 6 is dissociated and loosened while being strongly stirred and sheared by the stirring rock 5, thereby producing a mixed slurry 6.

The hydropulper 4 is a device that mechanically disintegrates paper with water, and is a mechanical stirring tank type using stirring blades,
There are rotating drum types.

The technical point of the present invention is that the waste paper is not simply dissociated with water, but the organic sludge 1 to be dehydrated (for example, in the case of surplus activated sludge, most of it is water and 1 to 2% activated sludge is suspended). turbidity) as a suspending medium,
The waste paper 3 is dissociated by a hydropulper 4.

6 waste paper for 2 sludge! v1144 lit is 3~
A concentration of about 4% (weight) is appropriate; too high a concentration is not preferable because stirring becomes difficult and the cutting power of the stirring motor increases.

The mixed slurry 6 of the slurry 2 and waste paper 6 is then added to the remainder 7 of the surplus activated sludge 1, and the polymer flocculant 8 is further injected. Dehydrator such as press 10
Dehydrated cake 11 with a moisture content of 50 to 60%
get. 12 is dehydrated separated water.

Note that a sufficient effect can be achieved when the addition rate of the mixed slurry 6 to the sludge 7 is 10% or more based on the weight of solids in the sludge.

Furthermore, it was found that when a belt press dehydrator or a filter press dehydrator was used as the dehydrator 10, the peelability of the dehydrated cake from the P cloth was significantly improved, and the maintainability was improved.

Furthermore, in the flocculation mixing 419, the flocculated sulfur 2
If the water is once supplied to the screen 16 to separate the separated water 14, concentrated, and then supplied to the dehydrator 10 without directly leading it to the dehydrator 10, the throughput of the dehydrator 10 is further improved.

〔Example〕

Surplus activated sludge from sewage plant 3!1 (solids concentration 1.8 cm)
A portion of the pulp was taken out and old newspaper was added to the bottom rotary blade hydropulper to give a suspended solids concentration of 5%.

As a result of stirring for 30 minutes to 1 hour, the old newspaper was completely dissociated by the excess activated sludge and converted into a mushy slurry.

This slurry was added to the remainder of the surplus activated sludge so that the solid content of the fiber content was 20%, and then a DAM-based cationic polymer was added at 0.5% to 88% and flocculated. Strong large flocs were formed. When this Q floc was fed to a 60° inclined wedge wire screen with a mesh opening of 0.7 tm, the liquid was rapidly separated in a few seconds, resulting in a concentrated sludge [5 to 5.2%].
Screen separated water of 50-120W9/l was obtained, and S
The S recovery rate was 98- or higher.

For comparison, when the above-mentioned cationic polymer was added to the surplus activated sludge in the same amount and fed to the screen without adding waste paper slurry, leakage occurred under the screen at a mesh opening of 0.7 mm. SS amount A large 2000-2500 pieces/
1, making separation using a screen almost impossible. Therefore, in order to increase the SS recovery rate to 95 inches or more, it was necessary to reduce the mesh size of the screen to 0.3. However, as a result of reducing the opening, the processing capacity of the screen (-slurry/-・screen area・Hr) decreases by 1/3 to 1/4 Vc compared to when the opening is 0.7 mm, and the required screen There was a problem that the area increased.

Next, the screen thickened sludge with a solids content of 5 to 5.2 was dehydrated using a screw press with a diameter of 3005 mψ and a length of 2100 m (screw rotation speed 0.3 rpm). 11200KaatZ
A dehydrated cake of kg wet cake was obtained, and this dehydrated cake could be easily incinerated without fuel (self-combustion) in a fluidized bed incinerator.

〔Effect of the invention〕

As described above, according to the present invention, waste paper slurried with organic sludge itself is used as a dehydration aid, so the filler (mainly clay) and fiber content contained in the waste paper are activated. By strengthening the 70-layer structure of the sludge, the problem of organic sludge being diluted by the addition of waste paper slurry and decreasing its concentration is resolved, and a dehydrated cake that is extremely effectively dehydrated and easily self-combustible can be obtained. Adding waste paper increases the calorific value, so it is possible to use it as solid fuel.If paper, which is the main component of municipal waste, is recovered and used as waste paper, waste disposal can be streamlined at the same time. This has many beneficial effects such as eliminating the cost of purchasing waste paper.

[Brief explanation of the drawing]

The drawings are system explanatory diagrams showing one embodiment of the present invention.
Surplus activated sludge, 2... Part of surplus activated sludge. 6...Waste paper, 4...Hydropulper, 5...Agitator, 6...Mixed slurry, 7...Remaining part of surplus activated sludge, 8...Polymer flocculant, 9...Coagulation Mixing tank, 1o
...dehydrator. 11... Dehydrated cake, 12.14... Separated water, 13
···screen. Patent applicant: Patent attorney representing Ebara Infilco Co., Ltd.
Masayuki Takagi

Claims (1)

[Claims] t. A part of the organic sludge to be dehydrated and waste paper are supplied to a hydropulper, the waste paper is separated and converted into a slurry, and the slurry and a polymer flocculant are added to the organic sludge. A method for dewatering organic sludge, which is characterized by adding to the remainder, coagulating it, and then dewatering it. 2. The dehydration treatment is preceded by separation I using a screen.
The method for dewatering organic sludge according to claim 1, which comprises an lvIm step.