JP2003211152A - Agent and method for removing organic substance in waste water - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an organic substance removing method which can purify various kinds of waste water such as factory effluent and domestic effluent in a short time in comparison with the activated sludge method, and safely and efficiently remove organic substances contained in the waste water. <P>SOLUTION: An organic substance removing agent contains a calcium silicate hydrate powder having a BET specific surface area of ≥30 m<SP>2</SP>/g or its granulated substance as an active ingredient. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an organic substance treatment / removal agent for various kinds of wastewater such as factory wastewater and domestic wastewater, and a method for removing organic matter from wastewater using the same.

[0002]

2. Description of the Related Art Conventionally, an activated sludge method has been widely used as a method for treating wastewater discharged from various factories and domestic wastewater.

In the activated sludge method, the activated sludge having a volume ratio of the waste water of 20 to 30% is added to an aeration tank (aeration tank), and air is introduced (air exposure) for 4 to 6 hours, and then the sludge is placed in a sedimentation tank. This is a method for purifying wastewater by discharging the supernatant water and returning the precipitated brown activated sludge to the aeration tank, and the activated sludge having a purification capacity is reused for wastewater purification. Further, aeration may be used for the purpose of removing the malodorous components in the waste water.

As described above, the activated sludge method is widely used as a wastewater treatment method, but it has a drawback that the treatment time is long in order to sufficiently remove organic substances. Therefore, a wastewater treatment method with a shorter treatment time is desired.

Although a method of treating wastewater using activated carbon is also known, activated carbon is expensive and has the ability to adsorb organic components contained in the wastewater, but the adsorption performance depends on the type of organic matter. Is insufficient, and the organic matter may not be sufficiently removed only by activated carbon treatment. Furthermore, activated carbon is flammable, and when storing 10 tons or more, it becomes a designated flammable material under the Fire Service Act, and handling is complicated. In addition, activated carbon containing water is highly corrosive,
When using an adsorption tower, it is necessary to select the material and coat the inner wall. Further, since activated carbon adsorbs oxygen in the air, there is a problem that the adsorption tower is in an oxygen-deficient state.

[0006]

The main object of the present invention is to:
It is an object of the present invention to provide a method capable of purifying various kinds of wastewater such as factory wastewater and domestic wastewater in a shorter treatment time than the activated sludge method, and further capable of safely and efficiently removing organic compounds contained in the wastewater.

[0007]

The inventor of the present invention has conducted extensive studies in order to achieve the above object. As a result, BE
The calcium silicate hydrate powder having a T specific surface area of 30 m ² / g or more, which is extremely large, has high adsorptivity for organic substances contained in water, and is relatively inexpensive and safe. It was found to be expensive. And, by using this as an organic matter removing agent in wastewater, it was found that the organic matter contained in the wastewater can be sufficiently removed, and further, the adverse effect caused in the wastewater treatment using activated carbon can be prevented, and the present invention is completed here. Came to.

That is, the present invention provides the following organic substance removing agent in waste water and a method for removing organic substance in waste water. 1. An agent for removing organic substances from wastewater, which comprises a calcium silicate hydrate powder having a BET specific surface area of 30 m ² / g or more or a granulated product thereof as an active ingredient. 2. A method for removing organic matter in wastewater, which comprises contacting the wastewater with the organic matter removing agent according to item 1.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The organic substance removing agent in waste water of the present invention contains calcium silicate hydrate powder having a BET specific surface area of 30 m ² / g or more as an active ingredient.

The calcium silicate hydrate particles having such a very large specific surface area usually have a porous structure, and various organic compounds contained in the waste water are treated with the calcium silicate hydrate. It can be efficiently adsorbed on the surface and inside the pores. The organic substance removing agent used in the present invention has an excellent performance in that it can sufficiently adsorb and remove even an organic substance that was difficult to remove by adsorption with activated carbon.
Further, the calcium silicate is preferable because it is nonflammable and inexpensive.

The calcium silicate hydrate, which is an active ingredient of the organic substance removing agent of the present invention, needs to have a specific surface area of about 30 m ² / g or more, preferably about 50 m ² / g or more. . In the present specification, the specific surface area is the specific surface area determined by the BET method based on the amount of N ₂ gas adsorbed.

If the specific surface area of the calcium silicate hydrate is smaller than the above range, it is not preferable because the removal performance of the organic substances in the recovered water cannot be sufficiently exhibited.

The organic substance removing agent used in the present invention may be any one as long as it satisfies the above-mentioned conditions, and its manufacturing method is not particularly limited.

For example, the BET specific surface area, which is an active ingredient of the organic substance removing agent of the present invention, is obtained by removing aggregates from concrete waste, crushing and crushing with a crusher or the like, and classifying as necessary. It is possible to obtain a calcium silicate hydrate powder having a ratio of 30 m ² / g or more.

In the present invention, particularly, a calcium silicate hydrate powder satisfying the above-mentioned conditions is obtained by a method in which water is added to a raw material containing a calcium silicate-forming raw material and a hydration reaction is carried out under wet grinding. Is preferably produced. According to this method, a product having high purity and high BET specific surface area can be easily manufactured. Hereinafter, regarding this manufacturing method,
The details will be described.

Various cements, granulated blast furnace slag and the like can be used as the raw material for producing calcium silicate.

Among these, in particular, granulated blast furnace slag is inexpensive and can be stably supplied, so that it is advantageous in that an organic substance removing agent of a constant quality can be produced. Granulated blast furnace slag has a vitreous structure and has a calcium content inside the SiO ₂ network skeleton. If the SiO ₂ skeleton is broken during the hydration reaction under wet pulverization, the calcium content will increase from the inside. The fraction elutes and sequentially reacts with its alkalinity to form calcium silicate hydrate. When granulated blast furnace slag is used as a raw material, calcium sulfate, calcium hydroxide, etc. may be added for the purpose of promoting the reaction.

Further, when cement is used as a raw material, excess calcium may be generated as calcium hydroxide in addition to calcium silicate only with cement, and the calcium silicate content may be reduced. In such a case, a general siliceous raw material such as fly ash, silica stone, or diatomaceous earth may be added to react with excess calcium hydroxide to produce calcium silicate hydrate.

Further, when the calcium content in the raw material is smaller than the silica content, unreacted silicic acid content remains in the slurry after the reaction, but this unreacted silicic acid content is useful for removing organic substances. Does not participate, so it is disadvantageous if a large amount remains. Therefore, an appropriate amount of calcium hydroxide, quick lime or the like may be added so that the unreacted silicic acid content becomes a calcium silicate hydrate.

These raw materials usually contain, as secondary components, calcium sulfate, calcium aluminate, ferrite and the like, and these are also hydrated by the hydration reaction in the same manner as calcium silicate. Yes, but no problem.

The mixing ratio of the above-mentioned raw materials may be appropriately determined so that the content ratio of the calcium silicate hydrate fine particles in the organic substance removing agent is as large as possible according to the kind of the raw materials used.

The amount of water added is 100 parts by weight with respect to 100 parts by weight of the raw material components containing the above-mentioned calcium silicate-forming raw material.
To about 2000 parts by weight, preferably 100 to
More preferably, the amount is about 1000 parts by weight.

In the wet pulverization and hydration reaction of the raw material, the raw material and water are usually charged into a pulverizer and the temperature is about 40 to 100 ° C. (preferably about 50 to 80 ° C.) and predetermined requirements (specific surface area, etc.) May be performed until particles satisfying the above are formed.

During the production of calcium silicate, a slurry is obtained in which the concentration and the fluidity of the produced solid content are different depending on the ratio of water used to the raw material. The obtained slurry can be used as it is as an organic substance removing agent.

Alternatively, the obtained slurry is dried at a temperature of about 80 ° C. or higher (preferably 100 to 200 ° C.), crushed if necessary, and then classified to a predetermined particle size to remove powdery organic substances. The agent can be obtained.

The obtained powder may be used as it is, or may be granulated and used according to the purpose. As the granulation method, various known granulation methods such as rolling, fluidized bed, extrusion, compression, crushing, and injection can be applied. As the binder used for granulation, the binder conventionally used can be used as it is. Examples of binders include alpha starch, sodium alginate, sugar, dextrin,
Clays such as corn syrup, gelatin, CMC, PVA, water glass, polyvinylpyrrolidone, polyacrylic acid, polyvinyl acetate, vinyl acetate-ethylene polymer, modified vinyl acetate, vinyl acetate-acrylic copolymer, cements and bentonite. Etc. can be mentioned.

The method for removing organic matter from wastewater using the organic matter removing agent of the present invention is not particularly limited as long as it can bring the organic matter removing agent into sufficient contact with the recovered water to be treated. .

As an example of the organic substance removing method, a batch type removing method and a continuous type removing method will be briefly described below.

The wastewater to be treated in the present invention is not particularly limited, and any wastewater containing organic matter such as wastewater discharged from various factories and domestic wastewater can be treated. be able to. (1) Batch-type removal method: By adding the organic substance removing agent of the present invention to a tank containing drainage, and allowing it to stand or stir,
The organic compound in the waste water can be removed by adsorbing it to the organic substance removing agent.

A tank, a pond or the like may be newly installed as a tank for containing the waste water, but if a coagulating sedimentation tank or the like in the waste water treatment facility is existing, it may be diverted or used in combination.

The addition amount of the organic substance removing agent may be appropriately determined according to the content of the organic compound in the waste water, but usually, the calcium silicate hydrate, which is the active ingredient, is added per 1 m ³ of the volume of the tank for containing the waste water. The amount is preferably about 0.1 to 300 kg. If the addition amount of the organic substance removing agent is too small, it becomes difficult to obtain a sufficient organic substance removing effect. Further, even if the amount of the organic substance removing agent added is too large, the removal effect will reach the ceiling, so excessive addition is uneconomical.

The time for standing or stirring the wastewater to which the organic matter removing agent is added may be appropriately determined depending on the organic matter content in the wastewater, the addition amount of the organic matter removing agent, etc., but usually 5 minutes to 2 minutes.
It may be about 4 hours. In this case, if the standing time or the stirring time is insufficient, a sufficient removing effect cannot be obtained.
Further, even if the standing or stirring time becomes longer than necessary, it is impossible to obtain a further removing effect.

The organic substance removing agent dispersed in the waste water by stirring can be removed by coagulation sedimentation or filtration.
At this time, the coagulating sedimentation tank or the like in the existing wastewater treatment facility may be used as it is. As the coagulant, those used in ordinary wastewater treatment facilities such as aluminum sulfate and polyacrylamine can be used as they are.

The organic substance removing agent to be used may be either a powdery removing agent or a removing agent granulated by a granulating operation, but a powdery one is particularly preferable in view of high treatment efficiency.

The above-mentioned treatment may be carried out batchwise by using only one tank for the drainage.
Organic substances can be efficiently removed by using a settling tank divided into a plurality of parts and allowing the waste water to pass through while overflowing for continuous treatment. (2) Continuous removal method After removing suspended matter from the wastewater in a coagulation adsorption tank or the like, if necessary, the wastewater is passed through the adsorption container filled with the organic substance removing agent of the present invention so that the wastewater is discharged during the passage. Organic matter can be removed from the.

As the adsorption container, any structure may be used as long as it can be filled with the organic substance removing agent of the present invention, can introduce waste water from one end, and can discharge waste water from the other end.
The material and the like are not particularly limited, but, for example, the same one as the activated carbon adsorption tower in a normal factory wastewater treatment facility can be used. At this time, the types of adsorption tower are fixed bed, moving bed,
A fluidized bed may be used, and the activated carbon adsorption tower of the existing equipment may be used as it is. The water flow rate of the waste water may be appropriately adjusted according to the amount of the waste water, the degree of pollution, the desired degree of purification, etc., and the conditions may be determined in advance by a laboratory test.
In this method, in view of the nature of the processing apparatus, the organic substance removing agent used is preferably one which is granulated by a granulating operation. According to the treatment method described above, various organic substances can be sufficiently removed from the waste water. Further, the organic substance removing agent used after the organic substance removing treatment can be reused by allowing the adsorbed organic substance to be desorbed by standing or stirring in a strong alkaline solution.

Further, the used organic matter removing agent can be treated in the same manner as raw concrete sludge, and for example, the collected treating agent is dehydrated and solidified by pressurizing, drying, etc. It becomes "ceramic waste" and can be treated as stable waste.
However, if solidification is not performed, it corresponds to “sludge” of industrial waste and must be disposed of at a managed landfill.

[0038]

Industrial Applicability The agent for removing organic substances from waste water of the present invention has excellent adsorption performance for various organic substances that may be contained in the waste water. Therefore, by removing the organic matter from the wastewater using the organic matter removing agent of the present invention, it is possible to prevent the adverse effect that occurs in the wastewater treatment using activated carbon.

Further, the organic substance removing agent is nonflammable and inexpensive, and can be regenerated as activated carbon to be reused as an organic substance treating agent.

[0040]

EXAMPLES The present invention will be described in more detail with reference to examples.

The adsorption rate of various organic substances was measured by the method described below using the following 5 kinds of test materials.

Example 1 Ordinary Portland cement and hot water at 70 ° C. were put into a pulverizer (vibration mill) at a solid-liquid ratio of 1: 6, and hydrated for 2 hours while wet pulverizing. 2 at ℃
After drying for 4 hours, it was crushed to obtain calcium silicate hydrate powder. The BET specific surface area of this powder was 70 m ² / g.

Example 2 To 90 g of the calcium silicate hydrate powder obtained in Example 1, 10 g of ordinary Portland cement was added and mixed,
Add 130 ml of water and knead, φ5 mm × with an extruder
It was molded into a cylindrical shape of 7 mm to obtain a granulated product of calcium silicate hydrate.

Example 3 After removing the aggregate part from the concrete waste material and selecting the paste part, it was crushed with a ball mill until the average particle size became 50 μm, and powder containing calcium silicate hydrate as a main component was obtained. Obtained. The BET specific surface area of this powder is 35 m ² /
It was g.

Comparative Example 1 Granular activated carbon for water treatment and refined sugar / food (specific surface area 150
0 m ² / g and an iodine adsorption amount of 1200 mg / g) were used as Comparative Example 1.

Comparative Example 2 Granular activated carbon for general water treatment (specific surface area 1200 m ² / g,
An iodine adsorption amount of 1050 mg / g) was used as Comparative Example 2. [Adsorption rate measurement method] 10 g of test powder was added to 1 of various organic substances.
% Aqueous solution 100 ml, and the mixture was stirred with a stirrer at 20 ° C. for 2 hours. This is suction filtered and 1
After diluting 0 times, the test powder was collected and dried at 100 ° C. for 24 hours.

Next, the total organic carbon content (TOC) in the diluted filtrate and the total organic carbon content (TOC) in the 0.1% organic substance aqueous solution are calculated using a total organic carbon meter (TOC meter: Toray Engineering Co., TOC-650). ) Was used to determine the adsorbed organic matter content in the aqueous solution by the following formula, assuming that the reduced amount of the total organic carbon was adsorbed on the test powder. The results are shown in Table 1 below.

Organic substance adsorption rate (%) = 100 × (TOC in diluted filtrate-TOC of 0.1% organic substance aqueous solution) /0.1
% TOC aqueous solution of organic matter The types of organic matter measured by TOC are as follows. (1) Synthetic detergent for kitchen Alkylbenzene compounds (2) Synthetic detergent for clothes Linear sodium alkylbenzenesulfonate (3) Sodium gluconate special grade reagent (4) Maltose monohydrate biochemical reagent (5) Citric acid special grade reagent (6) Styrene-butadiene rubber latex emulsion (7) Styrene-acrylic ester emulsion (8) Milk

[0049]

[Table 1]

As is clear from the above results, the organic substance removing agent of the present invention has an adsorption performance at least to the extent that it can be used as a substitute for activated carbon, and it is not suitable for specific types of organic substances. , Has a better adsorption performance than activated carbon.

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 4D024 AA04 AB04 BA05 BA11 BB01                       BB05 BC01 BC04 DB21                 4G066 AA17B AA22B AA30B AA73A                       AA73D BA26 CA01 DA08                       FA03 FA27

Claims (2)

[Claims] 1. An agent for removing organic substances from wastewater, which comprises a calcium silicate hydrate powder having a BET specific surface area of 30 m ² / g or more or a granulated product thereof as an active ingredient. 2. A method for removing organic matter from wastewater, which comprises contacting the organic matter removing agent according to claim 1 with wastewater.