JPS60187387A - Apparatus for evaporating waste water - Google Patents

Abstract

PURPOSE:To obtain an energy-saving type evaporator by opening a supernatant liquid pipe of a solid-liquid separating vessel and a condensed water pipeline to a chemical dissolving vessel, and opening a liquid chemical pipeline from a chemical storage vessel into a reaction vessel. CONSTITUTION:The original waste liquid to be treated is charged into the first reaction vessel, and the chemicals necessary for treatment are added by a pump 16. The liquid is sufficiently mixed and agitated with an agitator 2, and sent into the second reaction vessel 3 wherein the liquid is fully agitated with an agitator 4. The liquid is then charged into an evaporator (drum dryer) 5. The waste liquid is evaporated, because the surface of the drum is heated to about 150 deg.C. The steam is discharged from an air discharge duct 8 having an exhaust fan 7. The evaporation residue is formed as the result of the evaporation of waste liquid. The evaporation residue is scraped off with a scraper 18, and stored in a dried sludge receiver.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a non-discharge type wastewater evaporation treatment device, and more particularly to a wastewater treatment device that pre-treats wastewater using a chemical and performs evaporation treatment in an evaporator.

In recent years, wastewater discharge regulations have become significantly stricter.
Treatment of wastewater using a non-discharge method is being considered. One known method is to pre-treat wastewater using a chemical and then evaporate the treated wastewater. In such methods, dilution water has conventionally been taken in from outside the system to dissolve the chemicals used in the pretreatment. In addition, condensed water generated by cooling in the exhaust duct is led back to the evaporator for evaporation treatment. However, according to such a method, the amount of waste liquid that needs to be evaporated increases due to the addition of chemicals, which requires an extra amount of heat and requires an increase in the processing capacity of the evaporator itself.

The purpose of the present invention is to eliminate the above-mentioned drawbacks of the prior art, do not increase the amount of waste liquid required for evaporation treatment by adding chemicals, and increase the processing capacity of the evaporator by using the return water of condensed water from the exhaust duct. An object of the present invention is to provide an evaporation treatment device that can treat waste liquid without causing any waste. This objective is achieved by providing a drug dissolution tank and introducing the wastewater pre-treatment liquid and condensate water to dissolve the drug.

That is, the wastewater evaporation treatment device according to the present invention includes one or more reaction tanks, an evaporation device connected to the reaction tank by reaction treated water piping, one or more drug dissolution tanks and chemical solution storage tanks, and reaction treatment water piping. a solid-liquid separation tank provided below a branch pipe of the solid-liquid separation tank, a supernatant water pipe of the solid-liquid separation tank and a condensed water pipe of the evaporator open to the drug dissolution tank, and a drug solution pipe from the drug storage tank to the It is characterized by opening into the reaction tank.

Next, the present invention will be explained in detail based on the drawings.

The drawing is a system diagram of a wastewater evaporation treatment device showing one embodiment of the present invention. The raw liquid to be treated enters the first reaction tank 1,
The chemicals necessary for the treatment are added by the chemical liquid injection pump 16. Here, the mixture is thoroughly mixed and stirred by the stirrer 2, enters the second reaction tank 3, is stirred by the stirrer 4, and after a sufficient reaction is carried out, flows into the evaporator (drum dryer) 5.

Here, since the drum surface is heated to about 150° C. as described above, the waste liquid is evaporated. The steam is discharged through an exhaust duct 8 with an exhaust fan 7, and an evaporation residue is produced on the drum surface as a result of evaporation of the waste liquid. The evaporation residue is scraped off by a scraper 18 and stored in a dry sludge receiver.

As dilution water for the drug dissolution tank 12, condensed water in the exhaust duct is introduced through the condensed water piping 17, and to make up for the shortage, the waste liquid at the evaporator inlet is mixed into the precipitate generated by the reaction and supernatant water in the solid-liquid separation tank 10. Solid-liquid separation is performed, and the supernatant water is used as dilution water for drug dissolution. The automatic valve 9 is set to close automatically when dilution water is no longer needed in the chemical dissolution tank 12. In the drug dissolving tank 12, the introduced dilution water and the drug are sufficiently stirred by the stirrer 13, and when the drug has been completely dissolved, the drug solution is transferred to the drug solution storage tank 15 by the drug solution transfer pump 14.

The reaction product settled in the solid-liquid separation tank 10 is returned to the second reaction tank 3 by the return sludge pump 11.

The drawing shows a drum dryer as the evaporator, but
Any other type of evaporator can be used. Moreover, when there are two or more types of added chemicals, a medicine dissolving tank may be added.

Furthermore, if the reaction requires adjustment of pl+, such as a neutralization reaction, a pH meter 19 is provided in the first reaction tank 1.

With the above configuration, the amount of waste liquid required for evaporation treatment is not added due to the addition of chemicals, so there is no need for extra evaporation heat, and there is no need to increase the processing capacity of the evaporation device, resulting in an energy-saving evaporation treatment device. I was able to do this.

Next, the present invention will be explained in detail based on examples.

Example Using the processing apparatus shown in the drawings, nickel plating waste liquid with a pH of 1 or less was evaporated.

In order to neutralize the nickel plating waste liquid, flaky sodium hydroxide is used as a chemical, and this is transferred to the chemical dissolving tank 12.
The sodium hydroxide aqueous solution produced is injected into the first reaction tank 1 by the chemical injection pump 16, where the waste liquid is adjusted to p) 110 with a p)l total 19, and introduced into the second reaction tank 3. did. After sufficiently reacting in the second reaction tank, the reaction treated water was evaporated in a drum dryer 5.

The use of reaction treated water and condensed water according to the present invention to melt sodium hydroxide reduces the amount required for evaporation treatment by 25%.
We were able to reduce this.

[Brief explanation of drawings]

The drawing is a flow sheet of the wastewater evaporation treatment apparatus of the present invention. DESCRIPTION OF SYMBOLS 1... First reaction tank, 3... Second reaction tank, 5... Evaporator, 6... Drying slurry/nozzle receiver, 8... Exhaust duct, 10... Solid-liquid separation tank , 12... drug dissolving tank, 1
5... Chemical storage tank patent applicant Hitachi Plant Construction Co., Ltd.

Claims (1)

[Claims] In a non-discharge type wastewater evaporation treatment device, one or more reaction tanks, an evaporator connected to the reaction tank by reaction treated water piping, one or more drug dissolution tanks and chemical solution storage tanks, and reaction treatment water piping. It consists of a solid-liquid separation tank provided below a branch pipe, the supernatant water piping of the solid-liquid separation tank and the condensed water piping of the evaporator open to the drug dissolution tank, and the chemical liquid piping from the chemical storage tank connects to the reaction A wastewater evaporation treatment device characterized by having an opening in a tank.