CN111087129B - Comprehensive biochemical treatment method for foam drainage - Google Patents

Comprehensive biochemical treatment method for foam drainage Download PDF

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CN111087129B
CN111087129B CN201911382951.9A CN201911382951A CN111087129B CN 111087129 B CN111087129 B CN 111087129B CN 201911382951 A CN201911382951 A CN 201911382951A CN 111087129 B CN111087129 B CN 111087129B
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treatment
tank
aerobic aeration
water
aeration tank
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CN111087129A (en
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赵晓宁
邱林青
郭学峰
胡志勇
欧辉
荣欣宇
吴振锋
马勇
唐建
刘峰
陈琦
罗荣川
王晓红
罗平凯
田铭瑶
宋佳
王舜
白如玉
骆翼梦
赵福利
鲁书成
董培占
郭捷
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Puyang Tiandiren Environmental Protection Technology Co ltd
Sinopec Southwest Petroleum Engineering Co Ltd Oilfield Engineering Service Branch
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Puyang Tiandiren Environmental Protection Technology Co ltd
Sinopec Southwest Petroleum Engineering Co Ltd Oilfield Engineering Service Branch
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    • CCHEMISTRY; METALLURGY
    • C02TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02FTREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F9/00Multistage treatment of water, waste water or sewage
    • CCHEMISTRY; METALLURGY
    • C02TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02FTREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00Treatment of water, waste water, or sewage
    • C02F1/02Treatment of water, waste water, or sewage by heating
    • C02F1/04Treatment of water, waste water, or sewage by heating by distillation or evaporation
    • CCHEMISTRY; METALLURGY
    • C02TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02FTREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00Treatment of water, waste water, or sewage
    • C02F1/40Devices for separating or removing fatty or oily substances or similar floating material
    • CCHEMISTRY; METALLURGY
    • C02TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02FTREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00Treatment of water, waste water, or sewage
    • C02F1/44Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis
    • C02F1/441Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis by reverse osmosis
    • CCHEMISTRY; METALLURGY
    • C02TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02FTREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00Treatment of water, waste water, or sewage
    • C02F1/44Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis
    • C02F1/442Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis by nanofiltration
    • CCHEMISTRY; METALLURGY
    • C02TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02FTREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00Treatment of water, waste water, or sewage
    • C02F1/44Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis
    • C02F1/444Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis by ultrafiltration or microfiltration
    • CCHEMISTRY; METALLURGY
    • C02TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02FTREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00Treatment of water, waste water, or sewage
    • C02F1/52Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities
    • C02F1/5236Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities using inorganic agents
    • C02F1/5245Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities using inorganic agents using basic salts, e.g. of aluminium and iron
    • CCHEMISTRY; METALLURGY
    • C02TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02FTREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00Treatment of water, waste water, or sewage
    • C02F1/52Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities
    • C02F1/54Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities using organic material
    • C02F1/56Macromolecular compounds
    • CCHEMISTRY; METALLURGY
    • C02TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02FTREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2103/00Nature of the water, waste water, sewage or sludge to be treated
    • C02F2103/10Nature of the water, waste water, sewage or sludge to be treated from quarries or from mining activities
    • CCHEMISTRY; METALLURGY
    • C02TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02FTREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F3/00Biological treatment of water, waste water, or sewage
    • C02F3/30Aerobic and anaerobic processes
    • CCHEMISTRY; METALLURGY
    • C02TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02FTREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F5/00Softening water; Preventing scale; Adding scale preventatives or scale removers to water, e.g. adding sequestering agents
    • C02F5/02Softening water by precipitation of the hardness
    • C02F5/06Softening water by precipitation of the hardness using calcium compounds

Abstract

The invention discloses a comprehensive biochemical treatment method of foam drainage. Carrying out single-well recovery and oil removal settlement treatment on the foam drainage; the treated foam drainage is placed in a demulsification coagulation pool for treatment; placing foam drainage water after demulsification and coagulation in a softening tank for softening and hardness removal treatment; the softened water obtained after treatment is sequentially placed in an anaerobic tank, a primary aerobic aeration tank, a secondary aerobic aeration tank and a sedimentation tank for treatment; and sequentially carrying out ultrafiltration, nanofiltration and reverse osmosis treatment on the supernatant obtained in the sedimentation tank, wherein the produced water of the reverse osmosis treatment is discharged or recycled after reaching the standard, the concentrated water generated by the reverse osmosis is re-evaporated to produce industrial salt for utilization, and the cooling water is discharged after reaching the standard. The method carries out biochemical treatment on the gas production wastewater with high salt and strong foaming power, eliminates the restriction of a surfactant and organic matters on high-efficiency evaporation and reverse osmosis processes, improves the efficiency of low-temperature multi-effect evaporation, and realizes that foam drainage treatment meets the standard discharge of first-level sewage discharge standard. Simple process, low energy consumption and low cost.

Description

Comprehensive biochemical treatment method for foam drainage
Technical Field
The invention belongs to the technical field of wastewater treatment, and particularly relates to a comprehensive biochemical treatment method for foam drainage.
Background
Petroleum, natural gas and coal are used as three major energy sources, and still play an important role in industry, life and the like. Among them, gas field development is an important way for obtaining petroleum and natural gas. The stratum pressure is reduced in the middle and later stages of gas field development, the edge and bottom water is pushed, and operations such as fracturing and acidizing are carried out, so that accumulated liquid is generated in the well bottom and the shaft, the accumulated liquid in the shaft increases the back pressure on the gas layer, the production capacity of the well is limited, the accumulated liquid in the shaft is too large, and the gas well can be completely stopped spraying. The liquid column in the shaft can also damage the stratum near the shaft, the gas phase permeability is reduced, the ultimate recovery efficiency of the gas field is seriously influenced, and the natural gas yield is reduced and even the production is stopped due to flooding. People adopt various methods to eliminate accumulated liquid at the bottom of a well, wherein a foam drainage method is widely applied due to low cost, easy construction and no influence on the production of a gas well.
The wastewater discharged by the foam drainage method contains a large amount of foam drainage agents, various additives such as demulsifiers, corrosion inhibitors, scale inhibitors and the like and other chemical agents, and the pollution components are complex; the foam drainage contains more surface active substances, calcium and magnesium ions, soluble solids and the like, and has extremely high COD content. The emulsion is in an emulsion state at normal temperature, has high emulsification degree, has floating oil on the surface, has peculiar smell, is very easy to foam, has large foam amount and low defoaming speed, belongs to waste water which is difficult to treat,
although many methods for treating wastewater exist at present, the components in the foam wastewater are extremely complex, and various chemical components, solids, oils, emulsions and the like are difficult to treat by a common wastewater treatment method at present. The advanced oxidation method is a method which is commonly used for treating foam drainage, but the method has the defects of high treatment cost, poor water impact resistance load, large solid generation amount, complex process, high energy consumption and the like, consumes large energy, greatly improves the treatment cost, and has great limitation.
Disclosure of Invention
Aiming at the problems, the invention provides a comprehensive treatment process method of foam drainage. The method adopts a combined process, and is mainly characterized in that high-salt (more than or equal to 10% of total salt content and more than or equal to 3.5% of chloride ions and less than or equal to 30000mg/l), strong foaming capacity (more than or equal to 20cm) and high COD (more than 1000mg/l) wastewater are biochemically treated, and the influence of a surfactant on high-efficiency evaporation is eliminated, so that the wastewater meets the requirements of recycling and standard discharge, the treatment energy consumption and the treatment cost are greatly reduced, and the obvious reduction is realized. The treatment cost is reduced by times while the water treatment effect is improved. After the gas production wastewater is subjected to biochemical treatment, the technical index requirements of membrane treatment can be met, so that the energy consumption can be further reduced, the multi-effect evaporation scale investment can be reduced, the restriction factors of processes such as evaporation, reverse osmosis and the like can be eliminated, the stable standard-reaching discharge of the foam-discharged gas production wastewater can be realized, and the method has a good application prospect.
The invention is realized by the following technical scheme
A comprehensive biochemical treatment method of foam drainage comprises the following steps:
(1) carrying out single-well recovery and oil removal settlement treatment on the foam drainage;
(2) placing foam drainage subjected to the oil removal settlement treatment in the step (1) into a demulsification and coagulation tank for demulsification and coagulation treatment;
(3) placing foam drainage water subjected to demulsification and coagulation treatment into a softening tank for softening and hardness removal treatment;
(4) the softened foam drainage obtained after the softening and hardness removal treatment in the step (3) is sequentially placed in an anaerobic tank, a primary aerobic aeration tank, a secondary aerobic aeration tank and a sedimentation tank for treatment;
(5) and (4) sequentially carrying out ultrafiltration, nanofiltration and reverse osmosis treatment on supernatant bubble drainage obtained in the sedimentation tank, and discharging or recycling produced water of the reverse osmosis treatment.
The comprehensive biochemical treatment method of the foam drainage further comprises the following steps: placing concentrated water obtained by ultrafiltration, nanofiltration and reverse osmosis treatment in a low-temperature multi-effect evaporator for treatment, wherein the pressure is controlled to be-60 kPa-0.25 MPa in the evaporation treatment process; preferably, the low-temperature multi-effect evaporator is a low-temperature four-effect evaporator, wherein the first-effect evaporation temperature is controlled to be 110-140 ℃, the second-effect evaporation temperature is controlled to be 90-105 ℃, the third-effect evaporation temperature is controlled to be 70-85 ℃, and the fourth-effect evaporation temperature is controlled to be 50-65 ℃.
The comprehensive biochemical treatment method of the foam drainage further comprises the following steps: and (3) collecting sludge obtained in the processes of oil removal settlement treatment, demulsification coagulation treatment, softening and hardness removal treatment and biochemical treatment by pumping, and then performing filter pressing by a filter press until the water content in a mud cake is less than 60%, and recycling.
The comprehensive biochemical treatment method of the foam drainage comprises the following steps of (1) performing single-well recovery and oil removal sedimentation treatment: carrying out drainage pull transportation or pipeline transportation on gas field single well bubbles to recover the gas field single well bubbles to a centralized storage pool, and recovering free oil obtained from the upper part of the gas field single well bubbles through gravity separation to enter a sump oil recovery tank for storage; settling the separated suspended solids to the lower part of a storage pool to obtain solid-phase sludge, and allowing the solid-phase sludge to pass through a sludge collection system; and foam drainage water obtained from the middle part of the storage tank after oil removal and sedimentation enters a subsequent demulsification coagulation tank.
The comprehensive biochemical treatment method of the foam drainage comprises the following steps of (2) demulsifying and coagulating treatment: placing foam drainage obtained after oil removal settlement in a demulsification coagulation pool, adding a regulator into the demulsification coagulation pool, and stirring for 3-10 minutes; adding a coagulant, and stirring for 3-10 minutes; adding a flocculating agent, and stirring for 3-10 minutes; after stirring, naturally settling for 0.5-12 hours, and taking supernatant for soaking and draining; preferably, the regulator is any one of hydrochloric acid, caustic soda and lime milk, and the pH value of the water is regulated to 6-9; the coagulant is a 10% polyaluminium chloride solution in percentage by mass, and the addition amount of the coagulant is 10-40 ml/L; the flocculant is 1 per mill of polyacrylamide solution in percentage by mass, and the addition amount of the flocculant is 10-30 ml/L.
The comprehensive biochemical treatment method of the foam drainage comprises the following steps of (3) softening and hardness removing treatment: placing supernatant foam drainage obtained after natural sedimentation in the step (2) into a softening tank, adding a regulator into the softening tank, and stirring for 3-10 minutes; adding a precipitator, and stirring for 3-10 minutes; after stirring, naturally settling for 1-6 hours; supernatant obtained after sedimentation is softened water with the pH value of 6-9, the concentration of calcium and magnesium ions being less than or equal to 1000mg/l, the total salt content being less than or equal to 60000mg/l, the chloride ions being less than or equal to 30000mg/l, the foaming power being more than or equal to 20cm and the COD being less than or equal to 3000 mg/l;
preferably, the regulator is lime milk solution with the mass percentage of 10-20% or sodium hydroxide solution with the mass percentage of 10%, and the adding amount of the regulator is 5-20 ml/L; the precipitator is a sodium carbonate solution with the mass percentage of 10-20%, and the adding amount of the precipitator is 3-60 ml/L.
The comprehensive biochemical treatment method of the foam drainage comprises the following steps of (4): placing the foam drainage softened water obtained by softening and hardness removal treatment in the step (3) in an anaerobic tank, a primary aerobic aeration tank, a secondary aerobic aeration tank and a sedimentation tank in sequence for treatment; the hydraulic retention time of the foam drainage softened water in the anaerobic tank is more than or equal to 20 hours, the hydraulic retention time in the primary aerobic aeration tank is more than or equal to 30 hours, and the hydraulic retention time in the secondary aerobic aeration tank is more than or equal to 10 hours; continuous aeration is carried out in the hydraulic retention process of the first-stage aerobic aeration tank and the second-stage aerobic aeration tank, the pressure of compressed air in the aeration process is 0.06-0.07 MPa, and the air-water volume ratio of aeration is 20: 1-50: 1; the temperature of biochemical treatment in the anaerobic tank and the aerobic aeration tank is 10-40 ℃, and preferably 20-30 ℃;
feeding the effluent (overflow) of the secondary aerobic aeration tank into a sedimentation tank, adding a flocculating agent for coagulating sedimentation, and naturally settling for 1-3 hours; the supernatant obtained after sedimentation is biochemical effluent with the pH value of 6-9, the concentration of calcium and magnesium ions less than or equal to 1000mg/l, the total salt amount less than or equal to 60000mg/l, the chloride ions less than or equal to 30000mg/l, the foaming power less than 1cm and the COD less than or equal to 800 mg/l;
preferably, the flocculant is a polyaluminium chloride solution with the mass percentage of 10-20%, and the mass percentage of the added flocculant in the total water mass in the sedimentation tank is 0.1-1.5%.
According to the comprehensive biochemical treatment method for the foam drainage, salt-tolerant bacteria liquid is added into an anaerobic pool, and the salt-tolerant bacteria liquid comprises pectinate brassicae (Pectinatus brassicae), Clostridium sporogenes (Clostridium sporogenes), bifidobacterium (Clostridium bifidum) and facultative anaerobes (Facultativeanaerobes); adding halotolerant bacteria liquid into the first-stage aerobic aeration tank and the second-stage aerobic aeration tank, wherein the halotolerant bacteria liquid comprises halonas titanica (Telangoniac Halomonas), halonas variabilis (variable Halomonas), Bacillus atrophaeus (atrophic Bacillus, with the name of Bacillus subtilis black variant), Bacillus pumilus (Bacillus pumilus), Bacillus subtilis (Bacillus subtilis), Bacillus aryabhattai (Bacillus aryabhattai), and Bacillus endopythicus (Bacillus endophyticus); first-stage aerobicA potassium dihydrogen phosphate solution with the mass percentage of 10 percent and accounting for 0.2 to 0.5 percent of the total water mass in the aeration tank and the secondary aerobic aeration tank is also added in the aeration tank and the secondary aerobic aeration tank; preferably, the concentration of the mixed bacteria liquid in the salt-tolerant bacteria liquid added into the anaerobic tank, the first-stage aerobic aeration tank and the second-stage aerobic aeration tank is 108~109CFU/ml。
The comprehensive biochemical treatment method of the foam drainage comprises the step that the treatment volume load of the primary aerobic aeration tank is 0.8-1.2 kgCOD/(m)3D), the treatment volume load of the secondary aerobic aeration tank is 0.4-0.8 kgCOD/(m)3D); the sludge age of the anaerobic tank, the primary aerobic aeration tank and the secondary aerobic aeration tank is 0.5-1 d, and the concentration is 3-10 g/L.
The comprehensive biochemical treatment method of the foam drainage comprises the following steps of (5) ultrafiltration, nanofiltration and reverse osmosis treatment: delivering supernatant bubble drainage obtained after biochemical treatment and sedimentation tank in the step (4) to an ultrafiltration device (pH of water obtained after ultrafiltration is 6-8, SS is less than 5mg/L, and conductivity is less than 30000 mu s/cm) for ultrafiltration treatment; and conveying the ultrafiltration product water to a nanofiltration device for nanofiltration treatment, conveying the nanofiltration product water to a reverse osmosis membrane treatment device for reverse osmosis treatment, and directly meeting the requirements of primary sewage discharge standard of GB8978 Integrated wastewater discharge Standard.
Compared with the prior art, the invention has the following positive beneficial effects
The foam drainage contains more impurities, so the foam drainage has complex components, high oil content and high salt content (is difficult to treat). Contains not only organic sludge and oils, but also inorganic substances and various salts, is easy to foam, and is difficult to treat. In the prior art, an advanced oxidation method is generally adopted for treatment, oxidation can be carried out to a certain extent, but treatment is not thorough, various substances in the wastewater cannot be optimally treated, finally, a certain amount of impurities still exist in the wastewater, and the method is high in treatment cost and greatly reduces the treatment benefit of the foam wastewater.
The invention adopts the microorganisms with high salt tolerance to carry out biochemical treatment on the foam drainage, has simple treatment process and low energy consumption, can more thoroughly treat various substances in the foam drainage, and then leads the treated water to reach the standard and be discharged through ultrafiltration, nanofiltration and reverse osmosis treatment. The salt-containing high-concentration water after ultrafiltration, nanofiltration and reverse osmosis is recovered after low-temperature multi-effect evaporation, and the salt in the foam drainage water is efficiently recovered after ultrafiltration, nanofiltration and reverse osmosis treatment, so that the treatment additional value of the foam drainage water is improved.
The foam drainage has complex components, so that the treatment cost is greatly increased when the foam drainage is treated by adopting treatment methods such as oxidation, electrolysis and the like. The method achieves high-efficiency and better treatment effect under the conditions of low cost and low energy consumption, and has good social and economic benefits.
Detailed Description
The present invention will be described in more detail with reference to the following embodiments for understanding the technical solutions of the present invention, but the present invention is not limited to the scope of the present invention.
The invention provides a comprehensive biochemical treatment method of foam drainage, which comprises the following steps:
(1) carrying out single-well recovery and oil removal settlement treatment on the foam drainage water:
carrying out drainage pull transportation or pipeline transportation on gas field single well bubbles to recover the gas field single well bubbles to a centralized storage pool, and recovering free oil obtained from the upper part of the gas field single well bubbles through gravity separation to enter a sump oil recovery tank for storage; settling the separated suspended solids to the lower part of a storage pool to obtain solid-phase sludge, and allowing the solid-phase sludge to pass through a sludge collection system; foam drainage water obtained from the middle part of the storage pool after oil removal and sedimentation enters a subsequent demulsification coagulation pool;
(2) demulsifying and coagulating treatment:
placing foam drainage obtained after oil removal and sedimentation in the step (1) into a demulsification and coagulation tank (a pumping mode and other conveying modes known by persons skilled in the art can be adopted), adding a regulator into the demulsification and coagulation tank, and stirring for 3-10 minutes; then adding a coagulant, and stirring for 3-10 minutes; adding a flocculating agent, and stirring for 3-10 minutes; after stirring, naturally settling for 0.5-12 hours; wherein the stirring can be carried out by a stirring method known to those skilled in the art (e.g., mechanical stirring or air-aeration stirring);
the regulator is any one of hydrochloric acid, caustic soda and lime milk, and the pH value of the water is regulated to 6-9; the coagulant is a 10% polyaluminium chloride solution in percentage by mass, and the addition amount of the coagulant is 10-40 ml/L; the flocculant is a polyacrylamide solution with the mass percentage of 1 per mill, and the addition amount of the flocculant is 10-30 ml/L;
(3) softening and removing hardness:
placing supernatant foam drainage obtained after the emulsion coagulation tank is settled in a softening tank (a conveying mode known by a person skilled in the art such as pumping can be adopted), adding a regulator into the softening tank, and stirring for 3-10 minutes; adding a precipitator, and stirring for 3-10 minutes; settling for 1-6 hours after stirring; settling to obtain foam drainage supernatant, wherein the foam drainage supernatant after settling is softened water with the pH value of 6-9, the concentration of calcium and magnesium ions less than or equal to 1000mg/l, the total salt content less than or equal to 60000mg/l, the chloride ions less than or equal to 30000mg/l, the foaming power more than or equal to 20cm and the COD less than or equal to 3000 mg/l;
wherein the regulator is lime milk solution with the mass percentage of 10-20% or sodium hydroxide solution with the mass percentage of 10%, and the addition amount of the regulator is 5-20 ml/L; the precipitator is a sodium carbonate solution with the mass percentage of 10% -20%, and the addition amount of the precipitator is 3-60 ml/L;
(4) biochemical treatment:
soft water obtained after softening and hardness removal treatment in the step (3) is subjected to anaerobic hydrolysis acidification treatment in an anaerobic tank (a conveying mode known by persons skilled in the art such as pumping can be adopted), and the hydraulic retention time in the anaerobic tank is more than or equal to 20 hours; after the anaerobic tank is treated, the sewage enters a first-stage aerobic aeration tank and a second-stage aerobic aeration tank in sequence, the hydraulic retention time in the first-stage aerobic aeration tank is more than or equal to 30 hours, the hydraulic retention time in the second-stage aerobic aeration tank is more than or equal to 10 hours, continuous aeration is carried out in the hydraulic retention processes of the first-stage aerobic aeration tank and the second-stage aerobic aeration tank, the pressure of compressed air in the aeration process is 0.06-0.07 MPa, and the air-water volume ratio of aeration is 20: 1-50: 1; the primary aerobic aeration tank and the secondary aerobic aeration tank supply oxygen to the microorganisms through aeration (the dissolved oxygen content of the primary aerobic aeration tank and the dissolved oxygen content of the secondary aerobic aeration tank are both kept to be 3-6 mg/L), so that the growth of the microorganisms in the primary aerobic aeration tank and the secondary aerobic aeration tank is facilitated.
Wherein, halotolerant bacteria liquid is added into the anaerobic pool, and the halotolerant bacteria liquid comprises pectinate brassicae (Pectinatus brassiccus), Clostridium sporogenes (Clostridium sporogenes), double-enzyme bacilli (Clostridium bifermentans) and facultative anaerobe (Facultativeaerobe); adding a halotolerant bacteria liquid into the first-stage aerobic aeration tank and the second-stage aerobic aeration tank, wherein the halotolerant bacteria liquid comprises Halomonas titaniae (Thangoniac Halomonas), Halomonas variabilis (variable Halomonas), Bacillus atrophaeus (Bacillus atrophaeus, Bacillus subtilis black variant), Bacillus pumilus (Bacillus pumilus), Bacillus subulis (Bacillus subtilis), Bacillus aryabhattataii (Bacillus aryabyssinicus), Bacillus endopythicus (Bacillus endophyticus), and adding a potassium dihydrogen phosphate solution with the mass percentage of 10% into the first-stage aerobic aeration tank and the second-stage aerobic aeration tank according to the mass ratio (which is the mass ratio of foam drainage) of 0.2-0.5%. The concentration of mixed bacteria liquid in the salt-tolerant bacteria liquid added into the anaerobic tank, the first-stage aerobic aeration tank and the second-stage aerobic aeration tank is 108~109CFU/ml;
The treatment volume load of the first-stage aerobic aeration tank is 0.8-1.2 kgCOD/(m)3D), the treatment volume load of the secondary aerobic aeration tank is 0.4-0.8 kgCOD/(m)3D); the sludge age of the anaerobic tank, the primary aerobic aeration tank and the secondary aerobic aeration tank is 0.5-1 d, and the concentration is 3-10 g/L. The sludge with oil substances absorbed in the anaerobic tank can enter a sedimentation tank for sludge-water separation through a water distribution system and a reflux pump in the tank body, the supernatant bubble is discharged and enters a subsequent filtering procedure, the settled sludge is partially refluxed (refluxed into the primary aerobic aeration tank and the secondary aerobic aeration tank) to maintain the sludge concentration of the aerobic aeration tank, and the rest sludge is discharged in a residual sludge form to ensure that the sludge is sucked and absorbedAbility to attach oily substances. And keeping the sludge concentration of the anaerobic tank, the first-stage aerobic aeration tank and the second-stage aerobic aeration tank to be 3-10 g/L and the sludge age to be 0.5-1 d.
The temperature in the biochemical treatment process of the anaerobic tank, the primary aerobic aeration tank and the secondary aerobic aeration tank is 10-40 ℃, and preferably 20-30 ℃;
feeding the effluent (overflow) of the secondary aerobic aeration tank into a sedimentation tank, adding a flocculating agent (10 mass percent polyaluminium chloride solution) into the effluent (overflow) of the secondary aerobic aeration tank according to the mass ratio (accounting for the mass of the foam drainage) of 0.1-1.5% for coagulating sedimentation, and naturally settling for 1-3 hours; settling to obtain a foam drainage supernatant;
wherein the anaerobic tank, the first-stage aerobic aeration tank and the second-stage aerobic aeration tank are all anaerobic tanks, first-stage aerobic aeration tanks and second-stage aerobic aeration tanks which are well known to the technical personnel in the field. The method can be carried out by a pumping method, a conveying method, an activated sludge acclimation step and a culture step which are well known to those skilled in the art.
The biochemical treatment process effectively removes surfactants, oils, COD, BOD, ammonia nitrogen, chroma and the like in water. The pH value of the biochemical effluent water quality index is 6-9, the concentration of calcium and magnesium ions is less than or equal to 1000mg/l, the total salt amount is less than or equal to 60000mg/l, the chloride ions are less than or equal to 30000mg/l, the foaming power is less than 1cm, and the COD is less than or equal to 800mg/l, so that the entering membrane filtration condition is met;
(5) filtering and membrane treatment:
after biochemical treatment and natural sedimentation, the supernatant of the foam drainage water obtained in the step (3) is conveyed to an ultrafiltration device for ultrafiltration treatment (the pH of the water produced after ultrafiltration is 6-8, SS is less than 5mg/L, and the conductivity is less than 30000 mu s/cm); conveying the ultrafiltered produced water to a nanofiltration device for nanofiltration treatment, conveying the nanofiltered produced water to a reverse osmosis membrane treatment device for reverse osmosis treatment, wherein the reverse osmosis treated produced water directly meets the requirements of primary sewage discharge standard of GB8978 Integrated wastewater discharge Standard;
(6) low-temperature multi-effect evaporation:
conveying the concentrated water obtained after filtration and membrane treatment to a low-temperature multi-effect distillation device for evaporation treatment, wherein the pressure is controlled to be-0.06 MPa-0.25 MPa in the evaporation treatment process; preferably four-effect low-temperature evaporation: the primary evaporation temperature is controlled to be 110-140 ℃, the secondary evaporation temperature is controlled to be 90-105 ℃, the tertiary evaporation temperature is controlled to be 70-85 ℃, and the quaternary evaporation temperature is controlled to be 50-65 ℃;
(7) sludge collection:
the sludge settled by the settling process of each system is collected by pumping and centralized, and after filter pressing dehydration decrement treatment by a filter press, the water content of a sludge cake reaches less than 60 percent and the sludge cake is sent to a solid garbage treatment plant for treatment or used for firing common baked bricks for utilization.
The present invention will be described in more detail with reference to the following examples. The embodiment takes the application of bubble drainage treatment in exploration, development and gas production of the western and Sichuan gas field of the oil and gas separation company in southwest China petrochemical industry as a specific embodiment. The anaerobic tank, the primary aerobic aeration tank, the secondary aerobic aeration tank, the ultrafiltration device, the nanofiltration device and the reverse osmosis membrane are all devices well known to those skilled in the art in the process.
Wherein the halotolerant bacteria liquid added into the anaerobic tank comprises pectinate brassicae (Pectinatus brassicae), Clostridium sporogenes (Clostridium sporogenes), bacillus bifidus (Clostridium bifidum) and facultative anaerobe (Facultivanaerobe); the halotolerant bacteria liquid added into the first-stage aerobic aeration tank and the second-stage aerobic aeration tank is the same, the halotolerant bacteria liquid comprises halonas titanicae (Telanniunicum), halonas variabilis (variable Halomonas), Bacillus atrophaeus (Bacillus atrophaeus, which is named as Bacillus subtilis var. subtilis), Bacillus pumilus (Bacillus pumilus), Bacillus subulatus, Bacillus aryabhattataii (Bacillus aryabyssinicus), and Bacillus endopythicus (Bacillus endophyticus), and potassium dihydrogen phosphate solution with the mass percentage of 10% is further added into the first-stage aerobic aeration tank and the second-stage aerobic aeration tank according to the mass ratio (which is the mass ratio of foam drainage) of 0.2-0.5%.
The concentration of mixed bacteria liquid in the salt-tolerant bacteria liquid added into the anaerobic tank, the first-stage aerobic aeration tank and the second-stage aerobic aeration tank is 108~109CFU/ml;
Example 1
Exploration of the southwest oil and gas division of China petrochemical company in the Sichuan-Sichuan gas fieldExploring, exploiting and draining air bubbles by utilizing the method of the invention, the unit implementation daily output of the method is 600m3And (5) operating the project. The method comprises the following specific steps:
(1) gas production bubble drainage generated in the gas production process of a single well is collected to 600m in a centralized manner3In the centralized storage pool (oil separation settling tank), the free oil obtained from the upper part of the centralized storage pool is separated by gravity and recycled into 100m3The dirty oil recovery tank is used for storing; settling the separated suspended solids to the lower part of the centralized storage pool to obtain solid-phase sludge, and recovering the solid-phase sludge through a sludge collection system; the foam drainage water obtained from the middle part of the centralized storage pool after oil removal and sedimentation enters a demulsification coagulation pool for treatment;
(2) the foam drainage after oil removal and sedimentation enters a demulsification coagulation tank through a lift pump; then adding a sodium hydroxide solution with the mass fraction of 10% into the demulsification coagulation tank, adjusting the pH value of the solution to be 8-9, and mechanically stirring for 4 min; after stirring, adding 10% polyaluminium chloride solution by mass into the demulsification and coagulation tank, wherein the addition amount is 10ml/L foam drainage, and stirring for 8 min; then adding 0.1 percent by mass of polyacrylamide solution into the mixture, wherein the adding amount of the polyacrylamide solution is 10ml/L of foam drainage water, and stirring the mixture for 10min after the polyacrylamide solution is completely added. Naturally settling for 1 hour after stirring is finished, and obtaining supernatant liquid soaking drainage after settling is finished; pumping supernatant foam drainage water obtained by demulsification and coagulation and sedimentation into a softening tank for treatment;
(3) the supernatant after sedimentation was drained to 600m3Adding 15 mass percent of lime milk solution into the softening tank, soaking and draining 5ml/L supernatant liquid, mechanically stirring for 10min after completely adding the lime milk solution, then adding 20 mass percent of sodium carbonate solution, stirring for 5min after completely adding the sodium carbonate solution, and stirring for 15 ml/L; after stirring, naturally settling for 2 hours to obtain supernatant with pH value of 8.5, calcium and magnesium ion concentration of about 800mg/l and salt content of less than 60000mg/l, and then obtaining softened water;
(4) conveying the softened water obtained in the step (3) to a biochemical treatment system through a pump for treatment, wherein the method comprises the following specific steps:
a: pumping softened water to 700m3In the anaerobic tank (the anaerobic tank is added with corresponding halotolerant bacteria liquid of 0.7m3~3.5m3(the concentration of the mixed bacterial liquid was 10)8~109CFU/ml) and other nutrients known to those skilled in the art. ) Anaerobic hydrolytic acidification treatment is performed (hydrolysis refers to biochemical reactions that take place extracellularly before the organic substrate enters the cell. Hydrolysis is the process by which a complex, non-soluble polymer is converted to a simple, soluble monomer or dimer. Acidification is a typical fermentation process, i.e., acidogenic fermentation. ) The hydraulic retention time in the softened water anaerobic pool is 20 hours; the concentration of sludge in the anaerobic tank is 3-10 g/l, and the sludge age is 0.5-1 d;
b: the mixture after hydrolytic acidification in the anaerobic tank enters 1600m3The primary aerobic aeration tank is added with corresponding halotolerant bacteria liquid with the thickness of 1.6m3~8m3(the concentration of the mixed bacterial liquid was 10)8~109CFU/ml) and 10 percent by mass of potassium dihydrogen phosphate solution (the mass ratio of the added amount of the potassium dihydrogen phosphate solution to the total mass of the treatment solution in the first-stage aerobic aeration tank is 0.2 percent. ) And other nutrients known to those skilled in the art. ) Carrying out aerobic treatment, and simultaneously aerating from the bottom of the primary aerobic aeration tank to the tank, wherein the pressure of compressed air is 0.06-0.07 MPa during aeration, and the air-water ratio of aeration is 20: 1;
the hydraulic retention time in the first-stage aerobic aeration tank is 30 hours, and the treatment volume load of the first-stage aerobic aeration tank is 0.8 kgCOD/(m)3D), wherein the sludge concentration is kept to be 3-10 g/l, and the sludge age is 0.5-1 d;
c: the mixture after the aerobic treatment in the first-stage aerobic aeration tank is pumped to 1000m3The secondary aerobic aeration tank is filled with corresponding halotolerant bacteria liquid 1m3~5m3(the concentration of the mixed bacterial liquid was 10)8~109CFU/ml) and 10 percent by mass of potassium dihydrogen phosphate solution (the mass ratio of the added amount of the potassium dihydrogen phosphate solution to the total mass of the treatment solution in the first-stage aerobic aeration tank is 0.2 percent. ) And other nutrients known to those skilled in the art. ) Performing aerobic treatmentAnd meanwhile, aerating the second-stage aerobic aeration tank by the bottom of the second-stage aerobic aeration tank, wherein the pressure of compressed air during aeration is 0.06-0.07 MPa, and the air-water ratio of aeration is 20: 1;
the hydraulic retention time in the secondary aerobic aeration tank is 10 hours, and the treatment volume load of the secondary aerobic aeration tank is 0.4 kgCOD/(m)3D), wherein the sludge concentration is kept to be 3-10 g/l, and the sludge age is 0.5-1 d;
the dissolved oxygen amounts of the first-stage aerobic aeration tank and the second-stage aerobic aeration tank are kept to be 3-6 mg/L;
d: after the second-stage aerobic aeration tank is subjected to aerobic treatment, overflowing into a sedimentation tank, and then adding a polyaluminium chloride solution with the mass percentage of 10% into the sedimentation tank, wherein the adding amount of the polyaluminium chloride solution accounts for 1% of the total water amount; adding a flocculating agent, naturally settling for 1 hour, obtaining supernatant with the pH value of 6-9, the concentration of calcium and magnesium ions being less than or equal to 800mg/l, the total salt content being less than or equal to 60000mg/l, the chloride ions being less than or equal to 30000mg/l, the foaming power being less than 1cm, and the COD being less than or equal to 700mg/l, and pumping biochemical effluent into a filtration and membrane treatment system.
In the process, sludge adsorbed with oil substances in the secondary aerobic aeration tank enters a sedimentation tank for sedimentation and cement separation, part of the settled sludge flows back into the secondary aerobic aeration tank to keep the sludge concentration in the secondary aerobic aeration tank, and the rest of the sludge is discharged outside as excess sludge and is subjected to concentration and dehydration for reduction treatment, (suspended sludge in the primary aerobic aeration tank enters the secondary aerobic aeration tank through the aeration effect, the anaerobic tank performs sludge tank internal circulation through a water distribution system and a reflux pump in the tank body, and the rest of the sludge is periodically discharged through tank body deslagging measures for reduction treatment).
(5) Supernatant bubble drainage obtained by a sedimentation tank of the biochemical treatment system is conveyed to an ultrafiltration and membrane treatment system through a lifting pump for treatment, and the method comprises the following steps:
a: performing ultrafiltration treatment in an ultrafiltration device, wherein the maximum treatment capacity in the ultrafiltration process is 30m3H, entering 300m after the treatment is finished3The ultrafiltration water-producing tank;
the pH value of the ultrafiltration water is 6-8, SS is less than 5mg/l, and the conductivity of the water is less than 30000 us/cm;
b: the ultrafiltration water is pumped into a nanofiltration device for nanofiltration treatment, and the maximum treatment capacity in the nanofiltration process is 25m3H, pumping the water produced after the nanofiltration treatment into a reverse osmosis membrane treatment device for treatment, wherein the water yield of the reverse osmosis membrane is 12m3The water yield of the reverse osmosis membrane is 45-55%, the water produced after reverse osmosis membrane treatment reaches the standard and is discharged or is recycled as oilfield reinjection water, greening and miscellaneous water, and the treatment and recycling additional value is improved;
c: concentrated water obtained after the ultrafiltration device, the nanofiltration device and the reverse osmosis treatment is pumped into a four-effect evaporator for evaporation, wherein the first-effect evaporation temperature is controlled to be 110-140 ℃, the second-effect evaporation temperature is controlled to be 90-105 ℃, the third-effect evaporation temperature is controlled to be 70-85 ℃, and the four-effect evaporation temperature is controlled to be 50-65 ℃.
The evaporated water can be recycled again after evaporation, the obtained water vapor can also be used as a heat source for recycling and heating other substances, the cooling water produced is discharged after reaching the standard, and the solid salts obtained by evaporation can be recycled as the raw materials of a chlor-alkali plant;
(6) in the process, the sludge obtained by the precipitation in each step is conveyed to a sludge storage tank through a high-pressure lifting pump for collection, and is subjected to filter pressing treatment by using a filter press after collection until the water content in the mud cake is less than 60%, so that the obtained mud cake can be used for roadbed cushions, well site soil construction and the like.
The discharged produced water after treatment is discharged into a Yangyuan river, and the water quality is monitored on line, so that the requirement of the first-level sewage discharge standard GB8978 Integrated wastewater discharge Standard is met.
Example 2
The method has the unit implementation daily yield of 800m when the method is used by the Qing Branch company of China Petroleum province in exploration, development, gas production and drainage of gas fields in the west of Sichuan province3And (5) operating the project. The method comprises the following specific steps:
(1) gas production bubble drainage generated in the gas production process of a single well is collected to 600m in a centralized manner3In the centralized storage pool (oil separation settling tank), the free oil obtained from the upper part of the centralized storage pool is separated by gravity and recycled into 100m3Waste oil recoveryCollecting the tank for storage; settling the separated suspended solids to the lower part of the centralized storage pool to obtain solid-phase sludge, and recovering the solid-phase sludge through a sludge collection system; the foam drainage water obtained from the middle part of the centralized storage pool after oil removal and sedimentation enters a demulsification coagulation pool for treatment;
(2) the foam drainage after oil removal and sedimentation enters a demulsification coagulation tank through a lift pump; then adding a hydrochloric acid solution into the demulsification coagulation tank, adjusting the pH value of the solution to 6-6.5, and mechanically stirring for 10 min; after the mechanical stirring is finished, adding 10% polyaluminium chloride solution by mass into a demulsification coagulation tank, wherein the addition amount is 40ml/L foam drainage, and stirring for 4 min; then adding 0.1 percent by mass of polyacrylamide solution into the mixture, wherein the adding amount of the polyacrylamide solution is 30ml/L of foam drainage water, and stirring the mixture for 3min after the polyacrylamide solution is completely added. Naturally settling for 10 hours after stirring is finished, and obtaining supernatant liquid soaking drainage after settling is finished; pumping supernatant foam drainage water obtained by demulsification and coagulation and sedimentation into a softening tank for treatment;
(3) the supernatant after sedimentation was drained to 600m3Adding 10 mass percent of lime milk solution into the softening tank, soaking and draining 20ml/L supernatant liquid, mechanically stirring for 3min after completely adding the lime milk solution, then adding 10 mass percent of sodium carbonate solution, stirring for 10min after completely adding the sodium carbonate solution, wherein the adding amount of the sodium carbonate solution is 50 ml/L; after stirring, naturally settling for 5-6 hours to obtain supernatant with pH value of 9.0, calcium and magnesium ion concentration of about 800mg/l and salt content of less than 60000mg/l, and then obtaining softened water;
(4) conveying the softened water obtained in the step (3) to a biochemical treatment system through a pump for treatment, wherein the method comprises the following specific steps:
a: pumping softened water to 700m3In the anaerobic tank (the anaerobic tank is added with corresponding halotolerant bacteria liquid of 0.7m3~3.5m3(the concentration of the mixed bacterial liquid was 10)8~109CFU/ml)) is subjected to hydrolytic acidification (hydrolysis refers to biochemical reactions that take place extracellularly before the organic substrate enters the cell. Hydrolysis is the process by which a complex, non-soluble polymer is converted to a simple, soluble monomer or dimer. Acid(s)Chemolysis is a typical type of fermentation process, i.e., acidogenic fermentation. ) The hydraulic retention time in the softened water anaerobic pool is 28 hours; the concentration of sludge in the anaerobic tank is kept to be 3-10 g/l, and the sludge age is 0.5-1 d;
b: the mixture after hydrolytic acidification in the anaerobic pool enters 1600m3The primary aerobic aeration tank is added with corresponding halotolerant bacteria liquid with the thickness of 1.6m3~8m3(the concentration of the mixed bacterial liquid was 10)8~109CFU/ml) and 10% by mass of potassium dihydrogen phosphate solution (the mass of the potassium dihydrogen phosphate solution added into the primary aerobic aeration tank accounts for 0.5% of the total water to be treated in the tank), and aerating the tank from the bottom of the primary aerobic aeration tank, wherein the pressure of compressed air is 0.06-0.07 MPa during aeration, and the air-water ratio of aeration is 50: 1;
the hydraulic retention time in the first-stage aerobic aeration tank is 40 hours, and the treatment volume load of the first-stage aerobic aeration tank is 1.2 kgCOD/(m)3D), wherein the sludge concentration is kept to be 3-10 g/l, and the sludge age is 0.5-1 d;
c: the mixture after the aerobic treatment in the first-stage aerobic aeration tank is pumped to 1000m3The secondary aerobic aeration tank is filled with corresponding halotolerant bacteria liquid 1m3~5m3(the concentration of the mixed bacterial liquid was 10)8~109CFU/ml) and 10% by mass of potassium dihydrogen phosphate solution (the mass of the potassium dihydrogen phosphate solution added into the secondary aerobic aeration tank accounts for 0.5% of the total water to be treated in the tank), and simultaneously aerating the secondary aerobic aeration tank from the bottom of the secondary aerobic aeration tank, wherein the pressure of compressed air during aeration is 0.06-0.07 MPa, and the air-water ratio of aeration is 45: 1;
the hydraulic retention time in the secondary aerobic aeration tank is 20 hours, and the treatment volume load of the secondary aerobic aeration tank is 0.8 kgCOD/(m)3D), wherein the sludge concentration is 4-5 g/l, and the sludge age is 0.5-1 d;
the dissolved oxygen amounts of the first-stage aerobic aeration tank and the second-stage aerobic aeration tank are kept to be 3-6 mg/L;
d: after the second-stage aerobic aeration tank is subjected to aerobic treatment, overflowing into a sedimentation tank, and then adding a polyaluminium chloride solution with the mass percentage of 10% into the sedimentation tank, wherein the adding amount of the polyaluminium chloride solution accounts for 1.5% of the total water amount; adding a flocculating agent, naturally settling for 3 hours, obtaining supernatant with the pH value of 6-9, the concentration of calcium and magnesium ions less than or equal to 800mg/l, the total salt amount less than or equal to 60000mg/l, the chloride ions less than or equal to 30000mg/l, the foaming power less than 1cm and the COD less than or equal to 700mg/l after the settling is finished, and pumping biochemical effluent into a filtration and membrane treatment system.
In the process, sludge adsorbed with oil substances in the secondary aerobic aeration tank enters a sedimentation tank and then undergoes sedimentation and cement separation, part of the precipitated sludge flows back into the secondary aerobic aeration tank to keep the sludge concentration in the secondary aerobic aeration tank, and part of the precipitated sludge is discharged outside according to the form of the residual sludge to ensure the oil substance adsorption capacity of the sludge; (the suspended sludge in the first-stage aerobic aeration tank enters the second-stage aerobic aeration tank through aeration, the content of the suspended sludge in the tank body is effectively reduced by the anaerobic tank through a water distribution system and a reflux pump in the tank body, and the rest sludge is periodically discharged through a tank body deslagging measure for reduction treatment).
(5) Supernatant bubble drainage obtained by a sedimentation tank of the biochemical treatment system is conveyed to an ultrafiltration and membrane treatment system through a lifting pump for treatment, and the method comprises the following steps:
a: performing ultrafiltration treatment in an ultrafiltration device, wherein the maximum treatment capacity in the ultrafiltration process is 50m3H, after the treatment is finished, the mixture enters 400m3The ultrafiltration water-producing tank;
the pH value of the ultrafiltration water is 6-8, wherein SS is less than 5mg/l, and the conductivity of the water is less than 30000 us/cm;
b: the ultrafiltration water is pumped into a nanofiltration device for nanofiltration treatment, and the maximum treatment capacity in the nanofiltration process is 40m3H, pumping the water produced after the nanofiltration treatment into a reverse osmosis membrane treatment device for treatment, wherein the water yield of the reverse osmosis membrane is 20m3The water yield is 50%, and the produced water after reverse osmosis membrane treatment reaches the standard and is discharged or is recycled as oilfield reinjection water, greening and miscellaneous water;
c: concentrated water obtained after the ultrafiltration device, the nanofiltration device and the reverse osmosis treatment is pumped into a four-effect evaporator for evaporation, wherein the first-effect evaporation temperature is controlled to be 110-140 ℃, the second-effect evaporation temperature is controlled to be 90-105 ℃, the third-effect evaporation temperature is controlled to be 70-85 ℃, and the four-effect evaporation temperature is controlled to be 50-65 ℃.
The evaporated water can be recovered again after evaporation, or the obtained water vapor can be recycled as a heat source and used for heating other substances, and the solid salts obtained by evaporation can be recovered and used as raw materials of a chlor-alkali plant.
(6) In the process, the sludge obtained by precipitation in each step is conveyed to a sludge storage tank through a high-pressure lifting pump for collection, and is subjected to filter pressing treatment by using a filter press after collection until the water content in the mud cake is less than 60%, so that the obtained mud cake can be used as an industrial raw material, such as a roadbed cushion layer and soil for well site construction.
The discharged produced water after treatment meets the requirements of the first-level sewage discharge standard GB8978 Integrated wastewater discharge Standard.
Example 3
The method of the invention is used for the exploration and development of gas production fracturing bubble drainage in the Sulige gas field by the Changqing oil field branch of medium petroleum3And (5) operating the project. The method comprises the following specific steps:
(1) gas production bubble drainage generated in the gas production process of a single well is collected to 600m in a centralized manner3In the centralized storage pool (oil separation settling tank), the free oil obtained from the upper part of the centralized storage pool is separated by gravity and recycled into 100m3The dirty oil recovery tank is used for storing; settling the separated suspended solids to the lower part of the centralized storage pool to obtain solid-phase sludge, and recovering the solid-phase sludge through a sludge collection system; the foam drainage water obtained from the middle part of the centralized storage pool after oil removal and sedimentation enters a demulsification coagulation pool for treatment;
(2) the foam drainage after the preliminary oil removal and sedimentation in the step (1) enters a demulsification coagulation tank through a lift pump; then adding a lime milk solution with the mass fraction of 10% into the demulsification coagulation tank, adjusting the pH value of the solution to 7-8, and stirring for 10min by air; after the air stirring is finished, adding 10% by mass of polyaluminium chloride solution into a demulsification coagulation tank, discharging water by using 25ml/L foam, and stirring for 7 min; then adding 0.1 percent by mass of polyacrylamide solution into the mixture, wherein the adding amount of the polyacrylamide solution is 20ml/L of foam drainage water, and stirring for 7min after the polyacrylamide solution is completely added. Naturally settling for 5 hours after stirring is finished, and obtaining supernatant liquid soaking drainage after settling is finished; pumping supernatant foam drainage water obtained by demulsification and coagulation and sedimentation into a softening tank for treatment;
(3) the supernatant after sedimentation was drained to 600m3Adding 17 mass percent of lime milk solution into the softening tank, soaking and draining 13ml/L of supernatant into the softening tank, stirring for 7min by air after the lime milk solution is completely added, then adding 15 mass percent of sodium carbonate solution, stirring for 7min after the sodium carbonate solution is completely added, and stirring for 30 ml/L; after stirring, naturally settling for 4 hours to obtain supernatant with pH value of 8.0, calcium and magnesium ion concentration of about 800mg/l and salt content of less than 60000mg/l, and then obtaining softened water;
(4) conveying the softened water obtained in the step (3) to a biochemical treatment system through a pump for treatment, wherein the method comprises the following specific steps:
a: pumping softened water to 700m3In the anaerobic tank (the anaerobic tank is added with corresponding halotolerant bacteria liquid of 0.7m3~50m3(the concentration of the mixed bacterial liquid was 10)8~109CFU/ml)) is subjected to hydrolytic acidification treatment, and the hydraulic retention time in a softened water anaerobic pool is 25 hours; the concentration of sludge in the anaerobic tank is kept to be 3-10 g/l, and the sludge age is 0.5-1 d;
b: the mixture after hydrolytic acidification in the anaerobic tank enters 1600m3The primary aerobic aeration tank is added with corresponding halotolerant bacteria liquid with the thickness of 1.6m3~8m3(the concentration of the mixed bacterial liquid was 10)8~109CFU/ml) and 10% by mass of potassium dihydrogen phosphate solution (the mass of the potassium dihydrogen phosphate solution added into the primary aerobic aeration tank accounts for 0.4% of the total water mass in the tank), and aerating the tank from the bottom of the primary aerobic aeration tank, wherein the pressure of compressed air is 0.06-0.07 MPa during aeration, and the air-water ratio of aeration is 35: 1;
the hydraulic retention time in the first-stage aerobic aeration tank is 36 hours, and the treatment volume load of the first-stage aerobic aeration tank is 0.8 kgCOD/(m)3D), wherein the sludge concentration is kept to be 3-10 g/l, and the sludge age is 0.5-1 d;
c: the mixture after the aerobic treatment in the first-stage aerobic aeration tank is pumped to 1000m3The secondary aerobic aeration tank is filled with corresponding halotolerant bacteria liquid 1m3~5m3(the concentration of the mixed bacterial liquid was 10)8~109CFU/ml) and 10% by mass of potassium dihydrogen phosphate solution (the mass of the potassium dihydrogen phosphate solution added into the secondary aerobic aeration tank accounts for 0.3% of the total water mass in the tank)), and aerating the secondary aerobic aeration tank from the bottom of the secondary aerobic aeration tank, wherein the pressure of compressed air during aeration is 0.06-0.07 MPa, and the air-water ratio of aeration is 30: 1;
the hydraulic retention time in the secondary aerobic aeration tank is 28 hours, and the treatment volume load of the secondary aerobic aeration tank is 0.6 kgCOD/(m)3D), wherein the sludge concentration is kept to be 3-10 g/l, and the sludge age is 0.5-1 d;
the dissolved oxygen amounts of the first-stage aerobic aeration tank and the second-stage aerobic aeration tank are kept to be 3-6 mg/L;
d: after the second-stage aerobic aeration tank is subjected to aerobic treatment, overflowing into a sedimentation tank, and then adding a polyaluminium chloride solution with the mass percentage of 10% into the sedimentation tank, wherein the adding amount of the polyaluminium chloride solution accounts for 1.2% of the total water amount; adding a flocculating agent, naturally settling for 2 hours, obtaining supernatant with the pH value of 6-9, the concentration of calcium and magnesium ions less than or equal to 800mg/l, the total salt amount less than or equal to 60000mg/l, the chloride ions less than or equal to 30000mg/l, the foaming power less than 1cm and the COD less than or equal to 700mg/l after the settling is finished, and pumping biochemical effluent into a filtration and membrane treatment system.
In the process, sludge adsorbed with oil substances in the secondary aerobic aeration tank enters a sedimentation tank and then undergoes sedimentation and cement separation, part of the precipitated sludge flows back into the secondary aerobic aeration tank to keep the sludge concentration in the secondary aerobic aeration tank, and part of the precipitated sludge is discharged outside according to the form of the residual sludge to ensure the oil substance adsorption capacity of the sludge; (the suspended sludge in the first-stage aerobic aeration tank enters the second-stage aerobic aeration tank through aeration, the content of the suspended sludge in the tank body is effectively reduced by the anaerobic tank through a water distribution system and a reflux pump in the tank body, and the rest sludge is periodically discharged through a tank body deslagging measure for reduction treatment).
(5) Supernatant bubble drainage obtained by a sedimentation tank of the biochemical treatment system is conveyed to an ultrafiltration and membrane treatment system through a lifting pump for treatment, and the method comprises the following steps:
a: performing ultrafiltration treatment in an ultrafiltration device, wherein the maximum treatment capacity in the ultrafiltration process is 30m3H, entering 300m after the treatment is finished3The ultrafiltration water-producing tank;
the pH value of the ultrafiltration water is 6-8, wherein SS is less than 5mg/l, and the conductivity of the water is less than 30000 us/cm;
b: the ultrafiltration water is pumped into a nanofiltration device for nanofiltration treatment, and the maximum treatment capacity in the nanofiltration process is 25m3H, pumping the water produced after the nanofiltration treatment into a reverse osmosis membrane treatment device for treatment, wherein the water yield of the reverse osmosis membrane is 15m3The water yield is 60%, and the produced water after reverse osmosis membrane treatment reaches the standard and is discharged or is recycled as oilfield reinjection water, greening and miscellaneous water;
c: concentrated water obtained after the ultrafiltration device, the nanofiltration device and the reverse osmosis treatment is pumped into a four-effect evaporator for evaporation, wherein the first-effect evaporation temperature is controlled to be 110-140 ℃, the second-effect evaporation temperature is controlled to be 90-105 ℃, the third-effect evaporation temperature is controlled to be 70-85 ℃, and the four-effect evaporation temperature is controlled to be 50-65 ℃.
The evaporated water can be recovered again after evaporation, the obtained water vapor can be used as a heat source for recycling and heating other substances, and the solid salt obtained by evaporation can be recovered and used as a raw material of a chlor-alkali plant;
(6) in the process, the sludge obtained by precipitation in each step is conveyed to a sludge storage tank through a high-pressure lifting pump for collection, and is subjected to filter pressing treatment by using a filter press after collection, wherein the filter pressing treatment is carried out until the water content in the mud cake is less than 62%, and the obtained mud cake can be used as an industrial raw material, such as a roadbed cushion layer and soil for well site construction.
The discharged produced water after treatment meets the requirements of the first-level sewage discharge standard GB8978 Integrated wastewater discharge Standard.

Claims (7)

1. A comprehensive biochemical treatment method for foam drainage is characterized by comprising the following steps:
(1) carrying out single-well recovery and oil removal settlement treatment on the foam drainage;
(2) placing the foam drainage subjected to the oil removal settlement treatment in the step (1) into a demulsification and coagulation tank for demulsification and coagulation treatment;
(3) placing foam drainage subjected to demulsification and coagulation treatment in a softening tank for softening and hardness removal treatment;
(4) the softened foam drainage obtained after softening and hardness removal treatment in the step (3) is sequentially placed in an anaerobic tank, a primary aerobic aeration tank, a secondary aerobic aeration tank and a sedimentation tank for treatment;
the hydraulic retention time of the foam drainage softened water in the anaerobic tank is more than or equal to 20 hours, the hydraulic retention time in the primary aerobic aeration tank is more than or equal to 30 hours, and the hydraulic retention time in the secondary aerobic aeration tank is more than or equal to 10 hours; continuous aeration is carried out in the hydraulic retention process of the first-stage aerobic aeration tank and the second-stage aerobic aeration tank, the pressure of compressed air in the aeration process is 0.06-0.07 MPa, the volume ratio of air to water of aeration amount is 20: 1-50: 1, and the temperature range of biochemical treatment in the anaerobic tank and the aerobic aeration tank is 10-40 ℃;
feeding the effluent of the secondary aerobic aeration tank into a sedimentation tank, adding a flocculating agent for coagulating sedimentation, and naturally settling for 1-3 hours; the supernatant obtained after sedimentation is biochemical effluent with the pH value of 6-9, the concentration of calcium and magnesium ions less than or equal to 1000mg/l, the total salt amount less than or equal to 60000mg/l, the chloride ions less than or equal to 30000mg/l, the foaming power less than 1cm and the COD less than or equal to 800 mg/l;
the flocculant is a polyaluminium chloride solution with the mass percentage of 10-20%, and the adding mass of the flocculant accounts for 0.1-1.5% of the mass of the total water in the sedimentation tank;
the halotolerant bacteria liquid added into the anaerobic tank comprises pectinate brassicae, clostridium sporogenes, double-enzyme bacillus and facultative anaerobic bacteria; the halotolerant bacteria liquid added into both the first-stage aerobic aeration tank and the second-stage aerobic aeration tank comprises tyanic halomonas, variable halomonas, atrophic bacillus, bacillus pumilus, bacillus subtilis, bacillus ajoendothelial and endophytic bacillus;
a potassium dihydrogen phosphate solution with the mass percentage of 10 percent and accounting for 0.1 to 0.5 percent of the total water mass in the tank is also added into the first-stage aerobic aeration tank and the second-stage aerobic aeration tank;
the treatment volume load of the primary aerobic aeration tank is 0.8-1.2 kgCOD/(m)3D), the treatment volume load of the secondary aerobic aeration tank is 0.4-0.8 kgCOD/(m)3D); the sludge age of the anaerobic tank, the primary aerobic aeration tank and the secondary aerobic aeration tank is 0.5-1 d, and the concentration is 3-10 g/L;
(5) and (4) sequentially carrying out ultrafiltration, nanofiltration and reverse osmosis treatment on supernatant bubble drainage obtained in the sedimentation tank, wherein the produced water of the reverse osmosis treatment meets the standard and is discharged or recycled.
2. The integrated biochemical treatment method of bubble drain according to claim 1, further comprising the steps of: placing concentrated water obtained by ultrafiltration, nanofiltration and reverse osmosis treatment in a low-temperature multi-effect evaporator for treatment, wherein the pressure is controlled to be-0.06 MPa-0.25 MPa in the evaporation treatment process;
the low-temperature multi-effect evaporator is a low-temperature four-effect evaporator, wherein the first-effect evaporation temperature is controlled to be 110-140 ℃, the second-effect evaporation temperature is controlled to be 90-105 ℃, the third-effect evaporation temperature is controlled to be 70-85 ℃, and the fourth-effect evaporation temperature is controlled to be 50-65 ℃.
3. The integrated biochemical treatment method of bubble drain according to claim 1, further comprising the steps of: and (3) collecting sludge obtained in the processes of oil removal settlement treatment, demulsification coagulation treatment, softening and hardness removal treatment and biochemical treatment by pumping, and then performing filter pressing by a filter press until the water content in a mud cake is less than 60%, and recycling.
4. The integrated biochemical treatment method for the foam drainage according to claim 1, wherein the single-well recovery and oil-removal sedimentation treatment in step (1) is: carrying out drainage pull transportation or pipeline transportation on gas field single well bubbles to recover the gas field single well bubbles to a centralized storage pool, and recovering free oil obtained from the upper part of the gas field single well bubbles through gravity separation to enter a sump oil recovery tank for storage; settling the separated suspended solids to the lower part of a centralized storage tank to obtain solid-phase sludge, and recovering the solid sludge through a sludge collection system; foam drainage water obtained in the middle of the centralized storage tank after oil removal and sedimentation enters a subsequent demulsification coagulation tank.
5. The integrated biochemical treatment method for the foam drainage according to claim 1, wherein the demulsification and coagulation treatment in the step (2) is: placing foam drainage obtained after oil removal settlement in a demulsification coagulation pool, adding a regulator into the demulsification coagulation pool, and stirring for 3-10 minutes; adding a coagulant, and stirring for 3-10 minutes; adding a flocculating agent, and stirring for 3-10 minutes; after stirring, naturally settling for 0.5-12 hours, and taking supernatant for soaking and draining;
the regulator is any one of hydrochloric acid, caustic soda and lime milk, and the pH value of the water is regulated to 6-9; the coagulant is a 10% polyaluminium chloride solution in percentage by mass, and the addition amount of the coagulant is 10-40 ml/L; the flocculant is 1 per mill of polyacrylamide solution in percentage by mass, and the addition amount of the flocculant is 10-30 ml/L.
6. The integrated biochemical treatment method of bubble drainage according to claim 1, wherein the softening and hardness-removing treatment of step (3) is: placing supernatant foam drainage obtained after natural sedimentation in the step (2) into a softening tank, adding a regulator into the softening tank, and stirring for 3-10 minutes; adding a precipitator, and stirring for 3-10 minutes; after stirring, naturally settling for 1-6 hours; supernatant obtained after sedimentation is softened water with the pH value of 6-9, the concentration of calcium and magnesium ions being less than or equal to 1000mg/l, the total salt content being less than or equal to 60000mg/l, the chloride ions being less than or equal to 30000mg/l, the foaming power being more than or equal to 20cm and the COD being less than or equal to 3000 mg/l;
the regulator is lime milk with the mass percentage of 10-20% or sodium hydroxide solution with the mass percentage of 10%, and the adding amount of the regulator is 5-20 ml/L; the precipitator is a sodium carbonate solution with the mass percentage of 10-20%, and the adding amount of the precipitator is 3-60 ml/L.
7. The integrated biochemical treatment method for bubble drainage according to claim 1, wherein the ultrafiltration, nanofiltration and reverse osmosis treatments in step (5) are: conveying supernatant bubble drainage obtained after biochemical treatment and sedimentation tank in the step (4) to an ultrafiltration device for ultrafiltration treatment; and conveying the water produced after ultrafiltration to a nanofiltration device for nanofiltration treatment, conveying the water produced after nanofiltration treatment to a reverse osmosis membrane treatment device for reverse osmosis treatment, and directly meeting the requirements of primary sewage discharge standards.
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