JPS6239040B2 - - Google Patents

Description

[Detailed description of the invention]

<Industrial Application Field> The present invention relates to a purification device that floats and separates dissolved substances, suspended substances, sedimented substances, etc. in wastewater. <Prior art> Conventionally, there are various methods for separating and removing dissolved substances, suspended substances, sedimentary substances, etc. in wastewater, such as filtration, coagulation, precipitation, electrolysis, and pressure flotation.
Each has many problems in terms of technical, economic, processing capacity, and location conditions. As a countermeasure to this problem, the present inventor first mixed and stirred wastewater or pretreated wastewater with a large amount of low-pressure air and a chemical in the presence of a foaming agent such as a surfactant, and the resulting adhesive We proposed a low-pressure flotation separation method (Japanese Patent Application No. 54-2781) that traps various flocs and suspended solids in wastewater using rich foam, adds special chemicals, and floats and separates them as a solid scum. <Problems to be solved by the present invention> This patent application No. 54-2781 has a much higher throughput than other conventional methods (coagulation-sedimentation method, pressure flotation method), but it is not suitable for large-scale processing. Furthermore, improvement in processing capacity was desired. Furthermore, the dehydration properties of the separated scum are not very good, and the separated scum must be further dehydrated by a mechanical dehydration process, and improvements in this point have been desired. Furthermore, although the area occupied by the separation tank is much smaller than that of the other methods mentioned above, it is still large and the equipment is also large, so further reductions in size, miniaturization of the equipment, and cost reduction are desired. Ta. The present invention aims to dramatically improve processing capacity in the flotation separation process, eliminate the need for a mechanical dewatering process by improving the dewatering properties of separated scum, and reduce the size, cost, and footprint of the equipment. It is ivy. <Means for solving the above-mentioned problems> In order to solve the above-mentioned problems, the purification device of the present invention includes (A) a raw water tank 1 that stores raw water; (B) a raw water tank 1 that stores raw water; a conditioning tank 10 for storing raw water; (C) introducing into the conditioning tank 10 an agent for precipitating heavy metal compounds from the raw water or decomposing emulsion oil-containing wastewater in the raw water to form flocs; (D) a stirring device that stirs the conditioned raw water in the conditioned tank 10 and the injected drug; (E) flow from the conditioned tank 10; (F) a gas supply device 90 for injecting low-pressure gas (0.1 to 0.2 Kg/m ³ ) into the conditioned raw water from the conditioned tank in the flow path; and a pump that mixes and stirs the gas injected from the gas supply device 90 to generate foamy scum while delivering the foamed scum at a low speed that does not destroy the foamy scum; (G) a suction side of the pump in the flow path; Immediately before or after the discharge side, the condition imparting tank 1
(H) a flotation separation system chemical supply device 60 for injecting a chemical to promote the scum formation of various flocs generated in the process; at least one flotation cyclone that collects the liquid radially outwardly and the foam scum in the center by a difference, and floats and separates the foam scum from the liquid upwardly by buoyancy; (I) said flotation cyclone; The cyclone is equipped with a scum dewatering tank 110 for further separating liquid from the foamy scum overflowing at the upper part of the cyclone. <Function> As described above, according to the purification device of the present invention, the raw water in the raw water tank 1 is injected with a conditioning agent in the conditioning tank 10, and is stirred by the stirring device to precipitate heavy metal compounds. Either the emulsion is destroyed and a floc is produced. The conditioned raw water is injected with low-pressure air in the flow path to the flotation cyclone, mixed and stirred by a pump, and is accelerated by flotation system chemicals injected just before or after the pump. As a result, in the flow path that reaches the flotation separation cyclone, a large amount of hard foam scum, which is hard to break and has flocs adhered around fine air, is formed. Then, the conditioned raw water is fed into the flotation separation cyclone with a large amount of foam scum formed therein at a low speed that does not destroy the foam, and circulates in the flotation separation cyclone in a circular motion. Due to the centrifugal separation effect in this circular motion, the liquid, which has a heavy specific gravity, is separated radially outward, and the foam scum, which has a low specific gravity, is separated into the center, and the foam scum floats to the top due to the buoyant force. The foamy scum is then successively pushed upward and overflows, further separating the liquid at the scum separation layer. In this way, the substance to be removed remains attached to the foam and is removed. From the bottom of the flotation separation cyclone, the purified liquid separated from the foam scum is either discharged as is or sent to the second and subsequent flotation cyclones, where it is further purified by separation from the foam scum. After that, it is discharged. <Embodiments of the present invention> Examples of the present invention will be described below with reference to the drawings. In Figure 1, 1 is a raw water tank that stores wastewater to be treated or filtered water from the scum dehydration tank 110 (described later) (both are referred to as raw water), and 2 is a raw water A in the raw water tank that is given conditions. 3 is a pipe, 4 is a valve, and 5 is a water level detector that detects the water level of raw water A in the raw water tank 1 and sends a signal for starting and stopping the pump 2. Reference numeral 10 denotes a condition imparting tank, which is partitioned into three tanks, a first tank 13, a second tank 14, and a third tank 15 by partition plates 11 and 12, and each tank is separated by a partition plate 11a.
-11b and 12a-12b are opened for communication. The first tank 13 is provided with an overflow device 16 that returns raw water to the raw water tank 1 when the water level exceeds a set water level height. Reference numeral 30 denotes a condition-imparting chemical supply device, which includes, for example, a chemical tank 31 storing a chemical for destroying the emulsion in the emulsion oil-containing wastewater (hereinafter referred to as X agent), and a chemical tank 31 for adsorbing and collecting decomposed free oil. Chemical tank 3 storing chemicals (hereinafter referred to as OH agents)
2, the X agent is injected into the second tank 14 by the pump 33, and the OH agent is injected into the third tank 15 by the pump 34. In the third tank 15,
PH meter 1 for automatically adding the appropriate amount of OH agent
7 is provided. 22 is a pump that stirs the raw water and the injected X agent in order to mix and react in the second tank 14;
23 is a pipe in which the pump 22 is installed, 25 is a pump that stirs the OH agent injected in the third tank 15 for mixing and reaction, and 26 is a pump 25
It is a pipe with a 40 is the first flotation separation cyclone, 50 is the second
This is a flotation separation cyclone. 41 and 51 are cyclone bodies, respectively, and the cyclone body 4
The liquid sent into the tubes 1 and 51 circulates in a circular motion. Reference numerals 42 and 52 designate receivers for floating and separated scum, which is collected by being separated from the liquid by the centrifugal action during this circulation, floats upward, and overflows from the cyclone bodies 41 and 51. 4
3 and 53 are scum outlet ports. 110 is a scum dehydration tank that receives the scum flowing out from the scum outlet 43, 53 and further separates liquid from the scum using a filter cloth 111; 112 is a pipe that leads the filtrate from the scum dehydration tank 110 to the raw water tank 1; be. Reference numeral 60 denotes a flotation separation system chemical supply device, which includes a ZK agent tank 61 and a ZA agent tank that store chemicals (referred to as ZK agent and ZA agent) for scuming various flocs in the condition imparting tank 10. 62, the ZK agent in the ZK agent tank 61 is pumped into the pipes 70, 71 by the pumps 63, 64, and the ZA agent in the ZA agent tank 62 is pumped into the pipes by the pumps 65, 66, just before the pumps 73, 74 are sucked into the pipes 70, 71. It is injected immediately after the pumps 73 and 74 of 70 and 71 discharge. 70 is a pipe that guides the liquid in the third tank 15 of the condition imparting tank 10 to the first flotation separation cyclone 40;
A pipe 71 guides the underflow of the first flotation and separation cyclone body 41 to the second flotation and separation cyclone 50. 73 and 74 are provided in the pipes 70 and 71, and float at low speed by stirring the conditioned raw water, low-pressure air injected from an air pump 90 (described later), and a chemical injected from the flotation separation system chemical supply device 60. This is a pump that sends out to the separation cyclones 41 and 51. Furthermore, since the pumps 73 and 74 send the air to the flotation separation cyclones 40 and 50 located slightly above, the foam scum is broken down in the cyclones 41 and 51 using pumps with a pressure low enough to sufficiently perform the above-mentioned stirring. It is fed at a low speed so that it is maintained without any problems. 80 and 81 are flow rate control valves. Although not shown, the medicines in the medicine tanks 31 and 32 are configured so that they can also be injected into a pipe 71. Reference numeral 90 denotes an air pump serving as a gas supply device, which injects low-pressure air into the pipes 70, 71 immediately before the suction of the pumps 73, 74 via electromagnetic valves 91, 93 and flow control valves 92, 94. . 100 is a communication pipe that communicates the underflow of the second flotation separation cyclone main body 51 and the underflow of the first flotation separation cyclone main body 41;
Reference numeral 1 denotes a communication pipe that communicates the underflow of the first flotation and separation cyclone body with the underflow of the third tank 15 of the condition imparting tank 10, and has the role of maintaining the balance of the water level of each flotation and separation cyclone. Reference numeral 120 denotes a discharge tank for storing and discharging the underflow of the second flotation separation cyclone main body 51 in the final stage flowing from the pipe 72. 40 liquid levels can be adjusted. 122 is an overflow device. 130 is a circulation pump that sends the treated water in the discharge tank 120 to the second tank 14 of the condition-imparting tank 10 via the suction pipe 132, the discharge amount control valve 133, and the pipe 134 as necessary; This is a check valve for preventing the raw water in the supply tank from flowing back into the treated water storage tank 120. Next, the operation of the above-mentioned apparatus will be explained using the treatment of emulsion oil-containing wastewater as an example. First, the raw water A in the raw water tank 1 is sent to the first tank 13 of the condition imparting tank 10 by the pump 2. The delivery of the pump 2 is controlled by a water level detector 5, and an overflow device 16 prevents the water level from exceeding a set height. The raw water stored in the first tank 13 is separated by the partition plate 11a
The X-agent flows into the second tank 14 through the communication path consisting of . This X agent destroys the emulsion in the raw water. The destroyed emulsion oil-containing wastewater flows into the third tank 15 from the communication path made up of the partition plates 12a to 12b, where it is transferred from the chemical tank 32 to the OH
The agent is injected and stirred by the pump 25, and the decomposed and liberated oil and the like are adsorbed by colloidal floc produced from the X agent and the OH agent. The conditioned raw water processed above is pumped to pump 7.
3, it is sent to the upper part of the first flotation separation cyclone main body 41 through a pipe 70. At this time, since low pressure air (0.1 to 0.2 Kg/m ³ ) is injected from the air pump 90 immediately before the pump 73, the air is dispersed and stirred by the pump 73, and a large amount of fine bubbles are generated in the liquid. Along with this, in order to promote scum formation, the pump 7
As the ZK agent is injected into the suction side of 3 and the ZA agent is injected into the discharge side, flocs adhere to the fine air bubbles, thereby creating scum with a special composition that is easy to float and hard to break. It is sent to the first flotation separation cyclone 40 at low speed. The conditioned raw water is passed through the first flotation separation cyclone 40
When the liquid is fed into the chamber, it circulates in a circular motion, and by centrifugal separation, the liquid with a high specific gravity is separated radially outward, and the foam scum with a low specific gravity is separated in the center of rotation. Scum gathers in the center of the cyclone. As a result, the foamy scum adheres to each other and forms a lump (aggregate). Therefore, the mass of foamy scum floats upward strongly due to the large buoyant force, and is lifted upward and compacted by the subsequent foamy scum that floats up one after another from below, and is then consolidated into the cyclone body 41. The overflow is received by the saucer 42. In this way, the foamy scum is maintained floating above the liquid surface above the cyclone, so water is naturally dehydrated from the foamy scum, resulting in a state with extremely good dehydration properties, and it is further pushed up and overflows from the saucer 42. The scum enters the scum dehydration tank 110 through the outlet 43, where it is further naturally dehydrated. Scum dehydration tank 110
The filtrate is led to raw water tank 1. The residual water from which the scum has been centrifugally floated in this manner is further guided by a pump 74 from the lower part of the cyclone body 41 to the second flotation cyclone 50 through the pipe 71, if necessary. During this time, low pressure air is similarly injected by the air pump 90, and the pumps 64 and 66 inject low pressure air.
The ZK agent and the ZA agent are injected into the suction side and the discharge side, respectively, and mixed and stirred by the pump 74. In addition, if necessary, the chemical tank 31 is connected to the pipe 71.
The X agent inside is injected. Then, in the same process, the scum is separated in the second flotation separation cyclone body 51, is received in the tray 52 as an overflow of the cyclone body 51, enters the scum escape tank 110 through the outlet 53, and is naturally dehydrated. You will be led to raw water tank 1. The underflow is discharged to the outside through a drain tank 120 having a level regulator 121 through a pipe 72, or a part of the underflow is supplied to the circulation pump 13 as circulating water.
0 to the condition imparting tank 10. The water levels of the first and second flotation cyclones 40 and 50 are set by the level regulator 121 of the drainage tank 120, and the underflow pipe 72 of the second flotation cyclone 50 and the water level of the first flotation cyclone 40 are set by the level regulator 121 of the drainage tank 120. The underflow pipe 71 and the underflow pipe 70 of the condition imparting tank 10 are the communication pipe 1
Since they are connected by 00 and 101, mutual water level balance is automatically adjusted. Note that the opening degrees of the flow rate control valves 80 and 81 should be adjusted on-site depending on the performance of each pump, etc. Larger is desirable. Next, Table 1 shows actual measurement examples in which emulsion oil-containing wastewater was subjected to flotation separation treatment using the flotation separation cyclone apparatus of the present invention. (Actual measurement example) Raw water: Emulsion oil-containing wastewater (machine maintenance shop wastewater) X agent: Ferric chloride OH agent: Caustic soda ZK agent: Cationic polymer flocculant ZA agent: Anionic polymer flocculant First flotation separation Amount of liquid agent injected into raw water sent to cyclone 40: X agent…0.25Kg/m ³ (to condition imparting tank 10) OH agent…0.25Kg/m ³ (to condition imparting tank 10) ZK agent…0.01Kg/m ³ (To pipe 70) ZA agent...0.01Kg/m ³ (To pipe 70) PH of the raw water after injection of the above chemical sent to the first flotation cyclone 40 = 10.0 Pipe 71 to the second flotation cyclone 50 ^{Injection amount _} =8.5

[Table] The flotation time in the first and second flotation separation cyclones 40 and 50 was 1 minute. In addition, in the case of treating wastewater containing heavy metal compounds, the chemicals in the chemical tanks 31 and 32 are injected to precipitate the heavy metal compounds, and at the same time, in order to prevent the precipitated heavy metal compounds from settling, the liquid is A drug to make it easier to float (hereinafter referred to as an FA agent) is stored in the drug tank 31 (or 32) or in another layer, and the second (or third)
into tank 14 (or 15). Next, Table 2 shows an actual measurement example in which alkaline battery factory wastewater was subjected to flotation separation treatment using the flotation separation cyclone device of the present invention. (Actual measurement example) Raw water: Alkaline battery factory wastewater FA agent: Linear alkylbenzenesulfonate sodium ZK agent: Cationic polymer flocculant ZA agent: Anionic polymer flocculant Raw water sent to the first flotation separation cyclone 40 Injection amount of liquid agent FA agent…0.01Kg/m ³ ZK agent…0.01Kg/m ³ ZA agent…0.01Kg/m ³ Injection amount of agent injected into the pipe 71 to the second flotation separation cyclone 50 ZK agent …0.005Kg/m ³ ZA agent…0.005Kg/m ³

[Table] Note that the first and second flotation separation cyclones 40,
The flotation time at No. 50 was 1 minute in each case. In the above actual measurements, the quality of the treated water was extremely good, and the residence time in the cyclone was particularly short, which was extremely short compared to the time required for conventional coagulation and sedimentation, pressurized flotation, etc. It was also far less than low-pressure levitation. That is, for the above wastewater, other conventional methods,
That is, the results of measuring the separation time when separation was performed by the coagulation sedimentation method, pressure flotation method, and low pressure flotation method, respectively, and the separation time when separation was performed by the flotation separation cyclone device of the present invention are as follows. It was as shown in Table-3.

[Table] The number of flotation separation cyclones is arbitrarily selected depending on the quality of the raw water, the properties of the flocs, etc.
It may be one or more stages. Furthermore, the order of injection of the ZK agent and ZA agent may be reversed depending on the type of raw water. <Effects of the present invention> As explained above, in the purification device of the present invention,
The processing capacity for separating dissolved substances, suspended substances, and settled substances in wastewater has been significantly increased, and the scum dehydration and air drying properties are excellent, eliminating the need for mechanical filtration and dehydration processes, which are often avoided. Furthermore, since a cyclone, which is much smaller than a conventional flotation tank, is used, the installation area can be significantly reduced, the equipment can be significantly downsized, and the equipment cost can be significantly reduced.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of an embodiment of the present invention. 1... Raw water tank, 5... Water level detector, 10... Condition imparting tank, 21... Overflow device, 22,
25...Pump, 30...Conditioning system drug supply device, 31...Drug tank, 32...Drug tank, 40...
First flotation separation cyclone device, 50... Second flotation separation cyclone device, 41, 51... cyclone body, 42, 52... saucer, 43, 53...
Outlet, 60...Flotation separation system chemical supply device, 7
3, 74... Pump, 80, 81... Flow control valve, 90... Air pump, 100, 101... Communication pipe, 110... Scum dehydration tank, 120... Discharge tank, 130... Circulation pump.

Claims (1)

[Scope of Claims] 1 A raw water tank 1 for storing raw water, a conditioning tank 10 for storing raw water sent from this raw water tank 1, and a system for precipitating heavy metal compounds from the raw water or emulsifying oil-containing wastewater in the raw water. a conditional chemical supply device 30 for injecting a chemical into the conditional tank 10 into the conditional tank 10, and a conditional raw water in the conditional tank 10 and the injected chemical; A stirring device for stirring and a flow path from the condition imparting tank 10,
a gas supply device 90 for injecting low-pressure (0.1 to 0.2 Kg/m ³ ) gas into the conditioned raw water from the conditioned tank; a pump that generates foamy scum by mixing with gas injected from the pump and sends the foam at a low speed that does not destroy the foamy scum; A flotation separation system chemical supply device 60 that injects a chemical to promote scum formation of various flocs generated in the application tank 10.
The conditioned raw water sent out by the pump from the flow path is circulated in a circular motion to cause the liquid to flow outward in the radial direction due to the difference in specific gravity, and to collect the foam scum in the center, so that the buoyant force causes the conditioned raw water to circulate in a circular motion. A purification device comprising: at least one flotation separation cyclone which floats and separates foamy scum from a liquid to the upper part; and a scum dehydration tank 110 which further separates liquid from the foamy scum overflowing from the upper part of the flotation separation cyclone.