JPS6048199A - Sludge dewatering equipment - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] This invention relates to an efficient dewatering device for various types of sludge, including a coagulating tank for coagulating sludge, and a dewatering machine for dewatering the coagulated sludge obtained in the coagulating tank. , a sludge supply means for supplying the flocculated sludge from the flocculation tank to the dehydrator; the sludge supply means is a pump for pressurizing the flocculated sludge into the dehydrator, preferably a positive displacement screw pump, and the dewaterer is a screw press type. To be characterized by something.

The sludge to be dehydrated in the present invention is anaerobic or aerobic digested sludge of human waste or night soil, human waste septic tank sludge, sewage or human waste digested liquid, surplus sludge in activated sludge treatment of various industrial wastewater, and initial sedimentation of sewage. It is a type or mixture of pond sludge, coagulated sludge of various industrial wastewater, and coagulated sludge generated in tertiary treatment of human waste, sewage, etc.

A rotating screw is built into an outer cylinder made up of a punching plate, and sludge is supplied into one end of the outer cylinder, and as the screw rotates, the sludge is moved inside the outer cylinder to the other end, while all the moisture in the sludge is removed. Screw presses are conventionally known in which a cake is removed from a hole in a cylinder to obtain a dehydrated cake at the other end of the cylinder. This screw press relies on the rotation of the screw to transport the sludge in the outer cylinder and to increase the pressure inside the outer cylinder, which is the pressurizing force for dewatering, so if the sludge is suitable for the screw press, the pressure will increase smoothly. It was carried out in
It has the advantages of efficient dewatering, simple structure, easy operation management, no noise, and the ability to further lower the moisture content of sludge by heating the screw, but the strength of the sludge is weak. If the sludge is not suitable for the screw press, the sludge will slip even if the screw rotates, the screw will simply rotate idly and no pressure increase will occur, or the sludge will leak out from the hole in the punching plate of the outer cylinder. There are many problems in that the sludge cannot be sufficiently dehydrated.

Therefore, in order to efficiently dewater sludge using a screw press as a dewatering machine, the present invention adds a flocculant to the sludge to be dewatered and flocculates the sludge in a flocculating tank to increase the strength of the flocs. The water was then dehydrated by being press-fitted into a screw press. The present invention will be described below with reference to the drawings.

1 indicates a flocculation tank, and sludge is supplied to the flocculation tank through a supply pipe 2, and a flocculant is added thereto from a chemical injection device 3. .

The flocculant to be added may be either an inorganic flocculant or an organic flocculant, but it is also possible to use both in combination. Inorganic flocculants include aluminum chloride, polyaluminum chloride,
aluminum sulfate, iron chloride (it), iron (II) sulfate,
Iron(III) chloride, iron sulfate (f[0, Kotbarasu chloride,
Polyferric chloride, polyferric sulfate, etc., 11! It is possible to use II or several.

In addition, as the cationic organic flocculant, a homopolymer or a copolymer of chitosan aminoalkyl acrylate or aminoalkyl methacrylate with acrylamide or other monomers, a monomer Mannich-modified product containing acrylamide or methacrylamide as a constituent unit, or Hoffmann decomposition products, polyamide polyamines, polyvinylimidacillin, polyethylene imine, polydialkyl diallylammonium salts, etc. can be used, and one or more types of these can be used.

When these inorganic flocculants and/or cationic organic flocculants are added to sludge and stirred in a cypress, flocculation occurs and flocs are generated.

At this time, in order to grow flocs, it is preferable to further add a nonionic or anionic organic flocculant 'kti and stir. Nonionic or anionic
Examples of the s-collecting agent include polyacrylamide, polyacrylamide partially hydrolyzed FF products, and polyacrylic dispersion atrium.

The amount of flocculant added is /-s-5 weight ratio based on the SS of sludge in the case of an inorganic flocculant, 1 to 3 weight i% in the case of a cationic organic flocculant, and added later for floc growth. The amount of the nonionic or anionic organic flocculant used is about 0.3 to 1% by weight.

The flocs produced by flocculating sludge containing a large amount of fibers, such as raw human waste or surplus sludge from activated sludge treatment of paper pulp wastewater, are hard to break and strong, so simply flocculating the flocs as described above is sufficient. It is. However, even if surplus sludge such as sewage or food wastewater is coagulated, the strength of the resulting flocs is weak, so the coagulation process is carried out in two stages using a secondary coagulation tank °t and a secondary coagulation 4u/'.

The above-mentioned cationic organic flocculant is added to the sludge and sludge, and the mixture is strongly stirred in a second flocculation tank. This strong stirring is intended to uniformly and sufficiently react the sludge with the VC flocculant, neutralize the electric charge, and facilitate the formation of flocs in the next secondary wall collection tank. It is desirable that the agitation be strong enough to prevent the formation of pores with a diameter exceeding 70 mm.

The sludge whose charge has been neutralized in the secondary flocculation tank is supplied to the secondary flocculation tank 7', where a cyanionic organic flocculant is added to the chemical injection devices t and y', and the sludge is slowly stirred. to generate flocs. The anionic flocculant to be added is 1 bag of sodium polyacrylic or sodium polymethacrylate,
Partial hydrolyzate of polyacrylamide or polymethacrylamide, copolymer of acrylic acid or methacrylic acid and acrylamide or methacrylamide, acrylic acid or methacrylic acid and acrylamide or methacrylamide and 2-acrylamide-2-methylpropanesulfonic acid or One or more of a terpolymer with vinyl sulfonic acid, carboxymethyl sululose sodium, etc. can be used.

When a slow agitation is carried out in this secondary flocculation tank l', the sludge particles react with the cationic polymer flocculant and the charged sludge particles become oxidized to the anionic polymer flocculant. It coagulates well to form strong, large-sized flocs, and has extremely good dewatering properties.

In this way, once the sludge is treated in the coagulation tank and a strong floc is generated, i'1. The entire pump/l is press-fitted into the slurry inlet at one end of the screw press S.

The pump may be of any type, but a positive displacement screw pump is most preferred.

Crime 2.3N shows an example of a positive displacement screw pump, which is made of synthetic rubber and has a double-threaded hollow part 6t with an oval or oval cross section, and a stator that passes through the hollow part of the stator and rotates eccentrically. money) lrAl! l! The stator has a single threaded rotor gf with a circular cross section, and a gap 6' with a certain volume is formed between the stator and the rotor, and as the rotor rotates, this gap 6' is It moves along the valley iC, completes the pumping action, and discharges from the discharge lobe at the front end of the stake.

A rear cylinder /θ is connected to the rear end of the stake 1, and sludge is supplied to a supply port 10' in the rear cylinder. In addition, the rotary shaft L/ driven by a motor to rotate the R/G is supported by a bearing in the rear front and rear s.
Rush into ffj and universal joint l/rL
, l]b to the fifth end of the rotor extension.

The stator is made of gold M'J3J by vulcanization molding on the inner periphery of the outer tube 7', and is integrated with the outer tube 7'.

In this way, a positive displacement screw pump is formed between the double-threaded central part of the stake and the single-threaded rotor that passes through it and rotates eccentrically according to the inner shape of the hollow part. Since the transfer is carried out using a gap filter with a constant volume that moves in a spiral direction, there is no pulsation in the transfer and no impact is applied to the transferred object. Therefore, even if flocculated sludge is transferred, it can be supplied to each dewatering device without almost all of the flocs in the sludge collapsing, and chemicals such as flocculants added in advance by the chemical feeding device are aged during the transfer. Secondary flocculation is performed to lower the water content of sludge.

In this way, the flocs discharged from the discharge port t' of the screw pump are led to the mud supply port VC of the screw press S by a pipe/co.
Press fit. At that time, a pressure detector (not shown) is installed in the mud supply port of the screw press j, and the pressure signal is used to fully control the screw bong 4 to adjust the pressure in the mud supply port to θ, - ~ 1.3
It is preferable to do nige7earcmω8j5.

FIG. 4 is a longitudinal cross-sectional view of a screw press, which has a mud supply port lda at the upper end of one end of an oblong cylinder made of a perforated punching plate with a hole diameter of about l. Inside the cylinder, a tapered rotor/S is installed concentrically with the small diameter part facing one end of the cylinder and the large diameter FfB' facing the other end of the cylinder. A spiral R/42 whose outer diameter matches the inner diameter of the cylinder 13 is provided on the outer periphery, and as the rotor rotates, the helical blades /l move the flocs supplied to one end of the cylinder at the slurry inlet /da to the other end. The direction will be promoted.

Is the rotor tapered like this? The annular gap between the outer surface of the rotor and the inner periphery of the oblong cylinder gradually narrows from one end of the oblong cylinder toward the other end.

Therefore, the flocs supplied inside one end of the horizontally long cylinder move toward the other end under low pressure while dehydrating the moisture at the wide end side of the annular gap through the hole in the cylinder, and at the middle part of the horizontally long cylinder, the floc moves toward the other end with a wide annular gap. It has become narrower and is pressurized to a medium level! The other end side is pressurized by the claw surface and dehydrated in the same manner, and finally the dehydrated cake is discharged from the other end of the horizontally long VC cylinder.

Moreover, since the flocs are continuously press-fitted and supplied to the clam mud opening/hole by the screw pump μ through piping 7.2, the flocs fill the inside of the screw press tightly and are dehydrated to 4u Wb. .

The flocs have strength due to the coagulation process and do not deteriorate under the pressure inside the screw press, so the screw press dewaters the flocs at an ideal pressure increase, greatly improving the efficiency of sludge dewatering. .

Incidentally, if necessary, the rotor may be completely heated by supplying steam to the inside of the rotor.

In this way, is the present invention a sludge? The flocs are flocculated into strong flocs, which are then continuously pressurized into a screw press using an i-pump to maximize the functionality of the screw press and completely dewater the sludge.

[Brief explanation of the drawing]

Figure 1 is a flow sheet showing one example of the present invention, and Figure 2 is a longitudinal section of an example of the positive displacement screw pump used above.
) Figure 3 is a concave view of the same II-III model SL.
Figure 4 is a sectional view of an example of the screw press used in Figure #1. In the figure, 117' is a coagulation tank, U is a pump, and the S screw press is shown.

Claims (1)

[Scope of Claims] (Li) A flocculation tank for flocculating sludge, a dehydrator for dewatering the flocculated sludge, and a sludge supply means for supplying flocculated sludge from the flocculation tank to the dewatering machine, Sludge supply A sludge dewatering device characterized in that the means is a pump for pressurizing the flocculated sludge into the dehydrator, and the dewaterer is a screw press. (2. In the device according to claim (1), the sludge supply means is The pump is a positive displacement screw pump for sludge dewatering equipment.