JP4760120B2 - Apparatus and method for treating water containing hardly biodegradable organic matter - Google Patents

Description

  The present invention removes the hardly biodegradable organic substances in the water to be treated by adsorbing them on acid- and oxidation-resistant inorganic adsorbents and regenerating the inorganic adsorbents adsorbing the hardly-biodegradable organic substances. The present invention relates to a treatment apparatus and a treatment method for water containing hardly biodegradable organic substances that are reused for adsorption of water.

  Non-biodegradable organic substances such as nonionic surfactants cause health problems in the human body and have problems of adverse effects on aquatic animals such as fish.Therefore, they are discharged into environmental water based on environmental standards related to water pollution. Some are regulated.

Conventionally, as a method for treating water containing hardly biodegradable organic substances, 1) adsorption by activated carbon 2) decomposition by a chlorine-based oxidizing agent such as sodium hypochlorite in the presence of a nickel peroxide-based catalyst (for example, JP-A-2003-80276) Issue)
Etc. are known.

  However, 1) the activated carbon adsorption method has a problem that the adsorption amount is small and the regeneration activation cost of activated carbon after adsorption saturation is expensive.

On the other hand, 2) The method of decomposing with a chlorine-based oxidizing agent such as sodium hypochlorite in the presence of a nickel peroxide-based catalyst has a problem that harmful organic chlorine compounds such as trihalomethane are generated. There was a need for a method that would not occur.
JP 2003-80276 A

  It is an object of the present invention to provide a technique for efficiently removing organic substances including non-biodegradable organic substances such as nonionic surfactants in water to be treated to a low concentration without generating harmful chlorine compounds. And

There are many technical difficulties in concentrating and decomposing non-biodegradable organic substances, such as nonionic surfactants, phenols, and trihalomethanes, contained in the water to be treated at low concentrations. As a result of intensive studies on the decomposition treatment technique of such a hardly biodegradable organic substance, the present inventors have made it adsorbed on an inorganic adsorbent by adsorbing the hardly biodegradable organic substance to an acid-resistant and oxidation-resistant inorganic adsorbent. Concentrated and easily biodegradable by bringing the hardly biodegradable organic substance adsorbed on the inorganic adsorbent into contact with a solution containing persulfuric acid (peroxodisulfuric acid: H ₂ S ₂ O ₈ ) and / or persulfate. It has been found that organic substances can be peeled and decomposed. In other words, persulfuric acid and persulfate self-decompose and exert strong oxidizing power, and with this oxidizing power, the non-biodegradable organic matter on the inorganic adsorbent is efficiently dissolved on the solution side and desorbed and oxidatively decomposed. To do. Furthermore, the present inventors can regenerate the sulfate ions generated by reducing persulfate ions by oxidative decomposition of the hardly biodegradable organic substances by oxidizing them into persulfate ions by an electrolytic reaction, which can be recovered by inorganic adsorption. The present invention was completed by discovering that it can be reused for peeling and decomposition of the hardly biodegradable organic substances adsorbed on the agent.
That is, the gist of the present invention is as follows.

(1) An adsorbing means for contacting water containing a hardly biodegradable organic substance with an acid-resistant and oxidation-resistant inorganic adsorbent to adsorb the hardly biodegradable organic substance onto the inorganic adsorbent; The hardly biodegradable substance adsorbed on the inorganic adsorbent by contacting the adsorbed inorganic adsorbent with a solution containing persulfuric acid and / or persulfate (hereinafter referred to as “persulfuric acid (salt) solution”). A regeneration means for regenerating the inorganic adsorbent by peeling and decomposing the organic matter, and a persulfate (salt) solution is regenerated by generating a persulfate ion from the sulfate ion in the solution after regenerating the inorganic adsorbent by an electrolytic reaction. A non- degradable organic substance containing non-biodegradable organic substance, comprising: an electrolytic reaction apparatus to be treated; and a circulation line for circulating a solution between the regeneration means and the electrolytic reaction apparatus . A surfactant and the inorganic absorbent The adsorbent is one or more selected from the group consisting of porous silica, silica-based zeolite and smectite, and the adsorbing means contains the hardly biodegradable organic substance in a packed tower packed with the inorganic adsorbent. Means for passing water, and the regeneration means is means for passing the persulfuric acid (salt) solution through a packed tower filled with an inorganic adsorbent adsorbing the hardly biodegradable organic matter, and the regeneration A treatment apparatus for water containing hardly biodegradable organic substances, wherein the inorganic adsorbent regenerated by the means is repeatedly used for the adsorption treatment in the adsorption means.

(2) In (1), the said inorganic adsorbent is a silica-type zeolite, The processing apparatus of the hardly biodegradable organic substance containing water characterized by the above-mentioned .

(3 ) The processing apparatus for water containing hardly biodegradable organic substances according to ( 1 ) or (2) , wherein at least an anode of the electrodes of the electrolytic reaction apparatus is a conductive diamond electrode.

( 4 ) Contacting water containing a non-biodegradable organic substance with an acid- and oxidation-resistant inorganic adsorbent to adsorb the non-biodegradable organic substance to the inorganic adsorbent, and then adsorbing the non-biodegradable organic substance The inorganic adsorbent was brought into contact with a persulfuric acid (salt) solution, the non-biodegradable organic matter adsorbed on the inorganic adsorbent was peeled and decomposed to regenerate the inorganic adsorbent, and the inorganic adsorbent was regenerated. after the electrolytic reaction from sulfate ions in solution to produce persulfate ions to regenerate the persulfuric acid (salt) solution, flame biodegradation you reuse該過sulfate (salt) solution in playing of the inorganic adsorbent 1 or 2 wherein the non-biodegradable organic substance is a nonionic surfactant and the inorganic adsorbent is selected from the group consisting of porous silica, silica-based zeolite and smectite. More than species, the inorganic adsorption After passing the water containing the non-biodegradable organic substance through the packed tower packed with the non-degradable organic substance to adsorb the non-biodegradable organic substance to the inorganic adsorbent, the inorganic adsorbent adsorbing the non-biodegradable organic substance is packed. The persulfuric acid (salt) solution is passed through the packed tower to regenerate the inorganic adsorbent, and the regenerated inorganic adsorbent is repeatedly used for the adsorption treatment of the non-biodegradable organic matter. A method for treating water containing biodegradable organic matter.

( 5 ) In ( 4 ), the said inorganic adsorbent is a silica-type zeolite, The processing method of the hardly biodegradable organic substance containing water characterized by the above-mentioned .

(6 ) The method for treating water containing hardly biodegradable organic substances according to ( 4 ) or (5) , wherein at least an anode of the electrodes used for the electrolytic reaction is a conductive diamond electrode.

  According to the present invention, an acid-resistant and oxidation-resistant inorganic adsorbent (hereinafter sometimes referred to as “acid-resistant / oxidation-resistant inorganic adsorbent”) made of an inorganic compound such as silicon that has little adverse effects on humans, and Using inorganic persulfuric acid and / or persulfate (hereinafter sometimes referred to as “persulfuric acid (salt)”), it is possible to easily decompose and remove non-biodegradable organic substances in the water to be treated. In this case, only sulfate ions are discharged, which is extremely advantageous industrially.

  In other words, persulfuric acid (salt) is very effective in decomposing difficult biodegradable organic substances, but persulfuric acid (salt) is added directly to difficult biodegradable organic substances contained at low concentrations in the water to be treated. In order to oxidatively decompose the decomposable organic substance, it is necessary to heat the entire water to be treated to a temperature suitable for oxidative decomposition of the hardly biodegradable organic substance with persulfuric acid (salt), and the heating cost is high.

  However, according to the present invention, the hardly biodegradable organic matter in the water to be treated is adsorbed on the acid / oxidation resistant inorganic adsorbent and concentrated on the inorganic adsorbent, and the hardly biodegradable organic matter on the inorganic adsorbent is In order to regenerate inorganic adsorbent by contacting with persulfuric acid (salt) solution and regenerating inorganic adsorbent, it is only necessary to heat the persulfuric acid (salt) solution used for regeneration of inorganic adsorbent. Heat source or heat exchange for heating The vessel is small and sufficient.

  Since the inorganic adsorbent that adsorbs the hardly biodegradable organic substance is an acid / oxidation resistant inorganic adsorbent, it does not deteriorate even when it comes into contact with a persulfuric acid (salt) solution during regeneration. On the other hand, for example, activated carbon conventionally used for adsorption of hardly biodegradable organic substances has no oxidation resistance, and therefore cannot be regenerated using a persulfuric acid (salt) solution.

The acid / oxidation resistant inorganic adsorbent used in the present invention is preferably a silica-based zeolite (claims 2 and 5 ), but is not limited thereto.

Since the sulfate ion in the solution after regenerating the inorganic adsorbent (hereinafter sometimes referred to as “recycled waste liquid”) can be easily converted to a persulfate ion by an electrolytic reaction, a persulfate (salt) solution is thereby obtained. Can be recycled in the regeneration of the inorganic adsorbent, and a system that does not discharge the waste liquid can be obtained (claims 1 , 4 ).

The temperature of the regenerated waste solution used for the electrolytic reaction is preferably 10 to 90 ° C, and the temperature of the persulfuric acid (salt) solution used for regenerating the inorganic adsorbent is preferably 80 to 130 ° C. Moreover, it is preferable that the sulfate ion density | concentration of the solution used for an electrolytic reaction is 0.1-18M. Of the electrodes of the electrolytic reaction apparatus, at least the anode is preferably a conductive diamond electrode (claims 3 and 6 ).

  In addition, the inorganic adsorbent that has adsorbed the hardly biodegradable organic matter is oxidized by the persulfuric acid (salt) solution by drying and then oxidizing (burning) in an oxygen-containing gas prior to regeneration with the persulfuric acid (salt) solution. It is possible to reduce the amount of difficult-to-decompose organic matter to be decomposed, and to reduce the amount of persulfuric acid (salt) solution used, the amount of recycled waste liquid discharged, and the like.

  In the present invention, after water containing hardly biodegradable organic substances is passed through an adsorption tower filled with an inorganic adsorbent to carry out adsorption treatment of the hardly biodegradable organic substances, a persulfuric acid (salt) solution is passed through the adsorption tower. Water may be used to regenerate the inorganic adsorbent. After the water containing the hardly biodegradable organic substance is passed through the adsorption tower filled with the inorganic adsorbent, the adsorption process of the hardly biodegradable organic substance is performed. The inorganic adsorbent may be extracted from the adsorption tower, brought into contact with the inorganic adsorbent and the persulfuric acid (salt) solution, and then returned to the adsorption tower.

  Embodiments of the treatment apparatus and treatment method for water containing hardly biodegradable organic substances according to the present invention will be described in detail below.

  In the present invention, the non-biodegradable organic substances to be treated include nonionic surfactants, phenols, trihalomethanes and the like. In the present invention, these non-biodegradable organic substances are, for example, 0.5 to 100 mg / L. Applicable to wastewater, lakes, river water, industrial water, etc., contained at moderate concentrations.

  Acid / oxidation-resistant inorganic adsorbents used for adsorption of hardly biodegradable organic substances in the treated water are excellent in acid resistance and oxidation resistance, and include porous silica, silica-based zeolite, and smectite. These may be used alone or in combination of two or more.

  The particle size of the acid / oxidation-resistant inorganic adsorbent is appropriately selected depending on the use form, and when the adsorption treatment is performed by filling the packed tower and passing the water to be treated, the particles have an average particle size of about 300 to 3000 μm. Are preferably used.

  Examples of the persulfate in the persulfuric acid (salt) solution used for the regeneration of the inorganic adsorbent that has adsorbed the hardly biodegradable organic matter in the treated water include sodium persulfate and potassium persulfate. If the concentration of persulfuric acid (salt) in the persulfuric acid (salt) solution is excessively high, the production efficiency of persulfate ions from sulfate ions deteriorates in the electrolytic reaction described later. The solubility becomes low and it becomes difficult to peel off the hardly biodegradable organic substance from the inorganic adsorbent. In addition, the oxidative decomposition efficiency of the hardly biodegradable organic matter also deteriorates. For this reason, the persulfuric acid (salt) concentration of the persulfuric acid (salt) solution is about 10 to 30% by weight, and is preferably 0.1 to 18M, particularly preferably 0.2 to 3.0M in terms of sulfate ion. .

  Since persulfuric acid and persulfate have a higher self-decomposition rate and a stronger oxidizing power at higher temperatures, the higher the temperature of the persulfuric acid (salt) solution used to regenerate the inorganic adsorbent, the higher the regeneration efficiency, that is, inorganic adsorption Removal / decomposition efficiency of non-biodegradable organic substances adsorbed on the agent is improved. However, if it is too high, the production cost and heating cost increase, and the efficiency decreases due to the self-decomposition of persulfuric acid (salt). The temperature of the persulfuric acid (salt) solution used for the regeneration of the agent is preferably about 80 to 130 ° C, particularly 90 to 120 ° C. The persulfuric acid (salt) solution used for regeneration of the inorganic adsorbent is preferably heated to a predetermined temperature by a heat exchanger or the like as necessary.

  The persulfuric acid (salt) solution is used in an amount necessary to regenerate the inorganic adsorbent by peeling off and decomposing the hardly biodegradable organic substances adsorbed on the inorganic adsorbent.

  In addition, the inorganic adsorbent that has adsorbed the hardly biodegradable organic matter may be oxidized (combusted) in an oxygen-containing gas after drying prior to regeneration with a persulfuric acid (salt) solution. A part of the adsorbed hardly biodegradable organic matter can be removed, and the amount of persulfuric acid (salt) used for regeneration can be reduced. In this case, the drying conditions of the inorganic adsorbent are preferably 60 to 120 ° C. and about 0.1 to 2.0 hours, and the oxidation reaction is carried out at 600 to 900 ° C. in an oxygen-containing gas such as air or pure oxygen. It is preferable to carry out for about 1 to 2.0 hours.

  In addition, by such an oxidation reaction, a part of the hardly biodegradable organic substance adsorbed on the inorganic adsorbent can be burned and removed, but the hardly biodegradable organic substance that has entered the pores of the inorganic adsorbent is removed. It is difficult to remove, and there are problems such as residue of soot due to combustion and reduction in utilization efficiency at the time of reuse due to gas intrusion, and not only combustion treatment but also treatment with persulfuric acid (salt) solution can be used together desirable.

  When the inorganic adsorbent is regenerated using a persulfuric acid (salt) solution, persulfate ions in the persulfuric acid (salt) solution are reduced to oxidized sulfates by oxidizing the hardly biodegradable organic matter. Therefore, the reclaimed waste liquid after regenerating the inorganic adsorbent contains sulfate ions, but this solution is again converted into a persulfuric acid (salt) solution by converting sulfate ions to persulfate ions by electrolytic reaction. It can be used for the regeneration of the agent.

  In this electrolytic reaction, the lower the temperature, the better the generation efficiency of persulfate ions, and the less the electrode is consumed. The temperature of the regenerated waste liquid used for this electrolytic reaction is about 10 to 90 ° C, especially about 40 to 80 ° C. Preferably there is. Beyond this temperature range, the electrolysis efficiency decreases and the wear of the electrode also increases. On the other hand, if the temperature is below this temperature, the heating energy at the time of reuse for regeneration of the inorganic adsorbent becomes large, which is not preferable. The regenerated waste liquid used for the electrolytic reaction is cooled as necessary. At this time, it can be cooled by exchanging heat with a persulfuric acid (salt) solution used for regenerating the inorganic adsorbent.

  In addition, the lower the sulfate ion concentration in the regenerated waste solution used for the electrolytic reaction, the greater the efficiency of producing persulfate ions. On the other hand, when the sulfate ion concentration is lowered, the oxidation of the hardly biodegradable organic matter is difficult to proceed and it is difficult to peel from the inorganic adsorbent. From these viewpoints, it is desirable that the concentration of sulfate ion in the recycled waste liquid is in the range of 0.1 to 18M, particularly 0.2 to 3.0M.

  Below, the electrolytic reaction apparatus used for the electrolytic reaction of this regeneration waste liquid is demonstrated.

  In the electrolytic reaction apparatus, electrolysis is performed by pairing an anode and a cathode. There are no particular restrictions on the material of these electrodes, but when platinum, which is widely used as an electrode, is used as the anode of an electrolysis reactor, persulfate ions cannot be generated efficiently and platinum is eluted. There is a problem. On the other hand, the diamond electrode can efficiently generate persulfate ions and has little electrode wear. Therefore, it is desirable that at least the anode for generating persulfate ions among the electrodes of the electrolytic reaction apparatus is composed of a conductive diamond electrode, and it is more desirable that both the anode and the cathode are composed of a conductive diamond electrode.

  The conductive diamond electrode is a semiconductor material such as a silicon wafer used as a substrate, and after synthesizing a conductive diamond thin film on the wafer surface, the wafer is dissolved or synthesized in a plate shape under the condition that the substrate is not used. Mention may be made of self-standing conductive polycrystalline diamond. In addition, a laminate formed on a metal substrate such as Nb, W, or Ti can be used. However, when the current density is increased, a problem that the diamond film is peeled off from the substrate tends to occur.

It has been reported that persulfate ions are generated from sulfate ions with a conductive diamond electrode when the current density is about 0.2 A / cm ² (Ch. Cominellis et al., Electrochemical and Solid-State). Letters, Vol. 3 (2) 77-79 (2000), Special Table 2003-511555).

  The conductive diamond thin film is a conductive thin film that is doped with a predetermined amount of boron, nitrogen, or the like during synthesis of the diamond thin film, and is generally boron-doped. If the doping amount is too small, technical significance does not occur. If the doping amount is too large, the doping effect is saturated. Therefore, a doping amount in the range of 50 to 20,000 ppm with respect to the carbon amount of the diamond thin film is suitable. .

  As the conductive diamond electrode, a plate-like one is usually used, but a plate having a network structure can also be used. The shape and number of electrodes are not particularly limited.

In the electrolytic reaction performed using this conductive diamond electrode, the current density on the surface of the conductive diamond electrode is set to 10 to 100,000 A / m ^2, and the regenerated waste liquid containing sulfate ions is passed through in a direction parallel to the diamond electrode surface. It is desirable to perform the contact treatment at a speed of 1 to 10,000 m / hr.

  In the present invention, the acid-resistant / oxidation-resistant inorganic adsorbent is used to adsorb the hardly biodegradable organic matter in the water to be treated, the acid-resistant / oxidation-resistant inorganic adsorbent is regenerated using a persulfuric acid (salt) solution, and the waste solution is electrolyzed There are no particular restrictions on the specific method.

  Specific examples of the processing of the hardly biodegradable organic material according to the present invention will be described below with reference to FIGS. 1 to 5, but the apparatus and method of the present invention are not limited to those shown in the drawings. FIGS. 1 to 5 show an example in which water to be treated is passed through an adsorption tower filled with an acid / oxidation resistant inorganic adsorbent to carry out an adsorption treatment of a hardly biodegradable organic substance. The water flow system of the packed tower is not limited to the downward flow, and may be an upward flow. The packed tower may be either a fluidized bed system or a fixed bed system. In addition, the regeneration method of the inorganic adsorbent is also a tower water flow system.

  In the method of FIG. 1, treated water is passed through an adsorption tower 1 filled with an acid / oxidation resistant inorganic adsorbent to absorb and remove hardly biodegradable organic substances, thereby obtaining treated water. In the regeneration of the inorganic adsorbent that adsorbs the hardly biodegradable organic substances by passing the water to be treated, the water to be treated is stopped, and the persulfuric acid (salt) storage tank 2 is passed to the adsorption tower 1 to persulfate. The (salt) solution is heated by the heat exchanger 3 and passed through to regenerate the inorganic adsorbent. The regenerated waste liquid is discharged out of the system after being subjected to treatment such as neutralization and reduction treatment as necessary.

  In FIG. 1, a persulfuric acid (salt) solution is passed through the adsorption tower 1 to regenerate the inorganic adsorbent in the adsorption tower 1. In FIG. The inorganic adsorbent adsorbing the organic matter is transferred to the regeneration tower 4, the persulfuric acid (salt) solution is passed through the regeneration tower 4 to regenerate the inorganic adsorbent, and the regenerated inorganic adsorbent is adsorbed from the regeneration tower 4. The point which returns to the tower 1 and uses again for adsorption | suction of a non-biodegradable organic substance differs from the thing of FIG.

  The structure shown in FIG. 3 is the same as that shown in FIG. 1 except that an electrolytic tank 5 for obtaining a persulfuric acid (salt) solution by electrolytic reaction of the regenerated waste liquid is provided. In the regeneration, the persulfuric acid (salt) solution in the persulfuric acid (salt) storage tank 2 is heated by exchanging heat with the regenerated waste liquid in the heat exchanger 3 and then passed through the adsorption tower 1 to heat the regenerated waste liquid. After exchanging heat with the persulfuric acid (salt) solution in the exchanger 3 and cooling, it is fed to the electrolytic cell 5 to generate persulfate ions from the sulfate ions in the waste liquid to obtain a persulfuric acid (salt) solution. The sulfuric acid (salt) solution is circulated in the persulfuric acid (salt) storage tank 2 and reused for regeneration of the inorganic adsorbent.

  4 is different from that shown in FIG. 3 in that a regeneration tower 4 is separately provided as shown in FIG. 2, and an inorganic adsorbent adsorbing a hardly biodegradable organic substance is transferred to the regeneration tower 4. After regeneration, the adsorption and regeneration processes are performed in the same manner as in FIG. 3 except that the regenerated inorganic adsorbent is returned to the adsorption tower 1.

  5 is the same as that shown in FIG. 4 except that a drying / combustion device 6 for drying and oxidizing reaction is provided prior to regeneration of the inorganic adsorbent with a persulfuric acid (salt) solution. The inorganic adsorbent adsorbing the decomposable organic matter is first transferred from the adsorption tower 1 to the drying / combustion device 6 and dried, and then oxidized in an oxygen-containing gas, and then transferred to the regeneration tower 4 for regeneration. Except for being processed, adsorption and regeneration processes are performed in the same manner as in FIG.

  As the drying / combustion device 6, an electric furnace, a rotary kiln, or the like can be used.

  Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples. In the following, as the non-biodegradable organic substance-containing water, nonionic surfactant “NS208.5” (manufactured by NOF Corporation) dissolved in water at a concentration of 0.01 g / L was used. The TOC of this solution was 7.1 mg / L. As the acid / oxidation-resistant inorganic adsorbent, “High Silica Zeolite HSZ390HUA” manufactured by Tosoh (adjusted to an average particle size of 2000 μm, hereinafter simply referred to as “zeolite”) was used.

Example 1
The nonionic surfactant solution was applied to a water flow column (made of heat-resistant glass, inner diameter: 30 mmφ, height: 500 mm, packing height: 142 mm) filled with 100 mL of zeolite (weight 50 g) at a flow rate of 1.0 L / h. The liquid was passed.

  The TOC of treated water was 1 mg / L or less for about 25 days. The TOC adsorption amount at this time was about 35 g-TOC / L-zeolite (first adsorption treatment).

  The zeolite was regenerated by passing 10 L of a 5 wt% sodium persulfate aqueous solution (sulfate ion conversion concentration: 0.45 M) at 95 ° C. in 10 hours through the zeolite flow column adsorbing the TOC. After washing with water and confirming that the pH became neutral, the nonionic surfactant solution was passed through again (second adsorption treatment). Similarly to the first adsorption treatment, the treatment with a TOC of 1 mg / L or less was performed. Water could be obtained for a similar period.

  This operation was repeated 5 times, and the same treated water quality and treated water amount were obtained for both.

  From this result, the nonionic surfactant is adsorbed on the zeolite, the nonionic surfactant adsorbed on the zeolite is exfoliated and decomposed with sodium persulfate to regenerate the zeolite, and the regenerated zeolite is converted to the nonionic surfactant. It can be seen that it can be used repeatedly for the adsorption process.

(Example 2)
A sodium persulfate aqueous solution for regeneration was prepared by an electrolytic reaction as follows.

In the electrolytic cell for persulfuric acid generation, a flat diamond electrode made by Element Six was used for the anode, and a Ti-Pt electrode made by Permerec was used for the cathode (electrode area: 50 × 50 mm). The electrolytic solution was 10 L of a one-to-one mixed solution of sulfuric acid and sodium sulfate (sulfate ion concentration: 0.5 M / L). When the electrolysis was performed at a current density of 25 A / dm ² and a voltage of 10 V for 100 hours, the concentration of sodium persulfate was about 5% by weight. The current efficiency at this time was about 30%.

  Except that the sodium persulfate aqueous solution prepared by this electrolytic reaction was used as the aqueous sodium persulfate solution for regeneration, the adsorption treatment and the regeneration treatment were performed in the same manner as in Example 1. As in Example 1, TOC 1 mg / L or less treated water was obtained in substantially the same amount as in Example 1.

  The regeneration waste solution after regeneration of the zeolite was recovered, and an electrolytic reaction was performed in the same manner as described above using this as an electrolytic solution. As a result, a sodium persulfate aqueous solution was obtained in the same manner, and this sodium persulfate aqueous solution was used for adsorption. , Could play repeatedly.

  From this result, it can be seen that the persulfuric acid (salt) solution used for the regeneration of the zeolite can be regenerated by electrolytic reaction, and can be repeatedly reused for the regeneration of the zeolite, so that a system in which the regeneration waste liquid is not discharged can be obtained.

(Comparative Example 1)
Adsorption and regeneration were repeated in the same manner as in Example 1 except that a similar column was packed with activated carbon (“Kuraray Coal KW 10 × 40” manufactured by Kuraray Co., Ltd.) instead of zeolite. During the treatment, activated carbon fine powder and surfactant efflux were observed.

  This is because sodium persulfate oxidized activated carbon and activated carbon became weak, and sodium persulfate was consumed due to the oxidation of activated carbon, and the surfactant adsorbed on the activated carbon could not be oxidatively decomposed sufficiently. It is thought that. In other words, regeneration with persulfuric acid (salt) cannot be applied to activated carbon.

(Comparative Example 2)
In Example 1, nickel peroxide was supported on the zeolite in the water flow column, and the surfactant solution was passed through the water flow column while being injected so that the sodium hypochlorite concentration was 400 mg / L. Except for this, when treated in the same manner as in Example 1, the TOC of the treated water was 7 mg / L, which was almost equivalent to that of the raw water, and the TOX (organic halogen compound) was 0.5-1 mg / L. That is, in this method, not only organic substances could not be decomposed, but also organic chlorine compounds were produced.

  The apparatus and method for treating water containing hardly biodegradable organic substances of the present invention include organic substances discharged from chemical factories, paper factories, food and beverage production factories, garbage incineration plants, human waste treatment plants, sewage treatment plants, COD, interfaces, etc. Removal of organic components in wastewater containing activators, treatment of lakes and rivers contaminated with non-biodegradable organic substances such as nonionic surfactants, and reverse osmosis membrane treatment for reuse of industrial wastewater It is extremely useful industrially as a clogging prevention technique.

It is a systematic diagram which shows embodiment of the processing apparatus of the hardly biodegradable organic substance containing water of this invention. It is a systematic diagram which shows other embodiment of the processing apparatus of the hardly biodegradable organic substance containing water of this invention. It is a systematic diagram which shows another embodiment of the processing apparatus of the hardly biodegradable organic substance containing water of this invention. It is a systematic diagram which shows different embodiment of the processing apparatus of the hardly biodegradable organic substance containing water of this invention. It is a systematic diagram which shows different embodiment of the processing apparatus of the hardly biodegradable organic substance containing water of this invention.

DESCRIPTION OF SYMBOLS 1 Adsorption tower 2 Persulfuric acid (salt) storage tank 3 Heat exchanger 4 Regeneration tower 5 Electrolysis tank 6 Drying / combustion device

Claims (6)

An adsorption means for contacting the water containing the hardly biodegradable organic substance with an acid-resistant and oxidation-resistant inorganic adsorbent to adsorb the hardly biodegradable organic substance onto the inorganic adsorbent;
The inorganic adsorbent adsorbing the hardly biodegradable organic substance is brought into contact with a solution containing persulfuric acid and / or persulfate (hereinafter referred to as “persulfuric acid (salt) solution”) and adsorbed on the inorganic adsorbent. Regenerating means for regenerating and regenerating the inorganic adsorbent by peeling and decomposing the difficult biodegradable organic matter ,
An electrolytic reaction device that regenerates a persulfuric acid (salt) solution by generating persulfate ions from the sulfate ions in the solution after regenerating the inorganic adsorbent by an electrolytic reaction, and between the regeneration means and the electrolytic reaction device. A treatment apparatus for water containing hardly biodegradable organic matter, comprising a circulation line for circulating the solution ,
The non-biodegradable organic substance is a nonionic surfactant;
The inorganic adsorbent is one or more selected from the group consisting of porous silica, silica-based zeolite and smectite,
The adsorbing means is means for passing the hardly biodegradable organic substance-containing water through a packed tower filled with the inorganic adsorbent;
The regeneration means is means for passing the persulfuric acid (salt) solution through a packed tower packed with an inorganic adsorbent that has adsorbed the hardly biodegradable organic matter,
A treatment apparatus for water containing hardly biodegradable organic substances, wherein the inorganic adsorbent regenerated by the regeneration means is repeatedly used for the adsorption treatment in the adsorption means.   The treatment apparatus for water containing hardly biodegradable organic substances according to claim 1, wherein the inorganic adsorbent is silica-based zeolite. 3. The apparatus for treating hardly biodegradable organic substance-containing water according to claim 1 , wherein at least an anode of the electrodes of the electrolytic reaction apparatus is a conductive diamond electrode. Inorganic adsorption that adsorbs the non-biodegradable organic substance after contacting the non-biodegradable organic substance-containing water with the acid- and oxidation-resistant inorganic adsorbent, adsorbing the non-biodegradable organic substance to the inorganic adsorbent The agent is brought into contact with a persulfuric acid (salt) solution, and the non-biodegradable organic matter adsorbed on the inorganic adsorbent is peeled and decomposed to regenerate the inorganic adsorbent .
After regenerating the inorganic adsorbent, persulfate ions are generated from the sulfate ions in the solution by an electrolytic reaction to regenerate the persulfuric acid (salt) solution, and the persulfuric acid (salt) solution is used to regenerate the inorganic adsorbent. a processing method hardly biodegradable organic substance-containing water you reuse,
The non-biodegradable organic substance is a nonionic surfactant;
The inorganic adsorbent is one or more selected from the group consisting of porous silica, silica-based zeolite and smectite,
After passing the hardly biodegradable organic substance-containing water through the packed tower packed with the inorganic adsorbent to adsorb the hardly biodegradable organic substance to the inorganic adsorbent,
Regenerating the inorganic adsorbent by passing the persulfuric acid (salt) solution through a packed tower packed with an inorganic adsorbent adsorbing a hardly biodegradable organic substance;
A method for treating water containing hardly biodegradable organic substances, characterized by repeatedly using the regenerated inorganic adsorbent for adsorption treatment of hardly biodegradable organic substances. 5. The method for treating hardly biodegradable organic substance-containing water according to claim 4 , wherein the inorganic adsorbent is silica-based zeolite. 6. The method for treating hardly biodegradable organic substance-containing water according to claim 4 , wherein at least an anode of the electrodes used for the electrolytic reaction is a conductive diamond electrode.

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