JP2008221115A - Filtration concentrator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a filtration concentrator capable of preventing sludge from overflowing out of a filter cloth. <P>SOLUTION: The filtration concentrator 10 is provided with a filter cloth circulation part 11 and a filter cloth circulation part 12 which is arranged along the gravity direction in parallel to the filter cloth circulation part 11. The filter cloth circulation parts 11, 12 respectively have filter cloths 15, 18 which are endlessly formed and substantially elliptically circulated and driven, and the filter cloths 15, 18 perform filtration concentration of the sludge M supplied to surfaces 15a, 18a located on the upper sides thereof while conveying the sludge M in the conveyance directions A, B. In the filtration concentrator 10, an interval L between the surface 15b located on the lower side on the cloth 15 and the surface 18a located on the upper side on the filter cloth 18 becomes narrower as going to the conveyance direction B of the filter cloth 18. Therefore, as going to the conveyance direction B of the filter cloth 18, the sludge M is gradually sandwiched between the filter cloths 15, 18 and, as going to the conveyance direction B, a pressing force gradually becoming stronger is acted on the sludge M. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a filtration and concentration device that filters and concentrates sludge.

  Conventionally, sludge dewatering is known as a process for improving the treatment efficiency and disposal efficiency of sludge. In this sludge dewatering, fluid sludge is taken out as solid dehydrated sludge with little moisture, and one of the methods is a filtration concentration method.

2. Description of the Related Art As a filtration and concentration type filtration and concentration apparatus, there is known an apparatus that includes an endless filter cloth that is driven to circulate and that performs filtration and concentration while conveying sludge supplied to the filter cloth (see, for example, Patent Document 1). ). In such a filtration and concentration apparatus, sludge is sandwiched between two filter cloths, and a roller is pressed against the two filter cloths so that the tension of the filter cloth and the pressing force of the rollers act on the sludge. Squeeze.
Japanese Unexamined Patent Publication No. 60-9599

  However, in the filtration and concentration apparatus as described above, there is a risk that the sludge is compressed more than necessary at the location where the pressing force of the roller acts directly (curved surface portion of the roller), and the sludge flows and flows out from between the filter cloths. is there.

  Then, this invention makes it a subject to provide the filtration concentration apparatus which can prevent that sludge protrudes and flows out from a filter cloth.

  In order to solve the above-mentioned problems, a filtration and concentration apparatus according to the present invention has a filter cloth that is endlessly formed and driven to circulate in a substantially oval shape, and is supplied to a surface positioned above the filter cloth. It has a filter cloth circulation part that filters and concentrates sludge while transporting it in a direction crossing the direction of gravity, and the filter cloth circulation part is arranged in parallel along the gravity direction. The distance between the surface located on the lower side of the cloth and the surface located on the upper side of the lower filter cloth is characterized by becoming narrower in the direction of conveying the sludge of the lower filter cloth.

  In this filtration and concentration device, in the adjacent filter cloth circulation section, the distance between the surface located on the lower side of the upper filter cloth and the surface located on the upper side of the lower filter cloth conveys the sludge of the lower filter cloth. By narrowing in the direction, the sludge is gradually sandwiched between the upper filter cloth and the lower filter cloth in the direction. Therefore, the squeezing force can be gradually applied to the fluid sludge in the direction of conveying the sludge of the lower filter cloth, and the water can be gradually dehydrated. Therefore, the pressing force of the roller is applied to the sludge so that the sludge is not squeezed more than necessary, and it is possible to obtain a sufficient concentration effect while preventing the sludge from protruding and flowing out of the filter cloth.

  Here, the concentration effect due to gravity is difficult to obtain sufficiently in the upper part (side away from the filter cloth) of the sludge supplied to the upper surface of the filter cloth, but in the adjacent filter cloth circulation part, When the driving speed of the upper filter cloth has a speed difference with respect to the driving speed of the lower filter cloth, the shearing force due to the speed difference is applied to the sludge sandwiched between the upper filter cloth and the lower filter cloth. The sludge can be moved, and the concentration effect can be obtained more sufficiently.

  In the adjacent filter cloth circulation section, it is preferable that the distance between the surface located on the lower side of the upper filter cloth and the surface located on the upper side of the lower filter cloth can be adjusted. Thereby, the said pressing force which becomes strong gradually as it goes to the direction which conveys the sludge of a lower filter cloth can be made to act on sludge as desired.

  According to the present invention, it is possible to obtain a sufficient concentration effect while preventing sludge from protruding from the filter cloth and flowing out.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  First, a belt press dehydrator including a filtration concentration device according to an embodiment of the present invention will be described. FIG. 1 is a schematic configuration diagram showing a belt press dehydrator including a filtration concentration apparatus according to an embodiment of the present invention. This belt press dewatering machine is often used in sludge dewatering facilities for dewatering fluid sludge generated by processing at, for example, a sewage treatment facility, and is a so-called filtration and concentration type that performs filtration and concentration using an endless belt-shaped filter cloth. It is.

  The belt press dehydrator 1 includes a stirring and aggregating device 3, a filtration and concentration device 10, and a pressure dehydrating device 2. In the following description, the sludge introduced into the stirring and coagulating device 3 is introduced sludge, the sludge treated with the stirring and coagulating device 3 is coagulated sludge, the sludge treated with the filtration and concentrating device 10 is concentrated, and the pressure dewatering device 2 The sludge treated in step 1 is referred to as dewatered sludge, and these sludges are collectively referred to as sludge M. Incidentally, in general, concentrated sludge means sludge having a moisture content of about 94% to 98%, and dehydrated sludge means sludge having a moisture content of about 75% to 85%.

  The stirring and aggregating apparatus 3 is for performing sludge refining, and agglomerates by stirring the introduced sludge M to be introduced and the polymer flocculant G to be added (here, a cationic polymer). The stirring and aggregating apparatus 3 supplies the agglomerated sludge to the subsequent filtration and concentration apparatus 10.

  The filtration and concentration device 10 is for filtering and condensing the coagulated sludge, and includes a first filter cloth circulation part (filter cloth circulation part) 11 and a second filter cloth circulation part (filter cloth circulation part) 12 (in detail). , Described later). The filtration and concentration device 10 supplies concentrated sludge to the subsequent pressing and dewatering device 2.

  The press dewatering device 2 presses and filters concentrated sludge. Specifically, the press dehydrator 2 includes endless filter cloths 4 and 8, the filter cloth 4 includes a large number of rolls 5 and 7, and the filter cloth 8 includes a large number of filter cloths 8. Each of the filter cloths 4 and 8 is circulated and driven while sandwiching the concentrated sludge from the filter concentration apparatus 10. Thereby, the tension | tensile_strength of the filter cloths 4 and 8 and the pressing force of the roll 5 act on concentrated sludge, the said concentrated sludge is squeezed and filtered. This press dewatering device 2 discharges dewatered sludge to external equipment such as a dewatered cake.

  Next, the filtration concentration apparatus 10 mentioned above is demonstrated in detail.

  The filtration concentration apparatus 10 includes the first filter cloth circulation unit 11 and the second filter cloth circulation unit 12 as described above. Specifically, the filtration and concentration apparatus 10 includes a first filter cloth circulation unit 11 and a second filter cloth circulation unit 12 provided in parallel with the first filter cloth circulation unit 11 along the direction of gravity (downward in the drawing). And.

  The 1st filter cloth circulation part 11 has a pair of 1st pulleys 13 and 14 and the 1st filter cloth (filter cloth) 15 formed in endless form. The first pulleys 13 and 14 are spaced apart from each other along the horizontal direction, and the first filter cloth 15 is stretched over the first pulleys 13 and 14.

  Driving means (not shown) such as a motor is connected to the driving pulley of the first pulleys 13 and 14. Therefore, in the 1st filter cloth circulation part 11, the 1st filter cloth 15 carries out the circulation drive of the substantially elliptical track | orbit by rotationally driving a drive pulley, and the surface 15a located in the upper side of the said 1st filter cloth 15 is provided. The sludge M supplied to is concentrated by filtration while being transported in the transport direction (direction intersecting the direction of gravity) A, and this sludge is fed from the one end 11a on the first pulley 14 side to the second filter cloth circulation section 12 at the subsequent stage. Is dropped and supplied to one end 12a on the second pulley 17 side which will be described later. Further, the circulation drive speed of the first filter cloth 15 is variable, and specifically, 1.2 to 6.0 m / min.

  The 2nd filter cloth circulation part 12 is the structure substantially the same as the said 1st filter cloth circulation part 11, a pair of 2nd pulleys 16 and 17, and the 2nd filter cloth (filter cloth) 18 formed in endless form. The second pulleys 16, 17 are arranged apart from each other along the horizontal direction, and the second filter cloth 18 is stretched over the second pulleys 16, 17.

  Driving means (not shown) such as a motor is connected to the driving pulleys of the second pulleys 16 and 17, and the second filter is rotated by driving the driving pulley even in the second filter cloth circulation unit 12. The cloth 18 circulates and drives the substantially oval track, and the sludge M supplied to the upper surface 18a of the second filter cloth 18 is conveyed in the conveyance direction B substantially opposite to the conveyance direction A. The sludge M is filtered and concentrated, and the sludge M is supplied from the other end portion 12b to the subsequent pressing and dewatering device 2 as concentrated sludge. Further, the circulation drive speed of the second filter cloth 18 is variable, specifically, 1.8 to 9.0 m / min.

  In addition, a guide 19 is provided at one end 12 a of the second filter cloth circulation part 12 to guide the sludge dropped from the one end part 11 a of the first filter cloth circulation part 11 to the upper surface 18 a of the second filter cloth 18. On the other end 12b side of the second filter cloth circulation part 12, a guide 20 is provided for guiding the supply of the concentrated sludge to the squeezing and dewatering device 2.

  Further, for the first filter cloth circulation section 11, sludge is filtered by the first filter cloth 15 between the upper surface 15a and the lower surface 15b of the first filter cloth 15. The filtrate receiving pan 23 for collecting the filtrate W1 generated by the operation is disposed, and the second filter cloth 18 is disposed below the second filter cloth 18 with respect to the second filter cloth circulation section 12. A filtrate receiving pan 24 for collecting the filtrate W2 generated by filtering the sludge is disposed.

  Here, in the present embodiment, the first pulley 13 in the first filter cloth circulation unit 11, the second pulley 16 in the second filter cloth circulation unit 12, the first pulley 14 in the first filter cloth circulation unit 11, and the first pulley. The second pulley 17 in the two-filter cloth circulation unit 12 is connected to each other via each rod 25 configured to be extendable and contractible. That is, the distance between the surface 15b located on the lower side of the first filter cloth 15 and the surface 18a located on the upper side of the second filter cloth 18 by the rod 25 (in the adjacent filter cloth circulation portions 11 and 12, The distance L) between the surface 15b located on the lower side of the filter cloth 15 and the surface 18a located on the upper side of the lower filter cloth 18 can be adjusted. Here, this interval L can be adjusted to 3 to 10 mm.

  In particular, in this embodiment, the interval between the first pulley 13 and the second pulley 16 is made narrower than the interval between the first pulley 14 and the second pulley 17, and is positioned on the lower side of the first filter cloth 15. The distance L between the surface 15b to be moved and the surface 18a located on the upper side of the second filter cloth 18 becomes narrower in the transport direction B of the second filter cloth 18.

  In the present embodiment, the circulation driving speed of the first filter cloth 15 has a speed difference with respect to the circulation driving speed of the second filter cloth 18. Here, the second filter cloth 18 is driven to circulate faster than the first filter cloth 15 with a speed difference of 0.6 to 3.0 m / min.

  According to the filtration and concentration apparatus 10 configured as described above, the coagulated sludge supplied from the stirring and coagulating apparatus 3 is collected on the surface 15a located on the upper side of the first filter cloth 15 of the first filter cloth circulation unit 11. The filter is concentrated while being transported in the transport direction A, and is filtered and concentrated while being transported in the transport direction B on the surface 18a located above the second filter cloth 18 of the second filter cloth circulating unit 12.

  At this time, the distance L between the lower surface 15 b of the first filter cloth 15 and the upper surface 18 a of the second filter cloth 18 becomes narrower in the transport direction B of the second filter cloth 18. Therefore, the squeezing force that gradually increases as it goes in the transport direction B can be applied to the fluid sludge M containing a large amount of water, and the sludge can be gradually concentrated.

  That is, in the filtration and concentration apparatus 10, the sludge M is filtered and concentrated by gravity in the first filter cloth circulation section 11 (primary dehydration), and is filtered and concentrated by gravity in the second filter cloth circulation section 12, and the conveying direction. As it goes to B, the first filter cloth circulation part 11 and the second filter cloth circulation part 12 are squeezed with a gradually increasing squeezing force and gradually concentrated by filtration (secondary dehydration). Therefore, the roller pressing force is not applied to the sludge M and the sludge M is not compressed more than necessary, and the phenomenon that the sludge M flows and flows out from the filter cloths 15 and 18 (so-called side leak) is prevented. The concentration effect can be sufficiently obtained. As a result, since the moisture content of the sludge supplied as concentrated sludge to the subsequent pressing and dewatering device 2 is reduced, side leakage can also be prevented in the pressing and dewatering device 2.

  In the filtration and concentration device 10, as described above, the sludge M is not squeezed more than necessary by the pressing force of the rollers, but the surface 15b located on the lower side of the first filter cloth 15 and the second filter cloth 18 Since it squeezes by pinching with the surface 18a located on the upper side, the sludge M can be squeezed with a strength suitable for the sludge M.

  In general, the concentration effect due to gravity of the sludge supplied to the surface located on the upper side of the filter cloth is not sufficiently obtained in the upper part (side away from the filter cloth). However, in the filtration concentration apparatus 10 of the present embodiment, as described above, the circulation driving speed of the first filter cloth 15 has a speed difference with respect to the circulation driving speed of the second filter cloth 18. A shearing force due to a speed difference is applied to the sludge M sandwiched between 15 and 18, and the sludge M can be moved and stirred (so-called change of surface), and thus a concentration effect can be obtained more sufficiently.

  As described above, since the distance L between the surface 15b located on the lower side of the first filter cloth 15 and the surface 18a located on the upper side of the second filter cloth 18 can be adjusted, The squeezing force that gradually increases as the cloth 18 moves in the conveyance direction B can be applied to the sludge M as desired.

  Furthermore, as described above, the filter cloth circulation units 11 and 12 are arranged side by side along the direction of gravity, so that the distance in which the sludge M is conveyed by the filter cloths 15 and 18 in the filtration and concentration device 10 is long and saves space. Therefore, the concentration effect by gravity can be obtained more sufficiently in a space-saving manner.

  Moreover, since the maximum processing speed of the belt press dehydrator 1 is determined from the amount of sludge immediately before side leak occurs in the press dewatering device 2, the maximum processing speed is also improved by preventing side leak as described above. can do.

  Here, as a result of comparing the moisture content of the dewatered sludge obtained using the belt press dehydrator 1 of this embodiment and the conventional belt press dehydrator, the moisture content of the conventional belt press dehydrator is 80%. On the other hand, in the belt press dehydrator 1 including the filtration concentration device 10 of the present embodiment, the water content was always 80% or less, and the above effect of obtaining a sufficient concentration effect could be confirmed. .

  In some cases, an inorganic flocculant (for example, ferric chloride) may be added to the sludge M that has been conveyed by the first filter cloth 15 to further agglomerate the sludge M.

  The preferred embodiment of the present invention has been described above, but the present invention is not limited to the above embodiment.

  For example, in the above-described embodiment, the two filter cloth circulation units 11 and 12 are arranged in parallel along the gravity direction, but three or more filter cloth circulation units may be arranged in parallel along the gravity direction.

  In the above embodiment, the second filter cloth 18 is driven to circulate faster than the first filter cloth 15. However, the first filter cloth may be driven to circulate faster than the second filter cloth.

  In the above embodiment, the distance between the first pulleys 13 and 14 and the second pulleys 16 and 17 in the adjacent filter cloth circulation portions 11 and 12 can be adjusted by the extendable rod 25, respectively. The distance L between the surface 15b positioned below the surface 18a and the surface 18a positioned above the second filter cloth 18 can be adjusted. However, a pulley such as an idler pulley is separately used to adjust the position of this pulley. L may be adjustable.

It is a schematic block diagram which shows the belt press dehydrator containing the filtration concentration apparatus which concerns on one Embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Filtration concentration apparatus, 11 ... 1st filter cloth circulation part (filter cloth circulation part), 12 ... 2nd filter cloth circulation part (filter cloth circulation part), 15 ... 1st filter cloth (filter cloth), 15a, 18a ... surface located on the upper side, 15b ... surface located on the lower side, 18 ... second filter cloth (filter cloth), A ... transport direction (direction intersecting with the gravity direction), B ... transport direction (crossing with the gravity direction) Direction, direction of conveying sludge of lower filter cloth), L ... interval, M ... sludge.

Claims (3)

A filter cloth that is endlessly formed and has a filter cloth that circulates and drives in an approximately oval shape, and is filtered and concentrated while transporting sludge supplied to the upper surface of the filter cloth in a direction crossing the direction of gravity. With a circulation part,
The filter cloth circulation part is juxtaposed along the gravity direction,
In the adjacent filter cloth circulation section, the distance between the surface located on the lower side of the upper filter cloth and the surface located on the upper side of the lower filter cloth becomes narrower as the sludge of the lower filter cloth is conveyed. The filtration concentration apparatus characterized by becoming.   2. The filtration and concentration apparatus according to claim 1, wherein the driving speed of the upper filter cloth has a speed difference with respect to the driving speed of the lower filter cloth in adjacent filter cloth circulation sections.   The adjacent filter cloth circulation section is configured such that an interval between a surface located on the lower side of the upper filter cloth and a surface located on the upper side of the lower filter cloth is adjustable. The filtration concentration apparatus according to 1 or 2.

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