JPS58291A - Treatment of waste water containing melamine polymer - Google Patents

Abstract

PURPOSE:To reduce the amt. of sludge and to improve the removal rate for melamine polymers by adding inorg. acids to waste water contg. the melamine polymers to control the pH thereof to <=5.0 and separating the melamine polymers by coagulation. CONSTITUTION:Inorg. acids such as sulfuric acid, hydrochloric acid, nitric acid and others are added to waste water contg. melamine polymers discharged from paint, resin and textile plants, etc. to decrease the pH thereof to <=5.0, and the melamine polymers are separated away by coagulation. There are methylated melamine resins, butylated melamine resins, etc. and mixtures of these and acrylic resins, etc. as the above-described melamine polymers. It is preferable to control the pH to about a 4.5-2.0 range by adding inorg. acids. In order to cause the coagulation of the melamine polymers effectively, it is preferable to agitate the inorg. acids mechanically and pneumatically and to agitate these for about >=48hr at an ordinary temp.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel method for treating wastewater containing melamine polymers. More specifically, the present invention relates to a wastewater treatment method for purifying wastewater by insolubilizing and coagulating and separating mefmine-based polymers contained in the wastewater.

Wastewater discharged from mefmin resin manufacturing plants, mefmin paint factories, textile factories that process mefmin resins, etc. contains a large amount of mefmin polymers. Conventionally, various methods have been used to treat such wastewater, such as coagulation-sedimentation treatment, biological treatment, or a combination of coagulation-sedimentation treatment and biological treatment. However, in the coagulation and sedimentation treatment that has been mainly used in the past, there is originally a large amount of lII raw sutsushi, and this sutsushi has a high moisture content (which makes it difficult to concentrate, so it is necessary to install sea bream equipment for this treatment. At the same time, the disadvantage is that the removal rate of water-soluble methine-based polymers is surprisingly low.
% Biological II & weir has a drawback that the CODI11* rate increases when operated for a long period of time.1 Also, the combination of coagulation sedimentation and biological weir is effective in removing COD and produces a large amount of azaleas. There is also a point where the Sunbi cost is large. The active adsorption method, ozone oxidation method, etc. are also used in the pond, so J# cannot be adopted (because of the high cost of equipment and maintenance of fresh water I & SL).

In Sonin, Akira Hata et al. investigated an economical method that can simply separate melamine-based polymers contained in wastewater, generates less sfudge, and is economical in terms of the cost of constructing a wastewater treatment facility and the maintenance and management costs. Therefore, an inorganic acid is added to the above wastewater to reduce its P.
When R was varied variously, the coagulant-based polymer was coagulated and separated and was insoluble in water and did not decompose. It has excellent precipitation and transient properties.

The inventors have found that the present invention is less than 100%, and after further intensive study, they have arrived at the present invention. That is.

The present invention is a treatment for wastewater containing a melamine polymer, which is characterized by adding an inorganic acid to the wastewater containing the melamine polymer to lower the pH to 5.0 or less, and coagulating and separating the skeleton polymer. It is the law.

The novel idea of the present invention is to add an inorganic acid to wastewater to adjust the pH.
5.D or less, the melamine polymer is coagulated. Based on this idea, it became possible for the first time to provide a practical Yudan method in which the amount of sludge is extremely small, the p-separation of the sludge is easy, and the removal rate of melamine polymers is high.

Wastewater discharged from waste water companies, the above-mentioned paint, resin, textile factories, etc. containing the melamine-based polymers targeted by the present invention; One or a mixture of two or more of isobutylated mehumine resins, hekynamethoxymethylmethylammonium mehumine resins, etc. and water-soluble resins such as acrylic resins.
It contains a mixture of two or more types of 1111 resins such as V-type, 7-Kid type, and Eboki V-type Ruruiko polyester.

The inorganic acid added to the waste water is sulfuric acid, sulfuric acid, nitric acid, etc., and at least one of these is used. If the pH of the above-mentioned inorganic acid #i fresh water is 5.0 or higher, it will be difficult to coagulate, so it is necessary to add it so that the pH is below S. The above pea is preferably in the range of 4.5 to 2.0, and in order to effectively insolubilize and coagulate the melamine polymer, add % organic acid to the wastewater. It is preferable to mix and stir. The above-mentioned stirring can be carried out using a known machine I/1# and/or air stirring, and in this case, it is usually preferable to stir for 48 hours or more. After stirring for about 30 minutes and separating the solid and liquid, the removal rate of CO ~ from Marube hot water was about 50 liters.
When this treated water is made into biological boiling water, the COD is 3g and the removal rate is 4.
It is about 70-, but the ooD3. The removal rate of , is about 80-,
What is the CODM removal rate when bio-boiling water is used to treat water from Jin?
6 and 9 with O 悌 and above. In order to promote coagulation, it is preferable to heat K by blowing steam or the like into it during stirring.For example, if wastewater is heated to 5°C, the same effect as at room temperature can be obtained in about 24 hours. Ta.

The above-mentioned inorganic acid is added to adjust the pH to 5.0 or less to insolubilize and coagulate the melamine polymer.Then, the insolubilized melamine polymer is converted into bulk powder using a solid-liquid separator. In this case, the fresh water is directly sent to the J111iI liquid separator, where it is separated into solid-liquid separated water and sludge, and if it satisfies the standards for discharge to the public water area, the water is discharged as is. If the discharge standards are not met, the water will be sent to the next treatment facility, such as biological hot water. As the solid-liquid separator, a centrifugal separator, a vacuum cleaner, a filter press skimmer, etc. can be used. Another method is to insolubilize and coagulate the melamine-based polymer and send good wastewater to a pressure flotation device, float the sludge, and perform solid-liquid separation.

As described above, the method of the present invention involves adding an inorganic acid to wastewater containing a melamine polymer to lower the pH to below 5.0 liters; It is a practically useful method because it has the effect that it can be separated into spring crystals because the sludge itself and the separated sludge are very small and stable.

・Example methylated melamine tree 1111I The soft tubing wastewater from the factory had a concentration of melamine polymer of 2.2%, CODMII.
B cane at 4.560 llFm. Add sulfuric acid to this wastewater, adjust the pH to 4, and stir with @ Toshidoro*S''a by changing the agitation mode.-1 The generated sludge is separated with a centrifugal separator and treated with water (supernatant). C■6 was measured and the results are shown in Table 1.

Table I11 The above treated water was diluted with distilled water and CODM - approx. 500p
Pmm and good liquid as sludge negative 11 @-1”l COD, /
The results are shown in Table 2 after five days of biological treatment.

Table 2

Claims (1)

[Claims] Adding inorganic acid to wastewater containing mefmin-based polymers
A method for treating wastewater containing a melamine polymer, which comprises lowering H to 5.0 or less and coagulating and separating the polymer.