JP7009410B2 - Wastewater treatment method - Google Patents

Description

The present invention relates to factory wastewater and other wastewater treatment methods.

Conventionally, there has been a proposal regarding factory wastewater and other wastewater treatment mechanisms (Patent Document 1).
This wastewater treatment mechanism has an activated carbon adsorption tank for adsorbing contaminants in wastewater and an in-tank flow mechanism, supplies electrolytic water to the activated carbon adsorption tank, and uses the in-tank flow mechanism in the activated carbon adsorption tank. The wastewater and activated carbon are made to flow.
The flow in the tank reduces the number of stagnant parts in a certain place and can evenly exert the cleaning action of electrolyzed water on the activated carbon, so that it can be decomposed more efficiently than before. be.
On the other hand, there has been a further request to improve the purification efficiency of wastewater having an oil component and to cope with the consumption of activated carbon.

JP 2015-123442

Therefore, the present invention is intended to provide a wastewater treatment method capable of improving the purification efficiency of wastewater having an oil component and coping with the consumption of activated carbon.

In order to solve the above problems, the following technical measures are taken in the present invention.
(1) The wastewater treatment method of the present invention includes a step of adhering an oil component in wastewater by an adhering material, a step of adsorbing a dirt component in wastewater by an adsorbent, and a step of heating and activating the adsorbent of the dirt component. However, it is characterized in that the adhering material of the oil component is carbonized in the heating / activating step of the adsorbent of the dirt component.
Since this wastewater treatment method includes a step of adhering the oil component in the wastewater by the adhering material, the oil component in the wastewater, which is difficult to treat, can be reduced or removed by the adhering material. If the step of adhering the oil component in the wastewater by this adhering material is brought first, the processing load in the subsequent steps can be greatly reduced.

Further, since the step of adsorbing the dirt component in the wastewater by the adsorbent is provided, the dirt component in the drainage can be reduced by the adsorbent.
Then, since the adsorbent of the oil component is carbonized in the heating / activating step of the adsorbent of the dirt component, the adsorbent of the oil component is carbonized by utilizing the heat in the heating / activating step of the adsorbent. Can be done. Further, when the heated / activated adsorbent is reused, the carbide of the adsorbent is also activated at the same time by heating and can be used as the adsorbent.

Here, animal oil, vegetable oil, kerosene, A, B, C heavy oil, silicon oil and the like can be exemplified as the oil component. Examples of the adhering material include a filter medium made of PP (polypropylene) fiber, a polysulfone membrane, and the like. Activated carbon can be exemplified as the adsorbent.
Examples of the dirt component in the wastewater include organic substances, soluble COD components, ultrafine particles, and ss components. Specifically, MPA (3-methoxy-N, N-dimethylpropionic amide), citric acid, hydroxypropyl cellulose, PVA and the like can be exemplified. In addition, organic substances with a small molecular size, that is, ethylene glycol (HO-CH ₂ -CH ₂ -OH), propylene glycol, ethylene chlorohydrin (Cl-CH ₂ -CH ₂ -OH), propylene chlorohydrin, acetaldehyde ( CH ₃ -CHO), dioxins, etc. can be exemplified. Dioxins can be decomposed and detoxified by heating at 900 ° C. or higher for 3 hours in the heating / activating step. Further, it is possible to exemplify wastewater in which hydrophobic oils such as vegetable oil, animal oil, mineral oil and silicon oil are solubilized with a surfactant.
In the step of heating / activating the adsorbent of the dirt component, heating at 900 ° C. or higher for 3 hours can be exemplified, whereby the adsorbent can be activated / activated.

(2) The oil component may be floated by fine bubbles.
When the oil component is floated by fine bubbles in this configuration, the treatment efficiency in the oil component adhesion step is improved.
The diameter of the fine bubbles is approximately 40 μm to 1 mm, but it is preferable to adjust the diameter according to the properties and size of the oil component. Specifically, it can be adjusted by the angle of incidence of air with respect to the flow of water injected into the wastewater treatment tank. When the incident angle is shallow, the fine bubble diameter becomes large, and when the incident angle is deep, the impact force between the air and the water flow increases and the fine bubble diameter becomes small. For example, in the case of tar pitch having a large specific gravity as the content of the oil component, it is desirable to set a large fine bubble diameter in order to give sufficient buoyancy to the tar pitch.

The present invention has the above-mentioned configuration and has the following effects.
Since the oil component in the wastewater, which is difficult to treat, can be reduced or removed by the adhering material, it is possible to provide a wastewater treatment method capable of improving the purification efficiency of the wastewater having the oil component. ..
Further, since the carbide of the adhering material is also activated by heating and can be used as an adsorbent, it is possible to provide a wastewater treatment method capable of coping with the consumption of activated carbon.

The system flow diagram explaining the embodiment of the wastewater treatment method of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
As shown in FIG. 1, in the wastewater treatment method of this embodiment, the water quality of the wastewater raw water is measured by the sensor S-1 and via an automatic water sampling device (a fixed amount of sample is collected at regular time intervals). First, in the ss / oil component floating separation tank 1, the oil component was floated by fine bubbles.
As the oil component, animal oil, vegetable oil, kerosene, A, B, C heavy oil, silicon oil, and tar pitch were treated in a trace amount.

In addition, as the dirt component in the wastewater, those containing organic matter, soluble COD component, ultrafine particles, and ss component were treated. Wastewater containing MPA (3-methoxy-N, N-dimethylpropionamide), citric acid, hydroxypropyl cellulose and PVA as organic substances was treated. In addition, organic substances with a small molecular size, namely ethylene glycol (HO-CH ₂ -CH ₂ -OH), propylene glycol, ethylene chlorohydrin (Cl-CH ₂ -CH ₂ -OH), propylene chlorohydrin, acetaldehyde ( Wastewater containing CH ₃ -CHO) was treated.

The diameter of the fine bubbles is approximately 40 μm to 1 mm, but it was adjusted according to the properties and size of the oil component. That is, the diameter of the fine bubbles is adjusted by the angle of incidence of air with respect to the water flow injected from the fine bubble generation mechanism 2 into the ss / oil component floating separation tank 1. When the incident angle is shallow, the fine bubble diameter becomes large, and when the incident angle is deep, the impact force between the air and the water flow increases and the fine bubble diameter becomes small. When the oil component is a tar pitch with a large specific gravity, the fine bubble diameter is set to be large in order to give sufficient buoyancy to this.
Then, the drainage containing a large amount of levitation ss / oil component that overflows the ss / oil component levitation separation tank 1 (center of the figure) is allowed to flow down to the next electrolyzed water injection kneading tank 3 (stirred by the motor M) and regenerated adsorption. While adding the material with the spiral pump SP7, the electrolyzed water was injected from the electrolyzed water tank with the pump P3 to deodorize.

Activated carbon was used as the adsorbent in this embodiment.
The electrolyzed water was generated by the electrolysis mechanism E. As the electrical action on the wastewater, the electron e- transfer action to the dirt component in the drainage by passing an electric current, the oxidation action by electrolytic chlorine, hydrogen peroxide, radicals, etc., and the adjustment of the particle size of the dirt component by applying an electric current. There is an action and so on.

Next, the spiral pump SP10 was used to transfer the oil component to the step of adhering the oil component in the wastewater (composed of the oil component adhering separation tank 5) by the adsorbent 4 (different from the above-mentioned “adsorbent”). As the adhesive material 4, a strip-shaped filter medium made of PP (polypropylene) fiber is used, but a polysulfone film or the like can also be used.
Then, the wastewater flowing down from below the ss / oil component floating separation tank 1 (ss / oil component is decreasing) and the wastewater treated in the oil component adhesion separation tank 5 (oil component adheres to the adhering material 4). (Reduced) was merged in the primary treatment water tank 6 and temporarily stored. The regenerated adsorbent was added to the primary treatment water tank 6 by the spiral pump SP6.

As the next step of treating the ss / oil component, the wastewater from the primary treatment water tank 6 is drawn out by the spiral pump SP9, the water quality is measured by the sensor S-2, and the adsorbent is used to adsorb the dirt component in the wastewater (adsorbent filter tank). It was made to be transferred by the piping line 8 to (consisting of 7).
The dispersion scavenger was injected into the piping line 8 by the pump P1, and then the coagulant PAC (polyaluminum chloride) was injected by the pump P2. In addition, clean water after wastewater treatment was injected into this piping line 8 as feed / back water (FB water) while measuring the water quality with the sensor S-3.

The dispersion scavenger disperses in wastewater and captures dirt components. The disperse scavenger disperses in the wastewater to form a dispersible scavenger, which captures and captures dirt components. Polyacrylic amide was used as the material of the dispersion scavenger.
To adjust the concentration of the dispersion scavenger, 0.1 wt% of the stock solution of the dispersion scavenger was added to water. As the ratio of the addition of the dispersion scavenger to the wastewater, the ratio of 1 cc to 500 cc of wastewater was adjusted for the concentration as described above.

The adsorbent filtration tank 7 is formed by an upper fluidized bed filtration kneading area (stirred by motor M) and a fixed bed filtration area below it, and is pretreated with two sets on the right side of the figure and flows down to the intermediate tank. Then, I finished it with one set on the left side and let it flow down to the treatment water tank. A part of the intermediate tank was sent to the electrolysis mechanism E. The electrolyzed water generated by the electrolysis mechanism E was stored in the electrolyzed water tank.
Then, the final water quality was measured by the sensor S-4 from the treated water tank via the UF membrane filtration mechanism 9 by the spiral pump SP11, and the water was discharged as recycled water (FB water) or as wastewater.

Next, a step of heating / activating the adsorbent of the dirt component (composed of the heating / activating mechanism 10) was performed, and the adsorbent 4 of the oil component was carbonized. In this step, the adsorbent was activated and activated by heating at 900 ° C or higher for 3 hours.
Activated carbon was cooled with cooling / desalination industrial water. This cooling water can also be used for diluting raw wastewater through a water storage tank and a drainage return line. In addition, the activated / activated activated carbon was reused through the return line 11.

In the heating / activating mechanism 10, hot air at 1,200 ° C is blown from the LNG gas burner, and hot air at 900 ° C is applied to the adsorbent transferred by the screw conveyor S rotationally driven by the motor M.
The pipe covering the screw conveyor S is provided with a plurality of holes in the region below the adsorbent filter tank 7, and the treated water after filtration flows down from the holes. In addition, a part of the hot air was sent to the powder cyclone mechanism to collect dust, and the hot air was circulated to the heating / activating mechanism 10.

Exhaust gas was opened to the atmosphere via an electrolytic scrubber mechanism 12 and an activated carbon filter tank 13 in parallel. The electrolyzed water generated by the electrolytic mechanism E is supplied to the electrolytic scrubber mechanism 12.
When treated water (FB water) is mixed with raw wastewater and treated, even if the dirt components (COD concentration and TOC concentration as indicators) of the wastewater of high-concentration organic waste liquid increase and decrease, they are leveled and the effect on treatment is reduced. Can be done.

It is provided with an adhesion mechanism 15 for adsorbing the adsorptive functional agent 14 to the adsorbent. Tar pitch was used as the adsorptive functional agent 14. Then, the dirt component adsorbed on the adsorbent was thermally decomposed by the heat treatment mechanism 4, and the adsorbent was subjected to the wastewater treatment step again.
The adhesion mechanism 15 is provided in the middle of the screw conveyor S. In this adhesion mechanism 15, the adsorptive functional agent 14 (tar pitch) is heated to about 600 ° C. by an electric heater. The base material of the adsorbent is dehydrated at a high temperature, and softened tar and pitch adhere to and form a film on the surface of the base material of the adsorbent, and are sent to the heating / activation mechanism 10.

Next, the usage state of the wastewater treatment method of this embodiment will be described.
Since this wastewater treatment method includes a step of adhering the oil component in the wastewater by the adhering material 4 (composed of the oil component adhering separation tank 5), the oil component in the wastewater, which is difficult to treat, is reduced or removed by the adhering material 4. I was able to do it. Since the step of adhering the oil component in the wastewater by the adhering material 4 was brought in first, the processing load in the subsequent steps could be greatly reduced.
Further, since it has a step of adsorbing the dirt component in the wastewater by the adsorbent (composed of the adsorbent filter tank 7), the dirt component in the wastewater could be reduced by the adsorbent.

Then, since the adsorbent 4 of the oil component was carbonized in the heating / activating step of the adsorbent of the dirt component (composed of the heating / activating mechanism 10), the heat in the heating / activating step of the adsorbent was used. The oil component adsorbent 4 could be carbonized. Further, when the heated / activated adsorbent was reused, the carbide of the adsorbent 4 was simultaneously activated by heating and could be used as the adsorbent.
Since the oil component in the wastewater, which is difficult to treat, can be reduced or removed by the adhering material 4, the purification efficiency of the wastewater having the oil component can be improved as compared with the conventional case.

Further, since the carbide of the adhering material 4 can also be activated by heating and used as an adsorbent, it was possible to cope with the consumption of activated carbon.
Further, since the oil component is floated by fine bubbles in the ss / oil component floating separation tank 1, the treatment efficiency in the oil component adhesion step is improved.

It can be applied to various wastewater treatment applications by being able to improve the purification efficiency of wastewater having an oil component and to cope with the consumption of activated carbon.

4 Adhesive material
10 (heating / activation mechanism)

Claims (2)

Adsorption process of oil component in wastewater by adhesive material (4) consisting of polypropylene fiber and polysulfone film (different from "adsorbent") , adsorption step of dirt component in wastewater by adsorbent material made of activated carbon , and dirt component A wastewater treatment method comprising a step of heating / activating the adsorbent of the above, and carbonizing the adsorbent (4) of the oil component in the step of heating / activating the adsorbent of the dirt component. The wastewater treatment method according to claim 1 , wherein the oil component is floated by fine bubbles in the first stage of the adhesion step .

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