JP4531823B2 - Waste water treatment apparatus and waste water treatment method for reusing chemicals for waste water treatment - Google Patents

Description

  The present invention relates to a sewage treatment apparatus and a sewage treatment method for treating high-concentration wastewater having a relatively high concentration discharged from a factory or the like and a low-concentration wastewater having a relatively low concentration of contamination. The present invention relates to a sewage treatment apparatus and a sewage treatment method for reusing chemicals.

  As a general treatment method of waste water discharged from factories or the like, activated sludge treatment and coagulation sedimentation treatment are known. The activated sludge treatment is a treatment method in which various types of aerobic microorganisms are activated in an aeration tank for regenerating the flocculant to decompose organic substances in the waste water into carbon dioxide and water and to precipitate sludge. In addition, the coagulation sedimentation treatment is a treatment method in which a coagulant such as ferric chloride is added to waste water and chemically reacted with the pollutant and separated into a precipitate and a supernatant.

  By using these activated sludge treatment and coagulation sedimentation treatment in combination with one of the treatment equipment and treatment methods for wastewater discharged from conventional factories and the like, the water and the sediment that can be finally discharged can be collected. It was known to separate the waste to be concentrated and treated as sludge.

  In addition, waste liquids from factories and the like have been subjected to waste water treatment by separating them into high-concentration waste water having a relatively high pollution level and low-concentration waste water having a relatively low pollution level.

  FIG. 2 shows Prior Art 1. In the sewage treatment apparatus of the prior art 1, the first flocculating agent 14a is added to the high-concentration wastewater 10 having a relatively high concentration to separate the first precipitate and the first supernatant liquid. The coagulation sedimentation treatment tank 101 to be performed, and the second sediment 11a and the second sediment which are precipitated by performing the activated sludge treatment of the first supernatant liquid 10b separated into the first sediment 10a and the first supernatant liquid 10b in the aggregation treatment tank 101. An activated sludge treatment tank 102 that separates the supernatant liquid 11b, a low-concentration wastewater 12 with relatively low contamination, a raw water tank 103 that treats the second supernatant liquid 11b, and a downstream side of the raw water tank 103 A reaction tank 104 that is positioned and adds the flocculant 14b for the second time to the treated water from the raw water tank 103, and a third precipitate 13a that is located downstream of the reaction tank 104 and coagulates and precipitates the treated water from the reaction tank 104. And third above And a final treatment tank 105 to separate the viewed fluid 13b.

  In the sewage treatment method performed using the sewage treatment apparatus shown in FIG. 2, the first flocculating agent 14 such as ferric chloride is added to the high-concentration wastewater 10 having a relatively high concentration in the flocculation treatment tank 101. Is added to perform a coagulation sedimentation treatment. Next, the 1st deposit 10a and the 1st supernatant liquid 10b which precipitated by the coagulation sedimentation process are isolate | separated. Next, the separated first supernatant liquid 10b is transferred to the activated sludge treatment tank 102 that performs the activated sludge treatment, and the activated sludge treatment tank 102 performs the activated sludge treatment, and the second precipitate 11a and the second precipitate 11 precipitated by the activated sludge treatment. 2. Separated into supernatant 11b.

  The second supernatant liquid 11b is transferred to the raw water tank 103 for treating the low-concentration wastewater 12 having a relatively low concentration, transferred from the raw water tank 103 to the reaction tank 104, and after adding the second flocculant 14b, It moves to the final treatment tank 105. In the final treatment tank 105, the third precipitate 13a and the third supernatant liquid 13b that coagulate and precipitate are separated, and the third supernatant liquid 13b that can be discharged is discharged.

  The first precipitate 10a, the second precipitate 11a, and the third precipitate 13a precipitated in these steps are respectively transferred to the concentration tank 106, and the concentrated sludge (10a, 11a, 13a) is lime in the lime tank 107. Is added. The waste water 15 discharged during concentration in the concentration tank 106 and the waste water 16 output in the dehydration tank 108 are further transferred to the raw water tank 103 and subjected to the same processing as described above.

  Further, the residue transferred to the dewatering tank 108 and dehydrated is discarded as sludge 17.

  In the case of the prior art 1, the first flocculant 14a is added to treat the high-concentration wastewater 10 having a relatively high concentration in the coagulation sedimentation treatment tank 101. It was necessary to administer a relatively large amount. However, since most of the flocculant 14a is taken into the first precipitate 10a by a chemical reaction or the like, the flocculant 14a combined or mixed with the first precipitate 10a has been discarded as sludge as it is. . In order to recover these flocculants 14a and use them again, it is necessary to decompose the organic matter in the first precipitate 10a.

  In addition, since the sewage containing the septic substance is circulated from the concentration tank 106 and the dehydration tank 108 to the raw water tank 103, the pollution concentration is higher than that of the low-concentration waste water, and the second flocculant 14b introduced into the reaction tank 104 The amount was also introduced in a relatively large amount in order to precipitate and agglomerate those septic substances.

  Furthermore, the second precipitate 11a that is precipitated by the activated sludge treatment contains many kinds of aerobic microorganisms. These useful kinds of aerobic microorganisms are added to the concentration tank 106 together with the second precipitate 11a. The lime tank 107 and the dewatering tank 108 are sludged and discarded, so that they are hardly reused.

  Furthermore, in the concentration tank 106, a large amount of organic matter in the first precipitate 10a and aerobic microorganisms in the second precipitate 11a are contained, and in order to prevent their decay, lime is put into the lime tank 107. It was necessary, and for the lime treatment, a holding operation such as a cleaning operation of the dehydration tank 108 was required.

In order to solve the above-mentioned problem, a coagulation sedimentation treatment tank for coagulating and precipitating high-concentration wastewater with relatively high contamination by adding a coagulant to separate the first precipitate and the first supernatant liquid;
An activated sludge treatment tank for separating the second precipitate and the second supernatant liquid, which are subjected to activated sludge treatment of the first supernatant liquid separated in the coagulation treatment tank, and a first precipitate and a second precipitate. A flocculant regeneration aeration tank for mixing and aeration while allowing aeration for about 72 hours; and
A raw water tank for treating sewage containing low-concentration wastewater with relatively low contamination and a second supernatant, and an aeration tank for coagulant regeneration located in the treated water from the raw water tank. Sewage having a reaction tank for reacting the regenerated material from the reactor, and a final treatment tank located downstream of the reaction tank for coagulating and precipitating the treated water from the reaction tank and separating it into a third precipitate and a third supernatant liquid We propose a sewage treatment system that reuses chemicals for treatment.

Further, in a coagulation sedimentation treatment tank that treats high-concentration wastewater with a relatively high concentration, the coagulation sedimentation process is performed by adding a coagulant, and the first precipitate and the first supernatant liquid precipitated by the coagulation sedimentation process are separated. And
The first supernatant liquid is transferred to an activated sludge treatment tank for performing activated sludge treatment, activated sludge treatment is performed in the activated sludge treatment tank, and the second precipitate and the second supernatant liquid precipitated by the activated sludge treatment are separated,
The second supernatant liquid is transferred to a raw water tank that treats sewage containing low-concentration wastewater having a relatively low level of contamination, and from the raw water tank to the reaction tank,
The first precipitate and the second precipitate are transferred to the flocculant regeneration aeration tank, mixed and retained while being aerated for about 72 hours, and then aerated, and then transferred to the reaction tank located downstream of the raw water tank. It is confused with the treated water from the raw water tank 4, and as it is or after adding the flocculant,
In the final treatment tank, coagulation sedimentation treatment is performed to separate the third precipitate and the third supernatant liquid, the third supernatant liquid that can be discharged is discharged, and the third precipitate is sludge through the concentration tank and the dewatering tank. We propose a sewage treatment method that recycles sewage treatment chemicals that are separated and disposed of.

  According to the present invention, in the coagulation sedimentation treatment tank for treating high-concentration wastewater, the first sediment precipitated by the addition of the flocculant, and the second sediment precipitated by the activated sludge treatment in the activated sludge treatment tank, By continuing to move to a flocculant regeneration aeration tank and mixing and aeration for about 72 hours, the aerobic microorganisms in the second precipitate cause decomposition of the organic matter in the first precipitate. The mixed flocculant component is extracted and becomes reusable. By transferring these to the reaction vessel, the reaction vessel contains a high concentration of the flocculant, and the amount of the flocculant that has been conventionally charged for the second time can be reduced to about 70%. It was.

  Therefore, the amount of the flocculant used for the unit amount of the conventional treatment wastewater can be reduced from about 70% to about half, which is very effective economically.

  In addition, the decomposition of the organic matter in the first precipitate, which was conventionally discarded as sludge, is carried out by the aerobic microorganisms in the second precipitate, which has been conventionally discarded, and extracted with BOD and normal hexane in the effluent water. It has the effect of stabilizing the substance concentration.

  Since the mixed sludge of the first precipitate containing a large amount of organic matter and the second precipitate containing a large amount of aerobic microorganisms as in the past is not put into the concentration tank, it is possible to prevent corruption in the concentration tank. it can. As a result, it is no longer necessary to install a sludge tank in which lime is added to prevent rot and improve the performance of the dehydrator, thus reducing cleaning and maintenance work.

  An embodiment of the present invention will be described with reference to FIG. The sewage treatment apparatus that reuses the sewage treatment chemical that is an embodiment of the present invention and the sewage treatment chemical that is reused in the sewage treatment apparatus are coagulants such as ferric chloride.

  In the sewage treatment apparatus that reuses chemicals for sewage treatment according to an embodiment of the present invention, the high-concentration wastewater 10 having relatively high contamination is subjected to flocculation precipitation treatment by adding a flocculant, and the first precipitate 10a and the first precipitate 10a. Separation of the coagulation sedimentation treatment tank 1 for separation from the supernatant liquid 10b, and the second sediment 11a and the second supernatant liquid 11b that precipitate by performing the activated sludge treatment of the first supernatant liquid 10b separated in the coagulation treatment tank 1 The activated sludge treatment tank 2, the first precipitate 10a precipitated in the agglomeration treatment tank 1, and the second precipitate 11a precipitated in the activated sludge treatment tank are mixed and retained while being aerated for about 72 hours and aerated. An aeration tank 3 for regenerating the flocculant, a raw water tank 4 for treating sewage containing a low-concentration wastewater 12 having a relatively low concentration, and a second supernatant liquid 11b; and a downstream side of the raw water tank 4. Raw water tank 4 The reaction tank 5 is made to react with the treated water from the flocculant regeneration aeration tank 3 and the treated water, and the treated water from the reaction tank 5 is coagulated and precipitated by the reaction with the third precipitate. A final treatment tank 6 that separates the third supernatant liquid, a concentration tank 7, and a dehydration tank 8 are provided.

  The flocculant regeneration aeration tank 3 has a mixing device that mixes the first precipitate 10a and the second precipitate 11a and an aeration device that aerates air, and the air 30 from the aeration device is stored in the tank as needed. For 72 hours (3 days) while being aerated. As a result, the high concentration organic matter in the aggregating agent regeneration aeration tank 3 is decomposed, and the aggregating agent 14a is separated and reused.

  The mixture of the first precipitate 10a and the second precipitate 11a is a regenerated material in which the flocculant 14a is separated and reused by aeration for 72 hours (3 days) in the flocculant regeneration aeration tank 3. All 31 is transferred to the reaction vessel 5.

  The raw water tank 4 treats the low-concentration waste water 12 with relatively low contamination, the second supernatant liquid 11b, the circulating water 33 from the concentration tank 7, and the circulating water 34 from the dehydration tank 8 (sedation). ) The treated water 32 from the treated (settled) raw water tank 4 is sequentially transferred to the reaction tank 5.

  The reaction tank 5 is located on the downstream side of the raw water tank 4, and the treated water 32 from the raw water tank 4 and the regenerated material 31 from the aggregating agent regenerating aeration tank 3 are mixed to form a flocculant in the regenerated material 31. The treated water 32 from the raw water tank 4 is coagulated and precipitated by 14a, and the third precipitate and the third supernatant are separated from each other in the final treatment tank 6.

  In the reaction tank 5, the amount of the second flocculant 14 c charged increases or decreases depending on the amount of the regenerated flocculant 14 a in the regenerated material 31 from the flocculant regenerating aeration tank 3. Generally, the amount of the flocculant 14c charged in the reaction tank 5 for the second time is about 0 to 30% in comparison with the prior art 1.

  In the final treatment tank 6, it is subjected to a coagulation sedimentation process and separated into a third sediment 13 a and a third supernatant liquid 13 b. The third supernatant liquid 13b in which the values of BOD, COD, etc. have fallen below the regulation before being separated and can be discharged is discharged to the outside. Then, the separated third precipitate 13 a is sent to the concentration tank 7 and concentrated, the returned circulating water 33 is sent to the raw water tank 4, and the remaining sludge 35 is sent to the dehydration tank 8. The circulating water 34 that has been sent to the dehydration tank 8 and dehydrated is sent to the raw water tank 4, and the remaining residue is discarded as sludge 36.

  A sewage treatment method for reusing a sewage treatment chemical according to an embodiment of the present invention will be described with reference to FIG. The sewage treatment method that reuses the sewage treatment chemical according to the present invention performs a coagulation sedimentation treatment by adding a coagulant 14a in the coagulation sedimentation treatment tank 1 that treats the high-concentration wastewater 10 with relatively high contamination, The first sediment 10a and the first supernatant liquid 10b that are precipitated by the coagulation sedimentation process are separated, and the first supernatant liquid 10b is transferred to the activated sludge treatment tank 2 that performs the activated sludge treatment, and the activated sludge is treated in the activated sludge treatment tank 2. The raw water tank which processes and isolate | separates the 2nd sediment 11a and the 2nd supernatant liquid 11b which precipitate by activated sludge processing, and the 2nd supernatant liquid 11b processes the low concentration waste water 12 whose pollution is comparatively low concentration. 4 and transferred from the raw water tank 4 to the reaction tank 5, and the first precipitate 10a and the second precipitate 10b are transferred to the aggregating agent regeneration aeration tank 3 and mixed and allowed to stay for 72 hours. After aeration treatment, the final treatment tank 6 is transferred to the reaction tank 5 located downstream of the raw water tank 4 and confused with the treated water 32 from the raw water tank 4, and added as it is or after adding the flocculant 14c. 3, the third precipitate 13 a and the third supernatant 13 b that are agglomerated and precipitated are separated, the third supernatant 13 b that can be discharged is discharged, and the third precipitate 13 a is discharged via the concentration tank 7 and the dehydration tank 8. The separated sludge 36 is separated and discarded.

  The present invention is used for wastewater treatment from factories and the like. In particular, the present invention is highly applicable to wastewater treatment for treating high-concentration wastewater with a relatively high pollution level and low-concentration wastewater with a relatively low pollution level.

The flowchart explaining the sewage treatment apparatus and sewage treatment method which reuse the chemical | medical agent for sewage treatment which is embodiment of this invention The flowchart explaining the sewage treatment apparatus and method of prior art 1

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Coagulation sedimentation tank 2 Activated sludge treatment tank 3 Aeration tank for coagulant regeneration 4 Raw water tank 5 Reaction tank 6 Final treatment tank 7 Concentration tank 8 Dehydration tank 10 High concentration waste water 10a First sediment 10b First supernatant liquid 11a Second precipitation Substance 11b Second supernatant liquid 12 Low concentration waste water 13a Third precipitate 13b Third supernatant liquid 14a Flocculant (first time)
14c Flocculant (second time)
30 Aeration air 31 Recycled material 32 Treated water from raw water tank 33 Sewage discharged from the concentration tank 34 Sewage discharged from the dehydration tank 35 Concentrated residue 36 Sludge (waste)

Claims (2)

A coagulation sedimentation treatment tank for coagulating and precipitating high-concentration wastewater with relatively high contamination by adding a coagulant to separate the first precipitate and the first supernatant;
An activated sludge treatment tank for performing the activated sludge treatment of the first supernatant liquid separated in the coagulation treatment tank and separating the second precipitate and the second supernatant liquid to be precipitated;
A flocculant regeneration aeration tank in which the first precipitate and the second precipitate are mixed and retained while being aerated for about 72 hours, and aerated.
A raw water tank for treating sewage containing low-concentration wastewater with relatively low contamination and a second supernatant;
Located on the downstream side of the raw water tank, a reaction tank for reacting the regenerated material from the flocculant regeneration aeration tank with the treated water from the raw water tank,
A sewage treatment apparatus for reusing sewage treatment chemicals, which is located downstream of a reaction tank and has a final treatment tank for coagulating and precipitating treated water from the reaction tank and separating it into a third precipitate and a third supernatant. In a coagulation sedimentation treatment tank that treats highly concentrated wastewater with relatively high contamination, coagulation sedimentation treatment is performed by adding a coagulant, and the first precipitate and the first supernatant liquid precipitated by the coagulation sedimentation treatment are separated. ,
The first supernatant liquid is transferred to an activated sludge treatment tank for performing activated sludge treatment, activated sludge treatment is performed in the activated sludge treatment tank, and the second precipitate and the second supernatant liquid precipitated by the activated sludge treatment are separated,
The second supernatant liquid is transferred to a raw water tank that treats sewage containing low-concentration wastewater having a relatively low level of contamination, and from the raw water tank to the reaction tank,
The first precipitate and the second precipitate are transferred to the flocculant regeneration aeration tank, mixed and retained while aeration is performed for about 72 hours, and then aerated. It is confused with the treated water from the raw water tank 4, and as it is or after adding the flocculant,
In the final treatment tank, coagulation sedimentation treatment is performed to separate the third precipitate and the third supernatant liquid, the third supernatant liquid that can be discharged is discharged, and the third precipitate is sludge through the concentration tank and the dewatering tank. Wastewater treatment method that reuses wastewater treatment chemicals that separate and dispose of wastewater.

Images