JPH0775703A - Treatment of waste water - Google Patents

Abstract

PURPOSE:To effectively treat waste water with high removal efficiency without generating a large amt. of sludge by mixing a silicic flocculant with the waste water, agitating the mixture, introducing the waste water into a precipitate growth tank to grow the precipitate and then separating solid from liq. CONSTITUTION:The waste water contg. org. chemical material, suspended matter, emulsion, etc., is introduced into a mixing part 3 from a waste water pit 1, mixed in the mixing part 3 with the silicic flocculant obtained by dissolving the composite crystal mineral and amorphous mineral of silica with a reducing acid or a neutral acid and introduced from a tank 4 and agitated. The mixture is then introduced into a precipitate growth tank 6 in which a floc is formed and the precipitate is grown. A precipitate collecting tank is further installed, as required, to enlarge the floc. The liq. is then introduced into a flotation tank 10, and solid is separated from liq. by normal pressure flotation, pressure flotation or high-speed settling. The floated floc forms sludge which is discharged through a sludge discharge line 14. The treated water is discharged from the intermediate part of the tank 10 through a treated water discharge line 13.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for treating wastewater containing organic chemical substances, suspended substances or emulsions,
Specifically, by adsorbing and aggregating organic chemical substances or suspended substances or emulsions contained in wastewater using silica-based aggregating liquid, atmospheric pressure levitation, pressure levitation, and high-speed sedimentation for solid-liquid separation, The present invention relates to a method for treating wastewater, which removes the organic chemical substances, suspended substances, emulsions and the like.

[0002]

BACKGROUND OF THE INVENTION Conventionally, a pressure flotation method has been generally known as a means for solid-liquid separation by flotation of organic chemical substances, suspended substances, emulsions and the like in waste water. Floating treatments and high-speed sedimentation treatments using inclined plates are being tried.

However, all of these methods have various problems because they use Al-based and Fe-based aggregation liquids.

That is, the Al-based and Fe-based flocculating liquids used in the conventional flotation treatment and high-speed sedimentation treatment have a very weak function of adsorbing or condensing organic chemical substances, suspended substances, emulsions, etc. When using it, while adjusting the pH, a large amount of Al-based or Fe-based coagulating liquid is used to generate a large amount of aluminum hydroxide or iron hydroxide precipitates, and then physically suspended in those precipitates. A method of separating the flocs from water by floating or sedimenting the flocs and the like and then adding a polymer flocculant to increase the floc shape.

For this reason, a large amount of sludge is generated due to the Al-based and Fe-based coagulants that have been administered, and there is a problem that the treatment cost must also be borne.

Further, some of Al ions and Fe ions and some of the polymer flocculant remain in the water, and there is a concern about the influence on the environment.

Furthermore, as a result of actually using the Al-based and Fe-based flocculating liquids in the above-mentioned atmospheric levitation treatment, pressure levitation treatment, and high-speed sedimentation treatment, organic chemical substances, suspended substances, emulsions, etc. It has been found that the removal efficiency of is very low.

[0008]

Therefore, an object of the present invention is to treat wastewater that does not generate a large amount of sludge, is environmentally friendly, and has a high removal efficiency of organic chemical substances, suspended substances, emulsions and the like. To provide a method.

[0009]

The inventor of the present invention has come to the present invention as a result of extensive studies to solve the above problems.

In the wastewater treatment method according to the present invention, wastewater containing an organic chemical substance, a suspended substance, an emulsion or the like is introduced into a mixing section, and a silica complex crystal mineral
A silica-based aggregating solution obtained by dissolving an amorphous mineral with a reducing acid or a neutral acid is mixed and stirred, and then the mixture is introduced into a precipitation growth tank to form flocs in the precipitation growth tank to grow a precipitate. It is characterized in that the flocs are enlarged if necessary, and then the precipitate growth liquid is subjected to solid-liquid separation by an atmospheric pressure floating method, a pressure floating method or a high speed sedimentation method.

In a preferred embodiment of the atmospheric levitation method in the present invention, a hollow fiber device having fine pores on the surface is arranged in the flotation tank, and air is fed into the hollow fibers to directly produce fine particles from the fine pores. It is to send air bubbles into water and float flocs under normal pressure for solid-liquid separation.

As a preferred embodiment of the pressure levitation method,
The precipitation growth liquid is introduced into a flotation separation tank, and pressurized water formed by dissolving saturated air is discharged from the lower part of the separation tank in the flotation separation tank to generate bubbles, and the bubbles are attached to the flocs to float the flocs. Solid-liquid separation.

In a preferred embodiment of the high speed sedimentation method,
When the precipitation growth solution is introduced into a high-speed settling tank having an inclined plate on the upper part thereof, and when flocs are settled at high speed in the high-speed settling tank for solid-liquid separation, the inclined plate provided in the high-speed settling tank is There are two kinds of inclined plates that form an upflow channel and an upflow channel, and the precipitation growth solution is introduced into the downflow channel, and the flocs are brought into contact with the downflow channel inclined plate to cause the flocculation tank. The separated water is allowed to settle to the lower part and the separated water is transferred to the upward flow channel inclined plate, and relatively small flocs that could not be separated in the downward flow channel are introduced into the upward flow channel to incline the upward flow channel. This is to bring the flocs into contact with a plate and settle the flocs in the lower part of the settling tank for solid-liquid separation.

The present invention will be described in detail below.

The silica-based coagulating liquid used in the present invention is prepared by using a silica-based coagulating liquid raw material as a reducing acid or neutral acid (for example, dilute sulfuric acid)
It is obtained by dissolving in. Alternatively, the precipitate may be filtered after dissolution. When dilute sulfuric acid is used, the precipitate is mainly composed of CaSO ₄ .2H ₂ O.

As the silica-based flocculant raw material, silica composite crystalline minerals / amorphous minerals such as natural cristobalite,
While minerals of SiO ₂ containing 15 to 95 wt%, such as blast furnace slag is used, preferably 15 to SiO ₂
Blast furnace slag containing 50% by weight is used.

The silica-based flocculant raw material is used by pulverizing or pulverizing a silica composite crystal mineral / amorphous mineral, oxidizing the raw material containing sulfur, or mixing active carbon with the raw material. The particle size after pulverization or pulverization is preferably 5 mm or less, more preferably 4 mm or less, and in order to further increase the dissolution rate in dilute sulfuric acid, fine powder of 150 mesh or less is preferable.

Next, an example of the wastewater treatment method according to the present invention will be described with reference to the accompanying drawings.

(Atmospheric pressure levitation method) FIG. 1 is a flow chart showing an example of the atmospheric pressure levitation method adopted in the wastewater treatment method according to the present invention.

In FIG. 1, 1 is a drainage pit for storing drainage, and 2 is a drainage pump. Reference numeral 3 is a mixing section for mixing the waste water and the silica-based coagulating liquid.

Reference numeral 4 denotes a silica-based flocculating liquid tank for storing a silica-based flocculating liquid obtained by dissolving a silica-based flocculating liquid raw material with diluted sulfuric acid, and 5 denotes a silica-based flocculating liquid pump.

Numeral 6 is a precipitation growth tank for forming flocs to grow a precipitate, and numeral 7 is a stirrer.

Reference numeral 10 is a floating separation tank, and 11 is a hollow fiber device provided in the floating separation tank. Reference numeral 12 is an air supply means, 13 is a treated water discharge line, and 14 is a sludge discharge line.

In order to treat wastewater using each of the above devices, first, the wastewater stored in the drainage pit 1 is quantitatively sent to the precipitation growth tank 6 via the inflow pipe 8 using the drainage pump 2. In order to quantitatively feed the liquid, the flow meter 9 may be monitored and manually adjusted, but it may be automatically adjusted by opening and closing a control valve (not shown) interlocking with the flow meter 9.

On the other hand, an appropriate amount of the silica-based coagulation liquid is injected from the silica-based coagulation liquid tank 4 into the inflow pipe 8 using the silica-based coagulation liquid pump 5 according to the flow rate of the waste water.

After the silica-based coagulating liquid is injected into the inflow pipe 8, the mixture is mixed in the mixing section 3. The mixing section 3 may be a simple pipe, but a static mixer can also be used.

If the static mixer is used, the wastewater and the silica-based coagulating liquid can be immediately and efficiently mixed, and it is particularly preferable when a small amount of the silica-based coagulating liquid is added to a large amount of the wastewater. That is, when a small amount of silica-based coagulation liquid is added to a large amount of wastewater, OH ⁻ or metal ions in the wastewater react with the monomer silica in the coagulation liquid, or p
Due to fluctuations in H, gelation of silica may progress while monomer silica does not aggregate or adsorb organic chemicals, suspensions or emulsions in the wastewater, resulting in insufficient removal effect. Because there is.

Therefore, it is not necessary to use a special static mixer when there is no such a problem.

Further, in the present invention, when a static pipe is not used in the mixing section 3 and a simple pipe is used, the silica-based flocculating liquid may be directly added to the flocculation / growing tank 6. Therefore, in this case, the coagulation and growth tank 6 is the mixing section 3
Will also function.

Further, when a static mixer is used for the mixing section 3, the coagulation and growth tank 6 may be omitted or may be omitted.

When the precipitation growth tank 6 is provided next, rapid stirring is performed by the stirrer 7 in the precipitation growth tank 6.
The rotation speed of the stirrer is preferably 100 to 250 rpm. The residence time in the precipitation growth tank 6 is preferably in the range of 30 to 150 seconds. Flock (precipitation) is sufficiently generated by continuing stirring in the precipitation growth tank 6.

When it is desired to increase the size of the flock,
Alternatively, the pollutant concentration in the waste water may be high, or flocs may not be formed easily depending on the pH value of the precipitation growth solution. In that case, it is preferable to provide a precipitation collection tank (not shown) after the precipitation growth tank 6. In the settling tank, the flocs are slowly stirred by the stirrer, and the size of the flocs can be increased. The rotation speed of the stirrer is preferably 30 to 80 rpm. The residence time in the precipitation growth tank is preferably in the range of 30 to 300 seconds.

Then, the flocs (aggregates) are introduced into the flotation / separation tank 10 for levitating under normal pressure. The floating separation tank 10
As the hollow fiber device 11 provided inside, for example, one having the configuration shown in FIG. 2 is used.

That is, in FIG. 2, reference numeral 110 denotes an air introducing pipe, and one end of a hollow fiber 111 having a plurality of through holes is fixed to the air introducing pipe 110 so that air can be conducted therethrough. It is fixed in a spiral shape around the air introduction pipe 110 with one end as a base point through a partition member 112.
The partition member 112 is radially formed around the air introducing pipe 110, and by providing a fixing groove for fixing the hollow fiber 111 to the partition member 112, one hollow fiber 111 is attached to the air introducing pipe 110. You can wind it regularly when you wind it around. It is also preferable to fix the hollow fiber 111 in the fixing groove by a method such as welding after it is wound.

Reference numeral 113 is a cylindrical body having openings at both ends, and is fixed to the partition member 112 at both ends. The cylindrical body 113 is made of transparent resin in this embodiment, but is not particularly limited. Reference numeral 114 is a support member provided on the outer periphery of the air introduction pipe 110, and also has a function of fixing the partition member 112.

In this way, the one-stage module 115 which is an element for constructing the hollow fiber device 11 is formed. A plurality of such module stages can be connected to form a hollow fiber module (for example, 20 stages as one module). Therefore, when the required supply amount of air is small, the number of stages may be reduced, and when the required supply amount is large, the number of stages may be increased.

The method for forming the hollow fiber device 11 is not limited to the above-mentioned embodiment, and for example, a plurality of stages of modules may be integrally formed without forming each stage.

The hollow fiber device 11 having the above structure is arranged in the flotation / separation tank 10 with the Y direction facing the liquid surface. Therefore, when air is sent to the hollow fiber device 11, fine bubbles are released from the Y direction.

In the present invention, the hollow fiber device is preferably provided with a draft at the bottom of the flotation / separation tank 10 for circulating water in the tank. Further, a large number of hollow fiber devices 11 can be provided to send fine air to the entire surface of the flotation / separation tank 10. Further, the arrangement and the number can be changed appropriately.

When air is supplied from the air supply means 12, for example, a compressor to the hollow fiber device 11, fine bubbles are generated in the flotation / separation tank 10, and the flocs are attached to the flocs to increase the buoyancy and float.

Since some flocs settle in the flotation / separation tank 10 and do not come into contact with air bubbles, it is also preferable to provide a means in the flotation / separation tank 10 for floating the settling flocs.

In the present invention, the compressed air is supplied from the compressor used as the air supply means 12, but when fine air bubbles are generated in the floating separation tank 10, they are not in a pressurized state due to pressure loss. Atmospheric levitation,
Further, since it is not configured to discharge the pressurized water into the flotation separation tank 10 by using the treated water as driving water, it is distinguished from the pressurized flotation described later.

The floating flocs become sludge, which is discharged by a sludge scraper (not shown) and discharged to the outside of the system through the sludge discharge line 14. The treated water is discharged from the middle part of the floating separation tank 10 through a treated water discharge line 13.

When the treated water is used as intermediate water,
Sterilization by ultraviolet sterilization, bactericide administration, ozone sterilization, etc. is preferred. It is also preferable to adjust the pH of the treated water.

(Pressure levitation method) FIG. 3 is a flow chart showing an example of the pressure levitation method adopted in the wastewater treatment method according to the present invention. The pre-process of the flotation tank is the same as that shown in FIG.

In FIG. 3, reference numeral 21 is a pressurized water discharge portion provided in the floating separation tank 10. Reference numeral 22 is a pressure pump, 23 is an ejector for taking in air, 24 is a pressure tank, 25 is an air relief valve, and 26 is a pressure reducing valve.

The treated water is sent from the bottom of the flotation tank 10 to the pressure tank 24 by the pressure pump 22. Air is sucked by the ejector 23 on the way, and the sucked air is dissolved in the pressurized water to saturation according to Henry's law.

The pressured water in which the air is dissolved is adjusted in pressure by the pressure reducing valve 26, is sent to the pressurized water discharge part 21 provided at the bottom of the flotation separation tank 10, and is discharged into the flotation separation tank 10.

Since the discharged pressurized water is decompressed, the dissolved air becomes visible as fine bubbles and adheres to the flocs in the flotation tank 10. The floc with air bubbles floats because it has a large buoyancy.

The floating flocs are discharged as sludge through the sludge discharge line 14, and the treated water from which the flocs have been separated is discharged through the treated water discharge line 13.

(High-speed sedimentation method) FIG. 4 is a flow chart showing an example of the high-speed sedimentation method used in the wastewater treatment method according to the present invention. Since the pre-process of the high-speed sedimentation tank is the same as the pre-process of the flotation separation tank shown in FIG. 1, its description is omitted.

In FIG. 4, 30 is a high-speed settling tank,
Reference numeral 31 denotes an inclined plate for an upward flow passage and an inclined plate for a downward flow passage. The inclined plate 31 forms an inclined plate type downward flow passage 32 and an inclined plate type upward flow passage 33. 34 is a sludge return pump, 3
Reference numeral 5 is a sludge discharge valve, 36 is a sludge storage tank, and 37 is a drain line for returning the supernatant water of the sludge storage tank 36 to the high-speed sedimentation tank 30 or a drain pit (not shown).

The coagulation liquid introduced to the high-speed sedimentation tank 30 is mixed with the sludge sent from the sludge return pump 34 from the lower part of the high-speed sedimentation tank 30 at the side end portion of the high-speed sedimentation tank 30 to further promote the flocculation of flocs. , Grows to a floc group with extremely excellent precipitation properties.

Next, this mixed liquid flows into the inclined downward flow path 32, and is separated into a floc group and a liquid by the action of the inclined plate 31, the floc group descends to the lower part of the high-speed sedimentation tank 30, and the separated liquid is The process moves to the inclined plate type upward flow path 33. The relatively small flocs that could not be separated in the inclined plate type downward flow path 32 come into contact with the inclined plate 31 of the inclined plate type upward flow path 33 and are removed by sedimentation.

The flocs that have settled down become sludge and are withdrawn by the sludge discharge valve 35, and the sludge storage tank 36
Are stored in the pump, concentrated, extracted by the pump 361 through the sludge discharge line 14, and dehydrated if necessary.

It is also preferable to install a sludge scraper for scraping the sludge settled in the high-speed settling tank 30. In addition, stirring means may be attached for smoothing the discharge of sludge from the bottom surface or for stirring the sludge at the bottom surface so that the sludge does not solidify.

The treated water separated in the high-speed settling tank 30 is discharged through the treated water discharge line 13.

[0058]

EXAMPLES The present invention will now be described in more detail based on the examples of the present invention, but the present invention is not limited to the examples.

Example 1 (Treatment of garden pond water) (Production of silica-based coagulation liquid) Blast furnace slag (Ca basicity 1.
15, powder particle size 150 mesh or less) 42.5 g 1N
It was dissolved with 1 liter of (1 normal) dilute sulfuric acid to prepare a silica-based aggregating solution (SiO ₂ concentration of about 12000 ppm). Create the required amount in this way.

(Explanation of Apparatus Used) Using the apparatus shown in FIG. 1, pond water in a pond (drainage pit) 900 m ³ was treated.

The amount of waste water was 1.2 m ³ / Hr, and the silica-based coagulating liquid was supplied at 1.2 liter / Hr.

The precipitation growth tank had an effective capacity of 30 liters, and the floating separation tank had an effective capacity of 200 liters. The floating separation tank is equipped with a hollow fiber device of 90φ × 20 stages (1 module)
Three units were arranged.

The rotation number of the stirrer in the precipitation growth tank is 100 to 2
It was set in the range of 00 rpm. (Example of treatment) Garden pond water having the properties shown in Table 1 was treated. The results of the treatment are shown in Table 1. JI for analysis items
It was analyzed based on SK 0102.

SS is the suspended solids, BOD is the biochemical oxygen demand, and TP is the total phosphorus content.

Comparative Example 1 In Example 1, for comparison, the PAC aggregating liquid (polyaluminum chloride) was added in an amount shown in Table 1 while adjusting the pH with a NaOH solution instead of the silica aggregating liquid. The treating apparatus was the same as that in Example 1, but necessary pH adjusting apparatus and the like were added.

The processing results are shown in Table 1.

[0067]

[Table 1] As is clear from Table 1, the treatment method of the present invention effectively treats garden pond water.

Example 2 (Treatment of pond water into which domestic wastewater flows) (Explanation of the apparatus used) The pond water of the pond into which domestic wastewater flows was treated using the apparatus shown in FIG. The same silica-based coagulating liquid as in Example 1 was used.

The amount of drainage was 1.2 m ³ / Hr, and the silica-based coagulating liquid was supplied at 1.2 liter / Hr.

The precipitation growth tank had an effective capacity of 30 liters, and the floating separation tank had an effective capacity of 300 liters.

In the floating separation tank, the same two hollow fiber devices as in Example 1 were arranged. (Example of treatment) Pond water into which domestic wastewater having the properties shown in Table 2 flows was treated. The results of the treatment are shown in Table 2. The analysis items were analyzed based on JIS K 0102.

TOC represents the total amount of organic carbon and TN represents the total amount of nitrogen.

Comparative Example 2 In Example 2, for comparison, the PAC aggregating liquid (polyaluminum chloride) was added in an amount shown in Table 2 while adjusting the pH with a NaOH solution instead of the silica aggregating liquid. The processing apparatus was the same as in Example 2, but the necessary pH adjusting apparatus and the like were added.

The processing results are shown in Table 2.

[0075]

[Table 2] As is clear from Table 2, according to the treatment method of the present invention, pond water into which domestic wastewater flows is effectively treated.

Example 3 (Treatment of Food Factory Wastewater) (Explanation of Equipment Used) Food factory wastewater was treated using the apparatus shown in FIG. The same silica-based coagulating liquid as in Example 1 was used.

The amount of drainage was 1.8 m ³ / Hr, and the silica-based coagulating liquid was supplied at 3.6 liters / Hr.

The precipitation growth tank had an effective capacity of 60 liters, and the floating separation tank had an effective capacity of 300 liters.

One hollow fiber device used in Example 1 was placed in the floating separation tank. (Example of treatment) Wastewater from a food manufacturing plant having the properties shown in Table 3 was treated. The results of the treatment are shown in Table 3. The analysis items were analyzed based on JIS K 0102.

Comparative Example 3 For comparison in Example 3, the PAC aggregating solution (polyaluminum chloride) was added in an amount shown in Table 3 while adjusting the pH with a NaOH solution instead of the silica-based aggregating solution. The treating apparatus was the same as in Example 3, but the necessary pH adjusting apparatus and the like were added.

The processing results are shown in Table 3.

[0082]

[Table 3] As is clear from Table 3, the wastewater discharged from the food manufacturing plant is effectively treated according to the treatment method of the present invention.

Example 4 (Treatment of Wastewater Containing Acrylic Paint) (Explanation of Apparatus Used) The apparatus shown in FIG. 5 was used. Figure 5
[Fig. 3] is a flow chart showing an example of a method of treating wastewater containing acrylic paint. In FIG. 5, 41 is a drainage pit for storing acrylic paint-containing drainage, and 411 is a drainage pump.

42 is a silica-based coagulating liquid tank, 421, 4
22 is a silica-based coagulating liquid pump. Reference numeral 43 is a mixing tank for mixing the waste water and the silica-based coagulating liquid. Reference numeral 431 is a stirrer. Reference numeral 44 is a primary precipitation growth tank for growing flocs, and 441 is a stirrer, which is preferably movable. In addition, it is preferable to provide a wire mesh cage 442 that can be pulled up in the primary precipitation growth tank 44.

Reference numeral 443 is a NaOH solution tank for storing a NaOH solution used for adjusting the pH in the primary precipitation growth tank 54 to 6.0 to 6.5, and 444 is a NaOH solution pump. Reference numeral 45 is a secondary precipitation growth tank, and 451 is a stirrer. The configuration around the floating separation tank 10 is the same as that in FIG.

In order to treat the acrylic paint-containing wastewater using each of the above devices, first, the acrylic paint-containing wastewater stored in the drainage pit 41 is quantitatively sent to the mixing tank 43 using the drainage pump 411.

The silica-based aggregating liquid is a silica-based aggregating liquid tank 4
From the second step, an appropriate amount is sent to the mixing tank 43 by using the silica-based coagulating liquid pump 421. The mixed solution is sent to the primary precipitation growth tank 44,
When the pH is adjusted to 6.0 to 6.5 with stirring, the emulsion in the waste water becomes a ball shape and becomes a sponge ball to settle. The sludge that has settled is removed in batches by pulling up the wire mesh cage.

Since the wastewater from which the emulsion has been removed in the primary precipitation growth tank 44 still contains an organic solvent, a diffusing agent, etc., it is further sent to the secondary precipitation growth tank 45 and is sent by the silica-based coagulating liquid pump 422. It is mixed with a silica-based flocculating liquid and stirred by a stirrer 451 to grow flocs.

Then, the flocculation flocs are guided to the flotation / separation tank 10 for levitating the flocs under normal pressure, and in the flotation / separation tank 10, the organic solvent, the diffusing agent and the like are removed.

(Main equipment specifications and experimental conditions) Drainage volume 1.8 m ³ / H Mixing tank capacity 30 liters (with stirrer) Primary precipitation growth tank capacity 60 liters (with wire mesh basket) Secondary precipitation growth tank capacity 30 liters (With a stirrer) Floating separation tank capacity 300 liters Hollow fiber device 1 unit (1 module 90φ x 20 stages) Addition amount of silica-based coagulating liquid to mixing tank 900m
l / min Amount of silica-based coagulation liquid added to the secondary precipitation growth tank 90 m
l / min (Example of treatment) The acrylic paint-containing wastewater having the properties shown in Table 4 was treated. The results of the treatment are shown in Table 4. Regarding analysis items, JIS K 010 with turbidity and COD as indexes
It analyzed based on 2.

Comparative Example 4 In Example 4, for comparison, the PAC aggregating liquid (polyaluminum chloride) was added in the amount shown in Table 4 while adjusting the pH with a NaOH solution instead of the silica aggregating liquid. The processing apparatus was the same as in Example 4.

The processing results are shown in Table 4.

[0093]

[Table 4] As is clear from Table 4, according to the treatment method of the present invention, the emulsified acrylic paint-containing wastewater is effectively treated.

Example 5 The same process as in Example 1 was carried out except that in Example 1, the atmospheric pressure floating process was replaced by the pressurized floating separation process shown in FIG.

The results of the treatment are shown in Table 5. Analysis item is JI
It was analyzed based on SK 0102.

Comparative Example 5 In Example 5, for comparison, the PAC aggregating liquid (polyaluminum chloride) was added in an amount shown in Table 5 while adjusting the pH with a NaOH solution instead of the silica aggregating liquid. The treating apparatus was the same as that in Example 5, but necessary pH adjusting apparatus and the like were added.

The processing results are shown in Table 5.

[0098]

[Table 5] As is clear from Table 5, the treatment method of the present invention effectively treats the garden pond water, and particularly the remarkable treatment effect is obtained in T-P.

Example 6 The same processes as in Example 2 were carried out except that in Example 2, the atmospheric pressure floating process was replaced by the pressurized floating separation process shown in FIG.

The results of the treatment are shown in Table 6. Analysis item is JI
It was analyzed based on SK 0102.

Comparative Example 6 In Example 6, for comparison, the PAC aggregating liquid (polyaluminum chloride) was added in the amount shown in Table 6 while adjusting the pH with a NaOH solution instead of the silica aggregating liquid. The treating apparatus was the same as that in Example 6, but necessary pH adjusting apparatus and the like were added.

The processing results are shown in Table 6.

[0103]

[Table 6] As is clear from Table 6, according to the treatment method of the present invention, pond water into which domestic wastewater flows is effectively treated, and especially TOC
It can be seen that a remarkable processing effect can be obtained in T and P.

Example 7 The same processes as in Example 1 were carried out except that in Example 3, the atmospheric pressure floating process was replaced by the pressurized floating separation process shown in FIG.

The results of the treatment are shown in Table 7. Analysis item is JI
It was analyzed based on SK 0102.

Comparative Example 7 In Example 7, for comparison, the PAC aggregating liquid (polyaluminum chloride) was added in the amount shown in Table 7 while adjusting the pH with a NaOH solution instead of the silica aggregating liquid. The treating apparatus was the same as that in Example 7, but necessary pH adjusting apparatus and the like were added.

The processing results are shown in Table 7.

[0108]

[Table 7] Example 8 The same process as in Example 4 was carried out except that in Example 4, the atmospheric pressure floating process was replaced by the pressurized floating separation process shown in FIG.

The results of the processing are shown in Table 8. Regarding analysis items, turbidity and COD were used as indicators for analysis according to JIS K 0102.

Comparative Example 8 In Example 8, for comparison, the PAC aggregating liquid (polyaluminum chloride) was added in the amount shown in Table 8 while adjusting the pH with a NaOH solution instead of the silica aggregating liquid. The treating apparatus was the same as that in Example 8, but necessary pH adjusting apparatus and the like were added.

The processing results are shown in Table 8.

[0112]

[Table 8] As is clear from Table 8, the acrylic coating-containing wastewater is effectively treated according to the treatment method of the present invention.

Example 9 The same processes as in Example 1 were carried out except that in Example 1, the atmospheric floating process was replaced by the high-speed sedimentation process shown in FIG.

The high-speed settling tank had an effective capacity of 800 liters, and the sludge storage tank had an effective capacity of 50 liters.

The results of the treatment are shown in Table 9. Analysis item is JI
It was analyzed based on SK 0102.

Comparative Example 9 In Example 9, for comparison, the PAC aggregating liquid (polyaluminum chloride) was added in the amount shown in Table 9 while adjusting the pH with a NaOH solution instead of the silica aggregating liquid. The treating apparatus was the same as that in Example 9, but necessary pH adjusting apparatus and the like were added.

The processing results are shown in Table 9.

[0118]

[Table 9] As is clear from Table 9, the garden pond water is effectively treated according to the treatment method of the present invention.

Example 10 The same procedure as in Example 2 was carried out except that in Example 2, the atmospheric floating process was replaced with the high-speed sedimentation process shown in FIG.

The high-speed settling tank had an effective capacity of 800 liters, and the sludge storage tank had an effective capacity of 50 liters.

The results of the treatment are shown in Table 10. Analysis item is J
It was analyzed according to IS K 0102.

Comparative Example 10 In Example 10, for comparison, the PAC aggregating solution (polyaluminum chloride) was added in the amount shown in Table 10 while adjusting the pH with a NaOH solution instead of the silica-based aggregating solution. The processing apparatus was the same as in Example 10, but the required p
H adjuster etc. were added.

The processing results are shown in Table 10.

[0124]

[Table 10] As is clear from Table 10, the treatment method of the present invention effectively treats pond water into which domestic wastewater flows.

Example 11 The same processes as in Example 1 were carried out except that in Example 3, the atmospheric pressure floating process was replaced with the high-speed sedimentation process shown in FIG.

The high-speed settling tank has an effective capacity of 1000 liters,
The sludge storage tank had an effective capacity of 500 liters.

The results of the processing are shown in Table 11. Analysis item is J
It was analyzed according to IS K 0102.

Comparative Example 11 In Example 11, for comparison, the PAC aggregating solution (polyaluminum chloride) was added in the amount shown in Table 11 while adjusting the pH with a NaOH solution instead of the silica aggregating solution. The processing apparatus was the same as in Example 11, but the required p
H adjuster etc. were added.

The processing results are shown in Table 11.

[0130]

[Table 11] As is apparent from Table 11, the wastewater discharged from food manufacturing plants can be effectively treated according to the treatment method of the present invention.

Example 12 The same procedure as in Example 4 was carried out except that in Example 4, the atmospheric pressure floating process was replaced with the high-speed sedimentation process shown in FIG.

The high-speed settling tank has an effective capacity of 1000 liters,
The sludge storage tank had an effective capacity of 500 liters.

Table 12 shows the processing results. Analysis item is J
It was analyzed according to IS K 0102.

Comparative Example 12 In Example 12, for comparison, the PAC aggregating liquid (polyaluminum chloride) was added in an amount shown in Table 12 while adjusting the pH with a NaOH solution instead of the silica aggregating liquid. The processing apparatus was the same as in Example 12, except that the required p
H adjuster etc. were added.

The processing results are shown in Table 12.

[0136]

[Table 12] As is clear from Table 12, the acrylic paint-containing wastewater is effectively treated according to the treatment method of the present invention.

Example 13 (Explanation of the device used) A machine was used in which the levitation separation tank for atmospheric levitation shown in FIG. 1 was replaced with the levitation separation tank for pressure levitation shown in FIG. The wastewater that flowed into the merged treatment tank of the A Machinery Co., Ltd. head office factory was treated as the main wastewater treatment targeting the removal of oil.

The same silica-based coagulating liquid as in Example 1 was used. The amount of drainage was 2 m ³ / H, and the silica-based coagulating liquid was supplied at 6 liters / Hr.

The effective volume of the precipitation growth tank was 70 liters, and the floating separation tank for pressure floating was 700 liters.

(Processing Result) Table 13 shows the processing result.

[0141]

[Table 13] As is clear from Table 13, the treatment method of the present invention is effective in removing the oil component in the waste water containing the mechanical oil and the like.

Example 14 Treatment was carried out in the same manner as in Example 13 except that the target wastewater was replaced with the oil-containing kitchen wastewater and the wastewater amount was changed as shown in Table 14.

Table 14 shows the processing results.

[0144]

[Table 14]

[0145]

As is clear from the above description, according to the present invention, a wastewater treatment method is provided which is highly efficient in removing organic chemical substances, suspended substances, emulsions, etc. without generating a large amount of sludge. it can.

Further, according to the present invention, it is possible to provide a wastewater treatment method for effectively treating garden pond water, pond water into which domestic wastewater flows, food manufacturing factory wastewater, acrylic paint-containing wastewater.

[Brief description of drawings]

FIG. 1 is a flow chart showing an example of an atmospheric levitation method adopted in a wastewater treatment method according to the present invention.

FIG. 2 is a perspective view showing an example of a hollow fiber floating separation device.

FIG. 3 is a flow chart showing an example of a pressure levitation method adopted in the wastewater treatment method according to the present invention.

FIG. 4 is a flowchart showing an example of a high-speed sedimentation method adopted in the wastewater treatment method according to the present invention.

FIG. 5 is a flow chart showing an example of a method for treating wastewater containing acrylic paint according to the present invention.

[Explanation of symbols]

 1: Drain pit 2: Drain pump 3: Mixing part 4: Silica-based flocculating liquid tank 5: Silica-based flocculating liquid pump 6: Sedimentation growth tank 7: Stirrer 8: Inflow pipe 9: Flow meter 10: Floating separation tank 11: Hollow Thread device 110: Air introduction pipe 111: Hollow fiber 112: Partition member 113: Cylindrical body 114: Support member 12: Air supply means 13: Treated water discharge line 14: Sludge discharge line 21: Pressurized water discharge part 22: Pressurized pump 23 : Ejector 24: Pressurized tank 25: Air release valve 26: Pressure reducing valve 30: High-speed sedimentation tank 31: Inclined plate 32: Inclined plate type downward flow path 33: Inclined plate type upward flow path 34: Sludge return pump 35: Sludge discharge Valve 36: Sludge storage tank 37: Discharge line 43: Mixing tank 44: Primary precipitation growth tank 45: Secondary precipitation growth tank

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Claims (1)

[Claims] 1. Obtained by introducing wastewater containing an organic chemical substance, a suspended substance, an emulsion or the like into a mixing section, and dissolving a complex crystalline mineral / amorphous mineral of silica in the mixing section with a reducing acid or a neutral acid. The silica-based flocculating liquid is mixed and stirred, and then the mixture is introduced into a precipitation growth tank to form flocs in the precipitation growth tank to grow a precipitate, and if necessary, the flocs are increased in size, and then the precipitation growth liquid is kept at a constant temperature. Pressure levitation,
A method for treating wastewater, which comprises solid-liquid separation by a pressure floating method or a high-speed sedimentation method.