JP2007130545A - Method and apparatus for treating drainage - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for treating drainage which accurately flocculates an organic material in drainage, and a reaction product of phosphoric acid ions and calcium hydroxide in the drainage; and further, can easily reuse an agglomerate to be obtained as a fertilizer. <P>SOLUTION: This method is employed for treating the drainage by flocculating the organic material in the drainage using a flocculant, wherein the flocculant includes calcium hydroxide and/or a material capable of supplying calcium hydroxide in the water, and the flocculant is mixed with the drainage under the presence of the phosphoric acid ions, thereby generating the agglomerate including the organic material in the drainage, and the reaction product of the phosphoric acid ions and calcium hydroxide in the drainage. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

The present invention relates to a novel wastewater treatment method and wastewater treatment apparatus.

In recent years, from the viewpoint of environmental conservation, there is an increasing need for technologies for purifying various industrial wastewater containing organic matter, sewerage polluted wastewater, civil engineering wastewater, domestic wastewater, and the like.
As such a technique, in particular, a method of aggregating suspensions contained in waste water to treat the waste water has attracted attention. The agglomeration process is very useful from the viewpoint of easily suppressing the discharge of pollutants, and development of a technique for aggregating organic substances in the wastewater with higher accuracy is desired. Furthermore, if the obtained agglomerated processed product can be effectively used as, for example, a fertilizer or a biomass raw material, it is very preferable from the viewpoint of reducing environmental impact.
As a prior art, Non-Patent Document 1 discloses an agglomeration method using slaked lime, quicklime, magnesium oxide limestone, and the like.
However, in the aggregating treatment method disclosed in Non-Patent Document 1, organic substances and phosphate ions cannot be aggregated, and by using slaked lime or the like, extra sludge is generated instead.
In particular, when limestone is used, if sulfuric acid is present in the waste water, gypsum (CaSO ₄ .2H ₂ O) is generated, which covers the limestone surface and the reaction does not proceed.
Patent Document 1 proposes a method of aggregating phosphorus and organic suspension in waste water using a coagulant such as aluminum and iron.
However, the above method still cannot sufficiently coagulate the organic matter in the waste water. Further, when the aggregate obtained by this method is reused as a fertilizer, for example, food waste such as okara must be mixed, which is complicated and costly.
Chemical Engineering Association, Physics and Chemical Processing Technology and Equipment (below), pages 8-9 JP2002-205077

  A main object of the present invention is to provide a wastewater treatment method capable of efficiently agglomerating organic matter in wastewater and further easily reusing the obtained agglomerate as fertilizer.

  As a result of intensive studies to achieve the above problems, the present inventor has found that a specific wastewater treatment method can achieve the above object, and has completed the present invention.

That is, the present invention relates to the following wastewater treatment method.
1. A method of treating wastewater by aggregating organic matter in wastewater using a flocculant,
(1) the flocculant comprises 1) calcium hydroxide and / or 2) a substance capable of supplying calcium hydroxide in water;
(2) By mixing the flocculant with wastewater in the presence of phosphate ions, it contains 1) organic matter in wastewater and 2) i) phosphate ions in wastewater and ii) reaction products of calcium hydroxide. Agglomerates are formed,
A wastewater treatment method characterized by that.
2. (1) the step of measuring the phosphate ion concentration in the wastewater; and (2) when the phosphate ion concentration in the wastewater is below the specified value, the phosphoric acid and / Or the waste water treatment method of said 1 further including the process of adding a phosphate.
3. Item 3. The wastewater treatment method according to Item 1 or 2, wherein the substance is calcium oxide.
4). Item 4. The wastewater treatment method according to any one of Items 1 to 3, wherein the flocculant is a shell powder fired at 700 ° C or higher.
5. Item 5. The wastewater treatment method according to any one of Items 1 to 4, wherein the amount of the flocculant added is 100 mg or more per liter of wastewater.
6). Item 6. The wastewater treatment method according to any one of Items 1 to 5, wherein the initial concentration of phosphate ions when adding the flocculant is 25 mg / L or more.
7). When the pH of the wastewater is lower than 9, the pH in the wastewater is within the range of 9 to 11 by adding a flocculant containing 1) calcium hydroxide and / or 2) a substance capable of supplying calcium hydroxide in water. The waste water treatment method according to any one of Items 1 to 6, wherein:
8). Item 8. The wastewater treatment method according to any one of Items 1 to 7, wherein a polymer flocculant is further added.
9. An apparatus for treating wastewater by aggregating organic matter in wastewater using a flocculant,
(1) Means for measuring the phosphate ion concentration in the wastewater,
(2) Means for adding phosphoric acid and / or phosphate to the waste water until the phosphate ion concentration is equal to or higher than the specified value when the phosphate ion concentration is lower than the specified value;
(3) For drainage, 1) calcium hydroxide and / or 2) means for aggregating organic matter in the wastewater by mixing a flocculant containing a substance capable of supplying calcium hydroxide in water; and (4) Means for separating and collecting agglomerates,
Including wastewater treatment equipment.
10. An apparatus for treating wastewater by aggregating organic matter in wastewater using a flocculant,
1) The apparatus includes at least a) a drainage tank for temporarily storing wastewater, b) an agglomeration treatment tank connected to the drainage tank via a pipe, and c) connected to the aggregation treatment tank via a pipe. Each filtration tank is installed,
2) Means for measuring the amount of drainage flowing from the drainage tank into the aggregation treatment tank,
3) Means for measuring the phosphate ion concentration of the wastewater in the drainage tank,
4) Based on the result of the amount of wastewater and the phosphate ion concentration measured by the means of 2) and the means of 3), the phosphate ion concentration of the wastewater in the aggregating treatment tank is not less than a specified value. Means for calculating the necessary amount of phosphoric acid and / or phosphate to be added to the waste water in the agglomeration treatment tank;
5) A wastewater treatment apparatus including means for adding phosphoric acid and / or phosphate to the wastewater in the aggregation treatment tank based on the calculation result.

  According to the wastewater treatment method and the wastewater treatment apparatus according to the present invention, it is possible to efficiently aggregate 1) organic matter in wastewater and 2) i) phosphate ions and ii) calcium hydroxide reaction product in wastewater. it can.

  In particular, when the phosphate ion concentration in the wastewater is below the specified value, the wastewater can be discharged more reliably by adding phosphoric acid and / or phosphate to the wastewater until the phosphate ion concentration exceeds the specified value. Organic matter inside can be agglomerated.

  Moreover, since the obtained aggregate can be reused as a fertilizer and a biomass raw material, for example, it can also contribute to effective utilization of resources.

Wastewater treatment method The wastewater treatment method of the present invention is a method for treating wastewater by aggregating organic matter in wastewater using a flocculant, wherein (1) the flocculant is 1) calcium hydroxide and / or Or 2) containing a substance capable of supplying calcium hydroxide in water, (2) 1) organic matter in the wastewater and 2) i) phosphate ions in the wastewater and ii) agglomerates containing the reaction product of calcium hydroxide Is generated.

  The flocculant may contain 1) calcium hydroxide and / or 2) a substance capable of supplying calcium hydroxide in water.

  The substance capable of supplying calcium hydroxide in water is not particularly limited, but calcium oxide is preferable. Calcium oxide has excellent reactivity with water and easily changes to calcium hydroxide.

  Examples of such a flocculant include shellfish powders fired at 700 ° C. or higher. By baking the shell at 700 ° C. or higher, the calcium carbonate contained in the shell can be sufficiently changed to calcium oxide. Furthermore, a part of the calcium oxide reacts with moisture in the air and changes to calcium hydroxide.

  In particular, it is preferable to use a shell powder baked at 700 ° C. or more as a flocculant also from the viewpoint of reuse of shells which are general wastes.

  Although the kind of the shell is not limited, oyster shells and scallop shells are preferable from the viewpoint of waste disposal because a large amount of shells are generated in oyster and scallop farms.

  The firing temperature of the shell is not particularly limited, but is preferably 700 ° C or higher, more preferably 800 ° C or higher, and further preferably 800 to 900 ° C. If the firing temperature is less than 700 ° C., the calcium carbonate contained in the shell cannot be sufficiently changed to calcium oxide.

  The firing time is not particularly limited, and may be appropriately adjusted depending on the firing temperature or the like. For example, when oyster shells are used as shells and the firing temperature is 700 ° C. or higher, the calcium carbonate in the oyster shells can be sufficiently changed to calcium oxide by firing for about 0.5 to 1 hour.

  The firing atmosphere may be either an air atmosphere or an oxidizing atmosphere, and is not particularly limited.

  The method for making the shells into powder is not particularly limited as long as a conventional method is followed. For example, the pulverization may be performed using a known pulverizer or crusher. The pulverization may be performed at any stage before or after firing the shell. Depending on the firing conditions, shell powder may be obtained without special pulverization.

  The particle size of the powder is not particularly limited, but is preferably about 150 to 750 mesh.

  The amount of the flocculant added to the wastewater is not particularly limited, but is preferably 100 mg or more per liter of wastewater, and more preferably 500 to 5000 mg per liter of wastewater. By setting the addition amount of the flocculant to 100 mg or more per liter of the wastewater, when the organic matter in the wastewater is aggregated, phosphate ions present in the wastewater can be suitably taken into the aggregate.

  In this invention, the organic substance in waste_water | drain can be efficiently aggregated by mixing the said flocculant with waste_water | drain in presence of a phosphate ion.

  Specifically, a reaction product of calcium hydroxide and phosphate ions contained in the flocculant is generated by adding the flocculant to the wastewater containing phosphate ions. The reaction product is in a floc form, and organic matter in the waste water is taken into the floc product. As a result, organic substances in the waste water can be aggregated.

  Examples of the reaction product include hardly soluble salts such as calcium hydroxyapatite.

  The initial concentration of phosphate ions in the waste water when adding the flocculant is not particularly limited, but is preferably 25 mg / L or more, and more preferably 25 to 50 mg / L. When the initial concentration is 25 mg / L or more, it becomes easy to form a floc-like aggregate containing organic substances.

  When the initial concentration of phosphate ions in the waste water is less than 25 mg / L, the initial concentration of phosphate ions in the waste water is increased to 25 mg / L or more by supplementing the waste water with phosphoric acid and / or phosphate. can do. That is, even if the wastewater to be treated does not contain phosphate ions, the wastewater can be suitably treated by positively adding phosphoric acid and / or phosphate.

In summary, the wastewater treatment method of the present invention includes (1) a step of measuring the phosphate ion concentration of the wastewater, and (2) when the phosphate ion concentration of the wastewater is lower than the specified value, It is preferable to further include a step of adding phosphoric acid and / or phosphate to the waste water until the value becomes equal to or higher than the value.
The specified value of the phosphate ion concentration is not particularly limited, but is preferably 25 mg / L or more, and more preferably 25 to 50 mg / L. When the predetermined value is 25 mg / L or more, it becomes easy to form a floc-like aggregate containing organic substances.

  The phosphate is not particularly limited, and examples thereof include dibasic sodium phosphate and tribasic sodium phosphate. Of these, sodium triphosphate is particularly preferable.

  The drainage is not particularly limited as long as it contains organic matter. For example, various factory effluents, sewage polluted effluents, civil engineering effluents, domestic effluents and the like.

  Although pH in waste water is not specifically limited, 9-11 are preferable and 10.5-11 are more preferable. If the pH in the wastewater is within the range of 9 to 11, when the organic matter in the wastewater is aggregated, phosphate ions present in the wastewater can be suitably taken into the aggregate. The pH can be adjusted, for example, by adding the flocculant. Specifically, when the pH in the wastewater is lower than 9, the wastewater is added by adding a flocculant containing 1) calcium hydroxide and / or 2) a substance capable of supplying calcium hydroxide in water as described above. The pH inside can be in the range of 9-11. The pH can be adjusted by adding a neutralizing agent. Examples of the neutralizing agent include caustic soda.

  The biological oxygen demand of the wastewater (hereinafter abbreviated as “BOD”) is not particularly limited as long as it does not interfere with the effects of the present invention.

  The chemical oxygen demand (hereinafter abbreviated as “COD”) of the wastewater is not particularly limited as long as it does not interfere with the effects of the present invention.

  Mixing of the flocculant and the waste water can be performed, for example, by adding the flocculant to the waste water and stirring it using a known stirring device. The stirring speed is not particularly limited as long as it does not interfere with the effects of the present invention. The stirring time is not particularly limited, and may be set as appropriate according to the stirring speed and the like.

  After mixing, you may leave still. The standing time is not particularly limited and may be set as appropriate according to the situation.

  In the wastewater treatment method of the present invention, it is preferable to further add a polymer flocculant. By adding the polymer flocculant, the organic matter in the waste water can be agglomerated with higher accuracy. Moreover, the phosphate ion which exists in waste_water | drain can be taken in into an aggregate suitably. The polymer flocculant is not particularly limited, and examples thereof include an anionic polymer flocculant, a cationic polymer flocculant, and a nonionic polymer flocculant. Among these, anionic polymer flocculants are particularly preferable. As anionic polymer flocculants, product names “Diaflock AP-825B”, “Diaflock AP-520CH”, “Diaflock AP-825CH” (all manufactured by Dianitics Co., Ltd.) are particularly preferable. It is done.

  The agglomerates obtained by the above treatment may precipitate or float up in the waste water after the treatment.

  When the aggregate is precipitated, diatomaceous earth, kaolin or the like may be further added to the waste water before the treatment in order to enhance the sedimentation property.

  The aggregate obtained by the above treatment may be separated and collected by a known solid-liquid separation means. An example of such means is filtration. When the aggregate is separated and collected by filtration, the filter medium is not particularly limited, and for example, non-woven fabric, sand, anthracite, activated carbon and the like can be used. Among these, activated carbon is particularly preferable. By using activated carbon as a filter medium, water-soluble organic substances can also be removed.

  The agglomerates obtained above may be discarded as they are, but can be reused for fertilizers, biomass raw materials and the like. In particular, when it is reused as a fertilizer, it can be fertilized by a known fermentation process or the like without adding food waste such as okara.

  After separating and recovering the aggregate, the remaining supernatant may be further filtered using a known filtration device. Moreover, you may sterilize the said supernatant liquid or filtered water. The sterilizing treatment method is not limited, and for example, a known sterilizing agent may be used.

Wastewater treatment apparatus The present invention further includes the following wastewater treatment apparatus. That is, the wastewater treatment apparatus of the present invention is an apparatus for treating wastewater by aggregating organic matter in the wastewater using a flocculant,
(1) Means for measuring the phosphate ion concentration in the wastewater,
(2) Means for adding phosphoric acid and / or phosphate to the waste water until the phosphate ion concentration is equal to or higher than the specified value when the phosphate ion concentration is lower than the specified value;
(3) For drainage, 1) calcium hydroxide and / or 2) means for aggregating organic matter in the wastewater by mixing a flocculant containing a substance capable of supplying calcium hydroxide in water; and (4) Means for separating and collecting agglomerates,
including.

The wastewater treatment apparatus of the present invention (hereinafter also referred to as “the present invention apparatus”) can more effectively execute the wastewater treatment method of the present invention.
The device of the present invention only needs to include the above means (1) to (4).
In particular, as a preferred embodiment, for example, an apparatus for treating wastewater by aggregating organic matter in wastewater using a flocculant,
1) The apparatus includes at least a) a drainage tank for temporarily storing wastewater, b) an agglomeration treatment tank connected to the drainage tank via a pipe, and c) connected to the aggregation treatment tank via a pipe. Each filtration tank is installed,
2) Means for measuring the amount of drainage flowing from the drainage tank into the aggregation treatment tank,
3) Means for measuring the phosphate ion concentration of the wastewater in the drainage tank,
4) Based on the result of the amount of wastewater and the phosphate ion concentration measured by the means of 2) and the means of 3), the phosphate ion concentration of the wastewater in the aggregating treatment tank is not less than a specified value. Means for calculating the necessary amount of phosphoric acid and / or phosphate to be added to the waste water in the agglomeration treatment tank;
5) A wastewater treatment apparatus including means for adding phosphoric acid and / or phosphate to the wastewater in the aggregating treatment tank based on the calculation result.
Hereinafter, the apparatus of the present invention will be specifically described with reference to FIG.

Means (1)
The device of the present invention includes means for measuring the phosphate ion concentration of the waste water.

  For example, the phosphate ion concentration measuring device 2 having the phosphate ion concentration sensing unit 1 of FIG. In this case, the phosphate ion concentration sensing unit 1 detects phosphate ions contained in the wastewater in the drainage tank 4, and the phosphate ion concentration measuring device 2 measures the phosphate ion concentration in the wastewater.

  For example, as shown in FIG. 1, the wastewater may be supplied from the drainage tank 4 to the aggregation treatment tank 3 through a pipe 6 provided with a flow rate measuring device 5.

Means (2)
The apparatus of the present invention includes means for adding phosphoric acid and / or phosphate to the waste water until the phosphate ion concentration becomes equal to or higher than the specified value when the phosphate ion concentration is lower than the specified value.

  Here, the specified value of the phosphate ion concentration is not particularly limited, but is preferably set to 25 mg / L or more. When the phosphate ion concentration in the wastewater is 25 mg / L or more, when the organic matter in the wastewater is agglomerated, it becomes easy to form a floc-like aggregate suitably incorporating the organic matter.

  For example, when the specified value is set to 25 mg / L, phosphoric acid and / or phosphoric acid until the phosphate ion concentration in the wastewater becomes 25 mg / L or more if the phosphate ion concentration in the wastewater is lower than 25 mg / L. What is necessary is just to add salt to waste water.

  The means for adding phosphoric acid and / or phosphate is not particularly limited, and for example, a phosphoric acid / phosphate injection machine 8 provided with the pipe 7 of FIG. In this case, phosphate ions are supplied from the phosphate ion implanter 8 to the aggregation treatment tank 3 through the pipe 7.

  In particular, in order to easily and accurately adjust the injection amount of phosphoric acid and / or phosphate, the wastewater treatment apparatus of the present invention calculates the necessary amount of phosphoric acid and / or phosphate to be added. It is preferable to include the means to do. For example, in FIG. 1, the following control system for the addition amount of phosphoric acid and / or phosphate is adopted. First, data of the measurement result of the amount of wastewater that has entered the flocculation treatment tank 3 is sent from the flow rate measuring device 5 to the control device 9. Here, the flow rate measuring device 5 can measure the amount of drainage flowing from the drainage tank 4 into the flocculation treatment tank 3. As the flow rate measuring device 5, for example, a positive displacement type may be adopted. Further, data of the measurement result of the phosphate ion concentration of the waste water in the drain tank 4 is sent from the phosphate ion concentration measuring device 2 to the control device 9.

  Next, based on the sent data (the measurement result of the amount of wastewater flowing into the agglomeration treatment tank and the phosphate ion concentration of the wastewater), the control device 9 determines that the phosphate ion concentration of the wastewater in the agglomeration treatment tank 3 is a specified value. As described above, the necessary amount of phosphoric acid and / or phosphate to be added to the wastewater in the flocculation treatment tank is calculated.

  Then, based on the calculation result, the control device 9 sends an injection amount control signal to the phosphoric acid / phosphate injector 8.

  Thereby, the injection amount of phosphoric acid and / or phosphate can be adjusted easily and accurately.

Means (3)
The apparatus of the present invention includes means for aggregating organic matter in the wastewater by mixing 1) calcium hydroxide and / or 2) a flocculant containing a substance capable of supplying calcium hydroxide in water.

  As the flocculant containing 1) calcium hydroxide and / or 2) a substance capable of supplying calcium hydroxide in water, the above flocculant may be used. The flocculant may be prepared in the form of powder or slurry according to the structure of the apparatus.

  The means for mixing the flocculant with the wastewater is not particularly limited, and may be appropriately set according to the scale of the apparatus. For example, as shown in FIG. 1, a flocculant injector 10 including a pipe 11 can be used. In this case, the flocculant may be prepared in the form of a slurry, for example, and supplied from the flocculant injector 10 to the flocculant treatment tank 3 through the pipe 11. Further, in FIG. 1, the following control system for the amount of flocculant added is employed. First, data of the measurement result of the amount of wastewater that has entered the flocculation treatment tank 3 is sent from the flow rate measuring device 5 to the control device 9. Next, the control device 9 calculates a necessary amount of the flocculant based on the sent data (measurement result of the amount of drainage flowing into the flocculation treatment tank). Then, based on the calculation result, the control device 9 sends an injection amount control signal to the flocculant injector 10. Thereby, the injection amount of the flocculant can be adjusted.

  Moreover, the said flocculant can be mixed with waste water with powder, for example by using a rotary feeder.

  When the pH of the wastewater is low, the pH in the wastewater can be adjusted to about 9 to 11 by adding the flocculant. The pH of the waste water can be measured by a known means. For example, the measurement may be performed using a pH (hydrogen ion concentration) measuring device 13 including the pH (hydrogen ion concentration) sensing unit 12 of FIG.

  Furthermore, the device of the present invention may include a neutralizing agent supply means. By adding a neutralizing agent to the wastewater, the pH in the wastewater can be adjusted. As a neutralizing agent supply means, for example, a neutralizing agent injector 15 provided with the pipe 14 of FIG. In this case, the neutralizing agent is supplied from the neutralizing agent injector 15 to the aggregation treatment tank 1 through the pipe 14. Moreover, in FIG. 1, the following control system of the addition amount of a neutralizing agent is employ | adopted. First, data on the measurement result of the pH of the wastewater in the flocculation treatment tank 3 is sent from the pH measurement device 13 to the control device 9. Next, based on the sent data (the measurement result of the pH of the wastewater in the flocculation treatment tank 3), the control device 9 calculates the necessary amount of the neutralizing agent. Then, based on the calculation result, the control device 9 sends an injection amount control signal to the neutralizing agent injector 15. Thereby, the injection amount of the flocculant can be adjusted.

  The apparatus of the present invention may include a stirring means for uniformly mixing the flocculant and the waste water. Examples of the agitation means include air bubbling and agitation with a screw.

Means (4)
The device of the present invention includes means for separating and collecting the aggregate.
As a means for separating and collecting the aggregate, for example, an aggregate collection tank 17 provided with the pipe 16 of FIG. In this case, the aggregate staying in the aggregation treatment tank 3 is collected in the aggregate collection tank 17 through the pipe 16.
In the apparatus of the present invention, other known solid-liquid separation means such as filtration may be appropriately employed.

The separated / recovered agglomerates can be reused, for example, as a fertilizer by performing a fermentation treatment as necessary.
Furthermore, the apparatus of the present invention preferably has a means for filtering the supernatant liquid remaining after separating and collecting the aggregates. As a means to filter, the filtration tank 18 of FIG. 1 is mentioned, for example. In this case, the remaining supernatant can be supplied to the filtration tank 18 through the pipe 19 and filtered.
Moreover, this invention apparatus may have a water tank (not shown) for storing the filtrate obtained by the said filtration.

  According to the apparatus of the present invention, organic substances in waste water can be aggregated with high accuracy. Such an apparatus is also useful as a means for purifying seawater containing jellyfish.

  Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. However, the present invention is not limited to these examples.

<Example 1>
Wheat flour was dissolved in the drainage water to prepare simulated drainage with a concentration of 1000 mg / L. Furthermore, phosphate ions were added to the simulated waste water, and the phosphate ion concentration of the simulated waste water was 25 mg / L. The COD of the simulated waste water was 599 mg / L.
The oyster shell calcined at 700 ° C. for 45 minutes was pulverized and passed through a 150 mesh sieve.
1 L of the simulated waste water was placed in a waste water treatment beaker, and 300 mg of the flocculant was added thereto. Thereafter, the obtained mixture was rapidly stirred at a stirring speed of 150 rpm for 6 minutes. Furthermore, it was gently stirred at a stirring speed of 50 rpm for 6 minutes. The resulting stirred product was allowed to stand for 10 minutes to obtain a supernatant.

<Example 2>
Waste water treatment was performed in the same manner as in Example 1 except that the phosphate ion concentration of the waste water was 50 mg / L.

<Example 3>
Exhaust treatment was performed in the same manner as in Example 1 except that the amount of the flocculant added was 400 mg.

<Example 4>
Exhaust treatment was performed in the same manner as in Example 2 except that the amount of the flocculant added was 400 mg.

<Example 5>
Wastewater treatment was performed in the same manner as in Example 1 except that quick lime was used instead of the flocculant and 300 mg of quick lime was added.

<Example 6>
Waste water treatment was performed in the same manner as in Example 5 except that the phosphate ion concentration of the waste water was 50 mg / L.

Table 1 shows the pH, turbidity (degree), COD (mg / L), phosphate ion concentration (mg / L), and phosphate ion removal rate (%) of the supernatants obtained in Examples 1 to 6. Show.
In addition, the measuring methods of pH, turbidity (degree), COD (mg / L), and phosphate ion concentration (mg / L) are as follows.

<Test Example 1>
Measurement of pH The pH was measured by the glass electrode method (JIS K0102).

<Test Example 2>
Turbidity measurement Turbidity was measured using a turbidimeter.

<Test Example 3>
Measurement of COD The measurement of COD was performed by measuring the oxygen consumption (COD _Mn ) of potassium permanganate at 100 ° C. (JIS K0102).

<Test Example 4>
Measurement of phosphate ion concentration The phosphate ion concentration was measured by molybdenum blue (ascorbic acid reduction) absorptiometry (JIS K0102).

<Example 7>
Starch was dissolved in the waste water to prepare a simulated waste water having a concentration of 1000 mg / L. Furthermore, phosphate ions were added to the simulated waste water, and the phosphate ion concentration of the simulated waste water was 25 mg / L. The COD of the simulated waste water was 450 mg / L.
A flocculant baked at a temperature of 700 ° C. for 45 minutes was pulverized and sieved to a 150 mesh sieve.
1 L of the simulated waste water was placed in a waste water treatment beaker, and 300 mg of the flocculant was added thereto. Thereafter, the obtained mixture was rapidly stirred at a stirring speed of 150 rpm for 6 minutes. Furthermore, it was gently stirred at a stirring speed of 50 rpm for 6 minutes. The obtained stirred product was allowed to stand for 10 minutes to obtain a supernatant.

<Example 8>
Exhaust water treatment was performed in the same manner as in Example 1 except that the phosphate ion concentration was 50 mg / L.

<Example 9>
Exhaust treatment was performed in the same manner as in Example 1 except that the amount of the flocculant added was 400 mg.

<Example 10>
Exhaust treatment was performed in the same manner as in Example 2 except that the amount of the flocculant added was 400 mg.

<Example 11>
Exhaust lime was used as a flocculant, and wastewater treatment was performed in the same manner as in Example 1 except that 300 mg of the flocculant was added.

<Example 12>
Exhaust water treatment was performed in the same manner as in Example 11 except that the phosphate ion concentration was 50 mg / L.

Table 2 shows the pH, turbidity (degree), COD (mg / L), phosphate ion content (mg / L), and phosphate ion removal rate (%) of the supernatants obtained in Examples 7-12. Shown in
The pH, turbidity (degree), COD (mg / L) and phosphate ion concentration (mg / L) of the supernatant were measured by the same method as in Test Examples 1 to 4.

<Example 13>
Wastewater treatment was performed in the same manner as in Example 1 except that 100 mg of the flocculant was added and 1 mg of Diafloc AP-520CH was further added.

<Example 14>
Wastewater treatment was performed in the same manner as in Example 13 except that 1 mg of Diafloc AP-825B was added instead of Diafloc AP-520CH.

<Example 15>
Wastewater treatment was performed in the same manner as in Example 13 except that 1 mg of Diafloc AP-825CH was added instead of Diafloc AP-520CH.

Table 3 shows the pH, turbidity (degree), COD (mg / L), phosphate ion concentration (mg / L) and aggregate floc state of the supernatants obtained in Examples 13-15.
The pH, turbidity (degree), COD (mg / L) and phosphate ion concentration (mg / L) of the supernatant were measured by the same method as in Test Examples 1 to 4.
Moreover, the state of the aggregate floc was confirmed visually. After standing for 10 minutes, floc-like aggregates settled, and fine organic substances are hardly suspended in the supernatant liquid. ◎, floc-shaped aggregates settled, and fine organic substances floated in the supernatant liquid. The one that is

<Example 16>
Wheat flour was dissolved in the drainage water to prepare simulated drainage with a concentration of 1000 mg / L. Furthermore, phosphate ions were added to the simulated waste water, the phosphate ion concentration of the simulated waste water was 25 mg / L, and the total phosphorus concentration was 8.2 mg / L. In addition, the BOD of the simulated waste water was 320 mg / L.
The oyster shell calcined at a temperature of 800 ° C. for 45 minutes was pulverized and passed through a 150 mesh sieve.
1 L of the simulated waste water was placed in a waste water treatment beaker, and 100 mg of the flocculant was added thereto. The resulting mixture was rapidly stirred for 6 minutes at a stirring speed of 150 rpm. Further, the mixture was gently stirred for 6 minutes at a stirring speed of 50 rpm. Then, the obtained stirring process thing was left still for 10 minutes, and the supernatant liquid was obtained.
Moreover, the obtained supernatant liquid was filtered with the filter paper (No. 2), and filtered water was obtained.

<Example 17>
Exhaust treatment was performed in the same manner as in Example 16 except that the amount of the flocculant added was 200 mg.

<Example 18>
Exhaust treatment was performed in the same manner as in Example 16 except that the amount of the flocculant added was 300 mg.

<Example 19>
Furthermore, wastewater treatment was performed in the same manner as in Example 16 except that Diafloc AP-825B was added.

  Table 4 shows the BOD (mg / L), turbidity (degree), total phosphorus concentration (mg / L), and total phosphorus removal rate (%) of the supernatants obtained in Examples 16 to 19. The pH, turbidity (degree), BOD (mg / L), total phosphorus concentration (mg / L), and total phosphorus removal rate (%) are also shown in Table 3 together.

<Test Example 5>
Measurement of BOD BOD was measured by measuring biochemical oxygen consumption (JIS K0102).

<Test Example 6>
Measurement of total phosphorus concentration Total phosphorus concentration was measured by a peroxo potassium disulfide decomposition method (JIS K0102).
The pH and turbidity (degree) of the supernatant were measured by the same method as in Test Examples 1 and 2.

FIG. 1 shows a conceptual diagram of the waste water treatment apparatus of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Phosphate ion concentration sensing part 2 Phosphate ion concentration measuring device 3 Coagulation treatment tank 4 Drainage tank 5 Flow rate measuring device 6 Pipe 7 Pipe 8 Phosphate / phosphate injection machine 9 Control device 10 Coagulant injection machine 11 Pipe 12 pH (Hydrogen ion concentration) sensing unit 13 pH (hydrogen ion concentration) measuring device 14 Pipe 15 Neutralizer injector 16 Pipe 17 Aggregate collection tank 18 Filtration tank 19 Pipe

Claims (10)

A method of treating wastewater by aggregating organic matter in wastewater using a flocculant,
(1) the flocculant comprises 1) calcium hydroxide and / or 2) a substance capable of supplying calcium hydroxide in water;
(2) By mixing the flocculant with wastewater in the presence of phosphate ions, it contains 1) organic matter in wastewater and 2) i) phosphate ions in wastewater and ii) reaction products of calcium hydroxide. Agglomerates are formed,
A wastewater treatment method characterized by that. (1) the step of measuring the phosphate ion concentration in the wastewater; and (2) when the phosphate ion concentration in the wastewater is below the specified value, the phosphoric acid and / Or the waste water treatment method of Claim 1 which further includes the process of adding a phosphate. The wastewater treatment method according to claim 1 or 2, wherein the substance is calcium oxide. The waste water treatment method according to any one of claims 1 to 3, wherein the flocculant is a shell powder baked at 700 ° C or higher. The wastewater treatment method according to any one of claims 1 to 4, wherein the addition amount of the flocculant is 100 mg or more per liter of wastewater. The wastewater treatment method according to any one of claims 1 to 5, wherein an initial concentration of phosphate ions when adding the flocculant is 25 mg / L or more. When the pH of the wastewater is lower than 9, the pH in the wastewater is within the range of 9 to 11 by adding a flocculant containing 1) calcium hydroxide and / or 2) a substance capable of supplying calcium hydroxide in water. The waste water treatment method according to any one of claims 1 to 6. The wastewater treatment method according to any one of claims 1 to 7, further comprising adding a polymer flocculant. An apparatus for treating wastewater by aggregating organic matter in wastewater using a flocculant,
(1) Means for measuring the phosphate ion concentration in the wastewater,
(2) Means for adding phosphoric acid and / or phosphate to the waste water until the phosphate ion concentration is equal to or higher than the specified value when the phosphate ion concentration is lower than the specified value;
(3) For drainage, 1) calcium hydroxide and / or 2) means for aggregating organic matter in the wastewater by mixing a flocculant containing a substance capable of supplying calcium hydroxide in water; and (4) Means for separating and collecting agglomerates,
Including wastewater treatment equipment. An apparatus for treating wastewater by aggregating organic matter in wastewater using a flocculant,
1) The apparatus includes at least a) a drainage tank for temporarily storing wastewater, b) an agglomeration treatment tank connected to the drainage tank via a pipe, and c) connected to the aggregation treatment tank via a pipe. Each filtration tank is installed,
2) Means for measuring the amount of drainage flowing from the drainage tank into the aggregation treatment tank,
3) Means for measuring the phosphate ion concentration of the wastewater in the drainage tank,
4) Based on the result of the amount of wastewater and the phosphate ion concentration measured by the means of 2) and the means of 3), the phosphate ion concentration of the wastewater in the aggregating treatment tank is not less than a specified value. Means for calculating the necessary amount of phosphoric acid and / or phosphate to be added to the waste water in the agglomeration treatment tank;
5) A wastewater treatment apparatus including means for adding phosphoric acid and / or phosphate to the wastewater in the aggregation treatment tank based on the calculation result.

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