KR101618108B1 - Preparation methods of organic and inorganic complex flocculants for food waste waters - Google Patents

Abstract

The present invention relates to an organic-inorganic hybrid flocculant for the treatment of food wastes and a method for producing the same, which can provide an organic-inorganic hybrid flocculant having a high charge density and a high molecular weight to maximally improve flocculation effect of food wastewater, Organic-inorganic composite coagulant and a process for producing the same.

Description

[0001] The present invention relates to organic and inorganic complex flocculants for food wastewater treatment,

The present invention relates to a method for producing an organic / inorganic composite coagulant for treating food wastewater, and more particularly, to an organic / inorganic composite coagulant capable of coagulation treatment of food wastes which are difficult to completely aggregate, and a method for producing the same.

Food wastes are high concentrations of organic wastewater along with livestock wastewater and contain large amounts of organic matter (fat and protein), nitrogen, phosphorus and salts, and many microorganisms exist in the process of corruption. And then discharged or treated with marine dumping. When food processing is discharged after incomplete treatment, it may cause river pollution and eutrophication, or may cause red tides of seawater.

Food wastes are partially decomposed in the digestion process and discharged as methane gas. Most of the remaining food wastes remain long-chain organic acids, making it difficult to flocculate as a general flocculant. In addition, salts that are excessively used in foods increase the electrical conductivity of food wastewater It greatly shrinks the polymer chains of the flocculant, making flocculation more difficult.

The Protocol of 1996 and the International Convention for the Prevention of Marine Pollution by Waste Disposal (London Protocol) entered into force on March 24, 2006, and in March 2006, the State Council said, "Since 2012, the marine dumping of marine livestock and sewage sludge The ban on food wastewater and livestock wastewater was totally banned in 2012, and each of the water treatment facilities has been tasked with the treatment and recycling of food wastewater by its own technology. When food wastewater is condensed and coagulated with a coagulant, it is possible to recover the solid content, which can be recycled as organic fertilizer or fuel. According to the Ministry of Environment statistics, the domestic scale of food waste is 4.6 million tons / year in 2011 and 5.5 million tons / year in 2012. In 2011, a total of 9,398 tons / day was generated and 5,639 tons / day was treated as marine dumping Jang Hyun-min, Choi Seok-sun, Ha Jung Hyup and Jong Moon Park, Appl. Chem. Eng., 24, 279, 2013).

An anaerobic digestion process was used for high - concentration lipid digestion. However, a new method was required because it inhibited the growth of methanogenic bacteria due to long chain fatty acids during the digestion process, inhibited the stability of the reaction tank, In the 1960s, an aerobic digestion process was developed and showed excellent efficiency and stability in the treatment of high concentration organic wastewater and sewage sludge treatment. It is possible to maintain its own high temperature (about 55 ℃) due to decomposition of organic matter by high temperature aerobic microorganisms. Also, the hydraulic retention time is shortened because the pathogen killing speed is faster than anaerobic digestion process. However, this method of digestion alone has not been able to completely decompose lipid and food waste can not be recycled. Therefore, it has been studied as a new method of agglomerating and removing organic waste by coagulant.

As an inorganic coagulant of aluminum sulfate _{(Al 2 (SO 4) 3} , AS), poly-aluminum chloride _{((Al 2 (OH) nCl} 6 -n) n, PAC), poly aluminum silicate sulfate (Ala (OH) b (SO 4 ) c (SiO2) d (H 2 O) x, PASS), poly hydroxide chloride, aluminum silicate (AlNaxSiy (OH) zClb, PAHCS ), ferric sulfate _{(Fe 2 (SO 4) 3} · xH 2 O) and ferric chloride ( FeCl ₃ ). The characteristics of the inorganic coagulant are influenced by the air conditioning salts in the wastewater, the pH and the water quality, the applicable pH range is narrow, the amount of generated sludge is large, the ion increase is large in the water quality and the dehydration is weak.

Organic coagulants are largely divided into anionic coagulants and cationic coagulants. Anionic flocculants are composed of acrylic acid and 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS) (Korean Patent No. 10-0501817, 2001). Cationic flocculants are prepared from acrylamide and acrylic quaternary ammonium salts. In addition, polyamine and polydiallymmonium chloride have also been used as cationic flocculants for treating food wastewater (Shin Tae Ok, Korean Patent 10-1107581, 2011).

In general, the organic coagulant is not affected by the coexisting salts, temperature, pH and water quality, does not cause precipitation of the added coagulant, does not cause pH change due to small ion change before and after treatment, Improve. Because of these characteristics, organic coagulant is widely used for water treatment. However, coagulant for sewage treatment is not effective for livestock wastewater or food wastewater due to high concentration of organic matter and long chain fatty acid in sludge.

Therefore, the organic coagulant for food wastewater needs high molecular weight coagulant and the charge density is required to be more than twice as high as the conventional coagulant for wastewater treatment. Coagulants with high molecular weight and high charge density can aggregate long - chain fatty acids and food waste wastewater with a high concentration of organic matter into organic coagulants having high charge density and high molecular weight.

Accordingly, it is an object of the present invention to provide an organic / inorganic composite coagulant capable of maximally improving cohesion effect of food wastewater, which is difficult to completely flocculate, and a method for producing the same.

For this purpose, the present invention provides, as a preferred embodiment, a method for producing a water-soluble polymer, which comprises a first step of preparing a first solution containing a cationic water-soluble monomer, an acrylic crosslinking agent and an added acid; A second step of adding a second solution containing a cationic quaternary ammonium salt and a chelating agent to the first solution; A third step of introducing a third solution containing an aliphatic solvent and a surfactant into the mixed solution obtained in the second step; A fourth step of introducing an azo-based catalyst into the mixed solution obtained in the third step after nitrogen injection; And a fifth step of adding a redox catalyst to the mixed solution obtained in the fourth step to react and adding an inorganic coagulant and stirring the mixture.

In this embodiment, the cationic water-soluble monomer of the cationic quaternary ammonium salt of the second solution and the cationic water-soluble monomer of the first solution may have a molar ratio of 50-65: 50-35.

In this embodiment, the mixed solution obtained in the second step and the third solution may be mixed in a weight ratio of 1: 0.4 to 0.6.

In the above embodiment, the fourth step may be a step of feeding the azo-based catalyst at 40 to 50 ° C. for 24 to 48 hours.

In this embodiment, the fifth step may be a step of charging the redox catalyst at 25 to 50 ° C and reacting for 24 to 48 hours.

According to another aspect of the present invention, there is provided an organic or inorganic composite coagulant prepared by the production method of one embodiment.

The organic or inorganic composite coagulant of the above embodiment may have a viscosity of 300 cps or more and a charge density of 3.5 eq / g or more.

The present invention can provide a method for producing an organic / inorganic composite coagulant capable of maximally improving the flocculation effect of food wastewater which is difficult to completely flocculate.

Further, the present invention can provide an organic / inorganic composite coagulant having a high charge density and a high molecular weight.

FIG. 1 is a diagram illustrating a process for producing an organic / inorganic composite coagulant for food waste water.
FIG. 2 is a diagram illustrating a continuous reaction process for producing an organic / inorganic composite coagulant for food wastewater.
FIG. 3 is a photograph of the flocculation agent prepared in Examples 1 to 4 and Comparative Examples 1 to 4 of the present invention in a food wastewater (Yeosu city construction fire-extinguishing sludge) and measuring the flocculation state with an optical camera.

Hereinafter, the present invention will be described in detail.

Prior to this, terms and words used in the present specification and claims should not be construed as limited to ordinary or dictionary terms, and the inventor should appropriately interpret the concepts of the terms appropriately The present invention should be construed in accordance with the meaning and concept consistent with the technical idea of the present invention. Therefore, the constitution of the embodiment described in this specification is only one of the most preferred embodiments of the present invention, and does not represent all the technical ideas of the present invention, so that various equivalents and variations And the like.

DETAILED DESCRIPTION OF THE INVENTION The present invention will be described with reference to the drawings, wherein the first step of preparing a first solution containing a cationic water-soluble monomer, an acrylic crosslinking agent and an addition acid as illustrated in FIG. 1; A second step of adding a second solution containing a cationic quaternary ammonium salt and a chelating agent to the first solution; A third step of introducing a third solution containing an aliphatic solvent and a surfactant into the mixed solution obtained in the second step; A fourth step of introducing an azo-based catalyst into the mixed solution obtained in the third step after nitrogen injection; And a fifth step in which the redox catalyst is added to the mixed solution obtained in the fourth step to react, and the inorganic coagulant is added and stirred.

In the method for producing an organic / inorganic hybrid flocculant of the present invention, the first step is a step of preparing a first solution containing a cationic water-soluble monomer, an acrylic crosslinking agent and an added acid.

Examples of the cationic water-soluble monomer include acrylamide, methacrylamide, N, N-dimethylacrylamide, N-isopropylacrylamide, N-vinylformamide, N-vinylmethylacetamide, N-vinylpyrrolidone, Ethyl methacrylate, hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate, Nt-butyl acrylamide and N-methylol acrylamide.

Examples of the acrylic crosslinking agent include N, N-methylenebisacrylamide, N, N-methylenebismethacrylamide, triallylamine, triallylammonium salt, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, polyethylene glycol di Acrylate, triethylene glycol dimethyl acrylate, polyethylene glycol methacrylate, N-vinyl acrylamide, N-methylallyl acrylamide, glycidyl acrylate, acrolein and glyoxal.

The added acid may be used alone or in admixture of two or more selected from phthalic acid, tereflic acid, valeric acid, carraic acid, citric acid and sulfuric acid.

 The first solution may be a mixture of a cationic water-soluble monomer, an acrylic cross-linking agent, and an added acid in a weight ratio of 1: 0.00005 to 0.0002: 0.05 to 0.2 in consideration of the number of moles of the monomer. When the acrylic crosslinking agent is less than 0.00005, crosslinking is insufficient. When the acrylic crosslinking agent is more than 0.0002, the crosslinking structure is too developed and may cause gelation. If the added acid is less than 0.05, the pH of the whole solution can not be lowered, and the role of the catalyst for redox type catalyst system can not be supported. If it exceeds 0.2, the acidity of the whole solution can be greatly increased.

The second step in the method for producing an organic / inorganic hybrid flocculant of the present invention is to add a second solution containing a cationic quaternary ammonium salt and a chelating agent to the first solution prepared in the first step.

And the cationic water-soluble monomer of the first solution and the cationic quaternary ammonium salt of the second solution are in a molar ratio of 50-65: 50-35. When the molar percentage of the quaternary ammonium salt and the water-soluble monomer is 50 or less, the charge density of the solution is excessively low, so that the cohesion ability with respect to the food wastes remarkably decreases. When the molar ratio is 65 or more, the charge density of the solution is increased but the production cost of the product is increased .

The cationic quaternary ammonium salt is a salt of dimethylaminoethylacrylate methylchloride quaternary salt (DAQ), dimethylaminoethyl methacrylate quaternary salt, dimethylaminoethyl acrylamide quaternary salt, dimethylaminoethyl methacrylamide quaternary salt Or corresponding acid salts.

The chelating agent is not particularly limited, and known chelating agents such as EDTA, EGTA, ethylenediamine, oxine, and o-phenanthroline may be used.

In the method for producing an organic-inorganic hybrid flocculant of the present invention, the third step is to add the third solution to the mixed solution of the first solution and the second solution obtained in the second step.

The mixed solution obtained in the second step and the third solution may be mixed in a weight ratio of 1: 0.4 to 0.6.

The third solution is a mixed solution of an aliphatic solvent and a surfactant. Examples of the aliphatic solvent include at least one compound selected from the group consisting of naphthenic oil, paraffin oil, isoparaffin oil, hydrogenated oil and synthetic oil. Can be used.

The surfactant is not particularly limited, and hydrophilic and lipophilic surfactants can be used together. Examples of hydrophilic surfactants include alkylpolyethylene sulphates, phosphates or sulfonates, alkylbenzenesulphonates, dialkyldimethylammonium salts, alkylbenzylmethylammonium salts, lauric alcohol ethoxylates, polyhydric alcohol ethoxylates, polyoxyethylene alkyl esters, polyethylene consumption Tallow monooleate, and sorbitan monostearate. Examples of the lipophilic surfactant include fatty acid sorbitan esters, alkyl monoglyceryl ethers, and sorbitan monooleate.

When the third solution is added to the mixed solution obtained in the second step, it is preferable that the third solution is added at a rate of 20 to 40 mL / min considering the compatibility and reactivity.

The aliphatic solvent and the surfactant may be mixed to prepare a third solution, which may then be added to the mixed solution of the first solution and the second solution at a rate of 20 to 40 mL / min and stirred for 1 to 2 hours.

In the method for producing an organic / inorganic composite coagulant of the present invention, the fourth step is a step of injecting an azo-based catalyst into the mixed solution obtained in the third step after injecting nitrogen.

The azo-based catalyst that can be used in the present invention may be a lipophilic catalyst and a hydrophilic catalyst. Examples of the oleophilic catalyst include 2,2'-azobis (isobutylonitrile), AIBN, , 2,2'-azobis (4-methoxy-2,4-dimethylvaleronitrile), 2,2'-azobis (2,4-dimethoxylvaleronitrile), dimethyl 2,2'- Azobis (2-methylpropionate, 2,2'-azobis (2-methylbutyronitrile), 1,1'-azobis (cyclohexane-1-carbonitrile), 2,2'-azobis Azobis [2- (2-imidazolin-2-yl) propane], 2, Azobis [2- (2-imidazolin-2-yl) propane] disulfate dihydrate, 2,2'-azobis (2-methylpropionamidine) dihydrochloride, 2,2'- Azobis [N- (2-carboxyethyl) -2-methylpropionamidine] hydrate, 2,2'-azobis {2- [1- -Work] Azobis [2- (2-imidazolin-2-yl) propane] and 2,2'-azobis (1-imino-1-pyrrolidino- -Ethylpropane) dihydride.

As the azo-based catalyst, the molecular weight of the coagulant can be increased by using one or more lipophilic or hydrophilic catalysts in stages.

The reaction temperature at the time of introducing the azo-based catalyst is preferably 40 to 50 ° C. When the reaction temperature is lower than 40 ° C, the degree of reactivity is markedly decreased. When the reaction temperature is higher than 50 ° C, the reaction rate may be difficult to control.

When the reaction time is less than 24 hours, the reactivity is low and the molecular weight is small. When the reaction time exceeds 48 hours, the molecular weight is excessively high, Expression may be difficult.

The fifth step in the method for producing an organic-inorganic hybrid flocculant of the present invention comprises a fifth step of adding an oxidation-reduction catalyst to the mixed solution obtained in the fourth step to react, adding an inorganic flocculant, and stirring.

The present invention can increase the molecular weight of the flocculant using an oxidation-reduction catalyst.

Redox catalysts usable in the present invention include ammonium persulfate / sodium hydrogen sulfite (Korean Patent No. 10-175581), KBrO ₃ / HCl (GS Misra and H. Narain, Makromol. Chem., 113, 35, 1968.) And one or more selected from among ammonium persulfate (APS), potassium bromate and hydrogen peroxide as an oxidizing agent and a selected one of a reducing agent such as Sothium thiosulfate (STS), sodium hydrogen sulfite, sulfuric acid and hydrochloric acid More than one species can be used together.

In the fifth step of the present invention, the temperature at the time of introducing the redox catalyst is preferably 25 to 50 캜. When the reaction temperature is lower than 25 ° C, the degree of reactivity is significantly lowered, and when the reaction temperature is higher than 50 ° C, it is difficult to control the reaction rate.

The reaction time is preferably 24 to 48 hours. If the reaction time is less than 24 hours, the molecular weight is small. If the reaction time exceeds 48 hours, the molecular weight is excessively large, and thus it may be difficult to coagulate in actual use.

The redox catalyst is preferably slowly added at a rate of 5 to 10 mL / min in consideration of high reactivity. If the reaction rate is less than 5 mL / min, the reaction time becomes longer. If the reaction rate exceeds 10 mL / min, the reaction rate becomes higher and the gelation reaction may occur.

Wherein the inorganic coagulant is added and stirred by adding the inorganic coagulant to the redox catalyst, wherein the inorganic coagulant is selected from the group consisting of aluminum sulfate, aluminum chloride, aluminum polysulfate, polyhydroxy aluminum chloride, ferric sulfate and ferric chloride, More than two species can be used.

The polysulfic acid aluminum silicate (PASS) is a transparent liquid, which is an active silicic acid as a basic polyaluminum hydroxysilicate sulfate compound. It has no harmful organic matter and chlorine component. The settling rate of flocs is 10 times faster than that of sulfuric acid at 10 ° C or less. In addition, it can be used with an organic coagulant in a relatively broad range of pH ranges of 4 to 12 (Jang Hyun-min, Choi Seok-sun, and Jong-kwang Park, Appl. Chem. Eng., 24, 279, 2013).

The inorganic coagulant may be added in an amount of 7 to 9%, and then stirred for 1 to 2 hours. After that, a stabilizer may be further added.

 An inorganic coagulant is added during the reaction and emulsified into the already formed emulsified structure using a homogenizer to produce an inorganic or organic composite coagulant.

2 is a view illustrating a continuous reaction process for producing an organic or inorganic coagulant for food wastewater according to the present invention. The reactor was equipped with a water jacket reactor, a heating device, nitrogen gas was added into the reactor at a constant rate, and a reactor equipped with an initiator and a monomer feeder was used.

The present invention relates to a method for producing an organic / inorganic composite coagulant for negative wastewater, comprising the steps of: emulsifying a cationic water-soluble monomer and a cationic quaternary ammonium salt using a surfactant having hydrophilicity and lipophilicity and using a lipophilic azo- And the reaction time is lengthened by increasing the reaction time to increase the molecular weight of the coagulant. Thus, the coagulant of high molecular weight can be produced, and the coagulation treatment of the food wastes, .

The cationic quaternary ammonium salt content of the cationic water-soluble monomer is higher than that of the cationic water-soluble monomer, so that the total charge density can be increased to effectively produce an organic or inorganic composite coagulant.

According to another aspect of the present invention, there is provided an organic or inorganic composite coagulant prepared by the production method of one embodiment.

The organic or inorganic composite coagulant of the above embodiment has a viscosity of 300 cps or more and a charge density of 3.5 eq / g or more. It is a cationic polymer having a high charge density and is a water soluble polymer having high potential for food wastes having high organic, nitrogen, to be. The charge density of the organic and inorganic composite coagulant for food wastewater is preferably 3.5 to 6.5 eq / g, more preferably 4.5 to 6.5 eq / g. When the charge density is lower than 3.5 eq / g, If the charge density is higher than 6.5 eq / g, there is a disadvantage that the polymerization reaction is delayed and the manufacturing cost is high, and the radical polymerization reaction is hindered by the high cationic monomer having a high ion density.

Hereinafter, the present invention will be described in more detail with reference to examples.

Example 1

(First aqueous solution) was prepared with 49.0 g (35.0 mol, 18.1%) of acrylamide aqueous solution (AAM, 50%), 0.0038 g (0.001%) of methylene bisacrylamide (MBSS), 2.7 g Solution. 85.0 g (31.4%) of dimethylaminoethyl acrylate quaternary salt (DAQ) and 0.04 g (0.03%) of ethylenediaminetetraacetic acid tetrasodium salt (EDAT 4Na) were added thereto. 3.7 g (1.4%) of sorbitan monooleate (HLB 4.0-6.0, spam 80) and 5.6 g (2.0%) of sorbitan monostearate (HLB 9.0-15.0, Tw81) %) And then added with the first solution at 30 mL / min. Nitrogen was added for one hour while emulsifying. The reaction temperature was raised to 45 ° C, and 0.15 g (0.06%) of 2,2'-azobis (isobutyronitrile) (AIBN) The reaction was allowed to proceed. Subsequently, the reaction temperature was lowered to 30 ° C, and 0.2 g (0.07%) of ammonia sulfur sulfate (APS) and 4.5 g (1.7%) of sodium thiosulfate (STS) were added at a rate of 10 mL / min. 20 g (7.4%) of aluminum polysulfate aluminum silicate (PASS) was added. After stirring for one hour, 8 g (2.9%) of lauryl alcohol 9 was added and the reaction was stopped. At this time, the DAQ / AAM mol% was 50/50 and the solid content was 50%.

Example 2

Example 1 was repeated except that 40.0 g (28.1 mol, 15.3%) of an aqueous acrylamide solution (AAM, 50%) and 84.0 g (34.7 mol, 32.2%) of dimethylaminoethyl acrylate quaternary salt (DAQ) . ≪ / RTI > At this time, the DAQ / AAM mol% was 55/45 and the solid content was 50%.

Example 3

Except that 32.0 g (22.5 mol, 12.7%) of an aqueous acrylamide solution (AAM, 50%) and 84.0 g (34.3 mol, 32.9%) of dimethylaminoethyl acrylate quaternary salt (DAQ) . ≪ / RTI > At this time, the DAQ / AAM mol% was 60/40 and the solids content was 50%.

Example 4

The procedure of Example 1 was repeated except that 26.0 g (18.3 mol, 10.6%) of acrylamide aqueous solution (AAM, 50%) and 83.0 g (34.3 mol, 33.7%) of dimethylaminoethyl acrylate quaternary salt (DAQ) . ≪ / RTI > At this time, the DAQ / AAM mol% was 65/35 and the solids content was 50%.

Comparative Example 1

The procedure of Example 1 was repeated except that 72.0 g (50.6 mol, 24.7%) of acrylamide aqueous solution (AAM, 50%) and 83.0 g (34.3 mol, 28.4%) of dimethylaminoethyl acrylate quaternary salt (DAQ) . ≪ / RTI > At this time, the DAQ / AAM mol% was 40/60 and the solids content was 50%.

Comparative Example 2

Except that 59.0 g (41.5 mol, 21.1%) of an aqueous acrylamide solution (AAM, 50%) and 83.0 g (34.3 mol, 29.7%) of dimethylaminoethyl acrylate quaternary salt (DAQ) . ≪ / RTI > At this time, the DAQ / AAM mol% was 45/55 and the solids content was 50%.

Comparative Example 3

Example 1 was repeated except that 20.0 g (14.1 mol, 8.3%) of an acrylamide aqueous solution (AAM, 50%) and 83.0 g (34.3 mol, 34.6%) of dimethylaminoethyl acrylate quaternary salt (DAQ) . ≪ / RTI > At this time, the DAQ / AAM mol% was 70/30 and the solids content was 50%.

Comparative Example 4

The same procedure as in Example 1 was followed except that 2,2'-azobis (isobutyronitrile) was added in Example 1, followed by reaction for 3 hours, followed by reaction with ammonia sulfur sulfate and sodium thiosulfate for 6 hours . At this time, the DAQ / AAM mol% was 50/50 and the solid content was 50%.

Test Example

The organic and inorganic composite coagulants synthesized according to the above Examples and Comparative Examples were measured for physical properties by the following methods. The results are shown in Table 3 below.

[How to measure]

(1) Viscosity measurement

The viscosity of the 0.5% diluted distilled water and the stock solution was measured. The viscosity of the 0.5% distilled water diluent was measured using a spindle rotor number 62 at 12 rpm and the viscosity of the coagulant stock solution was measured using a spindle rotor number 63 at 100 rpm.

(2) Charge density

0.25 g / L of polydiallyldimethylammonium chloride, 0.2027 g / L (1.25x10-3 N) of polyvinylsulfate potassium salt and 0.05 g / L of toluidine blue were prepared.

10 mL of distilled water was placed in 3 mL of the sample, and the pH was adjusted to 7.0. 7 mL of polydiallyldimethylammonium chloride was added, stirred for 30 seconds, and then 200 μL of toluidine blue was added. The solution was titrated with polyvinyl sulfates potassium salt solution until the color of the sample solution changed from blue to pink. The charge density was calculated using Equation (1) shown below after appropriating the disclosures in the same manner as above.

[Equation 1]

A is the mL of the polyvinyl sulphate potassium salt solution added to the sample solution, B is the mL of the polyvinyl sulphate potassium salt solution added to the blank, N is the normal concentration of the polyvinyl sulphate potassium salt solution, V is ML of the sample.

(3) Intrinsic viscosity and number average molecular weight

The intrinsic viscosity was calculated by measuring the dropping time at 25 ° C using a Ubbelohde viscometer after 0.1, 0.2, 0.3 and 0.4% concentration of the flocculant solution was prepared. The viscosity average molecular weight (

) Is an intrinsic viscosity represented by the following formula (2)

) And viscosity average molecular weight (H. Tanaka, J. Polym. Sci., Polym. Chem. Ed., 17, 1239, 1979. M. Barari, M. Abdollahi and M. Hemmati, 20, 65, 2011).

&Quot; (2) "

(4) Sludge moisture content

The sludge cake obtained by dewatering each sample was dried at a temperature of 105 ° C for 2 hours, and the sludge moisture content was measured by comparing the weight of sludge before drying with that of sludge after drying.

(5) Coagulation test

An agglutination test was conducted while injecting 800, 1000 and 1200 ppm of coagulant into a 200 g solution of wastewater using a jar tester while stirring at a rotation speed of 200 rpm for 60 seconds.

(6) Dehydrated filtrate Turbidity

After the coagulation reaction was carried out for 10 minutes using a turbidimeter (Hach 2100Q, measurement range: 0.00-2000 NTU), the supernatant was measured with a 100 mesh filter net and 20 ml with a syringe.

Table 1 below shows the contents of the components and solid contents from Examples 1 to 4.

Table 2 shows the composition ratios and solid content of the reagents added to Comparative Examples 1 to 3.

First, the results shown in Table 3 were obtained by referring to the results of Examples 1 to 4 and Comparative Examples 1 to 4. In Examples 1 and 2, the viscosity of the stock solution was 330 and 370 cPs, and the charge density was 4.3 and 4.6 eq / g. The intrinsic viscosity was 8.8 and 9.1 dl / g, and the viscosity average molecular weight was 4.05 × 10 ⁶ and 4.23 × 10 ⁶ g / mol. In Examples 3 and 4, DAQ mol% was as high as 60 and 65, and viscosity, charge density, intrinsic viscosity and viscosity average molecular weight were all high. In Comparative Examples 1 and 2, the viscosity, the charge density, the intrinsic viscosity and the viscosity average molecular weight were smaller than in the Examples, which is because the DAQ mol% was as low as 40 and 45, and the DAQ mol% as high as 70 in Comparative Example 3, Due to the high DAQ content, the polymerization reaction was not actively progressed due to steric hindrance, and the charge density was the highest, but the viscosity, intrinsic viscosity and viscosity average molecular weight were slightly lower. Comparative Example 4 had 50 DAQ mol%, but the reaction time was shortened and the reactivity was low, and the viscosity, intrinsic viscosity and molecular weight were remarkably small.

In order to confirm the effect of the flocculant according to the present invention, flocculation test was carried out as shown in Table 4 below. The coagulant diluent concentration of 0.5% was used, and the raw waste water and water used were those of Yeosu city construction fire sludge. In Examples 1 to 4, the coagulation size was as large as 10 mm. At this time, the sludge moisture content was 81.9% on average and the sludge moisture content decreased with increasing DAQ mol%. The turbidity of the dehydrated filtrate was 155 NTU on average, but the turbidity was slightly improved with increasing DAQ mol%. In the case of the comparative example, the flocculation size was small in most cases, the flocculation size was slightly increased, and no remarkable flocculation effect was observed. The water content was 84.1% on average and the turbidity was higher than in all the examples. In particular, in Comparative Example 4, the molecular weight was very small and no aggregation was observed at all.

On the other hand, the coagulation state of food wastewater (Yeosu city construction fire extinguishing sludge) was photographed with an optical camera while 800 ppm, 1000 ppm and 1200 ppm of the coagulant prepared in Examples 1 to 4 and Comparative Examples 1 to 4 were applied, Respectively. At 800 ppm, the coagulation was not desirable, but the food wastewater was able to coagulate relatively stable at 1200 ppm.

Therefore, the present invention is directed to a method for recovering a food waste which can not be completely cleaned by coagulation treatment with an organic / inorganic hybrid coagulant for food wastewater, treating the waste in a form capable of being recycled by forming flakes and dehydration, You may.

It would be a more environmentally friendly and economical way to treat food wastewater treated by marine dumping at the public sewage treatment facility than the marine dumping or landfill treatment if the wastewater can be appropriately aggregated through the coagulation process and separated.

The preferred embodiments of the present invention have been described in detail above. It will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the appended claims.

Accordingly, the scope of the present invention is defined by the appended claims rather than the foregoing detailed description, and all changes or modifications derived from the meaning, range, and equivalence of the claims are included in the scope of the present invention Should be interpreted.

Claims (7)

A first step of preparing a first solution containing a cationic water-soluble monomer, an acrylic crosslinking agent and an added acid;
A second step of adding a second solution containing a cationic quaternary ammonium salt and a chelating agent to the first solution;
A third step of introducing a third solution containing an aliphatic solvent and a surfactant into the mixed solution obtained in the second step;
A fourth step of introducing an azo-based catalyst into the mixed solution obtained in the third step after nitrogen injection; And
And a fifth step in which the redox catalyst is added to the mixed solution obtained in the fourth step to react, and an inorganic coagulant is added to the mixture to stir the organic coagulant.
The method according to claim 1,
Wherein the cationic quaternary ammonium salt of the second solution and the cationic water-soluble monomer of the first solution are in a molar ratio of 50 to 65:50 to 35, respectively.
The method according to claim 1,
Wherein the mixed solution obtained in the second step and the third solution are mixed at a weight ratio of 1: 0.4 to 0.6.
The method according to claim 1,
And the fourth step is a step of introducing an azo-based catalyst at 40 to 50 ° C. for 24 to 48 hours.
The method according to claim 1,
And the fifth step is a step of adding an oxidation-reduction catalyst at 25 to 50 ° C. and allowing the reaction to proceed for 24 to 48 hours.
An organic or inorganic composite coagulant prepared by the method of any one of claims 1 to 5.
The method according to claim 6,
A viscosity of 300 cps or more, and a charge density of 3.5 eq / g or more.

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