JPH0775775A - Treatment of waste liquid to remove agricultural chemicals - Google Patents

Abstract

PURPOSE:To obviate the generation of environmental pollution even if a treated liquid is released into natural water systems by efficiently removing the agricultural chemicals in waste liquids, such as waste disinfecting liquids for rice seeds, bulbs, etc., waste liquids of seed presoaking for hastening of germination, liquid remaining in tanks of agricultural chemical spraying machines and waste washing liquids of spraying appliances. CONSTITUTION:This method for treatment of the waste liquid comprises removing the agricultural chemicals by adding a powder active carbon and inorg. and/or org. flocculating agent to the waste liquid contg. one or >=2 kinds of the agricultural chemicals in a dispersed and/or dissolved state to form flocs, passing the filtrate obtd. after the formed flocs are filtered through a granular active carbon column and further, passing the flocs through an anion exchange resin column.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention does not cause environmental pollution even when a disinfecting waste liquid such as seed paddy or bulbs, a germination soaking waste liquid, a residual liquid in a tank of a pesticide sprayer, a spraying device cleaning waste liquid, etc. is flowed into a natural water system. The present invention relates to a method for treating waste liquid containing harmful substances such as pesticides.

[0002]

2. Description of the Related Art In recent years, the role of pesticides in food production has become increasingly important. On the other hand, issues such as the safety of pesticides to users, the impact on the environment, and crop residues have been strongly recognized. For this reason, development of highly safe agricultural chemicals and development of efficient dosage forms and application methods have been actively carried out, and significant progress has been made in each. Furthermore, much attention has recently been paid to the treatment of agricultural chemical packaging containers and waste liquids.

Various attempts have been made to solve the problem of waste liquid treatment containing this pesticide. For example, a method in which a pesticide waste solution containing a thiuram agent is subjected to a coagulation treatment and then an activated carbon treatment (Japanese Patent Publication No. 62-24156); A method of processing (Japanese Patent Laid-Open No. 4-161266); etc. are disclosed. However, these methods have insufficient points in practical use, and further improvement is necessary. In the method, it is essential that the amount of the agricultural chemical substance contained in the filtrate after coagulation filtration is very small (the water solubility of thiuram is 30 ppm; CIPAC Handbook), and the waste liquid treatment containing the agricultural chemical substance with high water solubility is essential. Is not applicable.

The method (1) attempts to avoid the above problems by adsorbing a pesticide raw material, which is emulsified or dissolved in water, on activated carbon and then performing coagulation filtration, but it has high water solubility. A large amount of activated carbon is required in the case of waste liquid containing a high concentration of pesticides. As a result, the volume of the flocculation flocs increases, and the filtration operation requires a long time and / or excessive equipment. In addition, it is well known that a method combining activated carbon adsorption and coagulation filtration is used for the treatment of tap water, but in this case, an extremely small amount of solute is targeted mainly for the purpose of removing odor. The equipment is also very large.

[0005]

In response to increasing environmental problems in recent years, disinfectant waste liquid such as seed paddy and bulbs, germination soaking waste liquid, residual liquid in tank of pesticide sprayer, spraying device cleaning waste liquid, etc. are poured into a natural water system. However, it is strongly desired to develop a method for treating waste liquid containing agricultural chemicals so as not to cause environmental pollution. However, a simple and economical method for treating waste liquid to remove harmful substances such as agricultural chemicals has not been obtained.

[0006]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the inventors of the present invention exerted an excellent effect that cannot be predicted from the conventional known techniques, and provided a simple and economical pesticide. We have found a waste liquid treatment method that can remove harmful substances.

Conventionally, a method of adsorbing an organic substance dissolved in water onto activated carbon to remove it, and a method of coagulating and filtering a substance dispersed in water to remove are known means. On the other hand, the treatment of waste liquid that removes harmful substances such as pesticides is
The target is disinfecting waste liquid such as seed paddy and bulb, germination soaking waste liquid, residual liquid in tank of pesticide sprayer, spraying device cleaning waste liquid, etc. Further, harmful substances such as pesticides contained in these have a wide range of physical properties, from substances that are insoluble or sparingly soluble in water to substances that are water-soluble, and are usually contained in concentrations of 100 ppm or more. When these harmful substances such as pesticides are removed from the waste liquid, most of the substances that are insoluble or sparingly soluble in water are slightly dissolved and suspended and dispersed in water. Therefore, most of the harmful substances can be easily removed by coagulation filtration, and the dissolved portion can be efficiently adsorbed and removed with a small amount of activated carbon. In contrast, substances with high water solubility (100 ppm or more at room temperature)
Since it is dissolved at a high concentration, it cannot be removed by coagulation filtration, and it is necessary to remove it by adsorption using a large amount of activated carbon. In addition, for disinfection of seeds and bulbs, a pigment treatment such as Blue No. 1 is used as a marker to distinguish between seeds that have been treated with pesticides and seeds that have not been treated. Has
It is necessary to remove it by adsorption using a large amount of activated carbon.

That is, the adsorption of organic substances on activated carbon is mainly physical adsorption, and the adsorption power largely differs depending on the type of organic substance. Generally, the hydrophobic property and the low concentration adsorption power are large. Activated carbon, edited by Carbon Society of Japan, Kodansha). Therefore, substances with high water solubility reduce the adsorption power of activated carbon. A high concentration is a further disadvantageous condition for adsorbing activated carbon. In addition, a large amount of powdered activated carbon is required to remove the pigment, which is not a practical treatment method.

According to the present invention, 1% or less, preferably 0.05% to 0.3% of powdered activated carbon is added to a waste liquid containing harmful substances such as agricultural chemicals under stirring, and then an inorganic or / and organic flocculant is added to the flocs. The first step treatment for forming a slag is carried out, and the filtrate from which the flocs are removed is passed through a granular activated carbon column at a space velocity of 20 or less, preferably at a space velocity of 5 to 10 to remove a trace amount of residual harmful substances. It is an object of the present invention to provide a waste liquid treatment method comprising a two-step treatment and, if necessary, passing through an anion-exchange resin tower and removing a substance which is difficult to be removed by an activated carbon tower, for example, a dye, etc. Space velocity is a term that expresses the flow velocity through the packed bed and is calculated by the following equation.

[Equation 1] As the activated carbon packed in the activated carbon column, granular activated carbon conventionally used in this field can be used. By using an anion exchange resin together, it is possible to remove substances that are difficult to remove with activated carbon and to reduce the amount of activated carbon used. The life of anion exchange resin greatly affects the concentration of impurities in the waste liquid and the water flow rate of the waste liquid. The filtrate treated with granular activated carbon should have a space velocity of 100 or less, preferably a space velocity of 5 or less.
Pass through at a flow rate of ~ 50 to remove traces of harmful substances that remain dissolved.

Particularly, the usefulness of the treatment method of the present invention is remarkably exhibited when the water solubility of harmful substances such as pesticides contained in the waste liquid is 100 ppm or more. That is, in the first stage processing,
Adsorbing to 1% or less, preferably 0.05 to 0.3% of powdered activated carbon to reduce the concentration of harmful substances dissolved in water, it is possible to significantly extend the effective action period of the granular activated carbon tower used for the second stage treatment. it can. In this case, the addition of 1% or more of powdered activated carbon is not desirable because it increases the amount of agglomerated flocs, makes filtration difficult and increases sludge treatment.

Filtration performance of agglomerated flocs varies greatly depending on the physical properties of the agglomerated flocs. If the agglomerated flocs are fine, the agglomerated flocs will leak if the filter cloth or the like is coarse, and if the agglomerated flocs are fine, they will be clogged. Cause Examples of the filter material used in the natural filtration include filter cloth, filter paper, and polyurethane sheet. However, since filter cloth, filter paper and the like are easily clogged, a porous polyurethane sheet, for example, foamed polyurethane with open cells is used. Sheets are preferable. The separated floc can be incinerated in an incinerator. Pesticide components adsorbed on activated carbon can be decomposed by high-temperature regeneration treatment of activated carbon, so activated carbon can be used repeatedly as a second-stage treatment. Anion exchange resins used to remove substances that are difficult to remove with activated carbon have styrene type and acrylic type (methacrylic type) as a matrix structure, and are classified into gel type, porous type and MR type by the synthesis method. Strongly basic anion exchange resins are classified into type I (methylamine type) and type II (dimethylamine type) depending on the type of quaternary salt formed. Specific examples of the anion exchange resin used in the present invention include Amberlite IRA-410, Amberlite XT-5007, and Amberlite XT-5028 manufactured by Rohm and Haas Company, USA.

As an apparatus for carrying out the present invention, for example, an apparatus as shown in FIGS. In Figure 1,
Reference numeral 1 denotes a treatment tank for performing the first-stage treatment. The waste liquid sent through the pipe 7 is agitated in this treatment tank 1 together with powdered activated carbon, a flocculant, etc. supplied from a chemical tank 5 by a pipeline 8. It Reference numeral 4 represents a stirrer.
Next, the supernatant liquid in the treatment tank 1 is sent to the sub water tank 2 through the pipe 9, while the treatment waste liquid containing the aggregates that sinks to the bottom of the treatment tank 1 is passed from the bottom portion of the treatment tank 1 through the pipe 10 to the sub water tank 2. It is sent to a filtered water tank 3 inside, where aggregates and the like are removed, and it is sent to an adsorption tower 6 filled with granular activated carbon for performing a second stage treatment through a pipe 11 after being combined with the supernatant liquid, and the tower 6 The remaining removal components are removed by and become a clean liquid, which is discharged to the outside of the system by the pipe 12. In FIG. 2, an anion exchange resin tower 15 is added in addition to the filter press 13 and the activated carbon adsorption tower 6 instead of the filtered water tank 3 of FIG.

[0013]

EXAMPLES Examples of the present invention will be shown below, but the present invention is not limited thereto.

Example 1 1.5 kg of seed rice was soaked in 2 L (liter) of a 200 times solution of befrazoate 20% wettable powder (water solubility 443 ppm), and after 24 hours, the seed rice was taken out to obtain a steeping waste liquid. 0.4 g of powdered activated carbon was added to 1 L of this waste liquid, and after stirring for 1 hour, polyaluminum chloride solution (Taki Chemical Co., Ltd., 10% as Al ₂ O ₃ ) was added to 2
g and 5% NaOH to bring the pH to 7-8. Next, polymer flocculant (manufactured by Sanyo Kasei Co., Ltd., Sunflock SW)
Add 5 ppm of -210P) and stir. After standing, the supernatant was loaded on a column with a diameter of 18 mm packed with 5 g of granular activated carbon (particle diameter 5 to 0.5 mm), and the flow rate was 130 ml / hr (space velocity 10 1 / hr).
And pass 500 ml. The results are shown in Table 1.

Example 2 Disinfected paddy (befurazoate 15% emulsion 7.5 times diluted and fenitrothion 50% emulsion 100 times diluted 3 times seed weight).
% Spray, and soak 1 kg in Blue No. 1) in 2 L of water, and after 24 hours, remove the seed paddy to obtain a soaking waste liquid. To 1 L of this waste liquid, 0.25 g of powdered activated carbon was added, and after stirring for 1 hour, 1 g of a polyaluminum chloride solution (manufactured by Taki Chemical Co., Ltd., 10% as Al ₂ O ₃ ) was added, and 5% NaOH was added. pH 7 to
8 Then, 5 ppm of a polymer flocculant (Sanyo Chemical Co., Ltd., Sunfloc SW-210P) is added and stirred. After standing still, the supernatant liquid is treated with granular activated carbon (particle size 5 to 0.5 mm) 5
Space velocity flow rate 130 ml / hr in a column with a diameter of 18 mm filled with g
2.0L of water is passed at a space velocity of 10 1 / hr. The results are shown in Table 1.

Comparative Example 1 In Example 1, the treatment is carried out without adding powdered activated carbon. The results are shown in Table 1. Comparative Example 2 In Example 2, the treatment is performed without adding powdered activated carbon. The results are shown in Table 1.

[0017]

[Table 1]

Example 3 100 cc of Blue No. 1 solution was added to the anion exchange resin, and each adsorption capacity was determined. The results are shown in Table 2.

[Table 2]

[0019]

EFFECTS OF THE INVENTION According to the present invention, it is possible to efficiently remove pesticides in waste liquid such as disinfectant waste liquid such as seed paddy and bulb, germination soaking waste liquid, residual liquid in tank of pesticide sprayer, spraying equipment cleaning waste liquid, etc. It is possible to prevent environmental pollution even when the liquid is discharged into a natural water system.

[Brief description of drawings]

FIG. 1 is a schematic view showing an example of an apparatus used for carrying out the present invention.

FIG. 2 is a schematic view showing an example of an apparatus used for another embodiment of the present invention.

[Explanation of symbols]

 1 Treatment tank for first stage treatment 2 Sub water tank 3 Filtration water tank 4 Stirrer 6 Activated carbon tower 13 Filter press 15 Anion exchange resin tower

Continuation of front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display location C02F 9/00 502 P 7446-4D J 7446-4D H 7446-4D

Claims (9)

[Claims] 1. A floc is formed by adding powdered activated carbon, an inorganic and / or organic flocculant to a waste liquid containing one or two or more dispersed and / or dissolved pesticides, and the generated flocs are filtered. A waste liquid treatment method that removes pesticides by passing the filtrate through a granular activated carbon tower. 2. A powdery activated carbon, an inorganic and / or organic flocculant is added to a waste liquid containing one or more kinds of dispersed and / or dissolved pesticides to form flocs, and the generated flocs are filtered. A waste liquid treatment method that removes pesticides by passing the filtrate through a granular activated carbon tower and then an anion exchange resin tower. 3. The waste liquid treatment method for removing a pesticide according to claim 1 or 2, which is a pesticide having a water solubility of 100 ppm or more. 4. The waste liquid treatment method for removing agricultural chemicals according to claim 1 or 2, wherein the amount of powdered activated carbon added to the waste liquid is 1% by weight or less. 5. The waste liquid treatment method according to claim 1 or 2, wherein the filtrate is passed through the granular activated carbon tower at a flow velocity of 20 or less in space velocity. 6. The waste liquid treatment method according to claim 2, wherein the liquid is passed through the anion exchange resin tower at a flow velocity of 100 or less in space velocity. 7. The waste liquid treatment method according to claim 1, wherein a polyurethane sheet is used for filtering flocs. 8. The waste liquid treatment method according to claim 1, wherein flocs are filtered by a filter press method. 9. The waste liquid treatment method according to claim 1, wherein the waste liquid is a liquid containing a water-soluble dye.