JPH0780497A - Treatment of waste liquid - Google Patents

Abstract

PURPOSE:To simplify constitution and control of a device and also to enhance treating efficiency. CONSTITUTION:When a solid-based flocculation treating agent is added to waste liquid of agricultural chemicals in a mixing tank 3 for flocculation and precipitation through a feeder 4, firstly an inorganic flocculant is dissolved and a flocculation nucleus is produced. Mineral contained in waste liquid of agricultural chemicals, a solid component such as mud and the component of agricultural chemicals are stuck to the flocculation nucleus and flocculating particles are produced. A polymer flocculant is stuck to the flocculating particles and a large aggregate is formed. Further the large aggregate is produced efficiently by a settling agent. After the flocculating precipitate produced in such a way is filtrated by a filter 5, it is discarded and filtrate is sent to an adsorption tank 8 packed with activated carbon 82. The component of agricultural chemicals remaining in the filtrate is adsorbed an activated carbon 82 in the adsorption tank 8 and removed and the filtrate is discarded.

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 waste liquid such as agricultural chemical waste liquid.

[0002]

2. Description of the Related Art In order to efficiently harvest crops such as grains and vegetables, it is common to use pesticides composed of insecticides, fungicides, herbicides or germination and growth promoters. Contains toxic ingredients,
Careful consideration must be given to the disposal of waste liquid after processing.

As a method of disposing of the agricultural chemical waste liquid, for example, an adsorption treatment method using activated carbon is known. This method is used, for example, for treating a pesticide waste solution consisting of Benlate T wettable powder 20 containing benomyl and thiuram as active ingredients, and adding 2% of the amount of the waste solution to the pesticide waste solution diluted with water. After adsorbing benomyl and thiuram in the waste liquid, the liquid coagulant in an amount of 2.5% of the amount of the waste liquid is added to agglomerate and settle the suspended particles, and separate it into a supernatant liquid and an aggregate precipitate. Separately, the supernatant liquid is drained, and the coagulated sediment is dried and then incinerated or buried in soil and discarded.

In addition to this method, an inorganic coagulant solution, a neutralizing agent solution, and a polymer coagulant solution are sequentially added to an agricultural chemical waste liquid at regular intervals to coagulate the agricultural chemical components, and the coagulated water is then treated. There is also known a waste liquid treatment method in which solids are subjected to solid-liquid separation, filtered water is removed from pesticides in an agrochemical adsorption tower and drained, and solids are collected and incinerated.

[0005]

However, the above-mentioned adsorption treatment method using activated carbon requires a large amount of activated carbon, and this activated carbon is expensive, so that the running cost is high, and activated carbon contains agricultural chemical components. Since it is adsorbed, it cannot be regenerated and must be discarded.
There has been a problem that this disposal process requires much labor and costs are high.

In addition, in the above-mentioned other method, when the inorganic coagulant solution and the polymer coagulant solution are added at the same time, these react with each other, and aggregation nuclei due to the inorganic coagulant hardly occur,
It is necessary to add the inorganic flocculant solution, the neutralizing agent solution, and the polymer flocculant solution at regular intervals because efficient coagulation treatment cannot be performed. In addition to requiring a valve and a valve, it is necessary to control the timing of solution supply, which complicates the apparatus and complicates the processing.

The present invention has been made under such circumstances, and an object of the present invention is to provide a waste liquid treatment method which has a simple apparatus configuration and control and high treatment efficiency.

[0008]

According to the present invention, a waste liquid is added with a solid-state aggregating agent containing an inorganic aggregating agent made of a solid material, a polymer aggregating agent, a pH adjusting agent, and a sedimenting agent. A step of aggregating the chemically harmful component and the solid component contained in, a step of filtering the waste liquid to which the aggregating treatment agent is added, and the filtrate obtained by this step is brought into contact with activated carbon in the liquid. It is characterized by comprising a step of adsorbing and removing the contained chemically harmful components and a step of discharging the treatment liquid obtained in this step.

[0009]

[Function] For example, when a solid-based coagulation treatment agent is added to a waste liquid consisting of agricultural chemical waste liquid, the solid components in the agricultural chemical waste liquid are aggregated and settled as aggregate precipitates, and the agricultural chemical components that are chemically harmful components are aggregated. Adhere to the precipitate. In this coagulation-sedimentation process, the inorganic coagulant is first dissolved to form coagulation nuclei,
The solid component adheres to this to form aggregated particles, and the polymer aggregating agent further adheres to the aggregated particles, and this serves as a binder to form larger aggregates. In addition, the presence of the sedimentation agent allows large aggregates to efficiently aggregate and precipitate.

After removing the aggregated precipitate by filtration,
When the filtrate is passed through, for example, an activated carbon adsorption tower and brought into contact with activated carbon, the chemically harmful components remaining in the liquid are adsorbed by the activated carbon and removed.

[0011]

EXAMPLES Examples of the present invention will be described below. Figure 1
[FIG. 1] is a diagram showing an example of a waste liquid treatment apparatus for carrying out the method of the present invention, in which 1 is a waste liquid storage tank for storing a waste liquid, for example, an agricultural chemical waste liquid. This waste liquid storage tank 1 has a valve 12, a pump 13, a control valve 14, a flow meter 15,
A static mixer 16 is connected to the coagulation / sedimentation mixing tank 3 via a supply pipe 11 provided in this order. Further, 2 is an adjusting agent tank for storing the cationic surfactant, and this adjusting agent tank has a valve 22 and a pump 23 in the middle thereof.
Is provided and the other end side is branched, and the static mixer 1 is connected via valves 24 and 25.
Connected to 6.

The coagulation-sedimentation mixing tank 3 is a tank having a stirrer 31, a feeder 4 for supplying a coagulation treatment agent into the tank, and a bottom having an inverted conical shape. In this coagulation-sedimentation mixing tank 3, a solenoid valve 33 is provided on the lower side wall.
And a supply pipe 34 having a valve 35 at the bottom thereof.
Both 2 and 34 are connected to the filtration device 5.

The filtering device 5 is composed of, for example, an inner tank 51 having a large number of holes and an outer tank 52 provided outside the inner tank 51. This is a device for skipping to 52 and performing solid-liquid separation. The filtration device 51 is connected via a supply pipe 53 to an intermediate tank 6 which is a tank for temporarily storing the filtrate, and the intermediate tank 6 is provided with a solenoid valve 62, a pump 63, and a solenoid valve 64 in this order in the middle. It is connected to the filtrate tank 7 for storing the filtrate via the supply pipe 61.

The filtrate tank 7 is provided with a solenoid valve 72, a pump 63, a solenoid valve 73, a flow rate integrator 74, and a control valve 7 on the way.
5. The flow meter 76 is connected to the filtrate supply means 81 provided in the lower part of the adsorption tank 8 via the supply pipe 71 provided in this order. The adsorption tank 8 is filled with activated carbon 82, a porous holding plate 83 is provided on the surface thereof, and a supply pipe 84 is connected to the upper side wall of the tank.

Next, an example of the method of the present invention which is carried out using the above-mentioned agricultural chemical waste liquid treatment apparatus will be described. The waste liquid storage tank 1 stores the waste liquid after the treatment of pesticides used for disinfecting seeds such as seeds such as Helcede, Helcee T, Benrate, Benrate T, and Trihumin. , Valve 1
2 is opened, the pump 13 is operated, and the flow rate is controlled by the regulating valve 14, whereby the static mixer 16
For example, a fixed amount of agricultural chemical waste liquid is continuously supplied through the pipe 11
Is supplied to the coagulation sedimentation mixing tank 3.

At this time, if the pesticide contains a large amount of anionic or nonionic surfactant, the valves 22 and 24 are opened and the pump 23 is operated to remove SF- from the regulator tank 2, for example. 75 (manufactured by Sanyo Chemical Industry Co., Ltd.)
And the like are supplied to the static mixer 16, and the static mixer 16 mixes and reacts the agricultural chemical waste liquid and the surfactant, and the anionic or nonionic surfactant in the agricultural chemical waste liquid is mixed. Inactivate.

In the coagulation-sedimentation mixing tank 3, the supply pipe 11
A predetermined amount of, for example, a powdery aggregating treatment agent is continuously added from the feeder 4 to the agricultural chemical waste liquid supplied from the stirrer 31.
After mixing to dissolve the aggregating treatment agent, the solution is continuously fed to the inner tank 51 of the filtration device 5 via the electromagnetic valve 33.

The aggregating agent added here is an inorganic aggregating agent made of a solid material such as aluminum sulfate, a polymer aggregating agent made of a solid material such as sodium acrylate, and a pH of eg sodium carbonate. It is a solid-state aggregating treatment agent, for example, in the form of powder, granules, flakes or the like, obtained by mixing a regulator and a precipitating agent such as calcium carbonate.

When this aggregating agent is added, the inorganic aggregating agent is first dissolved to form aggregating nuclei, on which solid components such as minerals and seed paddy dust and mud contained in the agrochemical itself in the agrochemical waste liquid adhere. Aggregated particles are generated, and the polymer aggregating agent adheres to the aggregated particles, and this serves as a binder to form a larger aggregate. In addition, the presence of the settling agent promotes the production of agglomerate nuclei to efficiently produce large agglomerates, and the agglomerates thus produced settle and accumulate at the bottom of the aggregating and sedimenting mixing tank 3. At this time, chemically harmful components such as pesticide components remaining in the pesticide waste liquid also adhere to the aggregates. If the pesticide contains a large amount of anionic or nonionic surfactant, aggregation will be less likely to occur.Therefore, add a cationic surfactant as described above to add anionic or nonionic surfactant. It is necessary to inactivate the agent.

In the filtering device 5, the inner tank 51 is rotated to perform filtration, and the liquid component discharged from the inner tank 51 to the outer tank 52, that is, the filtrate is sent to the intermediate tank 6 via the supply pipe 53. When a predetermined amount of filtrate is stored in the intermediate tank 6, the solenoid valves 62 and 64 are opened and the pump 63 is operated to operate the supply pipe 6
The filtrate is supplied to the filtrate tank 7 via 1 and stored therein.

The filtrate stored in the filtrate tank 7 is opened through electromagnetic valves 72 and 73, the pump 63 is operated, and the flow rate is adjusted by the adjusting valve 75, while the supply pipe 71 and the filtrate supplying means 81 are used. Are supplied to the adsorption tank 8. When the filtrate passes through the activated carbon in the adsorption tank 8, the agricultural chemical components contained in the filtered liquid are adsorbed by the activated carbon and removed, and the filtered liquid in which the agricultural chemical component does not remain is discharged to the outside through the supply pipe 84. .

On the other hand, the coagulated sediment accumulated at the bottom of the coagulation sedimentation mixing tank 3 is passed through the valve 35 to the inner tank 5 of the filtration device 5.
It is discharged to 1 and filtered. Then, the liquid content is flown out to the intermediate tank 6, and the solid content remaining in the inner tank 51, that is, the coagulated sediment is dried and then incinerated or buried in the soil and discarded.

In the above method, if the pesticide does not contain an anionic or nonionic surfactant or if the amount used is small, it is not necessary to add a cationic surfactant, and the modifier tank 2 is used. Nor does it need any equipment attached to it. Further, the waste liquid which has been subjected to the coagulation treatment in the coagulation-sedimentation mixing tank 3 may be intermittently sent to the filtration device 5 via the electromagnetic valve 33. In this case, the coagulation treatment agent is added to the waste liquid and the waste liquid is added to the waste liquid. After the pesticide component and the solid component contained are coagulated and precipitated, the supernatant liquid is sent to the filtration device 5 via the solenoid valve 33.

Next, an experiment conducted to confirm the effect of the method of the embodiment of the present invention and its result will be described. In 2000 ml of pesticide waste liquid containing 950 ppm of pesticide component benomyl and 750 ppm of thiuram, 50% by weight of inorganic flocculant made of powdered aluminum sulfate, 5% by weight of polymer flocculant made of powdered sodium acrylate, powdered carbonic acid A coagulation treating agent prepared by mixing 25% by weight of a pH adjusting agent composed of sodium hydrogen and 20% by weight of a precipitation agent composed of powdery calcium carbonate was added, and the mixture was stirred at 200 rpm for 1 minute and left to stand for 1 minute. Thereafter, filtration was carried out using an 80-mesh filter cloth, 1900 ml of the filtrate was collected, this filtrate was passed through an adsorption tower filled with activated carbon, and the concentration of the pesticide component in the passed liquid was measured. Benomyl and thiuram were not detected in the permeate. From this result, even if a solid-state flocculating agent obtained by mixing a powdery inorganic flocculant, a polymer flocculant, a pH adjusting agent, and a precipitant is added, a liquid inorganic flocculant and a polymer flocculant are added. It was confirmed that high coagulation efficiency can be obtained without causing the inorganic coagulant and the polymer coagulant to react with each other to make the coagulation action less likely to occur unlike in the case of simultaneously adding. This is because even if the powdery inorganic coagulant and the polymer coagulant are added at the same time, the inorganic coagulant is dissolved first because the dissolution rate is different, and the polymer coagulant is dissolved after the coagulation nuclei are formed. This is because both do not react with each other.

Further, it was confirmed that the amount of activated carbon required for adsorbing pesticide components can be reduced because the coagulation treatment agent is once added to the agricultural chemical waste liquid to remove the coagulated precipitate and then the adsorption treatment with activated carbon is performed. This is because when an aggregating treatment agent is added to pesticide waste liquid, minerals, seed paddy dust, mud, etc. contained in the pesticide waste liquid become agglomerated precipitates. It is thought that this is because it is removed together with the object. As described above, it was confirmed from the results of this experiment that the method of the example of the present invention is suitable for the disposal of the agricultural chemical waste liquid.

As described above, in the waste liquid treatment method of the embodiment of the present invention, the solid-type flocculant obtained by mixing the inorganic flocculant, the polymer flocculant, the pH adjuster and the precipitant is used. Since the aggregating agent can be simultaneously supplied from one tank and the tanks and valves for storing the material solutions required for the liquid aggregating agent and the control of the supply timing are unnecessary, the device configuration and control Can be simplified.

Further, since the solid aggregating treatment agent contains a sedimentation agent, the formation of aggregating nuclei is promoted and large agglomerates are efficiently produced, so that the aggregating treatment efficiency can be enhanced.

Further, in the present invention, since the coagulation treatment agent is added to the agricultural chemical waste liquid to remove the coagulated precipitate, activated carbon is added to the filtrate to adsorb and remove the residual agricultural chemical components. The amount of activated carbon required to remove pesticide components can be reduced to about 1/10 of the conventional amount, and the running cost can be reduced.

[0029]

According to the waste liquid treatment method of the present invention, a solid-type aggregating treatment agent is used, and the aggregating treatment agent is added to the waste liquid to aggregate the chemically harmful components and the solid components contained in the waste liquid. After the removal, the chemically harmful components remaining on the activated carbon are adsorbed and removed, so that the configuration and control of the device can be simplified and the processing efficiency can be improved.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an example of a waste liquid treatment apparatus for carrying out the method of the present invention.

[Explanation of symbols]

 1 Waste liquid storage tank 3 Coagulation sedimentation mixing tank 4 Feeder 5 Filtration device 7 Filtration liquid tank 8 Adsorption tank 82 Activated carbon

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location C02F 1/28 ZAB D 1/56 ZAB Z 9042-4D

Claims (1)

[Claims] 1. An inorganic coagulant made of a solid material in the waste liquid,
A step of adding a solid-state aggregating agent containing a polymer aggregating agent, a pH adjuster, and a settling agent, and aggregating a chemically harmful component and a solid component contained in the waste liquid, and the aggregating agent is added. The step of filtering the waste liquid, the step of contacting the filtered liquid obtained in this step with activated carbon to adsorb and remove the chemical harmful components contained in the liquid, and the treatment liquid obtained in this step A waste liquid treatment method comprising the step of discharging.