JP4619971B2 - Waste water treatment method and waste water treatment equipment - Google Patents

Description

  The present invention relates to a wastewater treatment method and a wastewater treatment apparatus, and more particularly to a treatment method and a treatment apparatus for organic fluorine compound-containing wastewater.

  An organic fluorine compound, which is an example of a compound contained in water to be treated that is an object of water treatment, is a chemically stable substance. In particular, this organic fluorine compound has excellent properties from the viewpoint of heat resistance and chemical resistance, and is therefore used for applications such as surfactants.

  However, since this organic fluorine compound is a chemically stable substance, it is difficult to decompose microorganisms. For example, perfluorooctasulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) as the organic fluorine-based compounds are concerned about the influence on the ecosystem because degradation does not proceed in the ecosystem.

  That is, the above-mentioned perfluorooctasulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) are chemically stable, and it is said that a high temperature of about 1000 ° C. or higher is necessary for complete thermal decomposition. . Moreover, PFOS and PFOA were extremely difficult to decompose by treatment with conventional microorganisms or photocatalysts.

  By the way, as a conventional technique, a method and an apparatus for using nanobubbles are described in Japanese Patent Application Laid-Open No. 2004-121962.

  In this conventional technology, characteristics such as a decrease in buoyancy, an increase in surface area, an increase in surface activity, generation of a local high-pressure field, and a surface active action and a bactericidal action by realizing electrostatic polarization are utilized. More specifically, in this prior art, by interlinking them, various objects can be washed with high functionality and low environmental load by the adsorption function of dirt components, the high-speed cleaning function of the object surface, and the sterilization function. It is disclosed that it is possible to purify polluted water.

  As another conventional technique, a method for generating nanobubbles is described in Patent Document 2 (Japanese Patent Laid-Open No. 2003-334548).

  In this conventional technique, in a liquid, (1) a step of decomposing and gasifying part of the liquid, (2) a step of applying ultrasonic waves in the liquid, or (3) a step of decomposing and gasifying part of the liquid And a process of applying ultrasonic waves.

  As another conventional technique, a waste liquid treatment apparatus using ozone microbubbles is described in Patent Document 3 (Japanese Patent Laid-Open No. 2004-321959).

  In this prior art, ozone gas generated from the ozone generator and waste liquid extracted from the lower part of the treatment tank are supplied to the microbubble generator via a pressure pump. Moreover, this prior art discloses that the generated ozone microbubbles are vented into the waste liquid in the treatment tank through the opening of the gas blowing pipe.

However, the above-described conventional technology cannot effectively microbially decompose the organic fluorine compound.
JP 2004-121962 A JP 2003-334548 A JP 2004-321959 A

  An object of the present invention is to provide a wastewater treatment method and a wastewater treatment apparatus that can effectively microbially decompose an organic fluorine compound.

In order to solve the above-mentioned problem, the wastewater treatment method according to the present invention introduces micro-nano bubbles into water to be treated, which is a mixture of rapidly filtered organic fluorine compound-containing wastewater and water containing microorganisms. A method of bringing the treated water into contact with activated carbon after activating the microorganism, adsorbing the organic matter in the treated water onto the activated carbon, and decomposing the organic matter adsorbed on the activated carbon with the activated microorganism And

  According to this method, the hardly decomposable organic substance in the water to be treated is adsorbed and removed by activated carbon, and the microorganisms activated by the micro-nano bubbles decompose the adsorbed hardly decomposable organic substance on the activated carbon. For this reason, activated carbon can be self-regenerated and the regeneration of activated carbon is not necessary.

In addition, according to this method, suspended solids in the treated water are removed to prevent clogging of the activated carbon, and the organic fluorine compound and microorganism concentration are maintained in an appropriate range to completely decompose the organic fluorine compound. be able to.

Further, the wastewater treatment apparatus according to the present invention includes a rapid filter for rapidly filtering organic fluorine compound-containing wastewater , the organic fluorine compound-containing wastewater filtered by the rapid filter, and water containing microorganisms, and the organic A bubble generation tank equipped with a micro / nano bubble generating device for storing treated water obtained by mixing fluorine compound-containing wastewater and water containing microorganisms and introducing micro / nano bubbles into the treated water to be stored, and filled with activated carbon the treated water from the bubble generation tank containing the micro-nano bubbles are assumed to have the activated carbon adsorption tower to be supplied.

  According to this configuration, the hardly decomposable organic matter in the treated water is adsorbed on the activated carbon of the activated carbon adsorption tower, and the microorganisms in the treated water activated by the micro-nano bubbles decompose the hardly degradable organic matter adsorbed on the activated carbon. can do. As a result, the organic fluorine compound in the water to be treated can be completely removed. Furthermore, the activated carbon can be self-regenerated by decomposing the hardly decomposable organic matter adsorbed on the activated carbon, and the regeneration of the activated carbon is unnecessary.

In addition, according to this configuration, suspended solids in the treated water are removed to prevent clogging of the activated carbon, and the organic fluorine compound and microorganism concentration are maintained in an appropriate range to completely decompose the organic fluorine compound. be able to.

  Moreover, in the wastewater treatment apparatus of the present invention, the activated carbon adsorption tower may be further filled with a packing in an adsorption tower in which microorganisms can stay, and the packing in the adsorption tower may be made of polyvinylidene chloride. It is good to form in a string shape or a ring shape.

  According to this configuration, the organic fluorine compound adsorbed on the activated carbon can be effectively decomposed by causing a large amount of microorganisms to propagate in the packing in the adsorption tower and transferring the microorganism from the packing in the adsorption tower to the activated carbon.

  Moreover, the waste water treatment apparatus of this invention WHEREIN: The said bubble generation tank may further be equipped with the filling in a bubble generation tank which consists of a ring-shaped polyvinylidene chloride.

  According to this structure, a processing capability increases by breeding the microorganisms in biologically treated water on the filling in a bubble generation tank.

  In the wastewater treatment apparatus of the present invention, a part of the water to be treated flowing out from the activated carbon adsorption tower may be circulated to the bubble generation tank.

  According to this configuration, the water to be treated is circulated between the bubble generation tank and the activated carbon adsorption tower to return the microorganisms whose activity has been reduced by decomposing the organic matter adsorbed on the activated carbon to the bubble generation tank, It can be reactivated with nanobubbles and introduced into the activated carbon adsorption tower. As a result, it is possible to promote the decomposition of the organic fluorine compound adsorbed on the activated carbon by supplying a large amount of microorganisms through the activity.

  In the wastewater treatment apparatus of the present invention, part of the water to be treated flowing out from the activated carbon adsorption tower may be circulated upstream of the bubble generation tank.

  According to this configuration, by introducing the water to be treated containing microorganisms upstream of the bubble generation tank, the decomposition of the organic fluorine compound in the water to be treated proceeds before being introduced into the activated carbon adsorption tower, and the activated carbon adsorption The processing time can be improved by shortening the time required for decomposing the organic fluorine compound in the tower.

Also, waste water treatment apparatus of the present invention, storing the inclusive wash water microorganisms, the water tank unit including a micro-nano bubble generator for introducing the micro-nano bubbles in the washing water, provided above the water tank unit, wherein the bubble The exhaust gas discharged from the treated water stored in the generation tank is inserted, and the exhaust gas further includes an exhaust gas treatment tower including a sprinkling part for circulating and spraying the cleaning water stored in the water tank part. Also good.

According to this arrangement, the exhaust gas containing fluorine discharged from the water to be treated, by spraying wash water containing microorganisms was collected by dissolve the fluorine and organic matter in the exhaust gas to the wash water, the exhaust gas It can be purified. Furthermore, by introducing micro-nano bubbles in the wash water, can be decomposed by microorganisms activation was recovered by dissolve in wash water organics.

Further, in the waste water treatment apparatus of the present invention, the water tank part may be provided with a filling in the water tank that is retained in the washing water and in which microorganisms can stay, and the filling in the water tank is a string or ring. It may be in the form of polyvinylidene chloride.

  According to this structure, microorganisms propagate in the water tank filling, and the exhaust gas purification ability can be enhanced.

  The waste water treatment apparatus of the present invention may further include a relay tank that introduces treated water flowing out from the activated carbon adsorption tower and separates the exhaust gas from the treated water.

  According to this configuration, in the relay tank, the exhaust gas discharged from the treated water flowing out from the activated carbon adsorption tower is sucked and purified by the exhaust gas treatment tower, so that the exhaust gas is not sent to the next process.

  Moreover, the waste water treatment apparatus of this invention WHEREIN: The said relay tank may be equipped with the micro nano bubble generation apparatus which introduces a micro nano bubble to the said to-be-processed water.

  According to this configuration, even when the organic fluorine compound cannot be completely removed by the activated carbon adsorption tower, the microorganism activated by the micro / nano bubbles decomposes in the relay tank without leaving the organic fluorine compound remaining in the water to be treated. To do.

  In the wastewater treatment apparatus of the present invention, the relay tank may further include a filling in the relay tank that is held in the water to be treated and in which microorganisms can stay, and the filling in the relay tank has a string shape. Alternatively, it may be ring-shaped polyvinylidene chloride.

  According to this structure, the ability to propagate microorganisms in the relay tank and decompose the organic fluorine compound can be improved.

Moreover, the waste water treatment apparatus of this invention WHEREIN: The said bubble generation tank and the said activated carbon adsorption tower may be formed with lightweight resin, and may be fixed on a common base.

  According to this configuration, the wastewater treatment apparatus can be transported without being disassembled, and can be provided at a low cost.

  According to the present invention, the organic fluorine compound is adsorbed with activated carbon, and the organic fluorine compound adsorbed on the activated carbon is decomposed by microorganisms activated with micro-nano bubbles, so that the organic fluorine compound in the water to be treated can be completely decomposed. .

Embodiments of the present invention will now be described with reference to the drawings.
In FIG. 1, the waste water treatment apparatus of 1st Embodiment of this invention is shown. In this wastewater treatment apparatus, a rapid filter 2, a bubble generation tank 3, an activated carbon adsorption tower 4, a relay tank 5, and an exhaust gas treatment tower 6 each formed of a lightweight resin are fixed on a base 1, and wastewater treatment is performed. It is possible to carry it by truck without disassembling the device.

  The rapid filter 2 is filled with anthracite, which is a coal-based filter material. The rapid filter 2 removes suspended matter from the organic fluorine compound-containing wastewater supplied from the raw water tank 7 storing the organic fluorine compound-containing wastewater through the valve 9 through the valve 9 at a predetermined flow rate, and filtered. The contained waste water is supplied to the bubble generation tank 3.

  In the bubble generation tank 3, biologically treated water containing microorganisms is introduced as treated water in addition to the organic fluorine compound-containing wastewater. The biologically treated water does not have to be discharged from the same facility as the organic fluorine compound-containing wastewater.

  The bubble generation tank 3 is a sealed water tank including a micro / nano bubble generation apparatus 10 that introduces micro / nano bubbles into water to be treated. The micro / nano bubble generating apparatus 10 sucks out the water to be treated in the bubble generation tank 3 by the circulation pump 11 and injects it into the micro bubble generator 12, and the micro bubble generator 12 uses the flow rate of the water to be treated through the control valve 13. The self-supplied air is sheared to generate micro / nano bubbles (fine bubbles), and the micro / nano bubbles generated from the micro / nano bubble generator 12 are discharged into the bubble generation tank 3 together with the water to be treated. The micro / nano bubble generating apparatus 10 not only introduces micro / nano bubbles into the water to be treated in the bubble generating tank 3 but also forms a water flow for stirring the water to be treated, and mixes the organic fluorine compound-containing waste water and the biologically treated water. Also fulfills the function to do.

  The pump 14 introduces the water to be treated containing the micro / nano bubbles in the bubble generation tank 3 to the top of the activated carbon adsorption tower 4 through the valve 15. The activated carbon adsorption tower 4 has an activated carbon layer 16 filled with activated carbon. As the activated carbon, for example, coconut husk activated carbon is applied, but other types of activated carbon such as coal-based may be used, and an optimum one may be selected depending on the quality of water to be treated and the amount to be treated.

  The water to be treated flowing out from the bottom of the activated carbon adsorption tower 4 is introduced into the relay tank 5 through the valve 17 and once stored, it flows out to the next step. A part of the water to be treated flowing out from the activated carbon adsorption tower 4 is circulated to the bubble generation tank 3.

  The bubble generation tank 3 and the relay tank 5 are both sealed water tanks, but are respectively provided with exhaust ducts 19 and 20 for sucking exhaust gas discharged from the water to be treated. It is introduced into the tower 6.

The exhaust gas treatment tower 6 is integrally provided above the water tank part 22 and the water tank part 22 for storing cleaning water made of biologically treated water containing microorganisms, and the water tank part 22 to the exhaust gas introduced by the exhaust fan 21 from below. And a sprinkling section 23 for spraying the cleaning water .

The water tank 22 is replenished with biologically treated water containing microorganisms from the ball tap 24 so as to keep the amount of water stored constant. Moreover, the micro nano bubble generator 25 which introduces a micro nano bubble to the wash water to store is provided. The micro / nano bubble generator 25 includes a circulation pump 26, a micro / nano bubble generator 27, and a control valve 28, as in the micro / nano bubble generator 10.

The water sprinkling unit 23 is provided with a plastic filler 30 on a perforated plate 29 serving as a bottom plate, and the washing water pumped from the water tank unit 22 by the submerged pump 31 against the exhaust gas rising through the gap of the plastic filler 30. A water-filling nozzle 32 that waters from above is provided.

Then, the effect | action of the waste water treatment equipment which consists of the above structure is demonstrated.
In the bubble generation tank 3, by introducing micro-nano bubbles, microorganisms contained in the biologically treated water are activated and decompose organic substances in the treated water. Since the organic fluorine compound cannot be easily decomposed, it is sent to the activated carbon adsorption tower 4 by the pump 14 and adsorbed on the activated carbon layer 16.

  The activated carbon layer 16 that has adsorbed the organic fluorine compound is supplied with water to be treated containing microorganisms activated by micro-nano bubbles from one to the next, so that the organic fluorine compound adsorbed on the activated carbon is gradually decomposed. . When the adsorbed organic fluorine compound is decomposed, the activated carbon becomes a state where the organic fluorine compound can be adsorbed again.

  Conventionally, activated carbon that adsorbs organic matter has been required to be manually regenerated because its adsorption capacity is reduced. In the present invention, suspended matter is removed by the high-speed filter 2 to prevent clogging of the activated carbon. At the same time, the activated microorganism decomposes the organic fluorine compound adsorbed on the activated carbon in the activated carbon adsorption tower 4, so that the activated carbon can be self-regenerated and no regeneration work is required.

  In order to maintain the activity of microorganisms in the activated carbon, it is effective to increase the circulation amount of microorganisms by increasing the flow rate of water to be treated that is returned to the bubble generation tank 3 through the valve 18. That is, it is preferable to return the microorganisms whose activity has decreased in the activated carbon adsorption tower 4 to the bubble generation tank 3 and supply the microorganisms activated again by the micro-nano bubbles to the activated carbon adsorption tower 4.

In addition, fluorine gas is generated by the decomposition of the organic fluorine compound, but the fluorine gas flows out from the bottom of the activated carbon adsorption tower 4 together with the water to be treated into the bubble generation tank 3 and the relay tank 5 and is exhausted by the exhaust fan 21. 19 and 20 are introduced into the exhaust gas treatment tower 6. Fluorine was dissolve in the wash water by spraying wash water in the nozzle unit 23 and recovered. Thus, by actively sucking the fluorine gas in the relay tank 5, the fluorine gas is not released to the outside air in the next step.

Further, the washing water is recovered by dissolving organic substances contained in the exhaust gas. By introducing micro-nano bubbles to the tub portion of the exhaust gas treating tower 6, the organic material remaining in the wash water was completely decomposed, it can be easily brought dissolve the fluorine gas and organics to the wash water.

  In the next step, as a method for treating wastewater in which fluorine is dissolved, treatment by a chelate resin tower and coagulation sedimentation treatment by addition of a calcium agent are known, and are selected according to the fluorine concentration of water to be treated.

  Furthermore, FIG. 2 shows a wastewater treatment apparatus according to a second embodiment of the present invention. In the following description, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  The activated carbon adsorption tower 4 of the present embodiment is filled with a packing 33 in the adsorption tower made of polyvinylidene chloride formed in a ring shape on the activated carbon layer 16. As a result, microorganisms stay in the adsorption column packing 33 and propagate to a high concentration, and the microorganisms with a high concentration move to the activated carbon layer 16 due to the flow of the water to be treated, and the organic fluorine adsorbed on the activated carbon. Decomposes compounds quickly.

  In order to supply high-concentration microorganisms to activated carbon, it is effective to fill the adsorption tower packing 33 on the upper part (upstream side) of the activated carbon layer 16 as in this embodiment.

  FIG. 3 shows a third embodiment of the present invention. In the present embodiment, instead of the adsorption tower packing 33 in the second embodiment, an adsorption tower packing 34 made of polyvinylidene chloride formed in a string shape on the activated carbon adsorption tower 4 is packed. Such a string-like adsorption tower packing 34 can also propagate microorganisms at a high concentration and promote the decomposition of the organic fluorine compound.

  FIG. 4 shows a fourth embodiment of the present invention. In this embodiment, the bubble generation tank filling 35 made of polyvinylidene chloride formed in a string shape in the water to be treated of the bubble generation tank 3 is held. As a result, microorganisms stay on the filling 35 in the bubble generation tank and propagate, thereby increasing the concentration of microorganisms in the bubble generation tank 3 and consequently the concentration of microorganisms introduced into the activated carbon adsorption tower 4 and being adsorbed on the activated carbon. Promotes the decomposition of organic fluorine compounds.

  FIG. 5 shows a fifth embodiment of the present invention. In the present embodiment, the water to be treated that has flowed out of the activated carbon adsorption tower 4 is further diverted by the valves 36 and 37 and introduced into the raw water tank 7 a that stores the organic fluorine compound-containing wastewater further upstream of the bubble generation tank 3. Is. The raw water tank 7a has a sealed structure, and is provided with an exhaust duct 38 for sucking exhaust gas generated from the organic fluorine compound-containing wastewater by the fan 21.

  In the present embodiment, a part of the organic matter in the organic fluorine compound-containing wastewater is decomposed in the raw water tank 7a by introducing microorganisms derived from biologically treated water into the raw water tank 7a. Thereby, decomposition | disassembly of an organic fluorine compound can be advanced before introduce | transducing into the activated carbon adsorption tower 4, the time which stays in the activated carbon layer 16 can be shortened, and processing capacity can be improved.

  FIG. 6 shows a sixth embodiment of the present invention. In the present embodiment, a micro / nano bubble generating device 39 for introducing micro / nano bubbles into the relay tank 5 is provided. The micro / nano bubble generator 39 includes a circulation pump 40, a micro / nano bubble generator 41, and a control valve 42, similarly to the micro / nano bubble generators 10 and 25 of the above-described embodiment. In the present embodiment, even if the organic fluorine compound passes through the activated carbon layer 16 of the activated carbon adsorption tower 4 without being decomposed, it can be decomposed by microorganisms activated by micro-nano bubbles in the relay tank 5, and More advanced processing is possible.

  FIG. 7 shows a seventh embodiment of the present invention. In this embodiment, the relay tank 5 provided with the micro / nano bubble generating device 39 of the sixth embodiment is further filled with a filler 43 in the relay tank made of polyvinylidene chloride formed in a string shape held in the water to be treated. Is provided. As a result, microorganisms can stay in the relay tank filling 43 and can be propagated at a high concentration, so that the treatment capacity of the organic fluorine compound in the relay tank 5 is improved.

FIG. 8 shows an eighth embodiment of the present invention. This embodiment, the water tank 22 of the exhaust gas treating tower 6, in which the water tank filler 44 made of polyvinylidene chloride, which is formed in string-like retained in the washing water is provided. Thus, the water tank filler 44 bred high levels of microorganisms, organic matter remaining in the wash water was completely decomposed, can be easily brought dissolve the fluorine gas and organic substances in the water spray unit 23.

1 is a schematic view of a wastewater treatment apparatus according to a first embodiment of the present invention. Schematic of the waste water treatment apparatus of 2nd Embodiment of this invention. Schematic of the waste water treatment apparatus of 3rd Embodiment of this invention. Schematic of the waste water treatment apparatus of 4th Embodiment of this invention. Schematic of the waste water treatment apparatus of 5th Embodiment of this invention. Schematic of the waste water treatment apparatus of 6th Embodiment of this invention. Schematic of the waste water treatment apparatus of 7th Embodiment of this invention. Schematic of the waste water treatment apparatus of 8th Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Base 2 Rapid filter 3 Bubble generation tank 4 Activated carbon adsorption tower 5 Relay tank 6 Exhaust gas treatment tower 7,7a Raw water tank 10 Micro nano bubble generator 22 Water tank part 23 Sprinkling part 25 Micro nano bubble generator 33,34 Packing in adsorption tower 35 Filling in bubble generating tank 39 Micro-nano bubble generating device 43 Filling in relay tank 44 Filling in water tank

Claims (18)

Micronano bubbles are introduced into water to be treated, which is a mixture of rapidly filtered organic fluorine compound-containing wastewater and water containing microorganisms, to activate the microorganisms in the water to be treated, and then the treated water is brought into contact with activated carbon. Let
An organic matter in the water to be treated is adsorbed on the activated carbon, and the organic matter adsorbed on the activated carbon is decomposed by the activated microorganisms. A rapid filter for rapidly filtering organic fluorine compound-containing wastewater;
The organic fluorine compound-containing waste water filtered by the rapid filter and water containing microorganisms are introduced, and the treated water formed by mixing the organic fluorine compound-containing waste water and water containing microorganisms is stored and stored. A bubble generation tank equipped with a micro / nano bubble generator for introducing micro / nano bubbles into the water to be treated ;
A wastewater treatment apparatus comprising an activated carbon adsorption tower filled with activated carbon and supplied with the water to be treated containing the micro / nano bubbles from the bubble generation tank. The waste water treatment apparatus according to claim 2 , wherein the activated carbon adsorption tower is further filled with a packing in the adsorption tower in which microorganisms can stay. The waste water treatment apparatus according to claim 3 , wherein the packing in the adsorption tower is made of polyvinylidene chloride. The waste water treatment apparatus according to claim 3 or 4 , wherein the packing in the adsorption tower is formed in a string shape or a ring shape. The said bubble generation tank is further equipped with the filling in the bubble generation tank which consists of a string-like polyvinylidene chloride hold | maintained in the said to-be-processed water, The waste water treatment apparatus in any one of Claim 2 to 5 characterized by the above-mentioned. . Wastewater treatment device according to any one of claims 2 to 6, wherein a portion of the treated water flowing out of the activated carbon adsorption tower, characterized by circulating the bubble generation tank. Wastewater treatment device according to any one of claims 2 to 7, characterized in that a part of the treated water flowing out of the activated carbon adsorption tower, and reflux the upstream side of the bubble generation tank. A water tank unit equipped with a micro / nano bubble generator for storing washing water containing microorganisms and introducing micro / nano bubbles into the washing water ;
A watering part that is provided above the water tank part and through which the exhaust gas discharged from the water to be treated stored in the bubble generation tank is inserted, circulates and sprays the cleaning water stored in the water tank part to the exhaust gas. The waste water treatment apparatus according to any one of claims 2 to 8 , further comprising an exhaust gas treatment tower comprising: The waste water treatment apparatus according to claim 9 , wherein the water tank unit is provided in the water tank that is held in the washing water and in which microorganisms can stay. The waste water treatment apparatus according to claim 10 , wherein the filling in the water tank is string-like polyvinylidene chloride. The waste water treatment apparatus according to claim 10 , wherein the filling in the water tank is ring-shaped polyvinylidene chloride. The wastewater treatment apparatus according to any one of claims 9 to 12 , further comprising a relay tank that introduces treated water flowing out from the activated carbon adsorption tower and separates the exhaust gas from the treated water. The waste water treatment apparatus according to claim 13 , wherein the relay tank includes a micro / nano bubble generator for introducing micro / nano bubbles into the water to be treated. The waste water treatment apparatus according to claim 14 , wherein the relay tank further includes a filling in the relay tank that is held in the water to be treated and in which microorganisms can stay. The waste water treatment apparatus according to claim 15 , wherein the filling in the relay tank is a string-like polyvinylidene chloride. The waste water treatment apparatus according to claim 15 , wherein the filling in the relay tank is ring-shaped polyvinylidene chloride. The wastewater treatment apparatus according to any one of claims 2 to 17 , wherein the bubble generation tank and the activated carbon adsorption tower are formed of a lightweight resin and fixed on a common base.

Images