JPS5982911A - Composition for flocculating agent - Google Patents

Abstract

PURPOSE:To provide a compsn. for a flocculating agent which exhibits a better flocculating effect than in the case of adding an inorg. flocculating agent and a cationic flocculating agent separately by mixing both agents ata specific ratio. CONSTITUTION:A mixed soln. consisting of 360mg/l polyethylene imine, 586mg/l aluminum chloride is added to the waste water of chemical groundwood pulp having 6560 chromaticity and 6.75pH from a paper pulp plant; thereafter the soln is adjusted to 7.0pH and is subjected to a flocculating precipitation treatment by adding an aninoic org. flocculating agent at 1mg/l. When the chromaticity of the supernatant water is measured, the liquid has 92 chromaticity and is virtually colorless and transparent. A better flocculating effect than in the case of adding the respective flocculating agents alone or separately is obtd. and particularly the removal of chromaticity is high in the case of using mixedly the cationic flocculating agent and the inorg. flocculating agent in a way not to produce an insoluble resulted product of reaction in the state of an aq. soln. as in this invention.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a flocculant composition used for industrial wastewater treatment and the like.

Treat industrial wastewater to remove SS, COD, chromaticity, etc./
Inorganic or commercial flocculants are used as fillers, and these are used in combination when removal of chromaticity is a particular problem or when other advanced treatments are required. A common method of this kind is to add an inorganic flocculant to wastewater to adjust the pH, and then add an anionic organic flocculant to grow flocs, which are then separated by sedimentation.

However, this method requires a large amount of inorganic coagulant (■TE agent) to perform complete treatment, so the combination of an inorganic flocculant and a cationic organic flocculant has been proposed. and a cationic organic flocculant are added separately in any order to perform flocculation, and if necessary, an anionic flocculant is further added to grow flocs and sedimentation separation is performed. Although the aggregation effect was better than when treated alone, it was not necessarily satisfactory.

This invention was made by focusing on the above-mentioned conventional problems, and by mixing an inorganic flocculant and a cationic flocculant, it shows a better flocculating effect than the conventional case where they are added separately. The present invention aims to provide a flocculant composition.

The present invention is a flocculant composition comprising a cationic organic flocculant and an inorganic flocculant mixed together so as not to produce insoluble reaction products in aqueous solution.

When conventional cationic organic N collectors and inorganic flocculants are used together, they are added separately, and kneading,
This is to prevent a decrease in efficacy due to reaction when the two are mixed, but according to the knowledge of the present inventor, it is necessary to mix the two in an aqueous solution state so that insoluble reaction products are not produced. It was found that the aggregation effect did not decrease, but on the contrary, became better.

Cationic organic flocculants and inorganic flocculants may produce insoluble reaction products when mixed, so they can be prevented from being complicated, and in these conditions, when the mixed solution is added to raw water, it exhibits an excellent flocculating effect. .

The cationic organic flocculant is not particularly limited, and any conventionally used ones similar to these can be used, such as polyethyleneimine, dicyandiamide-formalin condensate, alkylene polyamine-alkylene dino ride condensate. , polydimethyldiallylammonium salt, Mannich modification of polyacrylamide, Hofmann decomposition product of polyacrylamide, epino-rohydricyamine condensate, cationized starch, cationized guna gum, chitosan, aminoalkyl (meth)acrylate (tertiary, (including quaternized products) or copolymers with acrylamide or other monomers, but in particular, polyethyleneimine, dicyandiamide, etc.
Formalin condensates and alkylenepolyamine-alkylene dinolide condensates are preferred.

The inorganic flocculant is not particularly limited, and conventionally used ones can be used, such as aluminum chloride, aluminum sulfate, aluminum polyhxate, ferrous sulfate, ferric sulfate,
Examples include ferrous chloride, ferric chloride, polyiron, etc.
Particularly preferred is aluminum chloride.

These cationic organic flocculants and inorganic flocculants are used singly or in combination to form a flocculant composition, but they are particularly suitable for use with polyethyleneimine, dicyandiamide-formalin condensate, or alkylene polyamine-alkylene cybaride condensate. A combination of aluminum chloride is preferred. These are mixed in the form of an aqueous solution to prevent the formation of insoluble products in the mixed solution. The above-mentioned flocculants can be used as a mixed solution in which no insoluble products are produced in all silk combinations, but the conditions under which insoluble products are produced differ depending on each combination.

For example, when mixing a 60% aqueous solution of a cationic organic flocculant and an 8-10% aqueous solution of an inorganic flocculant (as Ad2e3), Ktd is used to prevent the formation of insoluble products, and in the case of a combination of polyethyleneimine and sulfate band 1
The amount of polyethyleneimine must be 1 part by weight or less per part by weight, but in the case of a combination of polyethyleneimine and aluminum chloride, the amount of polyethyleneimine may be less than 1 part by weight per 6 parts by weight of aluminum chloride. A combination of dicyandiamide-formalin condensate and aluminum sulfate (--4 parts by weight of polyethyleneimine or less should be used for 6 parts by weight of sulfate), whereas a combination of dicyandiamide-formalin condensate and aluminum chloride Similarly, in the combination of ethylenediamine-ethylene dichloride condensate and sulfuric acid banding or aluminum chloride, insoluble products are likely to be produced at all blending ratios. From the above, it can be seen that aluminum chloride is more preferable than aluminum sulfate.

Since the conditions for producing an insoluble product vary depending on not only the mixing ratio but also the pH concentration, etc., it is possible to solubilize the product by appropriately selecting these conditions. In general,
It is desirable that the mixture be carried out at a mixing ratio that does not precipitate insoluble matter, and that the pH of the mixed solution be on the more acidic side than the pH at which the inorganic flocculant becomes a hydroxide and precipitates.

The mixed solution thus obtained is used as a flocculant by adding it to wastewater as it is or diluting it to an appropriate concentration. Such a mixed solution may be manufactured as a product and transported to the site for use, or may be prepared on site.

The mixed solution is used in the same manner as conventional cationic organic flocculants or inorganic flocculants, and the flocculation method is also the same as conventional ones. That is, the above-mentioned mixed solution is added to raw water, stirred, and adjusted to a pH suitable for aggregation (typically around pH 7) to perform aggregation. Furthermore, if necessary, an anionic organic flocculant is added to grow flocs, and sedimentation separation or 1.
l-1: Filtration separation can be performed. Examples of the anionic organic flocculant include a partial hydrolyzate of acrylamide, sodium acrylate, and the like. The amount of the composition of the present invention to be added varies depending on the object to be treated, and can be determined in advance by conducting a jar test.

The raw water to be treated in the present invention includes all raw water that is normally subjected to coagulation treatment, including SS, COD,
Organic or inorganic wastewater containing chromaticity, etc. has a significant effect, especially when the purpose is to remove chromaticity and COD, and the amount of sludge generated is small.

The flocculant composition of the present invention can perform flocculation treatment by itself, but it may also contain other additives, such as a sedimentation accelerator, or may contain other flocculants (cationic organic flocculants and inorganic flocculants). It is also possible to use it in combination with other agents (including agents).

Furthermore, the cationic organic flocculant and inorganic flocculant used in the present invention are not limited to those exemplified above.

As explained above, according to the present invention, a cationic organic flocculant and an inorganic flocculant are mixed to form a flocculant composition so as not to generate insoluble reactants in an aqueous solution state. , showed a flocculating effect that was superior to the case of adding each flocculant alone or separately,
In particular, it shows an excellent effect on removal.

Next, examples of the present invention will be described. Table 1 shows the flocculants used in the examples. Further, pH adjustment was performed using sulfuric acid or sodium hydroxide.

Table 1 Example 1 Chemical ground pulp wastewater from a pulp and paper factory (brown,
After adding a mixed solution of a cationic organic flocculant and an inorganic flocculant having the composition shown in Tables 2 to 4 to the mixture (pH 6.75, chromaticity 6560 degrees), the pH was adjusted to 7.0, and the anionic inorganic jh% A flocculant was added to perform coagulation and sedimentation, and the chromaticity of the supernatant water was measured. The results are as shown in Tables 2-4. As comparative examples, a case where an insoluble product was generated in a mixed solution of a cationic organic flocculant and an inorganic flocculant (A), and a case where an inorganic flocculant and a cationic organic flocculant were added separately and almost simultaneously (B). ), when a cationic flocculant is added alone (C
) and when an inorganic flocculant is added alone (D) VC
The results of tests conducted under the same conditions are also listed in Tables 2 to 4.

The * mark in the table indicates the amount of chemical added that gave the best treatment results for each treatment method.

Table 2 Continuation of Table 2 Table 6 Table 4 Example 2 The results of a similar test on activated sludge treated water (yellow, pH 75, color filter 861 ()) of human waste digestion and desorption fluid are shown in Table 5.
Shown below.

Table 5 From the above results, it can be seen that all of the examples exhibit better effects than the comparative examples.

Agent: Patent Attorney Sei Yanagi Hara

Claims (3)

[Claims] (1) A flocculant composition containing a cationic organic flocculant and an inorganic flocculant mixed together so as not to produce an insoluble reaction product in an aqueous solution state. (2) The cationic organic flocculant is polyethyleneimine,
Dicyandiamide-formalin condensate or ethylenediamine-ethylene dichloride condensate! The pupil aggregating agent composition according to claim 1, which is l+7+. (3) The flocculant composition according to claim 1 and 2, wherein the inorganic flocculant is aluminum chloride or aluminum sulfate.