JP6270328B2 - Sludge concentration and dehydration system - Google Patents

Description

  The present invention relates to a sludge concentration and dehydration system, and relates to a technology that contributes to improvement of concentration performance and dewatering performance.

  Conventionally, as this type of apparatus, there is a concentrator-integrated screw press described in Patent Document 1. This is a continuous concentrator that continuously concentrates sludge and discharges it as a concentrated sludge, which has a discharge leveling unit that equalizes the amount of concentrated sludge discharged per unit time, and a concentrator. It is provided with a positive displacement pump that continuously transfers the concentrated sludge discharged from the concentrator, and a screw press that is connected to the discharge side of the positive displacement pump and squeezes and dehydrates the concentrated sludge.

  Also, in order to add inorganic flocculant such as polyiron sulfate to the concentrated sludge discharged from the concentrator, the polyiron supply pipe connected to the polyiron supply pump communicates with the lower side wall of the chute connected to the positive displacement pump. doing.

WO2010 / 1068838

  In this type of apparatus, it is said that dehydration performance is further improved by making concentration and dehydration separate processes. However, when the concentrated sludge that has passed through the concentration process is transferred to the dehydration process under natural flow, the concentrated sludge cannot be pressed into the screw press responsible for the dehydration process, and the effect of reducing the cake moisture content in the concentrated sludge is also halved. End up. For this reason, as also in Patent Document 1, in order to transfer the concentrated sludge after the concentration step to the dehydration step, a transfer pump device is required.

  However, when using a pump device, the flocs of concentrated sludge are broken due to friction with pump parts and flow path wall surfaces, collisions with flow path projections, etc. Leakage becomes difficult due to leakage.

  The destruction of this floc is the same even when the effect of reducing the moisture content of the cake is obtained by adding an inorganic flocculant to the concentrated sludge. In addition, there is an attempt to add a flocculant to the concentrated sludge instead of the inorganic flocculant to strengthen the floc. However, the floc is not strengthened only by adding the polymer flocculant to the concentrated sludge. So that the destruction of the flock happens.

  For this reason, as a method of supplying concentrated sludge from the concentrator to the screw press without destroying the floc, the concentrator is placed above the screw press, and the concentrated sludge is allowed to flow into the screw press through a hopper under natural flow to concentrate. There is a method to press the sludge into the screw press with water head.

  However, since the concentration device is arranged at a high position, the height of the entire machine becomes high, and depending on the safety issues in maintenance and the height of the building where the device is placed, the device may be placed. There is a problem that becomes impossible.

  This invention solves the said subject, and it aims at providing the sludge concentration dehydration system which can press-fit a concentrated sludge to a screw press, without being accompanied by destruction of a floc.

In order to solve the above-mentioned problems, the sludge concentration and dewatering system of the present invention includes a flocculent sludge including a flocculant floc formed by adding a polymer flocculant to the sludge to be dewatered and stirring the flocculant before the concentration. A high-concentration sludge containing concentrated floc in the belt concentrator, and the concentrated sludge containing agglomerated floc concentrated in the belt concentrator. A press-fitting pump for press-fitting into a screw press together with a molecular flocculant is provided, and a press-fitting path stirring unit for adding and stirring the inorganic flocculant to the coagulated sludge in the path from the press-fitting pump to the screw press is provided.

Sludge concentration dehydration process of the present invention, by adding a polymer flocculant in dehydrated subjects sludge before concentration stirring portion and stirred to form flocs, flocculation sludge solid-liquid separation at a belt concentrator comprising floc After concentration, add the polymer flocculant to the concentrated sludge containing concentrated flocs, and stir to distribute the polymer flocculant between the aggregated flocs. The inorganic flocculant is added to the concentrated sludge containing the flocs flocs in the presence of the polymer flocculant in the press-fitting path agitating part in the path from the press-fitting pump to the screw press with the flocculant. Stirring to disperse the inorganic flocculant in the flocs floc.

  As described above, according to the present invention, the concentrated sludge in which the polymer flocculant is distributed between the flocculation flocs is press-fitted into the screw press with the polymer flocculant together with the press-fitting pump, thereby providing lubricity by the polymer flocculant. Thus, the fluidity of the coagulation floc can be improved, the destruction of the coagulation floc in the press-in pump can be suppressed, and as a result, the dewatering performance in the screw press can be improved.

  Further, the aggregated floc formed in the pre-concentration stirring part is not limited as long as it can be solid-liquid separated in the concentration part, and does not need strength sufficient to withstand the dehydration pressure in the screw press. Therefore, the amount of the polymer flocculant added in the pre-concentration stirrer may be smaller than the normal amount used in the screw press. In addition, the total amount of the polymer flocculant added in the stirring part before concentration and the polymer flocculant added in the stirring part after concentration is also compared with the amount used in a normal screw press. It is also possible to make the amount of the polymer flocculant equal or less.

  In addition, the inorganic flocculant is added by stirring and adding the inorganic flocculant to the concentrated sludge containing the flocs flocs in the presence of the polymer flocculant in the press-fitting path agitator in the path from the press-fitting pump to the screw press. The time until the dehydration operation by a screw press is shortened, and the effect of reducing the moisture content of the cake by the inorganic flocculant can be sufficiently exhibited.

  Furthermore, the aggregation floc and the inorganic flocculant are agitated in the presence of the polymer flocculant, so that the inorganic flocculant permeates into the aggregate of the floc floc while suppressing the destruction of the aggregation floc by the stirring operation. It is possible to promote the release of moisture from the lump.

The block diagram which shows the sludge concentration dehydration system in embodiment of this invention Schematic diagram showing the state of the aggregated floc in the same embodiment

  Hereinafter, a sludge concentration and dehydration system according to an embodiment of the present invention will be described with reference to the drawings. 1 to 2, the pre-concentration agitation unit 10 adds a polymer flocculant to the dewatered sludge and stirs the flocculator 12 through which the dewatered sludge flows from the sludge inflow system 11, and the flocculator 12. 1 comprises a first polymer flocculant supply system 13 for adding a polymer flocculant. The polymer flocculant is desirably cationic or both anionic and cationic, but is not limited thereto.

  The concentration unit 20 concentrates the aggregated sludge containing the aggregated floc formed by the pre-concentration agitation unit 10, and includes a pre-concentration device 21 following the flocculator 12, and the pre-concentration device 21 includes a belt concentrator.

  The post-concentration agitation unit 30 adds and stirs the polymer flocculant to the concentrated sludge containing the flocculated flocs concentrated in the concentration unit 20. It comprises a second polymer flocculant supply system 32 to which a flocculant is added. The rotation speed of the stirring device 31 is, for example, 3-30 rpm. This polymer flocculant may be either cationic or cationic / anionic, and the operation is not complicated if it is the same as the polymer flocculant supplied from the first polymer flocculant supply system 13.

The press-in pump 40 following the post-concentration stirring unit 30 presses the concentrated sludge containing the coagulation floc of the post-concentration stirring unit 30 into the screw press 50 together with the polymer flocculant.
The press-in path agitating unit 60 is for adding an inorganic flocculant to the agglomerated sludge and stirring in a path under a sealed pressure from the press-in pump 40 to the screw press 50, and a second agitator following the press-in pump 40. 61 and an inorganic flocculant supply system 62 for adding an inorganic flocculant to the second agitator 61.

  Various types of screw presses can be used regardless of whether they are uniaxial or biaxial. A discharge conveyor 51 for discharging dewatered cake and a storage tank 52 for storing desorbed water are provided below the screw press 50. The desorbed water desorbed by the screw press 50 is returned to the flocculator 12 through the return system 53. By returning the desorbed water from the screw press 50 to the flocculator 12, unreacted flocculant can be used. The return system 53 is not always necessary.

  With the above-described configuration, the pre-concentration agitation unit 10 adds the polymer flocculant from the first polymer flocculant supply system 13 to the dewatered sludge flowing into the flocculator 12 from the sludge inflow system 11. Then, the sludge to be dehydrated and the polymer flocculant are stirred by the flocculator 12 to form an agglomerated floc.

  In the concentration unit 20, the aggregated sludge including the aggregated floc supplied from the flocculator 12 is concentrated by solid-liquid separation with a belt concentrator constituting the preconcentrator 21. The separated water separated from the aggregated sludge is stored in the storage tank 52.

  The post-concentration agitation unit 30 supplies the concentrated sludge containing the aggregated flocs concentrated from the pre-concentration device 21 to the agitation device 31, and adds the polymer flocculant to the agitation device 31 from the second polymer flocculant supply system 32. Stir. By this stirring operation, the polymer flocculant is distributed between the aggregated flocs to strengthen the aggregated flocs, and the fluidity of the aggregated flocs is improved by imparting lubricity by the polymer flocculant. The polymer flocculant to be applied here may be the same as that applied in the pre-concentration stirring unit 10 or may be different.

  The press-fitting pump 40 press-fits the concentrated sludge containing flocculated floc together with the polymer flocculant into the screw press 50 through the second stirring device 61. In the present embodiment, the screw press 50 is used for press-fitting through the second stirring device 61, but the press-fitting pump 40 can also be press-fitted directly into the screw press 50.

  When injecting the concentrated sludge with the press-in pump 40, the polymer flocculant spread between the aggregated flocs imparts lubricity to the aggregated flocs in the concentrated sludge, improving the fluidity of the aggregated flocs and increasing the aggregated flocs in the press-in pump. Flock destruction is suppressed. As a result, the dewatering performance in the screw press 50 is improved.

  In addition, in the press-fitting path stirring unit 60, an inorganic flocculant is added to the concentrated sludge containing the floc floc in the presence of the polymer flocculant in the second stirrer 61 in the path from the press-in pump 40 to the screw press 50. And stir. For this reason, the time from the addition of the inorganic flocculant to the dehydration operation by the screw press 50 is shortened, and the effect of reducing the moisture content of the cake by the inorganic flocculant can be sufficiently exhibited.

  Furthermore, the aggregation floc and the inorganic flocculant are agitated in the presence of the polymer flocculant, so that the inorganic flocculant permeates into the aggregate of the floc floc while suppressing the destruction of the aggregation floc by the stirring operation. It is possible to promote the release of moisture from the lump. As shown in FIG. 2 (a), the aggregated floc F1 formed by the action of the polymer flocculant is a large mass. As shown in FIG. 2 (b), an inorganic flocculant is added in addition to the polymer flocculant. The agglomerated floc F2 that has been acted on becomes smaller and stronger, and moisture is released from the inside.

  In recent years, in the field of wastewater treatment facilities, the proportion of equipment to be renewed is higher than the construction of new equipment, and the size of the equipment to be renewed often becomes an obstacle to adoption. However, according to the present invention, the pump press can be pumped to any place while suppressing the breakage of the floc, so that the screw press, the concentrating device, and the layout can be freely set. Also, without installing a new concentrator, piping can be installed between another existing concentrator and a screw press, so that the existing concentrator can be effectively used as a new concentrator when the existing concentrator is idle. The initial investment cost can be suppressed.

DESCRIPTION OF SYMBOLS 10 Stirring part before concentration 11 Sludge inflow system 12 Flocculator 13 1st polymer flocculant supply system 20 Concentration part 21 Pre-concentration device 30 Stirring part 31 after concentration 32 Stirrer 32 Second polymer flocculant supply system 40 Press-in pump 50 Screw Press 51 Discharge conveyor 52 Storage tank 60 Press-in route agitation unit 61 Second agitation device 62 Inorganic flocculant supply system

Claims (2)

And concentrated before stirring unit for stirring by adding a polymer flocculant to dewatering target sludge, a belt concentrator for concentrating the aggregation sludge containing flocs formed by the concentrated before stirring unit, the flocs were concentrated in a belt concentrators It is equipped with a post-concentration stirring unit for adding and stirring the polymer flocculant to the concentrated sludge containing, and a press-fitting pump for press-fitting the concentrated sludge containing the coagulation floc of the post-concentration stirring unit together with the polymer flocculant into the screw press,
A sludge concentration and dehydration system comprising a press-in route agitation unit for adding an inorganic flocculant to agglomerated sludge and stirring in a route from a press-in pump to a screw press. The polymer flocculant is added to the sludge to be dehydrated in the agitation section before concentration, and agglomerated flocs are formed by stirring. The agglomerated sludge containing the agglomerated flocs is separated by solid-liquid separation using a belt concentrator , and concentrated. Add the polymer flocculant in the stirring section after concentration to the concentrated sludge containing, stir to spread the polymer flocculant between the flocs floc, and the concentrated sludge containing the flocs floc together with the polymer flocculant into a screw press with a press-in pump Press fit,
In the press-in path agitator in the path from the press-in pump to the screw press, the inorganic flocculant is added to the concentrated sludge containing the flocs floc in the presence of the polymer flocculant, and the inorganic flocculant is distributed in the flocs floc by stirring. Sludge concentration and dehydration method.

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