A surfactant composition and its use in breaking down sludge

Abstract

The application discloses a surfactant composition and application thereof in sludge disintegration. The surfactant composition comprises 3,4-didodecyloxybenzylamine and Gemini surfactant. The COD content in the sludge liquid phase after disintegration can be significantly improved by using the surfactant composition for sludge disintegration treatment, and the recovery rate of the available carbon source in the sludge can be improved. After the sludge is disintegrated by using the surfactant composition, the filtrate can be recovered by gravity sedimentation and the like, and the obtained filtrate can be reused in a biochemical tank, so that the denitrification carbon source can be effectively supplemented, the denitrification reaction in the biochemical process can be promoted, the use of commercial carbon source can be reduced, and the water treatment cost can be reduced. The application has important significance for the resource treatment of sludge.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of sludge treatment. More particularly, it relates to a surfactant composition and its application in breaking sludge. BACKGROUND

[0002] Sludge is a kind of extremely complex heterogeneous body composed of organic residues, bacterial cells, inorganic particles, colloids, etc. produced in the process of sewage treatment, and its main characteristics are high water content and high organic matter content, which is easy to rot and stink. In recent years, the output of sludge has shown an increasing trend year by year, and the output is amazing, but the proportion of sludge properly disposed of is still low. Because sludge contains a large amount of organic matter, its resource utilization not only can reduce the adverse effects of sludge on the ecological environment, but also can generate additional economic benefits. For example, the traditional sewage treatment system generally has the problems of insufficient denitrification carbon source and low efficiency of denitrification and phosphorus removal, which needs to be supplemented by external commercial carbon source, and the recovery of available carbon source in sludge to make up for the shortage of denitrification carbon source can reduce the cost of sewage treatment and meet the current requirements for sludge reduction, stabilization, harmlessness and resource treatment.

[0003] Although sludge contains a large amount of organic matter, the presence of extracellular polymeric substance (EPS) and other substances makes it difficult for the organic matter in sludge to be decomposed and utilized, which affects the reduction and resource treatment of sludge. Sludge disintegration is an important link in the process of sludge treatment, which aims to destroy the cell structure of sludge through physical, chemical or biological methods, release the intracellular organic matter and water, and thus improve the dewatering performance and biodegradability of sludge, and promote the resource utilization of sludge. The existing sludge disintegration methods include ultrasonic wave, surfactant treatment, etc. Among them, although the effect of ultrasonic wave disintegration of sludge is good, its energy consumption is large and the equipment cost is high, which is not conducive to popularization and use. Surfactants (such as CTAB, etc.) can reduce the surface tension of liquid and enhance the interaction between sludge particles, thereby destroying the floc structure of sludge and releasing the organic matter therein. Although the use of surfactants for sludge disintegration treatment has the advantages of simple operation, etc., compared with ultrasonic wave disintegration and other methods, the disintegration effect is relatively poor. If the disintegration rate of sludge by surfactants can be improved, and the chemical oxygen demand (COD) in the liquid after disintegration can be improved, it will be more conducive to the resource treatment of sludge. SUMMARY

[0004] The present application provides a surfactant composition and its application in breaking sludge to solve the problems in the prior art.

[0005] The first object of the present application is to provide a surfactant composition.

[0006] The second object of the present application is to provide the application of the composition in breaking sludge.

[0007] A third object of the present application is to provide the use of the composition in the preparation of a product for breaking sludge.

[0008] A fourth object of the present application is to provide a method for breaking sludge and recycling available carbon sources.

[0009] The above objects of the present application are achieved by the following technical solutions.

[0010] The present application provides a surfactant composition, which is composed of 3,4-didodecyloxybenzylamine (DDOBA) and Gemini surfactant; and the mass ratio of the 3,4-didodecyloxybenzylamine and the Gemini surfactant is 1-2:1-2.

[0011] The present application provides a surfactant composition, which is composed of 3,4-didodecyloxybenzylamine (DDOBA) and Gemini surfactant; and the mass ratio of the 3,4-didodecyloxybenzylamine and the Gemini surfactant is 1-2:1-2.

[0012] Preferably, in the surfactant composition, the mass ratio of the 3,4-didodecyloxybenzylamine and the Gemini surfactant is 1:1-2.

[0013] Further preferably, in the surfactant composition, the mass ratio of the 3,4-didodecyloxybenzylamine and the Gemini surfactant is 1:1-1.5.

[0014] More preferably, in the surfactant composition, the mass ratio of the 3,4-didodecyloxybenzylamine and the Gemini surfactant is 1:1.

[0015] Optionally, the Gemini surfactant is a non-ionic Gemini surfactant, a cationic Gemini surfactant and / or an anionic Gemini surfactant.

[0016] Optionally, the non-ionic gemini surfactant is polyethoxydilauryl ester, polyethoxydipalmitate and / or polyethoxydioleate; the cationic gemini surfactant is didodecyldimethylammonium bromide, didodecylamine sodium sulfonate and / or N,N-didodecyl-2,6-pyridine diamide sodium propionate; the anionic gemini surfactant is 1,4-butanediyl bis sodium dodecyl sulfonate and / or 1,4-butanediyl bis sodium hexadecyl carboxylate.

[0017] In a specific embodiment of the present application, the surfactant composition consists of 3,4-didodecyloxybenzylamine and cationic gemini surfactant, and the mass ratio of 3,4-didodecyloxybenzylamine and cationic gemini surfactant is 1-2:1-2.

[0018] Preferably, in the surfactant composition, the mass ratio of 3,4-didodecyloxybenzylamine and cationic gemini surfactant is 1:1-2.

[0019] Further preferably, in the surfactant composition, the mass ratio of 3,4-didodecyloxybenzylamine and cationic gemini surfactant is 1:1-1.5.

[0020] More preferably, in the surfactant composition, the mass ratio of 3,4-didodecyloxybenzylamine and cationic gemini surfactant is 1:1. When the mass ratio of 3,4-didodecyloxybenzylamine and cationic gemini surfactant in the surfactant composition is 1:1, the COD content in the filtrate obtained after the sludge is treated by using it is relatively the highest.

[0021] In a specific embodiment of the present application, the 3,4-didodecyloxybenzylamine is prepared by taking 3,4-dihydroxybenzaldehyde as raw material, generating 3,4-didodecyloxybenzaldehyde by alkylation reaction with bromododecane, then reacting with hydroxylamine hydrochloride to generate 3,4-didodecyloxybenzaldehyde, and then reducing with zinc powder. The preparation method is specifically referred to the method described in the literature (Hanying, Zhu Lu, Shen Ming, et al. Synthesis of a new double-chain surfactant DDOBA and preparation of highly monodisperse hydrophobic gold nanoparticles [J]. Acta Physico-Chimica Sinica, 2013, 29(1): 8.).

[0022] In a specific embodiment of the present application, the cationic gemini surfactant is didodecyldimethylammonium bromide, and its CAS number is 3282-73-3.

[0023] In view of the fact that the surfactant composition of the present application can significantly improve the disintegration effect on sludge and significantly increase the COD content in the sludge liquid phase after disintegration, the present application claims the application of the surfactant composition in disintegrating sludge.

[0024] The present application also claims the use of the surfactant composition in the preparation of a product for breaking sludge.

[0025] Similarly, the use of the surfactant composition in the preparation of a product for breaking sludge and recycling of available carbon source should also be within the protection scope of the present application.

[0026] Specifically, the sludge is raw sludge.

[0027] More specifically, the sludge is raw sludge generated in the process of domestic sewage or municipal treatment.

[0028] In a specific embodiment of the present application, the treated sludge is concentrated sludge generated in the process of municipal sewage treatment. Concentrated sludge refers to sludge obtained after concentration treatment of raw sludge (such as primary sludge, etc.).

[0029] The present application also provides a method for breaking sludge and recycling available carbon source, which comprises mixing the surfactant composition of the present application with sludge to be treated, and then performing solid-liquid separation after reaction at 35-45℃ for 2-6h, and collecting the liquid; wherein the amount of the composition is 0.5%-5% of the mass of the sludge.

[0030] Preferably, the amount of the surfactant composition is 1%-5% of the mass of the sludge.

[0031] Further preferably, the amount of the surfactant composition is 1%-3% of the mass of the sludge.

[0032] More preferably, the amount of the surfactant composition is 1% of the mass of the sludge.

[0033] Optionally, in the method, the solid-liquid separation is performed by gravity sedimentation, pressure filtration or filtration.

[0034] Specifically, the sludge is raw sludge.

[0035] More specifically, the sludge is raw sludge generated in the process of domestic sewage or municipal treatment.

[0036] The present application has the following beneficial effects:

[0037] The present application aims at the problem that the effect of sludge disintegration treatment by surfactant is not ideal, and provides a surfactant composition composed of 3,4-didodecyloxybenzylamine and Gemini surfactant. The sludge disintegration treatment by the surfactant composition can significantly improve the COD content in the sludge liquid phase after disintegration, and improve the recovery rate of available carbon source in the sludge. After the sludge disintegration treatment by the surfactant composition, the filtrate can be recovered by gravity sedimentation and the like, and the obtained filtrate can be reused in the biochemical tank, which can effectively supplement the denitrification carbon source, promote the denitrification reaction in the biochemical process, reduce the use of commercial carbon source, and reduce the water treatment cost. The present application has important significance for the resource treatment of sludge. BRIEF DESCRIPTION OF DRAWINGS

[0038] Figure 1 The COD determination results in the obtained filtrate after the sludge disintegration treatment by 3,4-didodecyloxybenzylamine (DDOBA), didodecyl dimethyl ammonium bromide (Gemini) and the surfactant composition of the present application embodiments 1-5, respectively.

[0039] Figure 2 The BOD5 determination results in the obtained filtrate after the sludge disintegration treatment by 3,4-didodecyloxybenzylamine (DDOBA), didodecyl dimethyl ammonium bromide (Gemini) and the surfactant composition of the present application embodiments 1-5, respectively. DETAILED DESCRIPTION

[0040] The present application will be further described below in combination with the drawings and specific embodiments, but the embodiments do not limit the present application in any form. Unless otherwise specified, the reagents, methods and devices used in the present application are conventional reagents, methods and devices in the technical field.

[0041] Unless otherwise specified, the reagents and materials used in the following examples are commercially available.

[0042] The 3,4-didodecyloxybenzylamine (DDOBA) used in the embodiment of the present application is prepared by using 3,4-dihydroxybenzaldehyde as raw material, generating 3,4-didodecyloxybenzaldehyde through alkylation reaction with bromododecane, then generating 3,4-didodecyloxybenzaldehyde through reaction with hydroxylamine hydrochloride, and then reducing with zinc powder, and the preparation method is specifically referred to the method described in the literature (Han Ying, Zhu Lu, Shen Ming, et al. Synthesis of a novel double-chain surfactant DDOBA and preparation of highly monodisperse hydrophobic gold nanoparticles [J]. Acta Physico-Chimica Sinica, 2013, 29(1): 8.). The manufacturer of the used 3,4-dihydroxybenzaldehyde is Aldrin, and the article number is D130075; the manufacturer of the used bromododecane is Aldrin, and the article number is B105789; the manufacturer of the used hydroxylamine hydrochloride is Aldrin, and the article number is H292538; the manufacturer of the used zinc powder is Aldrin, and the article number is Z683800.

[0043] The Gemini surfactant used in the embodiment of the present application is a cationic Gemini surfactant didodecyldimethylammonium bromide, the manufacturer of which is Aldrin, the article number is D105628, and the CAS number is 3282-73-3.

[0044] Example 1 Preparation of surfactant composition 1

[0045] The synthesized DDOBA and the Gemini surfactant didodecyldimethylammonium bromide are uniformly mixed in a mass ratio of 2:1 to obtain the surfactant composition 1.

[0046] Example 2 Preparation of surfactant composition 2

[0047] The synthesized DDOBA and the Gemini surfactant didodecyldimethylammonium bromide are uniformly mixed in a mass ratio of 1:1 to obtain the surfactant composition 2.

[0048] Example 3 Preparation of surfactant composition 3

[0049] The synthesized DDOBA and the Gemini surfactant didodecyldimethylammonium bromide are uniformly mixed in a mass ratio of 1:2 to obtain the surfactant composition 3.

[0050] Example 4 Preparation of surfactant composition 4

[0051] The synthesized DDOBA and the rhamnolipid are uniformly mixed in a mass ratio of 1:1 to obtain the surfactant composition 4.

[0052] Example 5 Preparation of surfactant composition 5

[0053] The Gemini surfactant didodecyldimethylammonium bromide and the rhamnolipid were mixed in a mass ratio of 1:1 to obtain a surfactant composition 5.

[0054] Sludge disintegration effect of different compositions in test example 1

[0055] An equal amount of concentrated sludge generated in a municipal sewage treatment process was placed in different reaction vessels, and the surfactant compositions 1-5 prepared above and DDOBA and didodecyldimethylammonium bromide alone were mixed with the concentrated sludge at a dosage of 1% (1% of the mass of the sludge), and the mixture was reacted at 40°C and 400 rpm for 2 hours; after the reaction was completed, solid-liquid separation was performed by gravity sedimentation, and the COD and BOD5 in the obtained filtrate were determined according to the Rapid Disintegration Spectrophotometric Method HJ / T 399-2007 and the Dilution and Inoculation Method HJ 505-2009, respectively. The results are shown in Tables 2 and 3, respectively. Figure 1 and Figure 2

[0056] The COD, BOD5 yield, and biodegradability (BOD5 / COD) of the filtrate obtained after sludge disintegration treatment with the prepared surfactant compositions 1-5 and the individual surfactants are shown in Table 1; Gemini in the table refers to didodecyldimethylammonium bromide.

[0057] Table 1 COD and BOD5 yield of sludge treated with surfactant compositions 1-5 and individual surfactants

[0058] Reagent name COD (mg / L) BOD5 (mg / L) BOD5 / COD Table 1 Live composition 1 42712 20923 0.49 Table 2 Live composition 2 84525 48836 0.58 Table 3 Live composition 3 51048 24662 0.48 Table 4 Live composition 4 38233 19729 0.52 Table 5 Live composition 5 36373 20121 0.55 DDOBA 23534 10325 0.44 Gemini 26269 12588 0.48

[0059] Combining Figure 1 , Figure 2 and the results shown in Table 1, it can be seen that compared with sludge disintegration treatment with individual surfactants (DDOBA or Gemini surfactant didodecyldimethylammonium bromide), the combination of DDOBA and Gemini surfactant didodecyldimethylammonium bromide can significantly promote sludge disintegration and significantly increase the COD value of the obtained filtrate after disintegration. Rhamnolipid can destroy the cell wall and cell membrane of bacteria, but when it is compounded with DDOBA or didodecyldimethylammonium bromide, the disintegration effect on sludge is significantly weaker than that of the surfactant compositions 1-3 described in the present application. The filtrate obtained after sludge disintegration treatment with the surfactant compositions 1-3 described in the present application can replace commercial carbon sources, providing sufficient (high COD value) and high utilization (high biodegradability) carbon sources for denitrification and phosphorus release processes in sewage treatment.

[0060] ​In addition, the content of NH4 + -N) in the filtrate obtained after the sludge is disintegrated using the surfactant composition of Example 2 is tested. It is determined that the amount of NH4 +- -N) in the filtrate is 117.5 mg / L, the amount of total nitrogen (TN) is 1380 mg / L, the amount of total phosphorus (TP) is 1027.5 mg / L, the ratio of COD to TN, COD:TN = 61, COD:TP = 82, NH4

[0061] The COD:TN of the general untreated influent is 4, and the COD:TP is 50. In combination with the above results, it can be seen that the filtrate can be effectively used to improve the carbon-nitrogen ratio of the wastewater in the denitrification section, and will not introduce a large amount of nitrogen and phosphorus elements to affect the effluent water quality.

[0062] The above results show that the surfactant composition of the present application can improve the disintegration efficiency of the sludge, greatly improve the release degree of the soluble organic matter in the sludge, and improve the COD yield. The sludge disintegration liquid (filtrate) obtained can be used as a high-quality carbon source to be returned to the biochemical tank to increase the carbon-nitrogen ratio of the wastewater, improve the efficiency of denitrification, and achieve the effect of deep denitrification of the wastewater.

[0063] The above examples are preferred embodiments of the present application, but the embodiments of the present application are not limited by the above examples, and any changes, modifications, substitutions, combinations, simplifications made without departing from the spirit and principles of the present application are equivalent replacement methods, and are all included in the protection scope of the present application.

Claims

1. A surfactant composition characterized in that, The composition consists of 3,4-bis-dodecyloxybenzylamine and dodecyl dimethyl ammonium bromide, and is used for breaking sludge; the mass ratio of the 3,4-bis-dodecyloxybenzylamine and dodecyl dimethyl ammonium bromide is 1-2:1-2.

2. The composition of claim 1, wherein, The mass ratio of the 3,4-bis-dodecyloxybenzylamine and dodecyl dimethyl ammonium bromide is 1:1-2.

3. The use of the composition of claim 1 or 2 in breaking sludge.

4. Use according to claim 3, characterized in that, The sludge is raw sludge.

5. The use of the composition of claim 1 or 2 in preparing a product for breaking sludge.

6. Use according to claim 5, characterized in that, The sludge is raw sludge.

7. A method of breaking down sludge and recovering a utilizable carbon source, characterized by, The composition of claim 1 or 2 is mixed with sludge to be treated, and after reaction at 35-45 ℃ for 2-6 h, solid-liquid separation is performed, and the liquid is collected; wherein the amount of the composition is 0.5%-5% of the mass of the sludge.

8. The method of claim 7, wherein, The solid-liquid separation is performed by gravity sedimentation, pressure filtration or filtration.

9. The method of claim 7, wherein, The sludge is raw sludge.

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