JPS627489A - Method for treating waste water of protein foam fire extinguishing solution - Google Patents

Abstract

PURPOSE:To prevent environmental pollution, by adding a polymer flocculant and polyaluminum chloride to a solution containing a protein foam fire extinguishing agent to perform flocculative sedimentation and filtering while adding hydrogen peroxide and ferrous sulfate to the filtrate to perform oxidizing treatment. CONSTITUTION:Waste water containing a protein foam fire extingushing agent is sent to a treatment tank 2 and polyaluminum chloride and sodium hydroxide are respectively added to said tank 2 under stirring from a polyaluminum chloride tank 4 and a sodium hydroxide tank 5 and a polymer flocculant is further added from a polymer flocculant tank 6. The formed flocs are sent to a centrifugal separator 10 to be separated into a filtrate and sludge. The filtrate is sent to an oxidizing tank 13 and hydrogen peroxide and ferrous sulfate are added to said filtrate to perform reaction. Further, calcium carbonate is added to perform discoloration. The treated filtrate is treated by a centrifugal separator 10 and activated carbon is added to the filtrate to adsorb a DOC component.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) This invention relates to a method for treating wastewater using protein foam fire extinguishing liquid.

(Prior art) Protein foam fire extinguishing agents are used in outdoor tanks as hazardous materials facilities and fixed foam fire extinguishing equipment attached to petroleum plants, etc. In the event of a fire, this extinguishing agent is used by the fire extinguishing equipment. It is mixed with water and then mixed with air and released as bubbles.

Conventionally, such foam fire extinguishing equipment has discharged water instead of foam extinguishing liquid in the chemical discharge test soap. Therefore, since the foam fire extinguishing fluid is not released except in the event of a fire, there is no need to particularly consider wastewater treatment of the foam fire extinguishing fluid, and no development has been made on the treatment method.

(Problem to be solved by the invention) Recently, fixed foam fire extinguishing equipment is required to undergo a foaming performance test once a year in addition to an operational function test. The aqueous solution is discharged. When this wastewater is discharged into rivers, it becomes a pollution problem because it pollutes the rivers.

(Measures to solve the problem) This invention was newly developed to solve these problems. Namely, a solution containing a protein foam extinguishing agent, a polymer flocculant, polyaluminum chloride, and sodium hydroxide, coagulated and precipitated and filtered, hydrogen peroxide and sulfurized ferrous iron added to the filtrate, oxidized and filtered, activated carbon added to the filtrate for adsorption treatment and filtered, COD
This is a method for treating wastewater using protein foam fire extinguishing fluid, which is characterized by reducing the value of fire extinguishing fluid.

(Example) Regarding this treatment method, an example will be given in which protein foam manufactured by Company A (5-type) was treated.

Add 2% polyaluminum chloride to sample solution COD 6000PPM, stir, add 1 ton of sodium hydroxide to make PR&Q, add polymer flocculant for 101s, and create 70ml filter paper on all floors 5A. It narrows down. Next, 8% hydrogen peroxide solution was added to the treated solution, and activated carbon (5%
Add 2 g (0% wet powder) and stir. As a result, the COD value was +40 PPMK.

As a possible wastewater treatment method other than this, for example, the following treatment method is listed as Comparison 1c.

Add polyaluminum chloride to the sample solution (also COD 6000PPM), add sodium hydroxide, and make PB.
&0, passed through a 5A filter paper, and then treated with an ion exchange resin (-IR+20BNa type). In this example, tjcOD was 2100.

As described above, with the processing method according to the present invention, the COD value can be greatly reduced.

To explain an example in which the treatment method of the present invention is implemented using an actual treatment device, as shown in the figure, wastewater containing a protein foam fire extinguisher is sent to a treatment tank 2 with a pump 1, and while being stirred with a stirrer 3, polychloride Add polyaluminum chloride from aluminum tank 4. Next, add sodium hydroxide from the sodium hydroxide tank 5, and add 1t144I to pHf 60.
Then, a fukotsuk occurs.

Foaming components in wastewater are aggregated in this floc.

Further, while continuing stirring, a polymer flocculant is added from the polymer flocculant tank 6. This polymer flocculant makes the flocs large and ready for cleaning.

Next, 70 pieces are sent to a centrifuge 10 using a slurry pump 8 while measuring the flow rate with a flow meter 9. The slurry entering the centrifugal separator 10 is separated into a liquid and sludge. Sludge is collected in a sludge receiving tank 11. On the other hand, the filtrate separated by the centrifuge 10 is transferred to an oxidation tank 15.
and hydrogen peroxide tank 15 while stirring with a stirrer 14.
and hydrogen peroxide solution from the ferrous sulfate injection tank 16, and @L
Ferrous acid fI: Add and react.

This reaction, commonly called 7-entone oxidation, strongly oxidizes the filtrate and reduces COD components.

Next, the first solution colored by 7-enton oxidation is decolorized by adding calicicum carbonate from calcium carbonate 4917.

After decolorization, the treatment solution is centrifuged in an apricot slurry bong 8 for +ms.
+o, and separated into hydrogen peroxide treated droplets and sludge by a centrifuge 10. Sludge, ji is sludge receiving tank 11
Collect 1C. Further, the hydrogen peroxide treated filtrate is sent to the treatment tank 2, and activated carbon is added from the activated carbon tank 7 while stirring with the stirrer 5. As a result, while the COD components are adsorbed in each step, the treated liquid is again sent to the centrifugal separator 10 by the slurry pump 8, where it is separated into treated droplets and activated carbon. The activated carbon is then collected in an activated carbon receiving tank 12. The treated filtrate then meets prescribed wastewater treatment standards.

(Effects of the Invention) According to the method for treating wastewater using protein foam fire extinguishing liquid according to the present invention,
It is a safe and excellent method that can treat wastewater with a high COD value without using special treatment equipment, and can significantly lower the COD value.

[Brief explanation of drawings]

1 is a system diagram of a processing device for carrying out the method of the present invention. 1.8...pump, 2...processing tank. 4... Polyaluminum chloride tank, 5... Sodium hydroxide tank, 6... Polymer coagulation tank, 7... Activated carbon tank,
10... Centrifugal separator, 11... Sludge receiving tank.

Claims (1)

[Claims] A polymer flocculant, polyaluminum chloride, and sodium hydroxide are added to a liquid containing a protein fire extinguishing foam, and the mixture is coagulated and precipitated and filtered, and hydrogen peroxide and ferrous sulfate are added to the filtrate. A method for treating wastewater using protein foam fire extinguishing fluid, which comprises adding activated carbon to the filtrate, performing adsorption treatment, and filtering to lower the COD value.