JPH05111683A - Flotation equipment for polluted material of waste water - Google Patents

Abstract

PURPOSE:To provide the flotation device which has the good sepn. efficiency of the BOD, SS and hexane extracts of the treating waste water of kitchens, etc. and is simple in the constitution. CONSTITUTION:This flotation device has a separating chamber having a mixing chamber 7 for the polluted material-contg. waste water and pressurized air- mixed water and a clean water forming chamber 14 segmented by an inclined partition plate by a vertical type partition plate 12 bent in the upper part and a means for supplying the pressurized air. The device includes a connecting pipe having the mixing chamber 7 and the clean water forming chamber 14 as an inlet and the mixing chamber as an outlet, a means for removing the flotation layer on the water surface, a treating waste water supplying pipe connected to the mixing chamber and a clean water discharge pipe.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for floating and separating contaminants contained in waste water, that is, solid matters, suspended matters, surfactants and the like. In the specification of the present application, drainage refers to wastewater containing solid substances such as wastewater from kitchens and factory wastewater, suspended solids, and contaminants such as surfactants.

[0002]

2. Description of the Related Art These wastewaters are discharged as harmless substances by removing the contents by various purifying devices. However, if the wastewater is discharged to the sewer system, for example, the terminal treatment facility must have the capacity to respond. Therefore, it is required to reduce pollutants contained in each wastewater to a certain extent. For example, in Tokyo, the allowable water quality for these drainages is specified as follows. BOD 600 mg / liter SS 600 mg / liter Normal hexane extract 30 mg / liter pH 5-9 That is, the waste water discharged to the sewer system needs to reduce the amount of pollutants in advance. The present invention relates to a flotation / separation device for pollutants contained in wastewater to achieve the above object. Known typical floating separation devices have a structure in which the whole amount or a part of the wastewater is pressurized in a separation tank into which the wastewater is introduced. In these devices, air generated by pressurization (mainly oxygen) Saturated water is not used, the amount of supply air for pressurization is increased, the amount of insoluble air (substantially nitrogen) is increased, and a separation means is also required to discharge these. As an example of this device, bubbles are generated by blowing pressurized air into the target wastewater, and the bubbles are adsorbed to the solid matter (flock) generated by the coagulation treatment of the pollutants in the wastewater. An example is one having a structure in which the specific gravity of the volume is lightened to cause the solids to float.
In this device, air must be sufficiently dissolved in the water of interest. Therefore, the tank is usually of a pressurized structure, and air is added to the water in the tank at a pressure of 3 to 5 Kgf / cm ² by a compressor or the like to excessively feed the air to melt under pressure. Excess air is exhausted from an air exhaust valve provided at the top of the tank.

[0003]

In these devices, water is retained in the tank for 3 to 5 minutes, during which the amount of air reaching the equilibrium with the pressure of air sent from the compressor is dissolved in the water. To pressurize the tank to withstand the pressure,
There was a problem that it had to be manufactured with special specifications. Further, as described above, the pressurized air-saturated water is not reused and a large amount of air is required for pressurization, so that the apparatus is inevitably increased in size. Further, when the wastewater contains a surfactant, for example, a bubbling phenomenon occurs.
Therefore, the surface of the wastewater may be covered with bubbles, and a phenomenon may occur in which the contaminants cannot be sufficiently separated from the wastewater. Therefore, in practical use, there is a strong demand for the development of a device that is small in size and that can smoothly remove pollutants even if a bubbling phenomenon occurs.

[0004]

The present inventors have completed the present invention as a result of research and development in order to meet the above demands. The present invention is a separation tank, a mixing chamber of waste water and pressurized mixed water in the separation tank,
It has a vertical partition plate with its upper end facing the mixing chamber and a pressurized air supply means, which is provided to be divided into a clean water generating chamber, an inlet to the clean water generating chamber, and an outlet to the mixing chamber. A connection pipe for feeding the clean water provided as pressurized mixed water to the mixing chamber, a device for removing the solid surface layer and the floss layer of the water surface provided on the water surface in the separation tank The present invention relates to a floatation / separation device for wastewater pollutants including a wastewater supply pipe containing pollutants and a clean water discharge pipe.

Next, the present invention will be described with reference to the schematic explanatory drawing 1 showing a typical structure of the flotation device of the present invention. Figure 1
In the figure, 1 is a separation tank, and a vertical partition plate 12 is provided in the tank.
Is provided and is divided into a mixing chamber 7 and a clean water generating chamber 14. The upper part of the vertical partition plate is structured to face the mixing chamber. The upper end of this structure may be bent or may be arcuate. This shape may be such that the mixed water forms a solid-liquid sorting zone as described later. The clean water producing chamber 14 and the mixing chamber 7 are connected by a connecting pipe having a pressurized air supply means shown below. That is, clean water generation room 1
A suction pipe 21 connected to the pressurizing pump 2 is connected to 4, which is connected via an air supply pipe 5 coming from an air holder 4 equipped with an air compression compressor 3 and a primary air supply pipe 26. Connected.

The outlet side of the pressurizing pump 2 is connected to an air-fuel mixture pipe 22 that opens into the mixing chamber 7. The pipe is provided with an ejector 6 for mixing water and air, and the ejector 6 is connected with a secondary air supply pipe 27 which is another pipe connected to the air supply pipe 5. An electromagnetic valve 8 is provided on the air supply pipe 5 on the outlet side of the compressor 3, and a check valve 9, 9'for adjusting the flow rate and a flow meter 10, 10 are provided on the primary air supply pipe 26 and the secondary air supply pipe 27, respectively. ′ 、 Needle valve 1
1, 11 'and the like, and the mixture water pipe 22 is provided with a pressure reducing valve 19. Reference numeral 24 denotes a pollutant-containing drainage pipe whose end 25 opens into the mixing chamber 7 of the separation tank 1.

A scraping machine 1 for removing a solid matter layer, an oil layer and a froth layer formed on the water surface on the surface of the separation tank 1.
5, scrap material receiver 16, further scrap material discharge pipe 17,
A clean water discharge pipe 18 is provided.

A method of operating the device of the present invention will be described below. First, the separation tank 1 is filled with water up to a predetermined level (the water introducing means is not a special device, so it is not shown). Next, the pressurizing pump 2 is started, water is sucked from the clean water generation chamber 14 of the separation tank 1, the air compression pipe compressor 3 is operated, and mixed air is passed through the ejector 6 to the end of the pipe 22. 23 is fed into the mixing chamber 7 in the separation tank 1. By such an operation, the air-mixed water in which the air is mixed is circulated from the clean water generating chamber 14 to the mixing chamber 7 and further to the clean water generating chamber 14.
After this circulation is stabilized, the pollutant-containing wastewater is introduced from the end 25 of the drainage pipe 24.

The waste water and the above-mentioned mixed air are mixed in the mixing chamber 7. That is, a gas-liquid mixing zone is formed. In this case, the air-mixed water is pressurized, and while violently impacting the vertical partition plate 12 while being mixed with the drainage, it rises along the partition plate surface. The upper end of the partition plate faces the mixing chamber side, and the mixed water circulates in the direction indicated by arrow a. Since the mixed water flows in this way,
Kinetic energy is given to the ascending mixed water in the tangential direction, and the solid matter is separated from the mixed water based on the principle of centrifugal force that "the heavier the water is, the more it moves to the outside". To do. Next, an oil layer with less bubbles is formed, and a layer having the smallest specific gravity, for example, a bubble layer made of a surfactant or the like is formed under the oil layer. This phenomenon is based on the same principle as debris flow formation. As is clear from the above description, a solid-liquid sorting zone is formed near the upper part of the partition plate of the mixing chamber, and the bubbling phenomenon on the water surface can be suppressed even if the surface-active agent is contained in the waste water. The layer formed on the water surface covers the entire surface of the water and does not dissipate the air in the water to the outside of the system. On the other hand, the scraper 15 is moved on the water surface to remove the solid matter layer, the oil layer and the floc layer. The liquid purified by removing the solids layer, oil layer, and floc layer is the clean water generation chamber 14
To the outside of the system through the clean water outlet 18. Further, flocs, oil, solid matter, etc. move to the scraped material receiver 16 and are then discharged from the scraped material discharge pipe 17 to the outside of the system. Then, part of the clean water is sucked through the suction pipe 21 and circulates in the mixing chamber as mixed air. In the device of the present invention, the efficiency of the flotation device is greatly affected by the partition plate and the mixing of the air-mixed water and the waste water in the mixing chamber. The relative arrangement structure of the mixed water supply pipe and the drain pipe in the mixing chamber for keeping this mixing in the optimum state is shown below.

FIG. 2 is an example showing a relative relationship between the drain pipe 24, the same end portion 25, the mixed water pipe 22, and the same end portion 23 in the mixing chamber 7. In the figure, 29 and 28 are small holes provided at the respective ends. FIG. 3 is a schematic cross section showing the relative position of each small hole. The small hole opens downward in the drain pipe and laterally in the mixed water pipe. The small hole 29 at the end of the drainage pipe is located above the small hole 28 at the end of the mixed water pipe, and the mixed water collides laterally with the drainage flowing out downward, so that the two easily mix. , The mixing is extremely smooth. And the mixed water is the vertical partition plate 1.
2 violently collides with 2 to form the gas-liquid mixing zone and the solid-liquid sorting zone as described above, and the pollutants in the waste water are separated.

Since the liquid circulates in the mixing chamber as described above and the pollutants in the wastewater are substantially floated and separated in the process, the liquid flowing over the partition plate 12 into the clean water generating chamber 14 is discharged. Is cleaned. By adjusting the flow rate of the mixed water, the air content rate, the flow rate of the waste water, etc., the desired cleaning rate can be obtained. If necessary, the cleanliness can be further increased by appropriately providing partition plates 12 ', 12 "and the like in the clean water generating chamber. Next, the behavior of water when these partition plates are provided will be described. Between the plate 12 and the partition plate 12 ', some water is introduced into the suction pipe 21. If this water is saturated with oxygen and further contains air that is not soluble in water (actually nitrogen), the partition The solid matter is separated by the plate 12 ', and the partition plate 12''further separates air contained in a small amount. That is, the efficiency of cleaning the wastewater is increased.

Next, the scraping machine will be described with reference to FIGS. In FIG. 4, the rotation band of the scraping machine 15 having the scraper 30 moves to scrape off the floating material layers 20 such as the solid material layer, the oil layer, and the floss layer that are floated and separated on the water surface in the separation tank, and the scraping inclined plate. After passing through 31, the scraped object receiver 16 is dropped. At this time, the levitated object may partially return in the opposite direction from between the scraper and the inclined plate at the inclined portion and may not be completely scraped. Therefore, by adopting the structure shown in FIG. 5, it is possible to prevent the above-mentioned floating object from returning.

That is, as shown in FIG. 5, the inclined plate 32 is made of a spring material such as a labyrinth packing, and when the floating object scraped off reaches the inclined plate 32 by the scraper 30, the inclined plate has its spring property. As a result, when the weight of the levitated material layer collected is lowered as shown at 32 ', there is no gap between the material and the spring type inclined plate, so that the floss is discharged to the scraped material receiver without returning. It At this time, since the floss is discharged together with a certain amount of water, it is possible to prevent clogging of the discharge pipe. In the device of the present invention, a coagulant or the like is added to the pollutant-containing wastewater in advance, the pH is further adjusted and introduced, and if combined with these devices, the wastewater can be treated extremely smoothly. Full automation is also easy.

[0014]

In the flotation / separation device of the present invention, the mixed liquid of the waste water and the pressurized mixed water first rises along the vertical partition plate.
At the upper end slope, kinetic energy is applied in the tangential direction, and the solid matter is separated from the mixed water by the principle of centrifugal force that “the heavier ones move outwards”, forming the floating uppermost layer on the water surface, and then forming bubbles. A layer of a surfactant or the like is formed below the difficult oil layer. It is considered that this phenomenon is similar to the debris flow formation, and the bubbling phenomenon can be suppressed even if the surfactant and the like are contained in the treated wastewater. Rotational energy is added to the pressurized mixed water along the tangent line of the partition plate for efficient zoning. As is well known, the pressure floating separation is intended to float and separate solid matter in wastewater with air. That is, air is blown into the waste water to contain (saturate) the oxygen in the water, and normally excess oxygen and nitrogen are released to the atmosphere. The composition of air is about 21% oxygen, about 78% nitrogen, and about 1% other, and oxygen has a high solubility in water,
The solubility of nitrogen is very low. In the apparatus of the present invention, the clean water generating chamber and the mixing chamber are connected by a connecting pipe having a pressurized air supply means, and the solid layer is formed on the entire surface of the water layer as described above.
Since an oil layer or the like is formed and air is not dissipated, nitrogen in the clean water generation chamber is reused. That is, energy is reused, the amount of air used is minimized, and running costs are reduced. Further, the pressurized air-mixed water and the water-mixed water can always be kept in a gas supersaturated state.

[0015]

EFFECTS OF THE INVENTION The feature is that the separation efficiency of BOD, SS, n-hexane extract in the wastewater from the kitchen or the like is high with a simple facility, and the efficiency does not decrease even if the surfactant is included. There is. Therefore, the discharge water of each device can be easily made below the discharge reference value. Further, unlike the conventional flotation device, since excess air is not exhausted and is circulated and used as mixed air, it is extremely easy to downsize the device.

[0016]

EXAMPLES Next, the results of floating separation of waste water by the apparatus of the present invention will be described by way of examples. Example Equipment used Separation tank Length 600 mm, width 400 mm, depth 5
00mm Target wastewater (restaurant wastewater) Content content (ppm) Raw water BOD 650 mg / liter SS 600 mg / liter Normal hexane extract 250 mg / liter pH 4.5 to 8.6 Pressure at the pump outlet side of mixed water 5. 5 to 6.0 kg
f / cm ² wastewater inflow 0.3 m ³ / h Admission water circulation rate 0.13 m ³ / h water temperature air amount in water at 23 to 25 ° C. was kept at 100 ppm. As a result, clean water shown in the following table was obtained. BOD 84 mg / liter SS 30 mg / liter Normal hexane extract 7.5 mg / liter pH 6.9 to 7.6 Removal rate is BOD 87% SS 95% Normal hexane extract 97% In addition, this value was shown previously in Tokyo. It meets the city's standards for sewer water supply.

[Brief description of drawings]

FIG. 1 is a schematic explanatory view showing a typical configuration of a flotation device of the present invention.

FIG. 2 is a view showing a relative relationship between a drain pipe and an air-fuel mixture pipe in a mixing chamber of a separation tank.

FIG. 3 is a view showing the relative positions of small holes at the ends of the drainage pipe and the mixed water pipe.

FIG. 4 is a diagram showing a configuration of a scraping machine for a floating material tank.

FIG. 5 is a diagram showing a configuration for preventing the scrape-back of the scraper of the floating object tank from returning.

[Explanation of symbols]

1 Separation Tank 2 Pressurizing Pump 3 Air Compressor 4 Air Holder 5 Air Supply Pipe 6 Ejector 7 Mixing Chamber 8 Solenoid Valve 9 Check Valve 9'Check Valve 10 Flow Meter 10 'Flow Meter 11 Needle Valve 11' Needle Valve 12 vertical partition plate 12 'vertical partition plate 12 "vertical partition plate 14 clean water generating chamber 15 scraping machine 16 scraping material receiver 17 scraping material discharging pipe 18 clean water discharging pipe 19 pressure reducing valve 20 floating material layer 21 Suction pipe 22 Mixed water pipe 23 Same end 24 Drain pipe 25 Same end 26 Primary air supply pipe 27 Secondary air supply pipe 28 Mixed air water pipe end small hole 29 Drain pipe end small hole 30 Scraper 31 Slope for scraping Plate 32 Spring-like scraping inclined plate 32 'Spring-like scraping inclined surface (deformed state)

Claims (1)

[Claims] 1. A separation tank, a mixing chamber for mixing wastewater containing pollutants and pressurized mixed water in the separation tank, and a clean water generating chamber, the upper end of which faces the mixing chamber. A vertical partition plate and a pressurized air supply means are provided, and the inlet is supplied to the clean water generation chamber and the outlet is provided to the mixing chamber. Connecting pipe, device for removing solid matter surface layer of water surface provided on the water surface in the separation tank, floss layer, levitation separation device for wastewater pollutants including pollutant-containing wastewater supply pipe and clean water discharge pipe ..