Liquid zeolite as well as preparation method and application thereof

Abstract

The invention relates to the technical field of wastewater treatment, and provides liquid zeolite as well as a preparation method and application thereof. The liquid zeolite provided by the invention comprises the following components in percentage by mass: 5-15% of natural zeolite, 0.2-2% of an additive and 83-94.8% of water, the additive comprises one or more of polyacrylamide, sodium alginate and metal chloride. The liquid zeolite provided by the invention can effectively solve the problem of sludge bulking in oily wastewater treatment, does not raise dust, can improve the working environment of operators, is convenient to use, is easy to accurately control the dosage, and is relatively low in cost. After the liquid zeolite is added, the sludge volume index (SVI) of the activated sludge can be reduced by more than 30%, the sludge settleability is obviously improved, and the effluent quality is obviously improved.

Description

Technical Field

[0001] The invention relates to the technical field of wastewater treatment, and in particular to a liquid zeolite and a preparation method and application thereof. Background Art

[0002] In the process of water injection development in oil fields, a large amount of water needs to be injected into the oil layer in order to maintain the oil layer pressure and improve the crude oil recovery rate. As the exploitation progresses, the injected water will carry crude oil and other impurities out of the oil well, forming a large amount of oily wastewater. With the deepening of water injection development in oil fields, the amount of oily wastewater has also increased rapidly. Oily wastewater has high polymer content, high oil content, high emulsification degree, high strength of emulsified oil-water interface film, not easy to demulsify, high wastewater viscosity, and difficulty in oil-water separation, making it difficult to handle.

[0003] The activated sludge method uses microorganisms in activated sludge to adsorb, decompose and metabolize organic matter in oily wastewater, converting it into carbon dioxide and water, thereby purifying the oily wastewater. In the process of using the activated sludge method to treat oily wastewater, since the load of the treatment device has been at a high level, sludge swelling often occurs, the sludge structure is loose, and the sedimentation is poor, resulting in a decrease in the effluent quality. In order to improve the sedimentation of sludge and reduce sludge swelling, powdered activated carbon is usually added as a sedimentation agent. However, powdered activated carbon particles are small, and dust is easily generated when added. The dosage is difficult to accurately control, and it is easy to explode when encountering open flames. It will also lead to a poor working environment and affect the health of operators. At the same time, the cost of powdered activated carbon is high, which will greatly increase the treatment cost of oily wastewater. Summary of the invention

[0004] In view of this, the present invention provides a liquid zeolite and a preparation method and application thereof. The liquid zeolite provided by the present invention is in a liquid state, can improve the dust problem when powdered activated carbon is added, the addition amount is easy to accurately control, and the cost is low, and can effectively solve the sludge swelling problem in the treatment of oily wastewater and improve the effluent quality.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0006] A liquid zeolite comprises the following components in percentage by mass: 5-15% natural zeolite, 0.2-2% additives, and 83-94.8% water; the additives comprise one or more of polyacrylamide, sodium alginate, and metal chlorides.

[0007] Preferably, the metal chloride includes one or both of magnesium chloride and potassium chloride.

[0008] Preferably, the polyacrylamide is anionic polyacrylamide; the weight average molecular weight of the polyacrylamide is 8 million to 12 million.

[0009] Preferably, the natural zeolite includes one or more of clinoptilolite, mordenite, analcime and chabazite.

[0010] Preferably, the ammonia absorption capacity of the natural zeolite is ≥90mmol / 100g.

[0011] Preferably, the mesh size of the natural zeolite is 150-250 meshes.

[0012] Preferably, the specific surface area of ​​the natural zeolite is 500 to 800 m 2 / g, porosity ≥50%.

[0013] The present invention also provides a method for preparing the liquid zeolite described in the above scheme, comprising the following steps:

[0014] The liquid zeolite is obtained by mixing natural zeolite, additives and water.

[0015] Preferably, the mixing comprises: dissolving the additive in water to obtain an additive solution; and pneumatically conveying the natural zeolite into the additive solution to obtain the liquid zeolite.

[0016] The present invention also provides the use of the liquid zeolite described in the above scheme or the liquid zeolite prepared by the preparation method described in the above scheme in the treatment of oily wastewater.

[0017] The present invention provides a liquid zeolite, comprising the following components in percentage by mass: 5-15% natural zeolite, 0.2-2% additives, and 83-94.8% water; the additives include one or more of polyacrylamide, sodium alginate, and metal chloride. The present invention uses natural zeolite as the main body of the liquid zeolite. The natural zeolite has rich pores, strong adsorption capacity, and is non-toxic. It can be used as a biological carrier to attach a large number of microorganisms, promote microbial aggregation, increase the particle size of sludge flocs, and increase density, thereby improving the sedimentation performance of sludge and improving sewage treatment efficiency. At the same time, the microorganisms adsorbed inside the natural zeolite are protected by the holes, which can improve the impact resistance; by adding additives, the present invention can make the natural zeolite dispersed evenly in the water, avoid zeolite coagulation, and reduce the wear on pumps and pipelines. At the same time, the additives used in the present invention can be used as microbial nutrients to promote microbial growth. The liquid zeolite provided by the present invention is in a liquid state, which can solve the dust problem when adding powdered activated carbon, improve the working environment of operators, is easy to use, and the dosage is easy to accurately control, reducing the labor intensity of operators, and has low cost. In addition, the liquid zeolite of the present invention can also increase the hydraulic load, improve the treatment capacity, reduce the impact of water quality and water quantity, ensure the stability of the treatment system; increase the rate of biodegradation, reduce the inhibitory effect of harmful substances, and improve the decolorization effect. In summary, the liquid zeolite provided by the present invention can effectively solve the sludge swelling problem in the treatment of oily wastewater, and has no dust problem and low cost. After adding the liquid zeolite of the present invention, the sludge volume index (SVI) of the activated sludge can be reduced by more than 30%, the sludge sedimentation is significantly improved, and the effluent water quality is significantly improved.

[0018] The present invention also provides a method for preparing the liquid zeolite described in the above scheme. The preparation method provided by the present invention has simple process and strong operability. DETAILED DESCRIPTION

[0019] The invention provides a liquid zeolite, comprising the following components in percentage by mass: 5-15% of zeolite, 0.2-2% of additives, and 83-94.8% of water; the additives comprise one or more of polyacrylamide, sodium alginate and metal chloride.

[0020] Unless otherwise specified, all raw materials / components used in the present invention are commercially available.

[0021] In terms of mass percentage, the liquid zeolite provided by the present invention includes 5-15% of natural zeolite, specifically 5%, 8%, 10%, 12%, 13% or 15%. In the present invention, the natural zeolite preferably includes one or more of clinoptilolite, mordenite, analcime and chabazite; in a specific embodiment of the present invention, commercially available natural zeolite for water purification can be used. Natural zeolite has the characteristics of high temperature resistance, acid and alkali resistance, radiation resistance, and high mechanical strength, and has low cost, large reserves, and is non-toxic. The present invention uses natural zeolite as the main raw material, which can reduce the preparation cost and improve microbial affinity.

[0022] In the present invention, the ammonia absorption of the natural zeolite is preferably ≥90mmol / 100g, more preferably 95-110mmol / 100g; the mesh number of the natural zeolite is preferably 150-250 mesh; the specific surface area of ​​the zeolite is preferably 500-800m 2 / g, specifically 500m 2 / g、600m 2 / g, 685m 2 / g、700m 2 / g or 800m 2 / g; the porosity of the natural zeolite is preferably ≥50%, more preferably 55% to 60%. The present invention controls the ammonia absorption, mesh number, specific surface area and porosity of the zeolite within the above range, which can ensure the rich pore size and strong adsorption capacity of the zeolite, thereby effectively improving the sedimentation of the sludge and improving the effluent quality.

[0023] In terms of mass percentage, the liquid zeolite provided by the present invention includes 0.2-2% additives, specifically 0.2%, 0.5%, 1%, 1.5%, 1.8% or 2%; the additives include one or more of polyacrylamide, sodium alginate and metal chloride; the polyacrylamide is preferably anionic polyacrylamide; the weight average molecular weight of the polyacrylamide is preferably 8 million to 12 million, more preferably 8 million, 9 million or 10 million; the metal chloride preferably includes one or both of magnesium chloride and potassium chloride. The additives used in the present invention can improve the dispersibility of zeolite and can also be used as microbial nutrients.

[0024] Calculated by mass percentage, the liquid zeolite provided by the present invention comprises 83-94.8% water.

[0025] The present invention also provides a method for preparing the liquid zeolite described in the above scheme, comprising the following steps:

[0026] The liquid zeolite is obtained by mixing natural zeolite, additives and water.

[0027] In the present invention, the mixing preferably includes: dissolving the additive in water to obtain an additive solution; and pneumatically feeding the natural zeolite into the additive solution to obtain the liquid zeolite. In a specific embodiment of the present invention, the additive solution is preferably placed in a closed system, and then pneumatically fed into the natural zeolite. The pneumatic feeding method of the present invention can improve the uniformity of the dispersion of zeolite in water and improve work efficiency.

[0028] The present invention also provides the use of the liquid zeolite described in the above scheme or the liquid zeolite prepared by the preparation method described in the above scheme in the treatment of oily wastewater; in the present invention, the liquid zeolite is specifically used as a sedimentation agent to improve the sedimentation performance of activated sludge; the application preferably includes: adding the liquid zeolite to a treatment device for oily wastewater; the treatment device is preferably an oxidation ditch; the liquid zeolite is preferably added from the inlet of the oxidation ditch, specifically, the liquid zeolite is preferably added when sludge swelling does not occur; in a specific embodiment of the present invention, the liquid zeolite is preferably stored in a storage tank equipped with a stirring or aeration device, and when in use, the liquid zeolite is pumped into the treatment device for oily wastewater by a pump; the amount of the liquid zeolite added is preferably 40-120 mg / L, more preferably 60-100 mg / L, and the liquid zeolite is preferably added in a continuous manner.

[0029] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] The natural zeolite used in the following examples is a commercially available water purification natural zeolite, which has an ammonia absorption capacity of 95 mmol / 100 g, a mesh size of 200 meshes, and a specific surface area of ​​685 m 2 / g, and the porosity is 55%.

[0031] Example 1

[0032] Take 9450 kg of water, stir, slowly add 50 kg of anionic polyacrylamide with a weight average molecular weight of 8 million into the water, continue stirring after the polyacrylamide is dissolved, add 500 kg of natural zeolite powder by air, mix well to obtain a liquid zeolite product.

[0033] Test Case

[0034] The liquid zeolite prepared in Example 1 was continuously added from the inlet of the oxidation ditch, and the water quality index of the oxidation ditch inlet water is shown in Table 1. Experiments were conducted simultaneously with and without adding liquid zeolite to test the effluent index, wherein the amount of liquid zeolite added in the experimental group with added liquid zeolite was 100 mg / L, and the operating parameters of the oxidation ditch were MLSS: 3000 mg / L, SRT: 20 days, SV30: 28%, SVI: 100 mL / g, pH value: 7.6, and temperature: 28°C.

[0035] The experimental results are shown in Table 1.

[0036] Table 1 Treatment effect of oily wastewater

[0037]

[0038] According to the data in Table 1, after adding the liquid zeolite of the present invention, the COD cr , ammonia nitrogen, oil, sulfide, total phosphorus and BOD contents all decreased, the water quality was significantly improved, and after 13 months of continuous operation, no sludge bulking occurred; while the experimental group without adding liquid zeolite experienced sludge bulking after 4 months of continuous operation, and the effluent quality decreased significantly.

[0039] At the same time, the SVI value of the activated sludge after adding liquid zeolite was tested on the 8th day of operation. The results showed that the SVI value of the activated sludge was 180 mL / g when no liquid zeolite was added, and the SVI value of the activated sludge was 100 mL / g after adding liquid zeolite.

[0040] Example 2

[0041] Take 830 kg of water, stir, slowly add 20 kg of sodium alginate into the water, continue stirring after the sodium alginate is dissolved, add 150 kg of natural zeolite powder by air conveyance, mix well to obtain the liquid zeolite product.

[0042] The liquid zeolite prepared in Example 2 was tested according to the method in the test example. The water quality of the inlet and outlet water is shown in Table 2.

[0043] Table 2 Treatment effect of oily wastewater

[0044]

[0045] According to the data in Table 2, after adding the liquid zeolite of the present invention, the COD cr , ammonia nitrogen, oil, sulfide, total phosphorus and BOD contents all decreased, and the water quality was significantly improved.

[0046] Example 3

[0047] Take 4650 kg of water, stir, add 100 kg of magnesium chloride into the water, continue stirring after the magnesium chloride is dissolved, add 350 kg of natural zeolite powder by air conveyance, mix well to obtain the liquid zeolite product.

[0048] Example 4

[0049] Take 94.8 kg of water, stir, add 0.2 kg of potassium chloride into the water, and continue stirring after the magnesium chloride is dissolved. Add 5 kg of natural zeolite powder by air conveyance, and mix well to obtain a liquid zeolite product.

[0050] The liquid zeolites prepared in Examples 3 to 4 were tested according to the methods in the test examples, and the results showed that the effluent quality could be significantly improved.

[0051] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A liquid zeolite, characterized in that: The invention comprises the following components in percentage by weight: 5-15% natural zeolite, 0.2-2% additives and 83-94.8% water; the additives comprise one or more of polyacrylamide, sodium alginate and metal chloride.

2. The liquid zeolite according to claim 1, characterized in that The metal chloride includes one or both of magnesium chloride and potassium chloride.

3. The liquid zeolite according to claim 1, characterized in that The polyacrylamide is anionic polyacrylamide; the weight average molecular weight of the polyacrylamide is 8 million to 12 million.

4. The liquid zeolite according to claim 1, characterized in that: The natural zeolite includes one or more of clinoptilolite, mordenite, analcime and chabazite.

5. The liquid zeolite according to claim 1 or 4, characterized in that: The ammonia absorption capacity of the natural zeolite is ≥90mmol / 100g.

6. The liquid zeolite according to claim 1 or 4, characterized in that: The mesh number of the natural zeolite is 150 to 250 meshes.

7. The liquid zeolite according to claim 1 or 4, characterized in that: The specific surface area of ​​the natural zeolite is 500 to 800 m 2 / g, porosity ≥50%.

8. The method for preparing the liquid zeolite according to any one of claims 1 to 7, characterized in that: The following steps are involved: The liquid zeolite is obtained by mixing natural zeolite, additives and water.

9. The preparation method according to claim 8, characterized in that: The mixing includes: dissolving the additive in water to obtain an additive solution; and blowing the natural zeolite into the additive solution by air to obtain the liquid zeolite.

10. Use of the liquid zeolite according to any one of claims 1 to 7 or the liquid zeolite prepared by the preparation method according to any one of claims 8 to 9 in the treatment of oily wastewater.

Images