JPH10151466A - Waste water purifying method and washing waste water treatment apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a washing waste water treatment method reduced in cost without using a filter when org. waste water such as washing waste water is treated with an electrochemical technique and an apparatus therefor. SOLUTION: Waste water 2 is introduced into an electrolytic treatment tank having an electrode 5 consisting of an anode 7 and a cathode 8 and a current is allowed to flow across the anode 7 and the cathode 8 to form a precipitate 9 of a substance constituting one of the anode 7 and the cathode 8 and an ionic substance in waste water 2 and the precipitate 9 is removed by a liquid cyclone 4 by utilizing the specific gravity difference between the waste water and the precipitate 9.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for removing ionic substances from wastewater such as household wastewater, commercial cleaning wastewater, textile wastewater, and plating solution.

[0002]

2. Description of the Related Art Conventionally, acidic plating solutions containing organic sulfonic acid, cleaning solutions or their waste liquids are subjected to a neutralization treatment with sodium hydroxide or the like, and the resulting tin or lead hydroxide is separated and solidified with concrete or the like. After that, it was landfilled. On the other hand, a waste liquid containing a sodium salt of an organic sulfonic acid has been discarded in a river or ocean as general wastewater after confirming that no pollution occurs.

As described in Japanese Patent Application Laid-Open No. Hei 5-23673, when an organic wastewater such as washing wastewater, dyeing wastewater, rice washing wastewater or car washing wastewater is treated by an electrochemical method, an anode is used. Insoluble anodes and soluble anodes are used as a component to decompose organic components with the insoluble anodes, and floculate the decomposed components together with fine particles produced by dissolving the soluble anodes to promote aggregation or sedimentation to separate decomposition products. It was discharged after filtration by a filter.

[0004]

However, the above-mentioned prior art has the following problems.

First, safety confirmation and disposal of waste liquids are very costly and costly. Second,
When flocculating together with the fine particles generated by dissolving the soluble anode and filtering the aggregates or sediment with a filter,
If a large amount of processing is to be performed, the filter must be replaced or cleaned frequently to cause clogging of the filter, which complicates the processing.

Accordingly, an object of the present invention is to provide a wastewater treatment method and a washing wastewater treatment device which do not use a filter or the like and which does not require a cost, in order to solve the above-mentioned problems.

[0007]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention uses a filter or the like to filter ionic substances in wastewater such as household laundry wastewater, commercial cleaning wastewater, textile laundry wastewater, and plating solution. Without draining these wastewaters into an electrolytic treatment tank having an electrode in which an anode and a cathode made of Al face each other, a current is passed between the anode and the cathode, and Al eluted from the electrodes near the anode and / or the cathode. After forming insoluble precipitates by the ions and the ionic substances in the wastewater, the wastewater containing the precipitates is led to the outside of the electrolytic treatment tank, and introduced into the liquid cyclone via a pump to remove the precipitates. The present invention provides a method for purifying wastewater by removing the ionic substance contained in the wastewater by returning the wastewater to the electrolytic treatment tank again and repeating the circulation.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A drainage method according to an embodiment of the present invention will be described below with reference to the drawings. However, in the present embodiment, a case where the wastewater treatment method of the present invention is applied to washing wastewater will be described.

FIG. 1 is a schematic diagram showing an outline of a purification apparatus for carrying out the method for purifying wastewater of the present invention. To explain the configuration of the purification device shown in FIG. 1, for example, washing wastewater 2 from a washing machine is put in an electrolytic treatment tank 1, and the washing wastewater 2 enters a liquid cyclone 4 via a pump 3. Then, it returns to the electrolytic treatment tank 1 and circulates repeatedly.

An electrode 5 made of aluminum (hereinafter, referred to as Al) is inserted into the electrolytic processing tank 1 in a state of being electrically insulated from the electrolytic processing tank 1, and serves as a means for flowing a current between the electrodes. Is supplied with a direct current from the electrolysis power supply 6 of FIG. Here, the electrode 5 uses, for example, Al having a size of 50 cm in length and 25 cm in width as the anode 7 and the cathode 8, and is arranged so as to face the cathode-anode-cathode-anode-cathode-anode-cathode. I have. In addition,
As shown in FIG. 1, the anode 7 is disposed so as to be sandwiched between the cathodes 8 in order to effectively use both surfaces of the anode 7.

Next, a method of purifying waste water using the purifying apparatus shown in FIG. 1 will be described below.

By energizing the electrodes, Al ions elute from the surface of the anode 7 in accordance with the amount of electricity supplied. Washing wastewater 2 mainly contains sodium linear alkylbenzene sulfonate as an anionic surfactant. This is because, in an aqueous solution, linear alkylbenzene sulfonic acid ions (hereinafter, referred to as LAS ions) and sodium ions are ionized, and when a direct current is applied to the electrode 5 from the electrolytic power supply 6, the LAS ions are The ions are attracted to the cathode 8. As described above, Al ions are eluted into the solution from the surface of the anode 7 and combine with the LAS ions to form a non-soluble precipitate 9. The state of the reaction at this time is shown in FIG.

At this time, a hydroxyl (OH) group is also attracted to the anode 7 and insoluble Al (OH) 3 is formed. However, the concentration of LAS ions is much higher than that of the hydroxyl group. Most of the reaction is a reaction of bonding with LAS ions.

Thereafter, the aqueous solution containing the precipitate 9 shown in FIG. 1 is put into the hydrocyclone 4 via the pump 3.
The term "hydrocyclone" as used herein refers to a device that causes a liquid such as water to flow therein to generate a swirling flow, and applies a centrifugal force of a different-phase molecule contained in the liquid to separate and capture the liquid from the liquid. Due to the swirling flow generated in the hydrocyclone 4, the washing wastewater 2 and the precipitate 9 are separated by a specific gravity difference,
The washing wastewater 2 having a low specific gravity is discharged from the upper part of the liquid cyclone 4, and the precipitate 9 is discharged from the lower part. Here, the sediment is removed by the liquid cyclone 4, but any device capable of separating the sediment from the wastewater by utilizing the difference in specific gravity may be used.

Therefore, the washing drainage 2 discharged to the upper part of the liquid cyclone 4 is returned to the electrolytic treatment tank 1 again, and is subjected to electrolytic treatment again, and the ionic substance is supplied to the liquid cyclone 4 as a precipitate 9. Then, in the liquid cyclone 4, the washing wastewater 2 and the precipitate 9 are separated, and the washing wastewater 2 is discharged from the upper part of the liquid cyclone 4 and returned to the electrolytic treatment tank 1 again.

By repeating the above process, the ionic substances are removed from the washing wastewater 2. The sediment 12 accumulates below the hydrocyclone 4, and dust and dirt attached to clothes are also separated by the hydrocyclone 4 and accumulate below the hydrocyclone 4 together with the sediment 12. Therefore, when the treatment is completed, the precipitate 12 may be separately disposed, and when the ionic substance is removed, the valve 10 may be opened to perform the drainage treatment.

The present invention can be applied not only to washing wastewater but also to a wide range of other wastewater treatments. Specific examples thereof include commercial cleaning wastewater, textile wastewater, plating liquid wastewater, and the like. And car wash drainage.

[0018]

As described above, according to the present invention, in order to remove ionic substances contained in washing wastewater, the wastewater is put into an electrolytic treatment tank having an electrode composed of an anode and a cathode, and the wastewater is placed between the anode and the cathode. When an electric current is passed, a precipitate is formed between the anode and cathode materials and the ionic substance in the wastewater in the vicinity of the anode and the cathode, and is supplied to the liquid cyclone with the wastewater,
Due to the swirling flow generated in this hydrocyclone, the sediment with different specific gravity and wastewater are separated by utilizing the difference in specific gravity, and the wastewater from which sediment is removed is discharged from above and returned to the electrolytic treatment tank again, and the sediment is removed. Can be discharged downward, so that a continuous separation action can be performed, so that there is no need to use a filter or the like, and it is possible to efficiently purify wastewater without fear of clogging.

Therefore, the present invention greatly contributes not only to industrial value but also to conservation of the global environment.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a configuration of a wastewater purification device of the present invention.

FIG. 2 is a diagram showing the movement of ions near an electrode.

[Explanation of symbols]

 Reference Signs List 1 electrolytic treatment tank 2 washing drainage 3 pump 4 liquid cyclone 5 electrode 6 electrolytic power supply 7 anode 8 cathode 9 sediment 10 valve 11 drainage

Claims (3)

[Claims] 1. A step of draining an electrolytic treatment tank having an electrode comprising an anode and a cathode, and supplying a current between the anode and the cathode to form at least one of the anode and the cathode. A method for purifying wastewater, comprising: a step of forming a precipitate with an ionic substance in the wastewater; and a step of removing the precipitate in the wastewater by using a specific gravity difference between the wastewater and the precipitate. 2. A step of draining water into an electrolytic treatment tank having an electrode in which an anode and a cathode made of Al are opposed to each other, and flowing an electric current between the anode and the cathode to cause Al ions eluted from the electrode. Forming a non-soluble precipitate with the ionic substance in the wastewater, guiding the wastewater containing the precipitate to the outside of the electrolytic treatment tank, and introducing the precipitate into a liquid cyclone via a pump. Removing the matter, returning the wastewater to the electrolytic treatment tank again, and repeating the circulation to remove ionic substances contained in the wastewater. 3. An electrode having an anode and a cathode facing each other,
An electrolytic treatment tank for putting waste water after washing therein, a means for flowing an electric current between the anode and the cathode, and an insoluble material formed by ions eluted from the electrode and ionic substances contained in the waste water. And a means for removing the sediment of the waste water by utilizing a difference in specific gravity.