JP5154898B2 - Flocculant - Google Patents

Description

The present invention relates to a flocculant .

  Conventionally, as a treatment of polluted water in rivers, lakes, marine areas, dams, etc., generally a coagulant is added to and mixed with the polluted water, then a polymer flocculant is added and mixed, and the supernatant that has become transparent by this treatment is discharged. How to do is known. By adding and mixing a coagulant to the polluted water, the suspended matter in the polluted water reacts and adsorbs to the coagulant to form granular flocs, and the flocs are further agglomerated with the flocculant to perform solid-liquid separation. Can do.

  Conventionally used coagulants include inorganic coagulants such as aluminum sulfate (sulfuric acid band), polyaluminum chloride (PAC), aluminum chloride, ferric chloride, and polyferric sulfate. Examples of the flocculant include nonionic, anionic and cationic organic polymer flocculants.

However, organic polymer flocculants are particularly expensive and are not suitable for use in the treatment of turbid water such as rivers and lakes that are required in large quantities.
In addition, depending on the type and turbidity of sludge and suspended solids, the inorganic coagulant is added alone or in combination of two or more, or in combination with a polymer flocculant, or when these flocculants are added The actual situation is that the treatment process is simple and not easy, such as pH adjustment with an agent or the like, and a stirring speed.

  In addition, when such an inorganic coagulant and polymer flocculant are used, the polymer flocculant can precipitate suspended substances, but if a large amount of polymer flocculant is used, a mass like a spice is formed. There was a problem that it was easy to become and it was not excellent in handling.

On the other hand, iron oxide and organic flocculant were blended with natural minerals mainly composed of alumina silicate impregnated with soil fungi as an inorganic flocculant purification treatment agent for polluted wastewater regardless of whether inorganic or organic. A technique in which sodium thiosulfate, calcium sulfate, and aluminum sulfate are blended with 100 parts by weight of the main component is known (see, for example, Patent Document 1).
JP 2004-8903 A

  However, when the polluted water is settled by the inorganic coagulation purification agent described in Patent Document 1, the adsorption function for the suspended substance is not sufficient and may be separated again, and the function as the coagulant is low. Met.

The present invention has been made in view of the above circumstances, and it is possible to obtain a polluted water treatment function capable of enlarging the floc floc to obtain a high sedimentation speed and allowing the floc to settle reliably without collapsing. An object of the present invention is to provide a very excellent flocculant .

In order to solve the above-mentioned problems, the invention according to claim 1 puts the discarded shell in an oxygen-free atmosphere.
A coagulation promoter formed by firing at 170 to 400 ° C. ,
A polymer flocculant;
A mixture of a coagulant and
5 to 95% by weight of the aggregation accelerator, 1 to 5% by weight of the polymer flocculant, and 1% of the coagulant.
It is characterized by being a ratio of -10 wt% .

The invention according to claim 2 is the flocculant according to claim 1 , wherein the flocculant is further mixed with a dispersing agent or an aggregating nucleating agent.

  According to the present invention, the aggregated floc can be enlarged to obtain a high sedimentation speed, and the floc can be surely settled without collapsing.

Hereinafter, the present invention will be described in detail.
The flocculant of the present invention comprises a coagulation accelerator, a polymer flocculant, and a coagulant as essential components, and further, if necessary, a dispersant and an aggregating nucleating agent are added and mixed. Specifically, the flocculant can be produced by mixing the following materials.

[1] Setting accelerator The setting accelerator accounts for 5 to 95% by weight of the flocculant.
In the present invention, a waste obtained by baking a waste containing an organic substance at a low temperature is used as a setting accelerator. Here, the waste containing organic matter includes, for example, marine waste and plant-derived waste. Marine waste refers to, for example, waste shells such as scallops, oysters, pearl oysters, etc., and marine organisms such as waste from which barnacles, jellyfish, seaweed, etc. attached to intakes and drains of power plants and port facilities are removed. The remains and sludge adhering to them. The plant-derived waste is, for example, weeds, grains, wood pieces, and the like.

A coagulation accelerator can be obtained by baking the waste containing the above organic matter at a low temperature of, for example, 170 to 400 ° C. for 30 minutes or more.
When marine waste is fired at a temperature higher than 400 ° C., organic components contained in the marine waste are volatilized, and the surface of the skeleton such as shells melts and the surface is flattened. Marine waste is porous because the multi-layer structure in the skeleton such as shells is maintained, and the surface area is increased. For this reason, the bond area with the particle | grains and polymer coagulant | flocculant in muddy water increases, and the floc which cannot be broken can be produced | generated. Further, a larger floc can be formed by holding the flocs. For this reason, the usage-amount of a polymer flocculent can be reduced.

In addition, since plant-derived waste is almost entirely composed of organic components, almost all of it is burned off when fired at a temperature higher than 400 ° C. However, when it is fired at low temperature in an oxygen-free atmosphere, plant-derived waste is discarded. Organic matter in the product can be carbonized.
On the other hand, when firing at a temperature lower than 170 ° C., organic carbides cannot be sufficiently obtained.
Such a carbide adjusts the charge in the muddy water, reduces the colloid content remaining after coagulation sedimentation, and the burned product of the attached sludge has the effect of increasing the specific gravity of the floc.

Low temperature firing is preferably performed in an oxygen-free atmosphere, and firing is preferably performed in an inert gas atmosphere or by a superheated steam method.
When firing in an oxygen-free atmosphere, organic matter such as mixed meat pieces contained in marine waste can be carbonized.

  Moreover, you may perform low-temperature baking for 30 minutes or more using superheated steam of 170-400 degreeC. When calcination is performed with superheated steam, the generated carbide can be expected to be activated by steam, and activated carbonization can be performed.

  In addition, the lower the firing temperature, the less the volatilization and burning of organic matter can be reduced. When firing at a low temperature of 300 ° C. or lower, more organic carbide is obtained than when firing at a temperature of 400 ° C. or higher. be able to. For this reason, in order to obtain many organic carbides, it is more preferable to perform baking at a low temperature of 170 ° C. to 300 ° C. for 30 minutes or more.

  Since the baked and pulverized powder is weakly alkaline (substantially neutral) and contains various contents, it has a function of balancing the charges charged in various turbidity particles in the treated raw water.

[2] Polymer flocculant The polymer flocculant accounts for 1 to 5% by weight of the flocculant. As the polymer flocculant, a mixture of several types of organic polymer polymers having different molecular weights in the same mole number is used. The polymer flocculant is a white powder and has a charge that is paired with the charge of particles in turbid water, thereby electrically adsorbing particles and generating floc.

Since the polymer flocculant is altered in an acidic solution and hardly shows any effect, it is preferably used in a neutral or weak alkaline solution.
When the raw water for treatment such as cement is highly alkaline, a relatively high anion organic polymer polymer which is a general-purpose product is used. When processing raw water from a weak acid to a weak alkali region, it can be processed using a general-purpose product by using an alkalizing agent. As the alkalinizing agent, for example, calcium oxide can be used.

  In addition, since the polymer flocculant becomes a sticky liquid when mixed with water, when used in a large amount, the sedimented floc is covered with a gel-like polymer flocculant, and the water drainage becomes very bad. There is. In the present invention, since the use of the polymer flocculant can be reduced by using the above-described aggregation accelerator, flocs with less stickiness and good water drainage can be generated.

[3] Coagulant A sulfuric acid band is used as the coagulant. The sulfuric acid band accounts for 1-10% by weight of the flocculant. The sulfuric acid band is a white powder and is acidic when dissolved in water. When a sulfuric acid band is introduced into muddy water, the effect of increasing the sedimentation rate by adjusting the charge of the particles and eliminating the repulsive force is shown. When a sulfuric acid band is added to the polymer flocculant, it also acts as a dispersant for the polymer flocculant, making it difficult to form a powder.

  The sulfuric acid band has the effect of accelerating the decay of flocs produced by the polymer flocculant, so care must be taken when adding excessive amounts. Conventionally, in order to prevent the floc from collapsing, the polymer flocculant was added in an amount more than necessary. However, in the present invention, by using the above setting accelerator, the floc is prevented from collapsing and the polymer flocculant is minimized. Can be limited.

  As the coagulant, other metal salts such as PAC can also be used. When PAC is used, it can be used for 0 to 20% by weight of the flocculant. PAC is a yellow powder and has a coagulation action stronger than that of a sulfuric acid band. Therefore, PAC is added when there are fine particles that cannot be adsorbed only by the polymer flocculant. Since PAC has deliquescence, caution must be exercised because drugs containing PAC are quick to call moisture. In addition, PAC has an effect of accelerating the decay of flocs generated by the polymer flocculant, as in the case of the sulfate band.

[4] Dispersant The dispersant is used as necessary, and can be used in an amount of 0 to 93% by weight of the flocculant. As the dispersant, for example, a finely pulverized mineral having a negative surface charge can be used.

[5] Aggregating nucleating agent In the case of turbid water that is difficult to treat, such as extremely low turbid soil, an aggregating nucleating agent is added as a nucleating nucleus. As the aggregating nucleating agent, for example, a paper pulp type microfiber (about 2 to 3 mm) can be used. When an agglomerated nucleating agent is used, the agglomerated nucleating agent becomes a nucleus for crosslinking under low turbidity conditions, and can become a nucleus for a large bridge in slow stirring.

  By adding the necessary amount of flocculant produced by mixing the above materials into the polluted water, the flocculant accelerator, particles in the turbid water and the polymer coagulant form a neutralized salt, and this neutralization Suspended molecules condense on the salt. Then, the polymer flocculant causes a cross-linking action on the coagulation molecules to enlarge the flocs, so that the floc bridges are entangled with the porous surface of the flocculant promoter, and the flocs are connected to each other. With a large specific gravity. As a result, a good supernatant can be obtained.

As described above, according to the present invention, the specific surface area of the aggregation accelerator can be greatly increased as compared with the conventional one, and the surface adsorption function can be improved.
In addition, since the aggregation promoter has a multi-layer structure, it has a strong adsorptive power, so even if it is stirred, the floc will not re-disintegrate, and it will sink into the water while adsorbing suspended molecules. As stabilized. Thus, the floc formed by adsorbing the suspended molecules can be easily recovered.

  In addition, in order to reduce the amount of polymer flocculant used and generate a floc with good drainage, when reducing the amount of residue by dewatering the precipitate, the load on the dehydrator is reduced and the dewatering efficiency is improved. Processing costs can be greatly reduced. Further, since the content of the polymer flocculant in the residue is extremely low, the residue can be reused as a soil conditioner or the like.

  Furthermore, in the present invention, the aggregation accelerator is manufactured by low-temperature firing marine waste, and since these materials are waste, they can be easily obtained and manufactured at low cost. it can.

  In order to confirm the effect of the present invention, 20000 ppm of inorganic turbid water was placed in two 200 ml graduated cylinders (water surface height 25 cm), a flocculant was added, and the time until complete sedimentation was measured.

As a flocculant according to the present invention, a mixture of 34 mg of a flocculant accelerator (low-temperature fired shell), 2 mg of a polymer flocculant, and 4 mg of a sulfuric acid band was added to turbid water in a graduated cylinder. The low-temperature fired shell was fired in a superheated steam atmosphere at 350 ° C. for 30 minutes.
For comparison, a mixture of 2 mg of the polymer flocculant excluding the aggregation accelerator and 4 mg of the sulfuric acid band was added to the turbid water in the graduated cylinder.

  As a result, when the flocculant of the present invention was added, it took 10 seconds to complete sedimentation, whereas when the material excluding the low-temperature fired shell was added, it took 16 seconds to complete sedimentation. Thus, by adding the aggregation accelerator, particles in the muddy water can be rapidly settled.

Claims (2)

An agglomeration promoter formed by firing waste shells at 170-400 ° C. in an oxygen-free atmosphere ;
A polymer flocculant;
A mixture of a coagulant and
5 to 95% by weight of the aggregation accelerator, 1 to 5% by weight of the polymer flocculant, and 1% of the coagulant.
A flocculant characterized by a ratio of 10 to 10% by weight . The flocculant according to claim 1 , further comprising a dispersing agent or an aggregating nucleating agent.