JP2010179248A - Method for treating livestock sludge - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an improved dehydration method of livestock sludge by which treatment cost can be reduced as compared with the conventional art and further working environment and neighboring area environment can be improved by reduction of malodor at a dehydration treatment process. <P>SOLUTION: The livestock sludge is subjected to deodorization treatment and modification treatment by one or more kinds of inorganic oxidants chosen from an oxidant group composed of chlorite, hypochlorite, bromate, bromite, hypobromite and hydrogen peroxide. Then vinyl polymerization-based cationic water-soluble polymer and/or vinyl polymerization-based amphoteric water-soluble polymer are added thereto, flocculation treatment is carried out and then dehydration by a dehydrator is carried out. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

The present invention relates to a method for treating livestock sludge, and more specifically, after adding an inorganic oxidant to a livestock sludge to deodorize and modify it, a vinyl polymerization cationic water-soluble and / or vinyl polymerization system The present invention relates to a method for treating livestock sludge, characterized in that an amphoteric water-soluble polymer is added, coagulated, and then dehydrated by a dehydrator.

In the case of dewatering sludge, a cationic flocculant has been used in the past, but in the case of difficultly dewatered sludge, after adding an inorganic flocculant, a prescription using a cationic organic polymer flocculant or a similar prescription And a combination of amphoteric organic polymer flocculants, inorganic flocculants, anionic flocculants and cationic flocculants (Patent Document 1), and nonionic polyvinyl alcohol and cationic and / or amphoteric A prescription using a flocculant in combination is disclosed. However, it is possible to handle sludge fluctuations sufficiently, stable treatment is possible, the moisture content of the dewatering cake is sufficiently reduced, and if the process after dewatering can be performed efficiently, it is still a complete recipe The current situation has not been proposed.

Regarding the sludge treatment method in livestock wastewater, prescriptions containing cationic or amphoteric water-soluble polymers occupy the mainstream, but the problem of odor at the work site has not been solved. Regarding sludge dewatering using an inorganic oxidant to prevent odor, Patent Document 4 has been proposed, but this formulation is prepared by adding an inorganic oxidant, stirring and reacting, and then coagulating inorganic agglomerates such as iron salt and aluminum salt. In this method, a cationic and / or amphoteric polymer flocculant is added and then dehydrated. In particular, aluminum salts are concerned about the association with Alzheimer's disease and tend to refrain from use. Therefore, regarding livestock sludge, prescriptions regarding odor prevention and efficiency of the sludge treatment process have not yet been proposed.
JP-A-8-52477 JP 2001-286899 A Japanese Patent Application No. 2007-316556 JP 2007-245036 A

The problem of the present invention is that it is possible to improve the working environment and the surrounding area environment by reducing the malodor during the dehydration process at the same time as the treatment cost of livestock sludge, and more sludge dewatering. It is to provide a processing method with improved performance.

As a result of detailed studies to solve the above-mentioned problems, the present inventor has found a prescription that is more efficient than the conventional method in dehydration treatment of livestock sludge, has a reduced dehydrated cake water content, and reduces odor. The present invention has been reached. That is, the invention of claim 1 of the present invention is a vinyl polymerized cationic substance after subjecting livestock sludge to deodorization treatment and modification treatment with one or more inorganic oxidants selected from the following oxidizer group. A livestock sludge treatment method comprising adding a water-soluble and / or vinyl polymerization-based amphoteric water-soluble polymer, aggregating and then dehydrating with a dehydrator.
Oxidizing agent group; chlorite, hypochlorite, bromate, bromate, hypobromite, hydrogen peroxide.

In the invention of claim 2, the vinyl polymerization water-soluble cationic polymer is obtained by copolymerizing 20 to 100 mol% of a monomer represented by the following general formula (1) and / or the following general formula (2). One or more selected from cationic water-soluble polymers obtained from the above, water-soluble cationic polymers having 10 to 90 mol% of structural units represented by the following general formula (4) and / or the following general formula (5) The vinyl polymerization amphoteric water-soluble polymer is represented by the following general formula (1) and / or the monomer represented by the following general formula (2) by 20 to 100 mol% and the following general formula (3). It is an amphoteric water-soluble polymer obtained by copolymerizing 5 to 50 mol% of the monomer, and the method for treating livestock sludge according to claim 1.

General formula (1)
R ₁ is hydrogen or a methyl group, R ₂ and R ₃ are an alkyl group having 1 to ₃ carbon atoms, an alkoxy group or a benzyl group, and R ₄ is hydrogen, an alkyl group having 1 to 3 carbon atoms, an alkoxyl group or a benzyl group. , Same or different. A represents oxygen or NH, B represents an alkylene group or alkoxylene group having 2 to 4 carbon atoms, and X ₁ represents an anion.
General formula (2)
R ₅ represents hydrogen or a methyl group, R ₆ and R ₇ each represent an alkyl group having 1 to 3 carbon atoms, an alkoxyl group or a benzyl group, and X ₂ represents an anion.
General formula (3)
R ₈ is hydrogen or CH ₂ COOY ₂ , Q is SO ₃ , C ₆ H ₄ SO ₃ ,
CONHC (CH ₃ ) ₂ CH ₂ SO ₃ , C ₆ H ₄ COO or COO, R ₉ is hydrogen, a methyl group or COOY ₃ , and Y ₁ and Y ₂ each represent hydrogen or a cation.








In the formula, R ₁₀ and R ₁₁ represent a hydrogen atom or a methyl group, and X ₃ ⁻ represents an anion.

According to a third aspect of the present invention, the inorganic oxidant, the polycondensation cationic water-soluble polymer, the vinyl polymerization cationic water-soluble and / or the vinyl polymerization amphoteric water-soluble polymer are added to the livestock sludge. It is added in order, It is the processing method of the livestock sludge of Claim 1 characterized by the above-mentioned.

The invention according to claim 4 is characterized in that the vinyl polymer cationic water-soluble and / or vinyl polymer amphoteric water-soluble polymer has a weight average molecular weight of 3 million or more and 20 million or less. It is the processing method of livestock sludge as described in any of these.

A fifth aspect of the present invention is the livestock sludge treatment method according to any one of the first to fourth aspects, wherein the dehydrator is a filter press or a rotary press.

In the present invention, livestock sludge is subjected to deodorization treatment and modification treatment with an inorganic oxidant, and then added with a vinyl polymerization cationic water-soluble and / or vinyl polymerization amphoteric water-soluble polymer for aggregation treatment. Then, it consists of dehydrating with a dehydrator. The feature of the present invention is that it is possible to reduce the amount of drug added by 10% to 20% compared to the case where no inorganic oxidant is added. In contrast, in the present invention, it is considered that the aggregation effect of the cationic or amphoteric water-soluble polymer added after the addition of the inorganic oxidant is increased. That is, a certain degree of coagulation occurs due to the addition of the inorganic oxidant, and there is no waste in the charge of the cationic group of the cationic or amphoteric water-soluble polymer, and it is used for the secondary secondary agglomeration reaction. Furthermore, as an important effect, it is possible to improve the working environment and the surrounding area environment by reducing malodor during the dehydration process.

Examples of the inorganic oxidant group used in the present invention include chlorite, hypochlorite, bromate, bromate, hypobromite, hydrogen peroxide, and the like. Of these, hypochlorite is recommended because it is often used for general purposes. It is possible to improve the working environment and the surrounding area environment by reducing the malodor during the dehydration process at the same time as the reforming process is carried out by adding the amount according to the preliminary test in advance and stirring appropriately. It is possible to provide the cleanliness of the sludge dewatering process by sterilization.

The addition amount of these inorganic oxidant group and cationic polymer or amphoteric polymer monomer is 50: 1 to 2: 1, preferably 10: 1 to 5: 1. If it is 50: 1 or less, there is no effect as an oxidizing agent, and if it is 5: 1 or more, it is disadvantageous in terms of cost.

Cationic and / or amphoteric water-soluble polymers used in combination with the inorganic oxidant group to be added are acrylic cationic monomers such as dimethylaminoethyl (meth) acrylate and dimethylaminopropyl (meth) acrylamide. A salt of an inorganic acid or an organic acid such as a homopolymer of a quaternary ammonium salt with methyl chloride or benzyl chloride, or a copolymer with acrylamide. For example, as a monomer, (meth) acryloyloxyethyl trimethylammonium chloride, (meth) acryloyloxy 2-hydroxypropyltrimethylammonium chloride, (meth) acryloylaminopropyltrimethylammonium chloride, (meth) acryloyloxyethyldimethylbenzyl Ammonium chloride, (meth) acryloyloxy 2-hydroxypropyldimethylbenzylammonium chloride, (meth) acryloylaminopropyldimethylbenzylammonium chloride, and the like. Copolymerization of these monomers with nonionic monomers It is a coalescence. Acrylamide is preferred as the monomer to be copolymerized. Also, amphoteric polymers can be synthesized and used by copolymerizing anionic monomers such as (meth) acrylic acid. In addition to these (meth) acrylic polymers, dimethyldiallylammonium chloride (co) polymers, polyvinylamine polymers, and polyamidine polymers can also be used.

The mol% of the ionic group in these cationic water-soluble polymers is as follows. That is, the cationic group in the cationic water-soluble polymer is 20 to 100 mol%, the nonionic group is 0 to 80 mol%, preferably the cationic group is 50 to 100 mol%, and the nonionic group is 0 to 0 mol%. 50 mol%. The cationic groups in the amphoteric water-soluble polymer are 20 to 100 mol%, anionic groups 5 to 50 mol%, nonionic groups 0 to 75 mol%, preferably cationic groups 50 to 90 mol%, It is 10-30 mol% of anionic groups and 0-40 mol% of nonionic groups. When the cationic group is less than 20 mol%, the cationic property is low and the dehydration efficiency is lowered. On the other hand, when the anionic group is 50 or more, the anionicity is too strong, and the effect of the cationic group is not manifested.

The molecular weight of the cationic water-soluble polymer or amphoteric water-soluble polymer is 3 million to 20 million, preferably 5 million to 15 million. If it is 3 million or less, the cohesive force is insufficient, and if it is 20 million or more, the cohesive force is too high, and the flocs become enormous and the dewaterability is lowered. In addition, the solution viscosity becomes too high, dispersibility is deteriorated, and handling of the aqueous solution is also deteriorated. The product form of the vinyl polymerization cationic water-soluble or vinyl polymerization amphoteric water-soluble polymer used in the present invention may be powder type, aqueous solution type, water-in-oil emulsion, salt aqueous solution dispersion type, etc. In view of the quickness of the polymer, the ease of modification such as crosslinking or branching with a polymer structure modifier, a water-in-oil emulsion is preferred.

The method for treating livestock sludge using the inorganic oxidant group of the present invention in combination with a vinyl polymerized cationic water-soluble and / or vinyl polymerized amphoteric water-soluble polymer is compared with a conventional cationic polymer single formulation. The amount can be reduced by 10% to 20%. The reason for this is considered to be that the loss of the cationic or amphoteric water-soluble polymer added thereafter is small by adding the inorganic oxidant. That is, a certain degree of coagulation occurs due to the addition of the inorganic oxidant, there is no charge waste of the cationic group of the cationic or amphoteric water-soluble polymer, and it is used for the secondary secondary agglomeration reaction. Furthermore, as an important effect, it is possible to improve the working environment and the surrounding area environment by reducing malodor during the dehydration process.

The characteristics of sludge in the livestock industry are as follows. In the case of livestock sludge, the fiber content in the sludge is high (in many cases, cutting of the litter is mixed), and the SS content (suspended particle suspension) is 10% by mass. Volatile suspended particle suspended matter (VSS component, amount reduced when burned) is high and organic content is higher than general sludge. The anion equivalent value is high, and 5.0 meq / L or more is the majority (general sludge is 2 to 6 meq / L). M-alkalinity is high, 3000 mg / L or more is the majority, and the average is 5000 mg / L (general sludge is 1000 to 6000 mg / L). In addition, it can be said that the electrical conductivity is high due to the large amount of livestock urine, and there is a high amount of soluble salt. Among these, the most characteristic is considered to be high electrical conductivity and M-alkaliness. Therefore, there are many cases of dehydration prescription with cationic or amphoteric polymers after sludge modification by using an inorganic flocculant such as polyiron in addition to the cationic polymer single prescription, and first with an inorganic oxidizing agent as in the present invention. A formulation in which a weak coagulation treatment is performed and then a stronger coagulation treatment is performed with a cationic or amphoteric water-soluble polymer is considered to be a formulation suitable for livestock sludge.

In the present invention, an inorganic oxidizing agent such as sodium hypochlorite is used in combination. It has been found that the use of this inorganic oxidant can not only reduce malodor during the dehydration process, but also improve the sludge aggregation effect. It will be clear from the examples described later. A possible reason for this is presumed that the soluble organic substances in livestock sludge are decomposed by oxidation. The sludge contains organic acids, polysaccharides, polypeptides, sulfur compounds such as organic acid decomposition products in wastewater, or organic acids and polyanionic polysaccharides that inhibit the performance of flocculants. By decomposing these substances below a certain level, it seems that as a result, the coagulation performance is improved and the malodor is reduced. In the case of liquid products such as sodium hypochlorite (effective chlorine 8% by mass), it is 0.05 to 0.3% by mass, preferably 0.1 to 0.3% by mass, based on the amount of sludge dispersion. is there. Moreover, in the case of powders, such as bromate, it is 0.005-0.05 mass% with respect to the amount of sludge dispersion liquid, Preferably it is 0.01-0.03 mass%.

As can be seen from the above-mentioned physical properties, the high electrical conductivity and M-alkalinity means that the content of inorganic salts is large and the content of organic substances is low. Deodorization and sludge modification can be achieved with only inorganic oxidants. it can. In the case of sewage sludge, papermaking sludge, etc., an example of using an inorganic oxidant and an inorganic flocculant in combination is a prior application.

In the livestock sludge treatment method of the present invention, when a polycondensation cationic polymer is used in combination, the dehydration efficiency can be further improved. That is, it is a prescription in which the inorganic oxidant, the polycondensation cationic water-soluble polymer, the vinyl polymerization cationic water-soluble and / or the vinyl polymerization amphoteric water-soluble polymer are added to the livestock sludge in this order. Specific examples of the polycondensation cationic water-soluble polymer include the following. It is a polycondensate of at least one compound selected from ammonia, an aliphatic monovalent amine and an aliphatic polyamine with an epihalohydrin. Examples of aliphatic monovalent amines and aliphatic polyamines include monomethylamine, monoethylamine, dimethylamine, diethylamine, trimethylamine, triethylamine, mono, di, and triethanolamine, and ethylenediamine, diethylenetriamine, and triethylenetetramine. And pentaethylenehexamine. A polycondensate can be obtained by reacting one or more of these ammonia and amines with an epihalohydrin such as epichlorohydrin. These polycondensates do not require the reaction of amines and epihalohydrin in one step, the first step is a reaction with an aliphatic monovalent amine followed by a crosslinking reaction with ammonia or an aliphatic polyamine to increase the molecular weight. You may manufacture things. The molecular weight of these polycondensates is 500 to 2 million, preferably 1000 to 2 million. The amount of these polycondensation-based cationic polymers added to the sludge is 0.02 to 0.3% by mass, preferably 0.02 to 0.3% by mass, based on the volatile suspended particle suspended matter (VSS component, the amount that decreases when burned). Is 0.03-0.1 mass%. These are mainly consumed for charge neutralization of substances whose anion equivalent value is detected, and contribute to the formation of small flocs produced by the coagulation action.

  The dehydrator can be dehydrated using conventional models such as decanters, filter presses, belt presses, screw presses, multiple disk molds or rotary presses, but when using a screw press or multiple disk dehydrator. preferable. Examples of sludge include raw sludge, digested sludge and surplus sludge in the livestock industry. Therefore, for the above reasons, the livestock sludge treatment method of the present invention improves the environment by reducing odor during sludge treatment compared to conventional cationic polymer single formulation or anionic polymer flocculant / cationic polymer flocculant formulation, sludge There are advantages such as an increase in the amount of water treatment, a reduction in the moisture content of the cake, a reduction in fuel costs during incineration, a reduction in the amount of waste dumped, and a positive impact on composting. In addition, the addition amount of the vinyl polymerization cationic water-soluble or vinyl polymerization amphoteric water-soluble polymer used in the present invention to sludge is based on the volatile suspended particle suspended matter (VSS component, amount reduced when burned). 0.1 to 1.0 mass%, preferably 0.2 to 0.7 mass%.

(Examples) Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. However, the present invention is not limited to the following Examples unless it exceeds the gist.

A water-soluble polymer having the composition shown in Table 1 was prepared as a test sample and tested. Collect 200 ml of pig sludge discharged from the pig farm site (pH 7.02, total ss 11,250 mg / L) in a poly beaker, add sodium hypochlorite to the sludge amount 1500 ppm, and beaker After 10 times of transfer and stirring, 150 ppm of a cationic or amphoteric water-soluble polymer (sample 1 to sample 5 in Table 1) was added to each solution, and the beaker was transferred and stirred 20 times. The solution was filtered through a −1179 L filter cloth (made of nylon), and the filtrate amount after 45 seconds was measured. The filtered sludge is dehydrated at a press pressure of 4 kg / m ² for 1 minute. Thereafter, the moisture content of the cake (dried at 105 ° C. for 20 hours) was measured. The results are shown in Table 2.

(Table 1)
Composition: mol%, EM; water-in-oil emulsion, PW; powder, PL; paste, molecular weight; weight average molecular weight

(Comparative Example 1)
Formulation (Comparative 1-1) in which an inorganic oxidizing agent is not added by the same test operation as in Example 1,
Were tested. The results are shown in Table 2.

(Table 2)
Inorganic oxidizer; ppm of sludge, amount of chemical added; ppm of sludge, amount of filtrate; mL,
Cake water content; mass%

200 ml of livestock sludge different from Example 1 (pH 8.00, total ss 11,000 mg / L) was collected in a polyvinyl carbonate, sodium hypochlorite was added to the sludge amount of 6,000 ppm, -Carry transfer and stir 10 times, add polycondensation polymer (sample-6) and beaker transfer and stir 10 times, then cationic or amphoteric water-soluble polymer (from sample-1 in Table 1) Sample 5) was added to each solution at 500 ppm, the beaker was transferred, stirred 10 times, filtered through a T-1179L filter cloth (made of nylon), and the amount of filtrate after 45 seconds was measured. Moreover, the prescription which does not add a polycondensation type | system | group polymer (sample-6) was performed regarding sample-1, sample-3, and sample-5. Next, the filtered sludge is dehydrated at a press pressure of 4 kg / m ² for 1 minute. Thereafter, the moisture content of the cake (dried at 105 ° C. for 20 hours) was measured. The results are shown in Table 3.

(Comparative Example 2)
According to the same test operation as in Example 2, a formulation without adding an inorganic oxidant (Comparative 2-1), a formulation with a combination of an oxidant and a condensed cationic water-soluble polymer (Comparative 2-2), and a cationic water-soluble high The test was performed on the molecular alone formulation (Comparative 2-3). The results are shown in Table 3.

(Table 3)
Inorganic oxidizer; ppm of sludge, amount of chemical added; ppm of sludge, amount of filtrate; mL,
Cake water content; mass%

Claims (5)

After adding one or more inorganic oxidizers selected from the following oxidizer group to livestock sludge and applying deodorization treatment and modification treatment, vinyl polymerization cationic water-soluble and / or vinyl polymerization amphoteric water-solubility A method for treating livestock sludge, characterized by adding a coagulant polymer, coagulating, and then dehydrating with a dehydrator.
Oxidizing agent group; chlorite, hypochlorite, bromate, bromate, hypobromite, hydrogen peroxide. The cationic water-soluble cationic polymer obtained by copolymerizing 20 to 100 mol% of a monomer represented by the following general formula (1) and / or the following general formula (2). At least one selected from a polymer, a cationic water-soluble polymer having 10 to 90 mol% of a structural unit represented by the following general formula (4) and / or the following general formula (5), 20 to 100 mol% of the monomer represented by the following general formula (1) and / or the following general formula (2), and the monomer represented by the following general formula (3) to 5 to The livestock sludge treatment method according to claim 1, wherein the treatment method is an amphoteric water-soluble polymer obtained by copolymerization of 50 mol%.
General formula (1)
R ₁ is hydrogen or a methyl group, R ₂ and R ₃ are an alkyl group having 1 to ₃ carbon atoms, an alkoxy group or a benzyl group, and R ₄ is hydrogen, an alkyl group having 1 to 3 carbon atoms, an alkoxyl group or a benzyl group. , Same or different. A represents oxygen or NH, B represents an alkylene group or alkoxylene group having 2 to 4 carbon atoms, and X ₁ represents an anion.





General formula (2)
R ₅ represents hydrogen or a methyl group, R ₆ and R ₇ each represent an alkyl group having 1 to 3 carbon atoms, an alkoxyl group or a benzyl group, and X ₂ represents an anion.
General formula (3)
R ₈ is hydrogen or CH ₂ COOY ₂ , Q is SO ₃ , C ₆ H ₄ SO ₃ ,
CONHC (CH ₃ ) ₂ CH ₂ SO ₃ , C ₆ H ₄ COO or COO, R ₉ is hydrogen, a methyl group or COOY ₃ , and Y ₁ and Y ₂ each represent hydrogen or a cation.












In the formula, R ₁₀ and R ₁₁ represent a hydrogen atom or a methyl group, and X ₃ ⁻ represents an anion. For the livestock sludge, the inorganic oxidant, polycondensation cationic water-soluble polymer,
The method for treating livestock sludge according to claim 1, wherein the vinyl polymerization-based cationic water-soluble and / or the vinyl polymerization-based amphoteric water-soluble polymer is added in this order. The livestock sludge according to any one of claims 1 to 3, wherein the vinyl polymer cationic water-soluble or vinyl polymer amphoteric water-soluble polymer has a weight average molecular weight of 3 million or more and 20 million or less. Processing method. The livestock sludge treatment method according to any one of claims 1 to 4, wherein the dehydrator is a filter press or a rotary press.