JPH11342309A - Liquid filtration treatment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To subject solid component containing liquid to filtration treatment for a long period of time, stably, and at low cost. SOLUTION: Coarse filter elements 4 that wire like bodies provided with projecting parts on the outer surfaces thereof are wound into cylindrical coils and a lot of clearances are formed between the peripheral wall parts by the projecting parts are arranged in a primary treatment tank 2 to subject liquid to primary filtration treatment. In a secondary treatment tank 24 in which fine filter elements 26 that filter aid is stuck in the clearances between the coarse filter elements 4 are arranged, the primarily treated liquid is subjected to secondary filtration treatment. And when the coarse filter elements 4 or the fine filter elements 26 are clogged, they are backwashed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for filtering a liquid containing solids, and more particularly to a method for performing a long-term stable filtration by performing two-stage filtration using a specific filter element. It is.

[0002]

2. Description of the Related Art Conventionally, a general method of treating livestock excrement is to collect excreta in a specific place (eg, a pond), leave it for a certain period of time, and spray it as compost on farmland or pasture. ing. However, this method has a problem that part of the urine from the excrement collected in the wild pond penetrates underground and contaminates the groundwater. In general, sewage treatment in agricultural settlements and the like is carried out in a sedimentation tank while sedimentation of organic matter while performing aerobic treatment, taking it out as sludge, and drying or incineration. The supernatant liquid is further subjected to secondary treatment and drained. . However, this method has a problem that the equipment is complicated and costly, and is not economical as a sewage treatment in an agricultural settlement or the like. As another method, there is a method in which a large number of permeable membranes are installed in a sedimentation tank, and minute sludge that cannot be precipitated is separated by osmotic pressure. However, in this method, it is necessary to always perform aeration on the membrane surface in order to prevent sludge from adhering to the membrane surface. However, in practice, the effect of preventing sludge from adhering to the membrane surface is not always sufficient. Therefore, there are problems that a trouble often occurs, the film life is relatively short (about three years), and the running cost is high.

[0003]

As described above, the conventional methods of treating sewage in livestock excreta and agricultural settlements have problems in equipment and cost. Therefore, there has been a strong demand for a simple and low running cost processing apparatus. Therefore, an object of the present invention is to provide a liquid filtration method that solves such a problem.

[0004]

The first aspect of the present invention is a method for filtering a liquid containing a solid content. In this method, first, the entire linear body 32 having a large number of projections 31 formed on the outer surface in the axial direction is wound around a cylindrical spiral winding, and the projections 31 are used between the peripheral wall portions of adjacent spiral windings. The coarse filter element 4 in which a number of gaps 33 are formed is disposed in the primary treatment tank 2, the liquid to be treated is supplied to the primary treatment tank 2, the primary filtration is performed, and then the filtration is performed in the gap 33 of the coarse filter element 4. The primary treatment liquid is supplied to the secondary treatment tank 24 in which the fine filter element 26 with the auxiliary agent 39 adhered is subjected to the secondary filtration treatment, and further, when the coarse filter element 4 is clogged, it is removed. A liquid filtration method comprising backwashing with a next treatment liquid and backwashing the fine filter element 26 with a first treatment liquid or a second treatment liquid when the filter element is clogged.

According to a second aspect of the present invention, there is provided an embodiment of the filtration method according to the first aspect, wherein a coarse filter element is arranged in a secondary treatment tank before steady operation.
A replenishing tank for replenishing the filter aid is further provided, and the primary treatment liquid is supplied thereto and mixed with the filter aid, and the mixed solution is supplied to the secondary treatment tank. And converted to a fine filter element. Further, the invention according to claim 3 is a preferred embodiment of the filtration method according to claim 1 or 2, wherein a floating deck is provided in the primary treatment tank of normal pressure type, and the floating deck is provided with a coarse deck. It is characterized by attaching a filter element.

[0006]

Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a process flow chart for performing human waste treatment by the liquid filtration method of the present invention, FIG. 2 is a longitudinal sectional view showing an example of a coarse filter element used in the liquid filtration method of the present invention, and FIG. It is a longitudinal section showing an example of a fine filter element used for the filtration processing method of the present invention. In FIG. 1, the human waste storage tank 1 and a normal pressure type primary treatment tank 2 whose upper part is open are communicated via a pipe b and a gate valve 19. A floating deck 3 floats on the liquid surface of the primary treatment tank 2, and a plurality of coarse filter elements 4 are detachably attached to the floating deck 3 at predetermined intervals. A scraper 5 for discharging sludge is provided in a lower portion of the primary treatment tank 2, and a gate 6 for discharging sludge is disposed on a side wall thereof. A sludge receiving hopper 7 is provided adjacent to the gate 6, and a sludge discharge feeder 8 is connected to the hopper 7.

[0007] The secondary side of the coarse filter element 4 of the primary processing tank 2 is connected to a closed secondary processing tank 2 through a pipe c.
4 primary side. The connecting pipe c is provided with a transfer pump 9, a check valve 9a, a three-way switching valve 10, and an on-off valve 12 for the primary processing liquid. An upper part in the secondary processing tank 24 is provided with a partition wall 25 which is vertically divided into two, and a plurality of fine filter elements 26 are attached to the partition wall 25 at predetermined intervals. A differential pressure measuring device 27 for measuring the differential pressure on both sides of the partition wall 25 is also arranged. Reference numeral 28 denotes a closed type replenishing tank to which a filter aid is supplied, and the filter aid is supplied to the secondary treatment tank 24. A normal pressure type final storage tank 29 whose upper part is opened by a pipe s is connected to the secondary side of the closed type secondary processing tank 24 via an on-off valve 15. Further, each symbol is as follows. Reference numeral 30 denotes a transfer pump for the secondary treatment liquid, and reference characters a to s denote pipes. 11 is a three-way switching valve, 12 to 16 are on-off valves, 18 to 2
2 is a gate valve.

Next, the coarse filter element 4 shown in FIG.
A coil body in which a linear body 32 having a large number of projections 31 provided on the outer surface at predetermined intervals is wound around a cylindrical coil winding, and the projections 31 form a large number of gaps 33 between the peripheral wall portions of each winding. 34, a metal core 35 having threaded portions formed at both ends and penetrating the center of the coil body 34, and an upper metal fitting penetrating the upper part of the metal core 35 and detachably screwed to the floating deck 3 as an attachment member. 36, a plurality of flow openings 36a provided in the peripheral wall of the upper metal member 36, a lower metal member 37 penetrating a lower portion of the core metal 35, and a pair of fixing members for fixing the upper metal member 36 and the lower metal member 37 to the core metal 35, respectively. A nut 38 is provided. Preferably, the linear body 32 is made of a metal such as stainless steel or a resin, which is a rust preventive material. The coarse filter element 4 performs filtration by lowering the inner pressure than the outer pressure of the coil body 34, and the outer liquid flows inward through the gap 33 as shown by the arrow due to the differential pressure, and The liquid obtained by separating the solids that cannot pass through flows out from the circulation port 36 a of the upper fitting 35.

The fine filter element 26 shown in FIG.
The filter aid 39 is held in the gap 33 in the coarse filter element 4 in FIG. 2 by utilizing the flow of a fluid, and the same parts as those in FIG. 2 are denoted by the same reference numerals. As the filter aid 39, for example, powdered zeolite or diatomaceous earth can be used. Filter aid 39 in gap 33
For example, a mixture obtained by adding zeolite or diatomaceous earth to a liquid is applied to the gap 3 of the coarse filter element 4.
3 is preferred. A filter element as shown in FIG. 3 is known from Japanese Patent Application Laid-Open No. 8-19682.

Next, the procedure for carrying out the liquid filtration method of the present invention will be described with reference to FIG. (1) Preparation for Startup First, a predetermined number of coarse filter elements 4
And a predetermined number of coarse filter elements 4 are installed in the secondary treatment tank 24. Then, the gate valve 18 is opened, the human waste is supplied from the pipe a to the human waste storage tank 1 and stored therein, and the gate valve 19 of the pipe b is further stored.
Is opened and a predetermined amount of human waste is supplied to the primary treatment tank 2.
Further, the gate valve 22 is opened, and a predetermined amount of a filter aid, for example, as a liquid mixture with water, is supplied from the pipe i to the supply tank 28 by a pump (not shown).

(2) Conversion of the coarse filter element 4 installed in the secondary treatment tank 24 to the fine filter element 26 This conversion is performed by first closing the on-off valves 12 and 15 and closing the on-off valves 13 and 1
6, the transfer pump 9 is started, a differential pressure is generated in the coarse filter element 4 of the primary treatment tank 2 to filter the human waste, and the primary treatment liquid is supplied to the supply tank 28 via pipes c, d and e.
To supply. The primary processing liquid is mixed with the filter aid in the supply tank 28, and the mixed liquid is supplied to the secondary processing tank 24 from the pipe k. The air below the partition wall 25 of the secondary processing tank 24 is extruded by the mixed liquid and passes through the coarse filter element 4,
It moves to the space above the partition wall 25 and is further discharged to the upper space of the primary treatment tank 2 via the pipe j. In the process, the filter aid in the mixture gradually adheres to the gaps of the coarse filter element 4.

When all the air in the secondary processing tank 24 is replaced with the mixed liquid, the excess liquid above the partition wall 25 circulates through the pipe j into the primary processing tank 2. In addition,
At the time of startup, the concentration of the filter aid flowing out from the secondary side to the primary treatment tank 2 without being attached to the gap 33 of the coarse filter element 4 of the secondary treatment tank 24 is small. The amount of the filter aid attached to the element 4 is negligible. When a predetermined amount of the filter aid has adhered to the gap 33 of the coarse filter element 4, that is, when the filter aid has been converted into the fine filter element 26, the on-off valves 12, 15 are opened and the on-off valves 13, 16 are closed. By doing so, the apparatus shifts to a steady operation state.

(3) Steady state of operation When the apparatus shifts to the steady state of operation, most of the human waste continuously supplied from the human waste storage tank 1 to the primary treatment tank 2 is filtered and separated by the coarse filter element 4. Is done. Then, the filtered primary processing liquid flows into the secondary processing tank 24 via the pipes c, d, and f. On the other hand, the separated solid precipitates at the bottom of the primary treatment tank 2 and is discharged from the gate 6 to the sludge receiving hopper 7 by driving the scraper 5 each time it reaches a predetermined amount. The scraper 5 is driven by a reciprocating drive device such as a cylinder (not shown), and the gate 6 is also opened and closed by a lifting drive device such as a cylinder (not shown). When a predetermined amount of sludge in the sludge receiving hopper 7 stays, the sludge discharge feeder 8 is driven to discharge and store the sludge to a storage facility outside the system. The primary processing liquid containing a small amount of solid is finely filtered by the fine filter element 26 in the secondary processing tank 24, and the secondary processing liquid containing substantially no solid is supplied to the pipe h,
After that, it is transferred to the final storage tank 29. This secondary treatment liquid containing urine components is transferred from a pipe n as needed by a pump or the like (not shown), and is sprayed as liquid fertilizer on agricultural lands or pastures, or treated to a standard that can be discharged to a public drainage facility. Supplied to

(4) Backwashing of the coarse filter element 4 in the primary treatment tank 2 If the operation is continued for a long time, the gap 33 of the coarse filter element 4 in the primary treatment tank 2 is gradually clogged, and the treatment capacity is reduced accordingly. Will come. Therefore, the coarse filter element 4 is back-washed to eliminate clogging. That is, for example, a three-way switching valve is provided by a backwash command output after a predetermined time elapses by a timer device or the like or when the differential pressure between the primary side and the secondary side of the coarse filter element 4 reaches a preset value. 10 by which a part of the secondary processing liquid supplied to the storage tank 29 is supplied to the pipe o,
c, and is supplied to the secondary side of each coarse filter element 4 in the primary treatment tank 2 to backwash it (the gate valve 20 is kept open at that time).

In FIG. 1, a three-way switching valve 11 is further provided in a pipe q shown by a dotted line. This pipe q is used when the number of coarse filter elements 4 is large and the filter elements 4 are divided into several groups. They are added and are not necessarily provided. The back-washing operation is terminated after a predetermined time elapses, for example, by a timer device, or when the differential pressure between the primary side and the secondary side of the coarse filter element 4 drops to a preset value. Return to the state.

(5) Reverse cleaning of the fine filter element 26 in the secondary processing tank 24
If the operation is continued for a long period of time, the space 33 gradually becomes clogged. That is, it is output when the measured value of the differential pressure measuring device 27 for measuring the differential pressure on both sides of the partition wall 25 (the differential pressure between the primary side and the secondary side of the fine filter element 26) reaches a preset value. The primary treatment water is supplied to the secondary treatment tank 2
4 to the secondary side. In this case, the on-off valves 12, 1
5 and 16 are closed, and the on-off valve 14 is opened. Then, the treated water on the secondary side of the primary treatment tank 2 is supplied to the secondary side of the secondary treatment tank 24 via pipes c, d, g, and h, and the filter aid is collected in the supply tank 28 from the pipe k. Let it. When the backwashing is completed, the state is returned to the original state, and a proper amount of the filter aid is again adhered to the surface of the fine filter element 26, and the operation shifts to the steady operation.

The secondary treatment liquid in the final storage tank 29 may be used for back washing. In this case, the transfer pump 30 is started, the transfer pump 9 is stopped, and the processing liquid is supplied through the pipe o, the on-off valve 21, and the pipe h. A processing liquid can be supplied to the side and it can be backwashed. The surplus primary processing liquid discharged from the lower side of the partition wall 25 of the secondary processing tank 24 flows into the supply tank 28 from the pipe k, and is returned to the primary processing tank 2 via the pipes r and j.

This backwashing operation is terminated when the value measured by the differential pressure measuring device 27 drops to a preset value, and the operation is returned to a normal operation state. Note that a timer device or the like can be used instead of the differential pressure measuring device 27. When the fine filter element 26 is back-washed in this manner, the filter aid 39 that has adhered to the gap 33 is removed, and the filter aid 39 is again attached to the gap 33 after the back washing. The attaching method may be the same as that described in “(2) Conversion of coarse filter element 4 installed in secondary treatment tank 24 to fine filter element 26”.

The conversion of the coarse filter element installed in the secondary processing tank 24 to the fine filter element 26, the reverse cleaning of the coarse filter element 4 in the primary processing tank 2, and the reverse cleaning of the fine filter element 26 in the secondary processing tank 24. Such operations can be automatically performed using, for example, a computer or a sequencer. In this case, the on-off valve and the gate valve that require remote control are an electric drive system, a hydraulic drive system, a pneumatic drive system, or the like.

[0020]

As described above, the invention according to claim 1 is
A specific coarse filter element is arranged in the primary treatment tank, and a fine filter element having a filter aid attached to the gap between the coarse filter elements is arranged in the secondary treatment tank, and the liquid to be treated is treated in the primary treatment tank. When the coarse filter element is clogged, it is back-washed with the secondary processing liquid, and when the fine filter element is clogged, it is removed from the primary processing liquid or the secondary processing tank. Since the back washing is performed with the treatment liquid, the liquid containing solid content can be filtered stably for a long period of time at low installation cost and running cost.

According to a second aspect of the present invention, the coarse filter element is arranged in the secondary treatment tank before the steady operation.
A replenishing tank for replenishing the filter aid is further provided, and the primary treatment liquid is supplied thereto and mixed with the filter aid, and the mixed solution is supplied to the secondary treatment tank. Is converted to a fine filter element, so that the coarse filter element can be brought into the fine filter element state by a simple operation. Further, in the invention according to claim 3, the floating deck is provided in the primary processing tank of normal pressure type, and the coarse filter element is attached to the floating deck, so that the structure and processing of the primary processing tank are facilitated, and the liquid level is further improved. , The coarse filter element always automatically follows it, so that there is no fluctuation in the filtration capacity.

[Brief description of the drawings]

FIG. 1 is a process flow chart for performing human waste treatment by a liquid filtration treatment method of the present invention.

FIG. 2 is a longitudinal sectional view showing one example of a coarse filter element used in the liquid filtration treatment method of the present invention.

FIG. 3 is a longitudinal sectional view showing an example of a fine filter element used in the liquid filtration treatment method of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Human waste storage tank 2 Primary treatment tank 3 Floating deck 4 Coarse filter element 5 Scraper 6 Gate 7 Sludge receiving hopper 8 Sludge discharge feeder 9 Transfer pump 9a Check valve 10 Three-way switching valve 11 Three-way switching valve 12 On-off valve 13 On-off valve 14 On-off valve 15 On-off valve 16 On-off valve 18 Gate valve 19 Gate valve 20 Gate valve 21 Gate valve 22 Gate valve 23 Check valve 24 Secondary treatment tank 25 Partition wall 26 Fine filter element 27 Differential pressure measuring instrument 28 Supply tank 29 Final Storage tank 30 Transfer pump 31 Projection part 32 Linear body 33 Gap 34 Coil body 35 Core metal 36 Upper fitting 36a Distribution port 37 Lower fitting 38 Nut 39 Filtration aid a to s Piping

Claims (3)

[Claims] 1. A method for filtering a liquid containing solid matter, comprising: a step of winding a whole of a linear body 32 having a plurality of projections 31 formed on an outer surface thereof in an axial direction into a cylindrical spiral winding; Part 31
The coarse filter element 4 in which a large number of gaps 33 are formed between the peripheral wall portions of the adjacent spiral windings is disposed in the primary treatment tank 2, the liquid to be treated is supplied to the primary treatment tank 2, and the primary filtration treatment is performed. The primary treatment liquid is supplied to the secondary treatment tank 24 in which the fine filter element 26 with the filter aid 39 adhered to the gap 33 of the coarse filter element 4 is subjected to a second filtration treatment. Liquid filtration characterized by backwashing the fine filter element 26 with a primary treatment liquid or a secondary treatment liquid when the fine filter element 26 is clogged, when the clogged filter element 4 is clogged. Processing method. 2. Before the steady operation, the coarse filter element 4 is arranged in the secondary processing tank 24, and a replenishing tank 28 for replenishing a filter aid 39 is further provided. Agent 39, and the mixed solution is used in the secondary treatment tank 24.
2. The liquid filtration method according to claim 1, wherein a filter aid 39 is attached to the gap between the coarse filter elements 4 to convert the coarse filter element 4 into a fine filter element 26. 3. The liquid filtration device according to claim 1, wherein a floating deck 3 that follows the liquid surface is provided in the primary treatment tank 2 of normal pressure type, and a coarse filter element 4 is attached to the floating deck 3. Processing method.