JP5381231B2 - Apparatus and method for treating wastewater containing sulfur-based COD component - Google Patents

Description

  The present invention relates to a treatment apparatus and a treatment method for wastewater containing sulfur-based COD components, and in particular, the wastewater containing sulfur-based COD components is passed through a long space including at least one carrier on which microorganisms are immobilized. And a biological treatment apparatus and method.

The blast furnace slag discharged from the blast furnace is mainly composed of CaO and SiO ₂ , but since the inside of the blast furnace is a strong reducing atmosphere, most of the sulfur contained in iron ore and coke is transferred to the slag. Blast furnace slag contains about 1-2% by mass of sulfur. The molten blast furnace slag discharged from the blast furnace is usually cooled and solidified to a predetermined temperature in a slag cooling field (slag yard), and then dug up by a bulldozer or a power shovel. After being placed, it is used as a civil engineering building material such as artificial crushed stone and ground improvement material.

  Here, when the cooling water comes into contact with the blast furnace slag during the cooling, or when rainwater comes into contact with the blast furnace slag during the temporary placement, the water contacted with components such as sulfur contained in the blast furnace slag It is known to leach into Similarly to the blast furnace slag, it is known that components such as sulfur are leached into rainwater and cooling water in steelmaking slag such as converter slag and hot metal desulfurization slag. The water in which the components such as sulfur are leached is referred to herein as “waste water”.

The sulfur component contained in the wastewater is present in the form of sulfide ions (S ²⁻ ), thiosulfate ions (S ₂ O ₃ ²⁻ ), sulfite ions (SO ₃ ²⁻ ), and the like. The sulfur component is measured as COD (Chemical Oxygen Demand: determined using potassium permanganate) in the wastewater standard. If the standard cannot be satisfied, the waste water cannot be discharged and oxidized to sulfate ions (SO ₄ ²⁻ ), or reacted with Ca (OH) ₂ to be recovered as gypsum (CaSO ₄ ). It will be necessary.

  Further, as another method for treating the sulfur-based components in the wastewater, a method of biological treatment using bacteria such as sulfur-oxidizing bacteria, for example, calcium is incorporated as disclosed in Patent Document 1. Examples of such an immobilized carrier suitable for sulfur-oxidizing bacteria include a method in which sulfur-oxidizing bacteria are acclimatized and propagated and biologically processed using a fixed bed bioreactor composed of this immobilized carrier. Furthermore, as disclosed in Patent Document 2, a method of treating with a Pseudomonas bacterium having a sulfur oxidation function under a neutral pH condition, or as disclosed in Patent Document 3, waste water Activated sludge mixed water is put into an aeration tank of a facility for biological treatment of wastewater, waste water containing sulfur-based COD components and organic compounds are supplied to this aeration tank, and oxidation-reduction potential (ORP) in the aeration tank And a method of treating wastewater while acclimatizing and growing sulfur-oxidizing bacteria by controlling the aeration in the aeration tank using the above as an index and controlling the pH in the aeration tank to a range of 4.0 to 7.5, and Patent Document 4 As an organic nutrient source for sulfur-oxidizing bacteria, there is a method of treating wastewater with sulfur-oxidizing bacteria while periodically adding rice bran or a phytic acid-containing organic compound.

JP-A-6-15294 JP-A-8-323390 JP-A-6-106187 JP 7-251195 A

  Furthermore, in recent years, for the purpose of quickly treating a large amount of wastewater, for example, a water channel or the like is provided with a carrier on which microorganisms are immobilized as shown in Patent Documents 1 to 4, and the wastewater is continuously or intermittently provided. A method for treating wastewater that is allowed to pass through waterways has been developed.

  However, when the above-described wastewater treatment method using a water channel or the like is used, wastewater containing low-concentration COD components can be treated effectively, but wastewater containing high-concentration COD components is treated in the middle of treatment. Since the dissolved oxygen is consumed up, the dissolved oxygen concentration is low on the downstream side of the water channel, and the COD component is not decomposed by the microorganisms on the downstream side of the water channel. Sulfate ions are generated along with the oxidation treatment, and the pH is lowered on the downstream side of the water channel. Therefore, the microorganisms activated normally in the neutral to weakly acidic range may sufficiently treat the COD component. There was a problem that I could not. Therefore, with respect to wastewater containing high-concentration COD components, the conventional wastewater treatment method cannot meet the wastewater standard, and development of a method for rapidly treating a large amount of wastewater is desired.

  The objective of this invention is providing the processing method and processing apparatus of the wastewater containing the sulfur type COD component which can be processed reliably and rapidly, even when it contains a high concentration COD component.

  As a result of diligent research to solve the above problems, the present inventors have found that a sulfur-based COD component is contained in a long space such as a water channel or a water tank having at least one microorganism-supporting material capable of supporting microorganisms. A method of biologically treating a COD component in the wastewater by passing wastewater containing the wastewater, wherein a part of the treated water after the wastewater has passed through the long space is taken out, and the wastewater Then, the waste water is mixed with a part of the treated water by passing through the long space again, so that the COD concentration can be reduced to a treatable concentration. Even if the COD concentration in the wastewater is extremely high and cannot be completely treated by only passing through the long space once, the treated water can be treated again. By passing through the long space Therefore, it is possible to prevent the high-concentration COD component from being discharged to the outside without being treated, and further, the problem about the decrease in pH and dissolved oxygen is that after adjusting the pH and oxygen of the treated water, It has been found that this problem can be solved by re-flowing into the long space.

The present invention has been made based on such findings, and the gist thereof is as follows.
(1) A waste water containing a sulfur-based COD component is passed through a long space including at least one microorganism-supporting material capable of supporting microorganisms, and the COD component in the waste water is biologically treated. A method, wherein a portion of treated water after passing through the long space is taken out, and the pH of the treated water is neutralized based on a measurement result of pH measured in a downstream region in the long space. A method for treating a wastewater containing a sulfur-based COD component , wherein the wastewater is mixed with the wastewater and passed through the long space after being adjusted to a weakly acidic range .

(2) The method for treating a wastewater containing a sulfur-based COD component according to (1), wherein the extracted treated water is blown with an oxygen-containing gas before being mixed with the wastewater to increase the dissolved oxygen concentration.

(3) The method for treating wastewater containing a sulfur-based COD component according to (2) above, wherein the oxygen-containing gas is blown in using an air lift pump.

( 4 ) The amount of the treated water to be taken out is adjusted based on the measurement result by measuring the pH and / or dissolved oxygen concentration in the downstream area in the long space before mixing with the waste water. The processing method of the waste water containing the sulfur type COD component of any one of (1)-( 3 ).

( 5 ) A waste water containing a sulfur-based COD component is passed through a long space including at least one microorganism-supporting material capable of supporting microorganisms to biologically treat the COD component in the waste water. A waste water supply means for supplying the waste water, a return means for taking out a part of the treated water that has passed through the long space, a pH adjusting tank for adjusting the pH of the treated water, Control means for controlling the pH of the treated water from a neutral to a weakly acidic range based on the measurement result of the pH measured in the downstream area within the long space, and the treated water adjusted to the pH and the waste water are mixed. And a wastewater treatment apparatus containing a sulfur-based COD component, comprising: a mixing tank for allowing the mixed water to flow into the long space.

( 6 ) The apparatus for treating wastewater containing a sulfur-based COD component according to the above ( 5 ), further comprising oxygen blowing means for blowing oxygen-containing gas into the extracted treated water.

( 7 ) The wastewater treatment apparatus containing a sulfur-based COD component according to ( 6 ), wherein the oxygen blowing means is an air lift pump.

( 8 ) The treatment apparatus for wastewater containing a sulfur-based COD component according to any one of ( 5 ) to ( 7 ), further comprising a control means for controlling the amount of the treated water to be taken out.

( 9 ) The waste water containing the sulfur-based COD component according to any one of ( 5 ) to ( 8 ), wherein the long space further includes stirring means for stirring waste water passing through the long space. Processing equipment.

  ADVANTAGE OF THE INVENTION According to this invention, even if it is a case where a high concentration COD component is contained, it became possible to provide a treatment method and a treatment apparatus for wastewater containing a sulfur-based COD component that can be reliably and rapidly treated.

It is a side cross section of the processing apparatus of the wastewater containing the sulfur type COD component by this invention. It is the perspective view which showed the shape of the microorganisms carrier material of this invention, (a) is the shape of the microorganisms carrier material used with the wastewater treatment apparatus of FIG. 1, (b) is used with the other wastewater treatment apparatus. The shape of the microorganism-supporting material obtained is shown. It is a side cross section about another embodiment of the processing apparatus of the wastewater containing the sulfur type COD component by this invention. It is a side cross section about another embodiment of elongate space by this invention. (a) is the perspective view which showed arrangement | positioning of the microorganisms supporting material of long space used for an Example and a comparative example, (b) is a cross section when the microorganisms supporting material of (a) is seen from upper direction. FIG. It is sectional drawing which showed the processing apparatus of the waste water containing the conventional sulfur type COD component, (a) shows the processing apparatus used for the comparative example 1 and (b) for the comparative example 2. FIG.

Hereinafter, the configuration of the present invention and the reasons for limitation will be described with reference to the drawings.
FIG. 1 is a side view of a cross section of a treatment apparatus for wastewater containing a sulfur-based COD component according to the present invention.
FIG. 2 (a) is a diagram showing the shape of the microorganism-supporting material used in the wastewater treatment apparatus of FIG. 1, and FIG. 2 (b) is the shape of the carrier used in another biological reaction tank. FIG.
FIG. 3 is a side view of a cross section of another embodiment of the wastewater treatment apparatus according to the present invention.

  The method for treating wastewater containing a sulfur-based COD component according to the present invention contains a sulfur-based COD component in a long channel 10 such as a water channel or a water tank having at least one microorganism-supporting material 11 capable of supporting microorganisms. This is a method of biologically treating COD components in the wastewater 20 by passing the wastewater 20 to be passed.

  The microorganism-supporting material 11 used in the present invention is not particularly limited as long as microorganisms for treating the COD component can be immobilized. For example, as shown in FIGS. 2 (a) and 2 (b), a string-like material is used. Microbial support material 11a (FIG. 2 (a)) and granular microbial support material 11b (FIG. 2 (b)). In addition, the material used for the microorganism-supporting material 11 is not particularly limited because the degree of adhesion of the microorganism does not vary greatly depending on the material. For example, nylon, vinylon, polyvinylidene, polypropylene, Or those composite materials etc. can be used.

  The microorganisms fixed to the microorganism-supporting material 11 may be microorganisms that can treat the sulfur-based COD component, and mainly include sulfur-oxidizing bacteria. Since the sulfur-oxidizing bacteria are bacteria widely distributed in the natural environment and are present in places where sulfur-based compounds such as slag yards are present, the microorganism is fixed to the microorganism-supporting material 11 by, for example, using a COD component. By bringing the microorganism-supporting material 11 into contact with the contained waste water for a certain period of time, the microorganisms can be spontaneously immobilized. It is also possible to use a method of immobilizing the microorganism-supporting material 11 by directly bringing it into contact with a culture solution of the microorganism.

Furthermore, the long space 10 is a space through which the waste water 20 or the like passes and processes the COD component, and includes, for example, a water channel and a water tank as shown in FIG. The waste water 20 is not particularly limited as long as it is a space where the waste water can be treated continuously or intermittently.
In addition, the long space 10 needs to include at least one microorganism-supporting material 11, and includes a plurality of microorganism-supporting materials 11 as shown in FIG. It is also possible.

  In addition, the method for installing the microorganism-supporting material 11 in the long space 10 is not particularly limited. For example, after creating a framework and immobilizing the microorganism-supporting material 11 in the framework, For example, a method of installing the frame in parallel or perpendicular to the flow direction may be used. In consideration of replacement and washing of the microorganism-supporting material 11 after long-term use, it is preferable that the framework is structured so that it can be taken out of the water channel, and the microorganism-supporting material 11 having a specific gravity smaller than that of water is used. It is also possible to perform COD processing in a floating state by fixing to a member or the like.

  Furthermore, it is preferable that the long space 10 includes a stirring means for stirring the waste water 20 passing through the long space 10. By stirring the waste water 20 by this stirring means, the COD concentration in the waste water 20 becomes constant, and stable treatment can be performed. The stirring means is not particularly limited as long as it can stir the waste water 20 in the long space 10. For example, a baffle as shown in FIG. 4, a stirrer, or the like can be used. Here, the stirring means 12 (baffle) shown in FIG. 4 is a partition wall having an opening 13 and has the effect of suppressing the occurrence of a short-circuit flow of water in the long space 10 and the occurrence of a dead water area. . Therefore, the entire space of the long space 10 can be effectively used for COD processing.

  And the processing method of the wastewater containing the sulfur type | system | group COD component by this invention takes out a part of the treated water 30 after passing through the inside of the said long space 10, and mixes with the said wastewater 20 as shown in FIG. Then, the inside of the long space 10 is passed.

Here, the following formulas (1) and (2) show an example of the reaction of the sulfur-based COD component by the microorganism, but both formulas are oxidation reactions and sulfuric acid is generated.
H ₂ S + 2O ₂ → H ₂ SO ₄ (1)
Na ₂ S ₂ O ₃ + 2O ₂ + H ₂ O → Na ₂ SO ₄ + H ₂ SO ₄ (2)
Therefore, by continuing to process the COD component in the waste water 20, in the downstream region in the long space 10, oxygen is reduced by an oxidation reaction, and pH is lowered by generation of sulfuric acid. Since the microorganisms such as sulfur-oxidizing bacteria require oxygen for their growth, they cannot live under conditions of low dissolved oxygen concentration. In addition, the optimum pH of sulfur-oxidizing bacteria is neutral to weak. There is a problem that the activity of the microorganism itself is lowered and the COD component cannot be treated because the pH is lowered due to being acidic.
By adopting the above configuration, the present invention reduces the COD concentration of the water 40 obtained by mixing the waste water 20 and the part 31 of the treated water to a treatable concentration, thereby ensuring the COD component in the waste water 20. Can be processed. Further, even if the COD concentration in the waste water 20 is extremely high and the COD component is not completely treated by passing through the long space 10 once, the treated water part 31 is treated with the long water. Since it can be made to pass through the shank space 10 again, the waste water 20 containing a high concentration COD component can also be treated effectively.

  Further, it is preferable that the extracted treated water 31 is blown with an oxygen-containing gas 51 to increase the dissolved oxygen concentration before being mixed with the waste water 20. In the downstream area of the long space 10, oxygen is reduced by an oxidation reaction for COD treatment. Therefore, if the oxygen-containing gas 51 is blown into the extracted treated water 31 to increase the dissolved oxygen concentration, This is because the microorganisms can live on the downstream side of the long space 10 and the COD component can be sufficiently processed. The oxygen-containing gas is preferably blown by using an oxygen blowing means 50 such as an air lift pump that is also used as a returning means that can also be used for oxygen-containing gas blowing or to transfer treated water described later. Further, the blowing of the oxygen-containing gas may be performed before the pH adjustment as shown in FIG. 1, or may be performed simultaneously with the pH adjustment as shown in FIG.

  Here, the oxygen blowing means 50 for blowing the oxygen-containing gas 51 is particularly limited as long as it can raise the dissolved oxygen concentration of the extracted treated water 31 by blowing the oxygen-containing gas 51. However, any means can be used, but the oxygen blowing means 50 can be taken out of the treated water 31 while blowing in the oxygen-containing gas 51, so that the oxygen blowing means 50 uses an air lift pump. Is preferred.

Further, the pH of the treated treated water 31 taken out is adjusted before mixing with the waste water 20 . The pH of the wastewater 20 is generally high (about 10 to 12.5), and after mixing with the treated water 31 that has been taken out, when the pH is adjusted from neutral to weakly acidic, This is because the COD component can be sufficiently treated without reducing the activity of the microorganism. Further, the pH adjuster 71 used for pH adjustment is usually an acid such as sulfuric acid. When the pH adjuster 71 is added after mixing with the wastewater 20 or at the same time as mixing, the wastewater 20 This is because the sulfide ions and the pH adjusting agent 71 may react with each other and hydrogen sulfide gas may be generated because the treated water 31 is not sufficiently diluted.
Here, the pH adjuster 71 used for adjusting the pH may be an acid such as hydrochloric acid in addition to sulfuric acid. If the concentration of the sulfur-based COD component of the wastewater 20 is high, Since pH becomes low, alkalis, such as sodium hydroxide, can also be used. It is more preferable to prepare both acid and alkali in preparation for the case where the quality of the extracted treated water 31 fluctuates.

As described above, the pH of the extracted treated water 31 is adjusted in the pH adjusting tank 70 before being mixed with the waste water 20 in the mixing tank 50 as shown in FIG . The pH adjusting tank 70 is a tank for storing the extracted treated water 31 and performing the operation of adding the pH adjusting agent 71, and can effectively adjust the pH of the extracted treated water 31. The size, shape, etc. are not particularly limited.

Further, the pH of the extracted treated water 31 is adjusted based on the measurement result obtained by measuring the pH in the downstream area in the long space 10 with a pH meter 61 as shown in FIG . This is because if the pH in the downstream area in the long space 10 is measured, the pH of the extracted treated water 31 immediately before the pH adjustment can be grasped, so that the pH can be easily and reliably adjusted. . Specifically, the pH of the extracted treated water 31 can be adjusted using a control means 60 as shown in FIG. Based on the result of the pH measured by the pH meter 61 provided in the downstream area in the long space 10, the amount of the pH adjusting agent 71 added to the extracted treated water 31 can be adjusted.

  In addition, when the pH at the downstream end of the long space 10 is too low under the condition that the dissolved oxygen concentration is not a limiting factor for the reaction, the general discharge standard is 5.8 to 8.6, and thus the biological activity In addition, since it is not preferable in terms of the quality of the discharged water, the amount of water to be taken out may be increased, or the input amount in the case of using an acid as the pH adjusting agent 71 by increasing the set value of pH in the pH adjusting tank 70 may be reduced. On the other hand, if the pH at the end of the downstream area in the long space 10 is too high, the amount of water to be taken out is reduced or the pH set value in the pH adjustment tank 70 is lowered to satisfy a general discharge standard. What is necessary is just to increase the input amount in the case of using an acid as the pH adjuster 71.

  A part 31 of the treated water is taken out from the treated water 30 that has passed through the long space 10, mixed with the waste water 20, and then returned to the upstream region in the long space 10. It passes through the space 10 again. Moreover, as the return means 90 for taking out the part 31 of treated water, the water channel 91 and the air lift pump 50, as shown in FIG. 1, the pump 92 etc. can be used as shown in FIG.

Further, the amount of the treated water 31 to be taken out is adjusted based on the measurement result by measuring the pH and / or dissolved oxygen concentration in the downstream area in the long space 10 before mixing with the waste water 20. It is preferable to do. If the pH and / or dissolved oxygen concentration in the downstream area in the long space 10 is measured, the pH and / or dissolved oxygen concentration of the treated water 31 to be taken out immediately before being taken out can be ascertained. This is because it becomes possible to make adjustment.
Specifically, the amount of the treated water 31 to be taken out is more preferably in the range of 1 to 50 times the amount of the waste water 20. The effect of the present invention is sufficiently obtained when the amount of the treated water 31 to be taken out is 1 time or more with respect to the amount of the waste water 20, while the effect of the present invention is obtained when the amount of the waste water 20 is 50 times or less. Is sufficiently obtained, and it is effective from the viewpoint of energy saving without increasing the treated water to be taken out more than necessary. In addition, adjustment of the amount of the treated water 31 to be taken out can be performed using a control means 60 as shown in FIG. Process water to be taken out for mixing with the waste water 20 based on the pH and / or dissolved oxygen concentration measured by the pH meter 61 and / or the dissolved oxygen concentration meter 64 provided in the downstream area in the long space 10. Adjust the water volume of 31.

  In addition, if the dissolved oxygen in the downstream region of the long space 10 is too low (for example, 1 mg / L or less) under conditions where pH is not a limiting factor for the reaction, it is not preferable for biological activity. It is effective to increase the blowing amount of 51 and / or increase the amount of treated water 31 to be taken out.

  For example, as a method of controlling the amount of the treated water 31 to be taken out, there is a method of using a treated amount per one movement from the upstream side to the downstream side in the long space 10. Since the dissolved oxygen concentration is affected by the water temperature and coexisting substances, it cannot be discussed strictly. However, the dissolved oxygen concentration of the mixed water 40 of the waste water 20 and the extracted treated water 31 that flows into the long space 10 is determined. In order to increase the concentration to about 5 mg / L and make the dissolved oxygen concentration in the downstream area in the long space 10 about 1 mg / L, about 4 mg / L of dissolved oxygen will be consumed. If the COD component is oxidized at 4 mg / L, 4 mg / L of COD component can be removed per cycle. Therefore, if the COD of the waste water 20 is 50 mg / L and the COD of the treated water 30 is 10 mg / L, 40 mg / L of COD can be removed, but this can be processed in 10 cycles. Therefore, the calculation can be performed by setting the amount of the treated water 31 to be taken out to about nine times the amount of the waste water 20. Actually, since there is also oxygen dissolution from the air (atmosphere), the amount of treated water to be taken out can often be set smaller than the calculated value described above.

  Further, it is essential to mix the extracted treated water 31 with the waste water 20 before passing through the long space 10. Mixing of the extracted treated water 31 and the waste water 20 is performed in a mixing tank 80, and water 40 obtained by mixing the extracted treated water 31 and the waste water 20 from the mixing tank 80 into the long space 10. Inflow.

  Furthermore, in the mixing tank 80, since it is in a condition that hydrogen sulfide gas is likely to be generated by mixing the treated treated water 31 and the waste water 20, the upper part of the mixing tank 80 was not opened and was generated. The hydrogen sulfide gas is preferably extracted little by little and treated. As a method for treating hydrogen sulfide gas, commercially available and known techniques such as alkali absorption and a method of oxidizing the liquid after alkali absorption with hypochlorous acid may be used. In the pH adjusting tank 70 as well, when hydrogen sulfide gas is likely to be generated, it is preferable that the generated hydrogen sulfide is processed without opening the upper part. Furthermore, when the microbial treatment in the long space 10 is insufficient, such as when the treatment facility is started up, the concentration of hydrogen sulfide gas contained in the exhaust gas from the pump may increase when the air lift pump 50 is used. There is. Since the air lift pump 50 has a large amount of exhaust gas, it is preferable to treat hydrogen sulfide with respect to the exhaust gas. However, the generation of hydrogen sulfide in the exhaust gas of the air lift pump 50 is a problem that is limited to the case where the above-described microorganism processing ability is low. In addition, it is possible to suppress the generation of hydrogen sulfide gas by an operational measure such as gradually increasing the load that is the absolute amount of the processing amount.

  As shown in FIG. 1, the treated water 30 is transported directly from the long space 10 as shown in FIG. 2 even after the dissolved oxygen concentration is increased by the air lift pump 50. It doesn't matter. Further, although not shown in the figure, it is preferable to install a water tank for monitoring the treated water 30 to be transported to the outside, and discharge it after confirming that the treated water satisfies the discharge standard. You may give a pH adjustment function to a water tank, or you may provide a pH adjustment tank in the front | former stage of a monitoring water tank.

  Moreover, the wastewater treatment apparatus containing the sulfur-based COD component according to the present invention for realizing the above-described wastewater treatment method according to the present invention includes at least one microorganism capable of supporting microorganisms as shown in FIG. An apparatus 1 for biologically treating COD components in waste water 20 by passing waste water 20 containing a sulfur-based COD component through a long space 10 such as a water channel or a water tank provided with a support material 11. The waste water supply means 21 for supplying the waste water 20 such as a pump, the return means 90 for taking out a part of the treated water 30 that has passed through the long space 10, the treated water 31 and the waste water 20 taken out are It is characterized by comprising a mixing tank 80 for allowing the mixed water to flow into the long space 10 after mixing.

  The above description is merely an example of the embodiment of the present invention, and various modifications can be made within the scope of the claims.

Examples of the present invention and comparative examples will be described.
Example 1
In Example 1, a water channel (long space) 10 (total length: 7 m, width: 0.9 m, water depth: 0.3 m) including 81 microorganism-supporting materials 11 shown in FIG. 5 and as shown in FIG. A pump (waste water supply means) 21 for supplying the waste water 20; a return means 90 for taking out a part of the treated water 30 that has passed through the water channel 10 from the water channel 10 and returning it to the upstream side of the water channel 10; The treated water 31 and the waste water 20 are mixed, the mixing tank 80 into which the mixed water 40 flows into the water channel 10, the air pump lift 50 that blows oxygen-containing gas into the removed treated water 31, and the removal Waste water using a treatment apparatus 1 comprising a pH adjusting tank 70 for adjusting the pH of the treated water 31 and a control means 60 for adjusting the pH and adjusting the amount of the treated water 31 taken out. Twenty treatments were carried out over 4 weeks.
The waste water 20 was an actual slag yard waste water. The COD concentration of this wastewater was 65 mg / L, the pH was 11.9, and the supply amount of wastewater was 15 L / min.
Further, the amount of the treated water 31 to be taken out is 75 L / min. For the evaluation to be described later, after the amount of the treated water to be taken out can be secured at 75 L / min, that is, after the treatment reaches a stable state, Evaluation was performed.

(Comparative Example 1)
In Comparative Example 1, as shown in FIG. 6 (a), a water channel (long space) 100 (total length: 7 m, width: 0.9 m, water depth: 0.3 m) including 81 microorganism-supporting materials 11 (FIG. 5). ), A pH adjustment tank 700 for adjusting the pH of the waste water 20, and an air pump lift 500 for blowing oxygen-containing gas into the waste water 20 in the pH adjustment tank 700. Using the apparatus, the treatment of the waste water 20 was carried out for 4 weeks.
As in Example 1, the waste water 20 was waste water from an actual slag yard. The COD concentration was 65 mg / L, the pH was 11.9, and the amount of waste water supplied was 15 L / min.

(Comparative Example 2)
In Comparative Example 2, as shown in FIG. 6 (b), a water channel (long space) 100 (total length: 7 m, width: 0.9 m, water depth: 0.3 m) including 81 microorganism-supporting materials 11 (FIG. 5). ), A pH adjusting tank 700 for adjusting the pH of the wastewater 20, and an oxygen dissolving tank 600 for blowing an oxygen-containing gas into the wastewater 20 by an air pump lift 500. The wastewater 20 was treated for 4 weeks using
As in Example 1, the waste water 20 was waste water from an actual slag yard. The COD concentration was 65 mg / L, the pH was 11.9, and the amount of waste water supplied was 15 L / min.

The results of Examples and Comparative Examples were evaluated.
(Evaluation method)
(1) The waste water 20, the mixed water 40, the treated water 30 and 300 immediately after flowing through the water channel 10 immediately before flowing into the water channel 10 and after passing through the water channel 10 are collected, and the COD concentration (mg / L) was measured. The measurement results are shown in Table 1.
(2) The waste water 20, the mixed water 40, the treated water 30 and 300 immediately after passing through the water channel 10 just before flowing into the water channel 10 and after passing through the water channel 10 were collected, and the pH was measured. . The measurement results are shown in Table 1.
(3) The waste water 20, the mixed water 40, the treated water 30 and 300 are recovered immediately before flowing into the water channel 10, 3.5m through the water channel 10 and immediately after passing through the water channel 10, and the dissolved oxygen concentration ( mg / L) was measured. The measurement results are shown in Table 1.
(4) During the treatment of wastewater, the amount of hydrogen sulfide (volume ppm) generated in the mixing tank, pH adjusting tank or oxygen dissolving tank was measured. The measurement results are shown in Table 1.

From the results in Table 1, with respect to the COD concentration (mg / L), in Example 1, the COD concentration (mg / L) decreased (15.8 → 8.7 → 4.1) as the water channel was advanced, and the COD component was effectively treated. I found out. On the other hand, in Comparative Examples 1 and 2, although the COD concentration (mg / L) decreased (55 → 39, 61 → 41) until it passed through the water channel for 3.5 m, the passage from the time when the water channel passed through 3.5 m. There was almost no change until it came out (39 → 38, 41 → 40), and it was found that there was almost no treatment with microorganisms on the downstream side of the waterway.
Further, with respect to pH and dissolved oxygen concentration (mg / L), Example 1 shows almost constant values from before passing through the water channel to after passing, whereas in Comparative Examples 1 and 2, pH and dissolved oxygen concentration are shown. It was found that both oxygen concentrations were greatly reduced after passing through the passage. It is considered that due to the decrease in pH and dissolved oxygen concentration, the treatment of the COD component by the microorganism was not performed, and a large difference was produced as compared with the result of the COD concentration in Example 1.
Furthermore, although it was able to reduce effectively about generation | occurrence | production of hydrogen sulfide about Example 1, it turned out that much hydrogen sulfide has generate | occur | produced in the pH adjustment layer about Comparative Examples 1 and 2.
In each of the examples and comparative examples, the wastewater introduced into the channel is 15 L / min and the COD concentration of the wastewater is 65 mg / L. However, in Example 1, the treated water to be taken out is 75 L / min. Thus, the mixed water containing waste water is being processed at a rate about 4 times that of Comparative Examples 1 and 2.

  ADVANTAGE OF THE INVENTION According to this invention, even if it is a case where a high concentration COD component is contained, it is possible to provide the processing method and processing apparatus of the wastewater containing the sulfur type COD component which can be processed reliably and rapidly.

DESCRIPTION OF SYMBOLS 1 Treatment apparatus 10/100 for waste water containing sulfur COD component Long space, water channel 11 Microorganism support material 12 Stirring means 13 Opening part 20 Waste water 21 Waste water supply means 30 Treated water 31 A part of treated water, extracted treated water 40 Water 50, 500 mixed with waste water and extracted treated water, oxygen blowing means, air lift pump 51 oxygen-containing gas 60, 600 return means 61, 63 pH meter 64 Dissolved oxygen meter 70, 700 pH adjustment tank 71 pH adjuster 80 Mixing tank 90 Return means 91 Water channel 92 Pump 100 Controller 120 Hydrogen sulfide concentration meter

Claims (9)

A method of biologically treating COD components in waste water by passing waste water containing sulfur-based COD components through a long space comprising at least one microorganism-supporting material capable of supporting microorganisms. And
A portion of the treated water after passing through the long space is taken out, and the pH of the treated water is in a neutral to weakly acidic range based on the measurement result of the pH measured in the downstream region in the long space. A method for treating wastewater containing a sulfur-based COD component , wherein the wastewater is mixed with the wastewater and passed through the long space.   The method for treating wastewater containing sulfur-based COD components according to claim 1, wherein the treated water taken out is blown with an oxygen-containing gas before being mixed with the wastewater to increase the dissolved oxygen concentration.   The method for treating a wastewater containing a sulfur-based COD component according to claim 2, wherein an air lift pump is used for blowing the oxygen-containing gas. The amount of the treated water to be taken out is adjusted based on the measurement result by measuring pH and / or dissolved oxygen concentration in the downstream region in the long space before mixing with the waste water. method of processing waste water containing a sulfur-based COD components according to any one of 3. An apparatus for biologically treating COD components in waste water by passing waste water containing sulfur-based COD components through a long space having at least one microorganism-supporting material capable of supporting microorganisms. And
Waste water supply means for supplying the waste water, return means for taking out a part of the treated water that has passed through the long space, a pH adjustment tank for adjusting the pH of the treated water, and the pH of the treated water. After mixing the control means for controlling from neutral to weakly acidic range based on the measurement result of pH measured in the downstream area in the long space, the treated water adjusted to pH and the wastewater, the mixing An apparatus for treating wastewater containing a sulfur-based COD component, comprising: a mixing tank for allowing the treated water to flow into the long space. 6. The apparatus for treating wastewater containing sulfur-based COD components according to claim 5 , further comprising oxygen blowing means for blowing oxygen-containing gas into the extracted treated water. The apparatus for treating wastewater containing a sulfur-based COD component according to claim 6 , wherein the oxygen blowing means is an air lift pump. The apparatus for treating wastewater containing sulfur-based COD components according to any one of claims 5 to 7 , further comprising control means for controlling the amount of treated water to be taken out. The said long space is a wastewater processing apparatus containing the sulfur type COD component of any one of Claims 5-8 further equipped with the stirring means which stirs the wastewater which passes through the said long space.

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