Process method for treating refined sugar ion exchange decoloration regeneration waste liquid

Abstract

The invention relates to the field of sewage treatment, and discloses a process method for treating refined sugar ion exchange decoloration regeneration waste liquid. The method comprises the steps of electric flocculation foam separation pretreatment and salt-tolerant activated sludge biological treatment, and the invention also discloses a system for realizing the method, and the system comprises a raw water tank, an electric coagulation tank, a flocculation tank, an air floatation tank, a salt-tolerant microorganism biochemical treatment tank and a precipitation tank. According to the method disclosed by the invention, the high-COD, high-salt and high-chroma waste liquid generated by a sugar refining process is effectively treated, so that higher emission standards are achieved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of sewage treatment, more particularly, it relates to a process for treating waste liquid of ion exchange decolorization regeneration of refined sugar. BACKGROUND

[0002] In recent years, domestic sugar companies have introduced advanced refined sugar complete equipment to provide the market with high-quality refined products that meet higher removal rates of sucrose impurities and color, more uniform crystalline particle size, and standard moisture content. Among them, sugar decolorization is the most important link of refined sugar. In the current refining process, after primary lime decolorization, the sugar solution is decolorized by ion exchange resin, and the decolorization rate can reach 80-90%. The sugar syrup can be refined into 25IU (national standard value of refined sugar) refined white sugar, reaching or exceeding the national standard of refined sugar.

[0003] The deep purification medium ion exchange adsorption resin of the refined sugar factory is installed in a cylindrical tank container. The sugar syrup is pumped into the decolorization resin tank, and the sugar syrup is contacted with the container and the resin. The impurities and pigments inside are adsorbed by the resin, and the sugar syrup is purified, and the decolorization resin adsorbs the pigments and impurities of the sugar syrup. When the resin handles a certain amount of water, the adsorption performance gradually decreases and becomes saturated. When the adsorption performance decreases to a certain extent, the resin needs to be regenerated to perform the next cycle of purification.

[0004] The regeneration of the decolorization resin is to clean and regenerate the resin with a certain amount of 8-9% brine as the main regeneration liquid to restore its best performance. The ion exchange resin decolorization system usually also has a recovery system to recover the sugar syrup and high-concentration brine. The salt-containing waste liquid that cannot be recovered needs to be treated after being discharged. However, the waste liquid has a very high pollutant concentration and is a complex waste liquid containing sugar, NaCl, a large amount of polyphenolic pigments, caramel pigments, heterocyclic organic matter, etc. The COD Cr 15000-24000 mg / L, total nitrogen 170-200 mg / L, NaCl 1.5-3%, color 2300-3500 times, pH 6.5-7.0.

[0005] Domestic high-quality refined sugar production started late, and there is not much mature water treatment experience for this waste liquid. Design and production units are troubled by the lack of mature technology for actual production. Discharge into the ordinary sewage system will damage the activated sludge system, and sugar industry is a state plan index control material. Production is intermittent, and most manufacturers can only treat this waste liquid as hazardous waste and entrust it to the local environmental protection company for hazardous waste treatment, which has a high treatment cost. Therefore, a new waste liquid treatment method is urgently needed to fill the gap. SUMMARY

[0006] The application aims to provide a new method for treating refined sugar ion exchange decolorization regenerated waste liquid, so as to effectively treat the high COD, high salt and high color waste liquid generated in the refined sugar process, and achieve higher discharge standards.

[0007] To achieve the above-mentioned application purposes, the application provides a process method for treating refined sugar ion exchange decolorization regenerated waste liquid, which adopts the following technical scheme: In a first aspect, the application provides a process method for treating refined sugar ion exchange decolorization regenerated waste liquid, which includes the steps of electrocoagulation foam separation pretreatment and salt-tolerant activated sludge biological treatment.

[0008] Further, the electrocoagulation foam separation pretreatment includes electrocoagulation treatment and flocculation treatment. The electrocoagulation treatment step adjusts the pH of the refined sugar ion exchange decolorization regenerated waste liquid to be acidic in the electrocoagulation tank, the residence time is 20-40 min, the voltage is 30-40 V, the electrode plate current density is 20-30 A / m 2 , the electrode plate material is aluminum, and the electrode plate thickness is 4-6 mm. The flocculation treatment step adds a flocculating agent in the flocculation tank, and the residence time is 10-20 min.

[0009] Further, the step of adjusting the pH of the refined sugar ion exchange decolorization regenerated waste liquid to be acidic uses 10% sulfuric acid to adjust the pH of the refined sugar ion exchange decolorization regenerated waste liquid to be 3-3.5.

[0010] Further, the flocculation treatment step uses anionic polyacrylamide as the flocculating agent, and the addition amount is 3 mg / L.

[0011] Further, after the electrocoagulation foam separation pretreatment, the process further includes a flotation treatment step, the residence time is 1-2 h, and the surface load is 1-2 m 3 / m 2 .h.

[0012] Further, the salt-tolerant activated sludge biological treatment step, the residence time is 25-30 d; the system oxygen supply amount is 1.8-2.2 kgO / kgCOD; the nutrient modulation ratio is C:N:P=100:10:1; the salt-tolerant activated sludge mixed liquid concentration MLSS is 4000-5000 mg / L, the settling ratio is 30-45%, and the sludge age is 20-30 d.

[0013] Further, the inoculation and acclimation of the salt-tolerant activated sludge is as follows: 400-600 mg / L of the salt-tolerant bacteria, 2800-3200 mg / L of the normal activated sludge, 3-5 days of muffled exposure, 10 days of 0.25 times of the design load, then 10 days of 0.5 times of the design load, then 10 days of 0.75 times of the design load, and finally 1.0 times of the design load, and after 45 days, the activated sludge is basically acclimated successfully.

[0014] Further, the salt-tolerant bacteria is a salt-tolerant bacteria agent (powder, mainly composed of bacilli and coccobacteria capable of forming endospores, and the viable bacteria content is ≥200 billion / g), which is a commercially available product purchased from Nanjing Sailai Biological Technology Co., Ltd. The normal activated sludge is the activated sludge in the secondary sedimentation tank of Shanghai Zhuyuan Sewage Treatment Plant, and the MLSS concentration is 10000 mg / L. Further, in the initial acclimation stage of the sludge, in order to accelerate the salt tolerance of the normal microorganisms, an organic nitrogen source is needed to be added, and amino acids (50-100 mg / L in terms of nitrogen content) are added to increase the cell membrane thickness of the activated sludge and improve the external membrane salt water osmotic pressure resistance of the bacteria, so as to accelerate the speed of sludge acclimation.

[0015] The present application provides a system for implementing any of the above methods in the second aspect, comprising: A raw water tank for storing refined sugar ion exchange decolorization regeneration waste liquid; An electrocoagulation tank for electrocoagulation treatment; A flocculation tank for flocculation treatment; An air flotation tank for air flotation treatment; A salt-tolerant microbial biochemical treatment tank for salt-tolerant activated sludge biological treatment; and A sedimentation tank for sedimentation treatment.

[0016] In summary, the present application has the following beneficial effects: The process method of the present application recovers high-COD caramel substances through efficient electrocoagulation pretreatment as carbon resources, and regenerates and treats the tail sewage to remove most of the difficult-biodegradable COD, color, and colloidal impurities. Higher discharge standards are achieved.

[0017] The organic foam separated by electrocoagulation is changed into waste liquid after stirring with a small amount of defoaming agent, and the organic carbon source waste liquid recovery rate is >60%, the COD Cr The removal rate is 65%-70%, and the color removal rate is 88%-92%, which is about 50% higher than the removal rate of the traditional method.

[0018] The waste liquid separated by foam in the electrocoagulation tank has a COD Cr150000~200000mg / L, T-N 200~600mg / L, salt 300~700mg / L, can be recycled as carbon source nutrients for other wastewater treatment plant denitrification.

[0019] After pretreatment, the tail sewage is treated by subsequent specific salt-tolerant activated sludge biological method, and the effluent COD Cr 100~180mg / L, removal rate is greater than 95%, total nitrogen 40mg / L is greater than 75%, color <50 times, removal rate is greater than 85%, which can completely meet the discharge standard of urban sewer.

[0020] Carbon reduction, emission reduction, and economy are particularly remarkable. By using the new method for treating refined sugar ion exchange decolorization regeneration waste liquid, carbon source resource recycling reduces carbon emission by more than 60%, and the water treatment cost is 120 yuan / m 3 Around, at present 30m 3 / d, daily treatment cost 3600 yuan / d, at present the waste liquid disposal cost is 1000 yuan / m 3 , daily treatment cost 30000 yuan / d, saving treatment cost (Guangming Dafeng Yingmao Sugar Industry Co., Ltd.) fee 88%. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 : a schematic diagram of a system for implementing the method of the present application; Figure 2 : the process and results of electric coagulation treatment; Figure 3 : the process and results of pretreatment experiment; Figure 4 : the process of subsequent biochemical treatment verification; Figure 5 : the treatment results of refined sugar ion exchange decolorization regeneration waste liquid. DETAILED DESCRIPTION

[0022] The technical solutions and effects of the present application will be further described in detail in combination with the embodiments and drawings. It can be understood that the specific embodiments described herein are only used to explain the present application, and not to limit the present application. In addition, it should be noted that, in order to facilitate description, only the parts related to the present application are shown in the drawings, not all structures.

[0023] The method of the present application, the waste liquid of the decoloring resin regeneration of refined sugar is stored in the raw water tank, is delivered to the electric coagulation tank, acid is added before entering the electric coagulation tank to adjust the waste liquid to be acidic, after the waste liquid enters the electric coagulation tank, electrochemical reaction is carried out, passes between the aluminum electrode plates added with a direct current power supply, the ion pair with points generated by the electrode plates acts on the wastewater, and under the action of the micro-bubbles generated at the cathode, 60-70% of the carbon source organic matters in the waste liquid are transferred into the bubbles and separated from the waste liquid, the bubbles rise to the surface of the electric coagulation tank, and the foam is scraped to the collection tank by the moving foam scraper to be recycled, which can be used as the carbon source nutrient for denitrification in the sewage treatment plant.

[0024] After the waste liquid separated by the foam separation of the electric coagulation tank, the waste liquid passes through the flocculation tank, the aluminum ions generated in the waste liquid by the electric conduction of the aluminum electrode plate of the electric coagulation tank are flocculated to form large flocs, and then enters the air flotation tank, in the air flotation tank, the flocs rise to the upper surface of the tank body under the action of the micro-bubbles, and are scraped off by the rotating slag scraper at the upper part to be separated from the waste liquid.

[0025] After the waste liquid separated by the air flotation tank, the waste liquid enters the salt-tolerant microbial biochemical treatment tank, a large amount of salt-tolerant microorganisms are cultured in the tank, which have exclusive decomposition ability for the refined sugar waste liquid, there is sufficient oxygen supply in the tank, and the microorganisms oxidize and decompose the pollutants in the waste liquid into carbon dioxide and water under the action of their own enzymes, after about 20-25 days of decomposition, the waste liquid can be biodegradable or be converted into biodegradable organic matter in the process, and most of the waste liquid is completely decomposed. The waste liquid further passes through a sedimentation tank, the biological activated sludge in the mixed solution of the effluent from the biological reaction tank is precipitated to the bottom of the tank, and the supernatant after purification is discharged up to the standard.

[0026] Embodiment The method comprises the following steps: Step 1, electric coagulation treatment The refined sugar decoloring resin regeneration waste liquid is delivered to the electric coagulation tank by a pump, acid is added before entering the electric coagulation tank to adjust the waste liquid to be acidic, the pH of the refined sugar ion exchange decoloring regeneration waste liquid is adjusted to 3-3.5 by using 10% sulfuric acid, after the waste liquid enters the electric coagulation tank, electrochemical reaction is carried out, passes between the aluminum electrode plates added with a direct current power supply, the ion pair with points generated by the electrode plates acts on the wastewater, and under the action of the micro-bubbles generated at the cathode, 60-70% of the carbon source organic matters in the waste liquid are transferred into the bubbles and separated from the waste liquid, the bubbles rise to the surface of the electric coagulation tank, and the foam is scraped to the collection tank by the moving foam scraper (prior art) to be recycled, which can be used as the carbon source nutrient for denitrification in the sewage treatment plant, the parameters are as follows: residence time 30 min, direct current voltage 36 V, electrode plate current density 20-30 A / m 2 , the electrode plate material is aluminum, the electrode plate thickness is 5 mm, and the waste liquid power supply index q=200 A.h / t wastewater. The foam separation process of electric coagulation is as shown in Figure 2 .

[0027] Step 2, flocculation treatment The waste liquid separated by the electric coagulation tank is further treated by a flocculation tank. A flocculant is added into the flocculation tank. The flocculant is an anionic polyacrylamide, and the addition amount is 3 mg / L. The aluminum ions generated in the waste liquid by electrifying the aluminum electrode of the electric coagulation tank form large flocculation bodies.

[0028] Step 3, air flotation treatment The flocculation bodies enter the air flotation tank. Under the action of micro-bubbles, the flocculation bodies rise to the upper surface of the tank body, are scraped off by a rotating scraper at the upper part, and are separated from the waste liquid. The residence time is 1-2 h, and the surface load is 1-2 m 3 / m 2 .h.

[0029] Step 4, salt-tolerant activated sludge biological treatment The waste liquid separated by the air flotation tank enters a salt-tolerant microbial biochemical treatment tank. A large amount of salt-tolerant microorganisms are cultured in the tank, and the microorganisms have exclusive decomposition ability for the refined sugar waste liquid. There is sufficient oxygen supply in the tank. The microorganisms oxidize and decompose the pollutants in the waste liquid into carbon dioxide and water under the action of their own enzymes. After a decomposition time of about 20-25 days, the waste liquid is biodegradable or is converted into biodegradable organic matter in the process. Most of the pollutants are completely decomposed. The tank is internally provided with fixed suspension type biological ropes, and the filling amount is 60%. The parameters are as follows: residence time, 25-30 d; system oxygen supply amount, 2 kg O / kg COD; nutrient modulation ratio, C:N:P=100:10:1; salt-tolerant activated sludge mixed liquid concentration, MLSS=4000-5000 mg / L; settling ratio, 30-45%; and sludge age, 20-30 d. The inoculation and domestication of the salt-tolerant activated sludge are as follows: 400-600 mg / L of common activated sludge and 3000 mg / L of salt-tolerant bacteria are added, and the mixture is subjected to aeration for 3-5 days. Then, the amount of the waste water is gradually increased from 0.25 times of the design load for 10 days, to 0.5 times for 10 days, to 0.75 times for 10 days, and finally to 1.0 times. After 45 days, the activated sludge is basically domesticated successfully.

[0030] The salt-tolerant bacteria are “salt-tolerant bacteria agent” (powder, mainly composed of bacilli and cocci capable of forming endospores, and the content of live bacteria is ≥200 billion / g), which is a commercially available product and is purchased from Nanjing Sailai Biological Technology Co., Ltd. The common activated sludge is the activated sludge in the secondary sedimentation tank of Shanghai Zhuyuan Sewage Treatment Plant, and the MLSS concentration is 10000 mg / L.

[0031] During the initial domestication stage of the activated sludge, in order to accelerate the salt tolerance of the common microorganisms, an organic nitrogen source is added. Amino acids (50-100 mg / L in terms of nitrogen content) are added to increase the thickness of the cell membrane of the activated sludge and to improve the ability of the bacterial outer membrane to resist external salt water osmotic pressure, so as to accelerate the speed of the domestication of the activated sludge.

[0032] Step 5, Precipitation treatment The wastewater passes through a sedimentation tank, where the bioactive sludge from the effluent mixture from the biological reactor settles to the bottom of the tank. The purified supernatant is then discharged in compliance with standards.

[0033] Performance testing (1) Raw water sample

[0034] (2) Results of pretreatment experiments The waste liquid is electrolyzed in an electrolytic cell, where high-valence metal ions are ionized and condensed (e.g., Figure 3 (As shown).

[0035]

[0036] Unit: mg / L (3) Subsequent biochemical treatment verification Inoculation and cultivation of salt-tolerant activated sludge, relying on microbial oxidation to decompose COD and color in wastewater (experimental process as follows) Figure 4 As shown, the processing results are as follows Figure 5 (As shown).

[0037]

[0038] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A process for the treatment of ion exchange spent liquor of refined sugar decolorization regeneration, characterized by, The step includes an electrocoagulation and flocculation pretreatment and a salt-tolerant activated sludge biological treatment.

2. The process for treatment of ion exchange spent decolorizing regenerating waste liquor of refined sugar as claimed in claim 1 wherein, The electrocoagulation and flocculation pretreatment includes an electrocoagulation treatment and a flocculation treatment. The electrocoagulation treatment step: adjusting the pH of the refined sugar ion exchange decolorization regeneration waste liquid to be acidic in an electrocoagulation tank, residence time 20-40 min, voltage 30-40 V, electrode plate current density 20-30 A / m 2 , the electrode plate material is aluminum, and the electrode plate thickness is 4-6 mm; The flocculation treatment step is that a flocculant is added in a flocculation tank, and the residence time is 10-20 min.

3. The process for treatment of ion exchange spent decolorizing regenerating waste liquor of refined sugar as claimed in claim 2 wherein, The step of adjusting the pH of the refined sugar ion exchange and decolorization regeneration waste liquid to be acidic is that the pH of the refined sugar ion exchange and decolorization regeneration waste liquid is adjusted to 3-3.5 by using 10% sulfuric acid.

4. The process for treatment of ion exchange spent decolorizing regenerating waste liquor of refined sugar as claimed in claim 2 wherein, The flocculation treatment step is that the flocculant is an anionic polyacrylamide, and the addition amount is 3 mg / L.

5. The process for treatment of ion exchange spent decolorizing regenerating waste liquor of refined sugar as claimed in claim 2 wherein, The electroflocculation foam separation pretreatment is followed by a flotation treatment step: residence time 1-2 h, surface load 1-2 m 3 / m 2 .h.

6. The process for treatment of ion exchange spent decolorizing regenerating waste liquor of refined sugar as claimed in claim 1 wherein, The salt-tolerant activated sludge biological treatment step, The residence time is 25-30 d. The system oxygen supply amount is 1.8-2.2 kgO / kgCOD. The nutrient modulation ratio is C:N:P=100:10:

1. The salt-tolerant activated sludge mixed liquid concentration MLSS is 4000-5000 mg / L, the settling ratio is 30-45%, and the sludge age is 20-30 d.

7. The process for treatment of ion exchange spent decolorizing regenerating waste liquor of refined sugar as claimed in claim 6 wherein, The salt-tolerant activated sludge inoculation and domestication step is that 400-600 mg / L of salt-tolerant bacteria and 2800-3200 mg / L of ordinary activated sludge are added at the beginning, and the system is covered and exposed for 3-5 d, then the design load is increased to 0.25 times for 10 days, then to 0.5 times for 10 days, then to 0.75 times for 10 days, and finally to 1.0 times gradually, and the wastewater amount is increased, and after 45 days, the activated sludge is basically domesticated successfully.

8. The process for treatment of ion exchange spent decolorizing regenerating waste liquor of refined sugar as claimed in claim 7 wherein, The salt-tolerant bacteria are salt-tolerant bacteria agents, which are obtained by market purchase; the MLSS concentration of the ordinary activated sludge is 10000 mg / L.

9. The process for treatment of ion exchange spent decolorizing regenerating waste liquor of refined sugar as claimed in claim 7 wherein, In the initial domestication stage of the sludge, in order to accelerate the salt tolerance of ordinary microorganisms, an organic nitrogen source nutrient needs to be added, and amino acids (50-100 mg / L in terms of nitrogen content) are added to increase the thickness of the cell membrane of the activated sludge and improve the ability of the bacterial outer membrane to resist external salt water osmotic pressure, so as to accelerate the speed of sludge domestication.

10. A system for implementing the method of any one of claims 1 to 9, characterized in that The system comprises: a raw water tank for storing refined sugar ion exchange and decolorization regeneration waste liquid; an electrocoagulation tank for electrocoagulation treatment; a flocculation tank for flocculation treatment; a gas flotation tank for gas flotation treatment; a salt-tolerant microbial biochemical treatment tank for salt-tolerant activated sludge biological treatment; and a sedimentation tank for sedimentation treatment. ​

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