JP2001286900A - Method for flocculating organic sludge and polymer flocculating agent - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the flock strong in flock strength to the hardly dehydratable sludge many in an organic material content and large in the negative charge on the surface of the sludge. SOLUTION: An amphotetic polymer expressed by a following general formula (1) in which a ratio of (cation equivalent value Cv)/(anion equivalent value Av) is 1.0-1.4 and a cationic polymer expressed by a following general formula (2) are added in organic sludge in the proportion of 25-80 wt.% cationic polymer. (Where, (1)≠(2), R1 is H or CH3, (R2, R3 and R4) are H or CH3 or lower alkyl group, X is Cl or Br).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coagulation method and a coagulation method which are carried out as a pre-operation when dewatering an organic sludge generated from sewage, human waste or organic industrial wastewater by a centrifugal dehydrator or a belt press dehydrator. The present invention relates to a polymer flocculant used in the method.

[0002]

2. Description of the Related Art Conventionally, in the dehydration treatment of organic sludge, a cationic polymer coagulant and an amphoteric polymer coagulant or a coagulant obtained by mixing a cationic polymer and an amphoteric polymer are added to sludge to coagulate organic substances. To obtain a floc, and the floc is dewatered by a dehydrator.

[0003]

However, the conventional flocculant has a large amount of organic matter and can only obtain floc having a low strength even when flocculating hardly dewaterable sludge having a large negative charge on the sludge surface. Therefore, when the floc is applied to a dehydrator, the floc is easily broken, the water content of the floc cannot be reduced, and there is a problem in the releasability in the dehydrating operation by the belt press dehydrator. Further, it is difficult to follow the fluctuation of the sludge concentration, the fluctuation of the organic matter content, and the like, and it is also difficult to perform a stable dehydration treatment operation.

The present invention has been made as a result of intensive studies to stably dehydrate sludge having a large amount of organic matter and a sludge with a large negative charge on the surface of the sludge and having a variable sludge concentration and organic matter content. It was invented.

[0005]

[Means for Solving the Problems] (Chaotin equivalent value C _V )
The ratio of / (anion equivalent value A _V ) is 1.0 to 1.4, and the amphoteric polymer represented by the following general formula (1) and the cationic polymer represented by the following general formula (2) are used. It is to add and mix the organic sludge at a ratio of 80% by weight.

[0006]

Embedded image

At the time of addition and mixing, the amphoteric polymer and the cationic polymer may be added to the organic sludge immediately before and after, but each polymer is mixed to form a flocculant, and when the flocculant is a powder, Is dissolved in water, and if liquid, it is diluted with water and added and mixed, so that the coagulation operation is performed smoothly.

Accordingly, the amphoteric polymer represented by the general formula (1) wherein the ratio of (chaotin equivalent value C _V ) / (anion equivalent value A _V ) is 1.0 to 1.4, and the above-mentioned general formula (2) The cationic polymer represented by
A polymer coagulant mixed at a ratio of up to 80% by weight can be provided. In particular, by making the polymer coagulant liquid, a product suitable for coagulation operation of organic sludge can be provided.

The amphoteric polymer represented by the general formula (1) and the cationic polymer represented by the general formula (2) can be produced by an aqueous solution polymerization method, an emulsion polymerization method, a bulk polymerization method, or a suspension polymerization method.

Although the polymer flocculant of the present invention may be used alone for sludge dewatering, it can be used in combination with a sulfate band, ferric chloride, ferrous sulfate and ferric polysulfate as an inorganic flocculant. A better effect can be obtained in terms of dehydration and filter cloth releasability.

The amount of the polymer flocculant of the present invention to be added to sludge is usually 1.0 to 1.5% / per sludge TS.
The amount of the inorganic flocculant to be added is preferably such that the amount of charge of the sludge is measured, and the amount of the inorganic flocculant that neutralizes about の of the charge is added.

[0012]

EXAMPLES The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples.

Acryloyloxyethyltrimethylammonium chloride 80 mol%, acrylamide 20
mol% of the cationic polymer K-1 and acryloyloxyethyltrimethylammonium chloride 14 mol%, acrylic acid 10 mol%, and acrylamide 76 mol% of the amphoteric polymer KA-.
1 and methacryloyloxyethyltrimethylammonium chloride 30 m
ol, acrylic acid 10mol%, acrylamide 60m
ol% of each component of the commercially available amphoteric polymer R-1 having a composition as shown in Tables 1 and 2, and the sewage digested sludge having a high organic content (VTS / TS: 74.8%).
After adding ferric polysulfate 3% / TS to the mixture, a polymer flocculant was added, and the mixture was centrifugally dehydrated to measure the water content of the cake.

As comparative examples, a test was also conducted on a cationic polymer K-1 alone, a commercially available amphoteric polymer R-1 alone, and a mixture of 10% cationic polymer K-1 and 90% R-1.

As shown in Table 1, the water content of the cake was reduced in the example as compared with the comparative example.

In Example 5 and Comparative Example 7, a test was conducted in which a large amount of a polymer flocculant was added at 1.5% / TS. In Comparative Example 7, the floc was redispersed and became smaller, and the water content increased. In Example 5, the floc was hardly redispersed, and the treatment could be performed stably.

[0017]

[Table 1]

[0018]

[Table 2]

[0019]

According to the method of the present invention, a flocculation operation having a high floc strength can be performed on a hardly dewaterable sludge having a large amount of organic matter, which has conventionally been difficult to dewater, so that the water content of the dewatered cake can be reduced. Since the filter fabric has good releasability, excellent dehydration treatment is possible in a dehydrator such as a screw decanter or a belt press. Further, the polymer flocculant of the present invention makes it difficult to re-disperse floc caused by excessive addition and has a wide optimum addition amount range, so that a stable treatment can be performed even when the sludge concentration and the organic matter content fluctuate.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (reference) C08L 33/00 C08L 33/00 F term (reference) 4D015 BA05 BA06 BA11 BA12 BA19 BB06 BB14 BB17 CA12 DA05 DA13 DA15 DA16 DB07 DB13 DB15 DC02 DC06 DC07 EA03 FA03 FA19 4D059 AA01 AA03 AA23 BE16 BE37 BE55 BE56 BE57 DA17 DA23 DA24 DB24 DB26 EB20 4J002 BG01W BG07W BG07X BG13W BG13X FD200 GD05 4J100 AJ02R AL08P AL15P ALQPAMQ

Claims (2)

[Claims] 1. An amphoteric polymer represented by the following general formula (1) having a ratio of (chaotin equivalent value C _V ) / (anion equivalent value A _V ) of 1.0 to 1.4, and the following general formula (2) A cationic polymer represented by
A method for coagulating organic sludge, comprising adding and mixing 80% by weight into organic sludge. Embedded image 2. An amphoteric polymer represented by the following general formula (1) having a ratio of (chaotin equivalent value C _V ) / (anion equivalent value A _V ) of 1.0 to 1.4, and the following general formula (2): A cationic polymer represented by
A polymer flocculant mixed at a ratio of 80% by weight. Embedded image