JP4548963B2 - Sewage treatment electrolyzer - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a sewage treatment electrolytic apparatus for treating domestic wastewater or factory wastewater.
[0002]
[Prior art]
As this type of sewage treatment apparatus, for example, a sewage treatment apparatus described in JP-A-10-258288 is known. This device supplies a constant current to the iron electrode to elute iron ions, and causes the iron ions eluted from the electrode to react with phosphate ions in the sewage to coagulate and precipitate water-insoluble iron phosphate. It removes phosphorus from the inside.
[0003]
By continuing to supply current to the electrode, the electrode is consumed and iron ions are not eluted, so that it is necessary to periodically replace the electrode in order to stably remove phosphorus.
[0004]
Therefore, paying attention to the fact that when a constant current is supplied to the electrodes, the voltage between the electrodes increases as the electrodes are consumed, when the voltage between the electrodes reaches a predetermined value, the control unit informs the user by a notification means such as a buzzer. It came to inform.
[0005]
The inter-electrode voltage notified by the control unit using a buzzer, etc. is set to the inter-electrode voltage when the electrode weight is reduced by a predetermined amount, which requires electrode replacement. The user who has learned the information contacts the maintenance company and replaces the electrode.
[0006]
The phosphorus can be removed by the iron ions eluted from the remaining electrodes after the notification by the notification means until the electrodes are replaced, and stable phosphorus removal performance can be maintained until the electrodes are completely removed. It was like that.
[0007]
However, when treating factory wastewater with such a sewage treatment device, the electrical conductivity of the wastewater varies from factory to factory, and the higher the electrical conductivity, the lower the resistance during electrode electrolysis and the more easily the electrolytic current flows. When a constant current is supplied, the higher the electric conductivity, the lower the interelectrode voltage.
[0008]
Therefore, when removing sewage phosphorus with high electrical conductivity, the voltage between the electrodes is lower than in normal sewage, and even when the electrode weight that requires electrode replacement is reduced by a predetermined amount, May not rise to a predetermined voltage.
[0009]
If it is time to replace the electrode without knowing it, the voltage between the electrodes will rise rapidly and reach the specified voltage while the remaining electrodes are consumed. Only then will the notification means know when to replace the electrode.
[0010]
Therefore, a predetermined amount of iron ions cannot be supplied to the sewage until the electrode is replaced, and there is a drawback that the phosphorus removal performance is significantly reduced.
[0011]
[Problems to be solved by the invention]
This invention is made | formed in view of the said fault, and makes it a subject to provide the electrolytic device for wastewater treatment which can detect the replacement | exchange time of an electrode reliably irrespective of the electrical conductivity of wastewater.
[0012]
[Means for Solving the Problems]
The first means for solving the above problems is as follows. A treatment tank into which sewage flows, at least a pair of electrodes made of iron or aluminum, a power supply for supplying a constant current to the electrodes, and a voltage detection unit for detecting a voltage between the electrodes Based on the output of the sensor, a notification unit that notifies when the voltage detection unit detects a reference voltage for replacing the electrode, a sensor that detects electrical conductivity of sewage flowing into the treatment tank, and the like. A control unit for setting the reference voltage; It is provided with.
[0013]
The second means for solving the above problems is as follows: A treatment tank into which sewage flows, at least a pair of electrodes made of iron or aluminum, a power supply for supplying a constant current to the electrodes, and a voltage detection unit for detecting a voltage between the electrodes A notification unit that notifies when the voltage detection unit detects a reference voltage that is a replacement time of the electrode, and a control unit that sets the reference voltage based on an initial voltage value detected by the voltage detection unit; , It is provided with.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the present invention will be described below in detail with reference to the drawings.
[0017]
First, the schematic configuration of the electrolytic cell for a sewage treatment apparatus according to the present embodiment will be described. The container of the electrolytic cell is a box-shaped container having a substantially rectangular plane shape. The tank body 1 has a predetermined depth, and the tank body 1 covers the tank body 1 and is provided with two electrode unit service ports 31. And the upper lid 4 having a relatively small height for closing the electrode unit service port 31 of the inner lid 3.
[0018]
A concave portion 33 having an opening 32 for mounting the electrode unit on the bottom surface is formed in a lower portion of the inner lid 3 covered with the upper lid 4, and a peripheral portion of the opening 32 functions as a support member for the electrode unit 51. is doing.
[0019]
In the recess 33, a plurality of electrode units 51 are arranged at regular intervals in the direction in which the longitudinal direction of the electrode plate 51 a is the same as the long side of the tank body 1 and perpendicular to the longitudinal direction of the electrode plate 51 a. The electrode unit rows 5 are formed in two rows.
[0020]
In addition, a sewage outlet 11 is provided at the upper part of the side wall that forms the short side of the tank body 1, and the inner lid 3 is located at a position corresponding to the side wall upper part facing the side wall provided with the sewage outlet 11. A sewage inlet 35 is provided so that sewage flows into the electrolytic cell.
[0021]
Next, each part of the electrolytic cell described above will be described more specifically.
[0022]
The tank body 1 is where sewage is introduced and metal ions are eluted from the electrode plate 51a into the sewage, and has a height and volume necessary for this treatment.
As described above, the sewage outlet 11 is provided in the upper part of one side wall that forms the short side of the tank body so that the pipe is led out in the horizontal direction. The sewage outlet 11 is provided with a packing 11a.
[0023]
Below the sewage outlet 11 on the one side wall, an inclined surface portion 12 that is inclined so that the bottom portion is located on the center side of the tank body 1 is formed. An inclined surface portion 13 is also formed on the side wall facing the inclined surface portion 12 so as to have a symmetrical shape with the inclined surface portion 12.
[0024]
The inclined surfaces 12 and 13 are formed in the vicinity of the lower portion of the electrode unit row 5 so as to generate convection of sewage in the electrolytic cell. In addition, shelf portions 14 and 15 that are communicated with the inclined surface portions 12 and 13 and project outward are formed on the top portions of the inclined surface portions 12 and 13, respectively, and the lower surfaces of the shelf portions 14 and 15 serve as the electrolytic cell. It functions as a fixed surface for installation.
[0025]
The middle lid 3 located above the shelf 15 is provided with a sewage inlet 35, and the sewage flowing into the electrolytic cell through the sewage inlet 35 is dispersed by the shelf 15. Yes.
[0026]
Between the two electrode unit rows 5 on the bottom surface of the tank body 1, a smooth chevron 16 having the same inclination angle as the inclined surfaces 12 and 13 is formed. The center part of the space sandwiched between the surface parts 12 and 13 is configured to be the center of the electrode unit row 5, and the sludge discharge port 17 is provided in this part (that is, below the electrode unit row 5). The sludge discharge port 17 is closed by a rubber plug 17a, and a pipe joint 17b is attached to the outer surface of the sludge discharge port 17 through bolts 17c and nuts 17d through packings 17e and 17f.
[0027]
Further, ribs 19 for fixing the diffusing pipe are formed on the bottom of the tank body 1 so as to surround the sludge discharge port 17 (in this embodiment, a total of eight places).
The rib 19 is provided with a notch 19a for fitting the diffuser tube at the upper end of the rib 19 so that the diffuser tube 25 is fixed in a state of being slightly lifted from the bottom surface.
[0028]
Support legs 22 are formed at four locations on the bottom surface of the tank body 1, and the electrolytic cell can be installed using the support legs 22.
[0029]
In addition, a flange portion 23 is formed at the upper end edge portion of the tank body 1 and a downward reinforcing rib 24 is formed to improve the strength of the end edge portion.
[0030]
The inner lid 3 has a height necessary for securing a wiring space for the power cable relay terminal box 6 and the power cable 62 of the electrode unit 51 in the upper part of the electrode unit row 5, and the upper surface of the inner lid 3 is electrolytic. It constitutes the upper surface of the tank.
[0031]
Further, the lower end of the peripheral edge of the inner lid 3 has a flange portion 34 that comes into contact with the flange portion 23 at the upper end edge of the tank body 1, and is further configured as a bent piece 34a in which the front end of the flange portion 34 is bent downward. It is formed so as to cover the upper end of the tank body 1. The inner lid 3 and the tank body 1 are fixed by screws or the like at the flange portions 23 and 34 with screws 34b.
[0032]
In addition, a small space plane portion 30 is formed in the middle lid 3 located above the shelf portion 15, and a sewage inlet 35 is attached to the plane portion 30. The height position of the sewage inlet 35 is lower than the upper surface of the recess 33 of the inner lid 3, and even when sewage leaks from the joint surface between the sewage inlet 35 and the inner lid 3, the sewage flows into the recess 33. The relay terminal box 6 (electric part) disposed in the recess 33 can be prevented from being short-circuited due to water immersion.
[0033]
The sewage inlet 35 includes a flanged pipe 35a having a mounting flange below, a straight pipe 35b connected to the flanged pipe 35a, and a 90-degree elbow pipe 35c rotatably attached to the straight pipe 35b. A connecting pipe 35d for supplying sewage from a processing apparatus that performs processing before flowing into the electrolytic cell is attached to the 90-degree elbow pipe 35c.
[0034]
Further, in the portion from the sewage inflow port 35 of the inner lid 3 to the side wall facing the sewage inflow port 35, the concave portion 33 having a substantially rectangular planar shape with the long side in the direction orthogonal to the long side of the electrolytic cell is formed. Two are formed. The depth of the recess 33 is set at a position below the peripheral edge of the inner lid 3 and slightly above the sewage surface in the tank body 1. An electrode unit insertion opening 32 is formed on the bottom surface of the recess 33.
[0035]
In addition, an attachment of a relay terminal box 6 for connecting the electrode unit 51 to a power source is formed on one side of the electrode unit insertion opening 32 in a shelf shape higher than the position of the opening 32. A portion 33a is formed.
[0036]
The electrode unit 51 is a set of two rectangular iron plate electrodes (electrode plates 51a), and these two electrode plates 51a are held at a predetermined interval by an upper holder 51b. . A terminal 51c for connecting the power cable 62 is provided on the upper surface of the holder 51b, and the terminal 51c and the electrode plate 51a are connected in the holder 51b.
[0037]
The holder 51b has a width larger than the width (dimension in the longitudinal direction) of the electrode plate 51a, and the both ends of the width larger than the electrode plate 51a are arranged around the electrode unit insertion opening 32 of the inner lid 3. One pin hole 51e for engaging with the arranged pin 36 is provided. The pin hole 51a has a large diameter portion so that the pin 36 can be easily inserted in the lower portion, and the upper portion has a small diameter portion in order to increase the accuracy of the fixing position. A handle 51d is provided on the upper surface of the holder 51b.
[0038]
A separator 52 is attached between the adjacent electrode units 51. The separator 52 is made of plastic as an insulating material, and the size of the flat plate portion 52a is substantially equal to the size of the electrode plate 51a, and the upper portion thereof is used as a wide support portion 52b like the electrode holder. On both sides, one hole 52c that engages with a pin 36 'disposed around the electrode unit insertion opening 32 of the inner lid 3 or a bolt 38 attached to the inner lid 3 is provided, and a support portion A handle 52d is provided on the upper surface of 52b.
[0039]
Further, the pins 36 ′ and the bolts 38 are alternately arranged. A rubber plug 17 a that closes the sludge discharge port 17 is connected to the lower portion of the separator 52 located above the sludge discharge port 17 through a chain 55.
[0040]
When the separator 52 and the electrode unit 51 are mounted on the tank body 1, first, the separator 52 is inserted while the holes 52c of the support portion 52b are engaged with the pins 36 'or the bolts 38, respectively. Next, the electrode unit 51 is inserted while the pin hole 51e of the holder 51b is engaged with the pin 36. At this time, the holder 51 b of the electrode unit 51 is placed on the support portion 52 b of the separator 52.
[0041]
Next, while the fixing plate 53 having a substantially L-shaped cross section is engaged with the bolt 38, it is placed on the holder 51 b of the electrode unit 51, and the service nut 39 is fastened to the bolt 38 and finally fixed. Reference numeral 53 a denotes a cushioning and insulating material attached to the fixed plate 53.
[0042]
Thereby, the line connecting the sewage inflow port 35 side and the sewage outflow port 11 side and the longitudinal direction of the electrode plate 51a coincide, that is, become parallel, and the electrode unit 51 and the separator in a direction perpendicular to the longitudinal direction of the electrode plate 51a. 52 are alternately arranged, and two electrode unit rows 5 each including eight electrode units 51 and seven separators 52 are formed. In addition, the center line of this electrode unit row | line | column 5 is comprised so that the center of the above-mentioned sludge discharge port 17 may be passed.
[0043]
Two relay terminal boxes 6 having four relay terminals are arranged on the attachment portion 33 a formed in the concave portion 33 so that the longitudinal direction is the column direction of the electrode unit rows 5. Therefore, the arrangement direction of the four relay terminals 61 and the row direction of the electrode unit row 5 are the same.
[0044]
The relay terminal 61 and the electrode unit 51 are connected by a power cable 62, and the power source and the relay terminal 61 are connected by a power cable 63.
[0045]
In the lower part of each electrode unit row 5, two diffuser tubes 25 are arranged as a set of diffuser devices. Air diffuser holes for supplying air blown from the blower 80 into the sewage are formed in the air diffuser pipe 25, and the tips of the two air diffuser pipes 25 are communicated with each other through a communication pipe 28. The other end of the diffuser pipe 25 is connected to a connecting pipe 26 located on the center side of the tank body 1 and a connecting pipe 27 located outside the connecting pipe 26.
[0046]
The connecting pipe 26 and the connecting pipe 27 rise along a side wall that forms the long side of the electrolytic cell, and are led out of the tank body 1 from a notch 37 at the upper end of the inner lid 3. A connecting pipe 26 led out of the tank body 1 is connected to a blower 80 via a connecting pipe 81, and a plug 29 is attached to the connecting pipe 27 led out of the tank body 1.
[0047]
In the inner lid 3, a recess 33 having an electrode unit insertion opening 32 on the bottom surface is covered with the upper lid 4 and fixed to the inner lid 3 with screws 41. The upper lid 4 protects a person from inadvertently touching the terminal 51 c of the electrode unit 51 to prevent an electric shock, is closed during normal use, and is opened when the electrode unit 51 is replaced. Further, two handles 42 are formed on the upper surface of the upper lid 4.
[0048]
Reference numeral 70 denotes a sensor mounting portion formed of a recess formed in the inner lid 3, which is formed at two positions adjacent to the tank recess 1 and adjacent to the two recesses 33. In either one of the two sensor mounting portions 70, a lid switch 71 that operates by opening and closing the upper lid 4 and a pressure switch 75 that operates by changing the discharge side pressure of the blower 80 are accommodated between the upper lid 4 and the upper lid 4. Two sets of sensor units 7 are installed. The sensor unit 7 will be described with reference to FIGS. FIG. 8 is an enlarged view of the sensor unit 7, and FIG. 9 is a control circuit for the electrode unit. For simplification, only one electrode unit row 5 is shown in FIG. 9, but actually another electrode unit row is similarly connected.
[0049]
As shown in FIG. 8, the lid switch 71 includes a switch body 72 attached to the inside of the switch box 79 and a magnet 73 attached to the inside of the upper lid 4, and when the upper lid 3 is closed. When the reed switch in the switch body 72 is turned on by the action of the magnet 73 and the upper cover 4 is opened, the magnet 73 does not act on the switch body 72 so that the reed switch in the switch body 72 is turned off. Designed to. Two lid switches 71 are attached corresponding to the corners of the two upper lids 4 so as to detect the opening and closing of the two upper lids 4 respectively.
[0050]
On the other hand, the pressure switch 75 is a diaphragm type when the air outlet of the diffusing pipe 25 is clogged, the pressure on the discharge side of the blower 80 rises abnormally, and air is not supplied to the sewage, or as the blower 80. When the diaphragm constituting the blower 80 is damaged, that is, when the pressure on the discharge side of the blower 80 is abnormally low and air is not supplied to the sewage. Detect as pressure. In FIG. 8, 76 and 77 are pipes for introducing the discharge side pressure of the blower 80 to the pressure switch 75. Reference numeral 78 denotes a control circuit wire.
[0051]
As shown in FIG. 9, the eight electrode units 51 arranged in one electrode unit row 5 are connected to the power source 9 via the relay terminal 61 and further via the control panel 8. The control panel 8 receives ON / OFF information of the two lid switches 71 and the two pressure switches 75. When the opening of the upper lid 4 is detected by any one of the lid switches 71, or when it is detected by the operation of any one of the pressure switches 75 that the air is not normally supplied from the diffusion tube 25, the electrodes The power line of the unit 51 is turned off.
[0052]
Next, a voltage setting device for setting an electrolysis voltage for detecting the replacement time of the electrode plate 51a will be described in detail below.
[0053]
The voltage setting device 82 shown in FIGS. 10 and 11 is mounted on a wall surface in the vicinity of the position where the electrolytic cell is disposed.
[0054]
The voltage setting device 82 includes a constant current power source 83 that supplies a DC constant current to the electrode unit 51, a power lamp 84 that indicates that a current is supplied to the electrode unit 51, and an electrode of the electrode unit 51. A voltage detection unit 85 that detects an electrolysis voltage between the plates 51a, a voltage display unit 86 that displays an output voltage of the voltage detection unit 85, and an electrode plate 51a of 16 electrode units 51 that the voltage detection unit 85 detects. A maximum voltage detector 87 that detects a maximum voltage value, an alarm lamp 88 that is turned on when the output of the maximum voltage detector 87 exceeds a reference voltage, and a reference voltage that is set later. Voltage setting switch 89 and a voltage display changeover switch 90 for switching the output voltage displayed on the voltage display section 86 for each electrode unit 51.
[0055]
Every time the voltage display changeover switch 90 is operated, the voltage displayed on the voltage display unit 86 is switched in units of electrode units 51 in a forward feed. Reference numeral 89 denotes a voltage setting switch for setting a reference voltage for replacing the electrode plate 51a. When the voltage setting switch 89 is turned while viewing the display 91 on the display panel, and the mark 92 of the voltage setting switch 89 is set to an arbitrary position, A reference voltage is set corresponding to the number at the position corresponding to the mark 92. For example, in FIG. 10, the reference voltage is set to 25V.
[0056]
When a constant current is supplied to the electrode plate 51a, the voltage between the electrodes increases as the electrode plate 51a is consumed. When the voltage increases to the reference voltage set by the voltage setting switch 89, the alarm lamp 88 sets the replacement timing of the electrode plate 51a. I can know. Therefore, it is not necessary to open the upper lid 4 and check the electrode plate 51a.
[0057]
As shown in FIG. 12, even if the same electrolysis current is supplied to the same electrode, the voltage between the electrodes varies depending on the electrical conductivity of the sewage flowing into the electrolytic cell.
[0058]
In order to maintain the phosphorus removal performance from the time of replacement of the electrode plate 51a to the time when the electrode plate 51a is replaced by contacting a maintenance company, the weight of the electrode plate 51a is a predetermined amount (this embodiment In this case, it is preferable to notify the replacement of the electrode plate 51a.
[0059]
As shown in FIG. 12, for example, if the electrical conductivity of the sewage is 400 μs / cm, if the voltage for detecting the replacement time of the electrode plate 51a is set to 24V, about 3 months from the start of use. Thus, the weight of the electrode plate 51a is reduced by about 90% to notify.
[0060]
However, when sewage with an electric conductivity of 600 μs / cm flows into the electrolytic cell set as described above, the interelectrode voltage becomes 15 V even after about 3 months from the start of use, and the electrode Since the inter-voltage does not rise to 24V, it is not possible to report the electrode replacement at this time.
[0061]
Further, if the electrolytic cell continues to be used, the remaining electrode plate 51a is consumed, the voltage between the electrodes suddenly increases, the voltage between the electrodes reaches 24V, and the electrode replacement is notified. The remaining amount of the plate 51a is small, and until the electrode plate 51a is replaced, almost no ions can be eluted from the electrode plate 51a, resulting in a problem that the phosphorus removal performance is significantly lowered.
[0062]
In the present embodiment, since the voltage setting switch 89 that can set the voltage that requires replacement of the electrode plate 51a is provided, it is necessary to replace the electrode according to the electrical conductivity of the sewage flowing into the electrolytic cell. The voltage can be set by turning the voltage setting switch 89, and it is possible to prevent the state in which iron ions are not eluted from the electrode plate 51a and phosphorus cannot be removed.
[0063]
The specific setting method is that when the electrolytic cell is installed, the installer or the like confirms the voltage between the electrodes of all the 16 electrode units 51 with the voltage display unit 86 while also confirming that the connection of the electrode unit 51 is forgotten. Considering the variation of each electrode unit 51, the voltage that needs to be replaced is the average value of all the 16 electrode units 51, or sewage flows concentrated on a specific electrode unit 51, Considering the case where the consumption of the plate 51a becomes intense, the voltage value displayed highest among the 16 pieces is subjected to an experiment or the like according to the conditions depending on the size of the electrode plate 51a, the distance between the electrode plates 51a, etc. If the voltage setting switch 89 is set so as to be several times the initial value (1.5 times in this embodiment) based on the data obtained from the above, the electrode plate 51a is set according to the electrical conductivity of the sewage. Must be replaced If the time to be, it can be performed notification of the electrode plates 51a-exchange.
[0064]
Further, in the present embodiment, 16 electrode units 51 are provided, but each electrode unit 51 is electrically connected in series so that the same current is supplied to each electrode unit 51. It has become. Since the amount of iron ions eluted from the electrode plate 51a is proportional to the current supplied to the electrode plate 51a, there is almost no difference in the degree of consumption of the electrode plate 51a of each electrode unit 51 by electrolysis.
[0065]
Accordingly, when the inter-electrode voltage of at least one electrode unit 51 out of the 16 electrode units 51 rises to the voltage set by the voltage setting switch 89, the alarm lamp 88 can notify the user. The inconvenience of not being able to be notified when the electrode plate 51a needs to be replaced due to the variation in voltage can be solved, and the replacement work of the electrode plate 51a can be performed at a time, thereby improving the maintenance workability. .
[0066]
In addition, although the voltage which needs replacement | exchange of the electrode plate 51a was set based on the voltage between electrodes at the time of electrolytic cell installation, the electrical conductivity of the wastewater which flows into an electrolytic cell is the state which uses water. As long as there is no significant change, it will be approximately constant at each office. Therefore, the electrical conductivity of the sewage flowing into the electrolytic cell is measured, and as shown in FIG. A method may be used in which a reference voltage that requires replacement of the electrode plate 51 a is obtained from a “curve” or the like, and a voltage that requires replacement of the electrode plate 51 a is set by the voltage setting switch 89.
[0067]
For home use, a combined septic tank and electrolytic tank may be considered. The electrical conductivity of domestic wastewater that flows into the combined septic tank varies depending on the time of day in each household, but it is almost constant in the combined septic tank, and the electrical conductivity of the sewage flowing into the electrolytic tank is the same as in the office. It becomes almost constant. Therefore, the reference voltage may be set with the same configuration as described above for home use.
[0068]
The electrolyzer configured as described above is used as a wastewater treatment system for a business establishment, for example, as shown in FIG.
[0069]
The electrolytic cell used for the business-use wastewater treatment system will be described below.
[0070]
Sewage discharged from the business site is first decomposed by microorganisms in the activated sludge tank A, and the sewage in the activated sludge tank A passes through the intermediate flow rate adjusting tank B to the electrolytic tank C as a certain amount of sewage. be introduced. At this time, the sewage falls from the sewage inlet 35 formed in the upper part of the electrolytic cell C to the shelf 15 of the tank body 1 and is dispersed to form a substantially uniform flow between the electrode units 51 to the sewage outlet 11 side. Flowing.
[0071]
Particularly in the present embodiment, the electrode unit rows 5 are arranged in two rows in a direction substantially orthogonal to the direction in which the sewage flows, and the size in the width direction of the tank is reduced, so that the sewage is stagnated at the end in the width direction of the tank. It is prevented. Therefore, it is possible to prevent the phosphorus removal efficiency from being lowered by the ions eluted from the electrode unit at the tank end and the phosphorus removal efficiency from being lowered.
[0072]
At this time, divalent iron ions are eluted from the anode of the electrode unit 51 by the electrolytic action of the electrode unit 51, and hydrogen gas is generated from the cathode. On the other hand, the divalent iron ions are oxidized into trivalent iron ions by aeration from the diffuser tube 25. Further, the hydrogen gas concentration is diluted by the air ejected from the air diffuser 25, thereby avoiding the danger of explosion.
[0073]
Trivalent iron ions react with orthophosphoric acid in the sewage water, and are formed into poorly soluble phosphorus compounds. The sludge containing the phosphorus compound is actively floated in the electrolytic cell C by aeration from the air diffuser 25 and is discharged from the sewage outlet 11 to the coagulation sedimentation tank D which is the next step. Then, the suspended solid containing the phosphorus compound is precipitated and removed in the coagulation sedimentation tank D.
[0074]
In addition, when sewage is introduced into the electrolytic cell C, air is blown out from the air diffuser 25 toward the bottom surface of the tank body 1, and foam-like bubbles rise upward, and the sewage inflow side and the sewage outflow of the tank body 1. By forming an inclined shape of the mountain-shaped portion 16 in the vicinity of the lower portion of the electrode unit row 5 at the center of the bottom surface of the tank body 1 that is intermediate between the inclined surface portions 12 and 13 provided on the side wall and the electrode unit row 5 The sewage is drawn from the periphery of the air diffuser 25 toward the bottom of the tank main body 1, and the sewage effectively causes convection in the electrolytic cell C so that the suspended matter is discharged smoothly.
[0075]
Further, the longitudinal direction of the electrode plate is parallel to the line connecting the sewage inflow port 35 and the sewage outflow port 11 (in this embodiment, the same as the longitudinal direction of the tank), that is, the sewage is in the electrode plate. By flowing along the plate-shaped surface and convection generated in the tank along the plate-shaped surface of the electrode plate, the phosphorus compound can be efficiently suspended.
[0076]
As described above, since the electrolytic cell C does not accumulate sludge in the electrolytic cell, it is not usually necessary to discharge the sludge in the electrolytic cell C, and only when the electrode unit 51 is replaced. I can do it.
[0077]
In this embodiment, both the anode and the cathode are made of iron, and the polarity is periodically changed in order to avoid the consumption of only one electrode and to avoid the immobilization of the anode. In addition, since the insulating separator 52 is disposed between the adjacent electrode units 51, it is possible to prevent electrolysis between the adjacent electrode units 51, and the consumption of each electrode plate 51a is made substantially uniform. . If the separator 52 is not provided, the electrode plate 51a other than the outermost electrode undergoes electrolysis on both sides, and melts at a rate approximately twice that of the outermost electrode plate 51a. It becomes impossible to achieve uniform consumption of 51a.
[0078]
In the electrolytic cell C operating as described above, when the electrode unit 51 is replaced, the upper cover 4 is first opened, the power cable 62 connected to the relay terminal 61 of the relay terminal box 6 is removed, and the electrode unit 51 and The fixing plate 53 that fixes the separator 52 is removed.
[0079]
In this case, since the relay terminal 61 and the electrode unit 51 of the relay terminal box 6 are adjacent and connected in a one-to-one correspondence, the wiring of the power cable 62 can be shortened and orderly. 51 forgetting connection can be easily identified.
[0080]
In the electrode unit 51, when the upper lid 4 is opened, the magnet 73 embedded in the upper lid 4 does not act on the switch portion in the switch body 72, and the power supply circuits of both electrode unit rows 5 are turned off. It is possible to ensure safety without a person accidentally getting an electric shock.
[0081]
Moreover, since the lower part of the separator 52 is connected to the rubber plug 17a via the chain 55, when replacing the electrode unit 51, the rubber plug 17a can be pulled out simultaneously with the removal of the separator 52.
[0082]
During the operation of the electrode unit 51, when an abnormality occurs in the system of the blower 80 and aeration is not normally performed, if the operation is continued as it is, the electrolytic reaction is continued almost normally. As the concentration of hydrogen gas generated from the cathode increases, there is a risk of explosion, and it becomes impossible to clean the electrode surface by convection and aeration of sewage in the tank. Although there is a risk that sludge adheres between 51a and the electrode plates 51a communicate with each other through the sludge and short-circuit occurs, in this embodiment, when the abnormality of the diffuser is detected by the pressure switch 75 Since the power supply of the electrode unit row 5 is cut off, such a danger can be avoided.
[0083]
As described above, the electrolytic cell of the present embodiment is provided with the voltage setting switch 89 that can set the voltage at which the electrode is replaced, and the voltage at which the electrode is replaced according to the electrical conductivity of the sewage flowing into the electrolytic cell. Thus, it is possible to prevent the iron ions from being eluted from the electrodes and the phosphate ions cannot be removed.
[0084]
In the present embodiment, the reference voltage used as a guide for replacing the electrode plate 51a is set by the voltage setting switch 89. However, as in the voltage setting device 93 shown in FIGS. At the time of installation, the control unit automatically sets the reference voltage by pressing the automatic voltage setting switch 94 based on the voltage between the electrodes detected by the voltage detection unit by pressing the automatic voltage setting switch 94. May be. The same parts as those in the embodiment described above are denoted by the same reference numerals, and the description regarding the same reference numerals is omitted.
[0085]
When the electrolyzer is installed, that is, when energization of the electrode unit 51 is started, by pressing the automatic setting voltage switch 94, it is accumulated from experiments or the like according to conditions such as the size of the electrode plates 51a and the distance between the electrode plates 51a. Based on the obtained data, the control unit 95 becomes a reference for the replacement timing of the electrode plate 51a so as to be a value several times the voltage between the electrodes detected by the voltage detection unit 85 (1.5 times in the present embodiment). The voltage can be automatically set and displayed on the voltage display unit 86. The reference voltage value automatically set by the automatic voltage setting switch 94 is stored in the control unit 95.
[0086]
Reference numeral 96 denotes a display changeover switch for switching the display displayed on the voltage display section 86 between the voltage value detected by the voltage detection section 85 and the voltage value set by the automatic voltage setting switch 94. Each time the display changeover switch 96 is pressed, the display is changed over.
[0087]
Further, an electric conductivity measuring sensor for detecting the electric conductivity in the sewage, for example, a field conductivity meter (ES-10) manufactured by HORIBA, Ltd. is provided in the electrolytic cell, and the electric conductivity measuring sensor detects the electric conductivity measuring sensor. The control unit 94 automatically sets the voltage that becomes the replacement timing of the electrode plate 51a based on the data accumulated from experiments or the like according to the conditions such as the distance between the electrode plates 51a depending on the electrical conductivity of the sewage. However, the same effect is obtained.
[0088]
Furthermore, in the present embodiment, an iron material is used for the electrode plate 51a. However, the same effect can be obtained by using an electrode plate made of aluminum.
[0089]
In the present embodiment, the reference voltage is set to a voltage value when the electrode plate 51a is reduced by about 90% by weight. However, the present invention is not limited to this, and the electrode plate 51a can reach any weight. The voltage value at the time of decrease may be set as the reference voltage.
[0090]
【The invention's effect】
According to claim 1 of the present invention, Based on the electrical conductivity of sewage, It is time to replace the electrodes Standard By providing voltage setting means for setting the voltage, it is possible to eliminate the inconvenience of not being able to be notified when the electrode needs to be replaced due to variations in voltage during electrolysis due to the electrical conductivity of sewage. Play.
[0091]
According to claim 2 of the present invention, Based on the voltage between the electrodes when a constant current is supplied to the electrodes, It is time to replace the electrodes Standard By providing voltage setting means for setting the voltage, it is possible to eliminate the inconvenience of not being able to be notified when the electrode needs to be replaced due to variations in voltage during electrolysis due to the electrical conductivity of sewage. Play.
[Brief description of the drawings]
FIG. 1 is a plan view of an electrolytic cell according to an embodiment of the present invention.
FIG. 2 is a plan view of the electrolytic cell with a top cover removed.
FIG. 3 is a plan view of the electrolytic cell with its upper lid and electrode unit removed.
4 is a cross-sectional view taken along the line IV-IV in FIG. 1, wherein the electrode unit row at the sewage outlet is in a state where the separator is visible, and the electrode unit row at the sewage inlet side is in a state where the side of the electrode unit is visible. .
5 is a cross-sectional view taken along the line VV in FIG.
6 is an enlarged view of a portion A in FIG.
FIG. 7 is an enlarged view of a sludge discharge port portion of the electrolytic cell.
FIG. 8 is an enlarged view of a sensor unit of the electrolytic cell.
FIG. 9 is a control circuit diagram of an electrode unit of the electrolytic cell.
FIG. 10 is an external view of the voltage setting device.
FIG. 11 is a circuit diagram of the voltage setting device.
FIG. 12 is a diagram showing the relationship between the period of use and the electrolysis voltage with respect to the electrical conductivity of the sewage.
FIG. 13 is an example of a system when the electrolytic cell is applied to wastewater treatment for business establishments.
FIG. 14 is an external view of a voltage setting device according to another embodiment of the present invention.
FIG. 15 is a circuit diagram of a voltage setting device according to another embodiment of the present invention.
[Explanation of symbols]
1 Tank body (treatment tank)
32 Electrode unit insertion opening (opening)
33 Concave part (storage part)
35 Sewage inlet
51a Electrode plate (electrode)
85 Voltage detector
88 Alarm lamp (notification part)
89 Voltage setting switch (Voltage setting means)

Claims (2)

A treatment tank into which sewage flows,
At least a pair of electrodes disposed in the treatment tank and made of iron or aluminum; and
A power supply for supplying a constant current to the electrodes;
A voltage detector for detecting a voltage between the electrodes;
An informing unit for informing when the voltage detecting unit detects a reference voltage to be the replacement time of the electrode;
A sensor for detecting electrical conductivity of sewage flowing into the treatment tank;
A control unit for setting the reference voltage based on the output of the sensor;
An electrolyzer for wastewater treatment, comprising: A treatment tank into which sewage flows,
At least a pair of electrodes disposed in the treatment tank and made of iron or aluminum; and
A power supply for supplying a constant current to the electrodes;
A voltage detector for detecting a voltage between the electrodes;
An informing unit for informing when the voltage detecting unit detects a reference voltage to be the replacement time of the electrode;
A control unit for setting the reference voltage based on an initial voltage value detected by the voltage detection unit;
An electrolyzer for wastewater treatment, comprising:

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