CN116891320A - Shale gas exploitation fracturing flow-back wastewater pollutant degradation method - Google Patents

Shale gas exploitation fracturing flow-back wastewater pollutant degradation method Download PDF

Info

Publication number
CN116891320A
CN116891320A CN202310892496.7A CN202310892496A CN116891320A CN 116891320 A CN116891320 A CN 116891320A CN 202310892496 A CN202310892496 A CN 202310892496A CN 116891320 A CN116891320 A CN 116891320A
Authority
CN
China
Prior art keywords
wastewater
reaction vessel
fenton reaction
added
tank
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
CN202310892496.7A
Other languages
Chinese (zh)
Inventor
衡云华
康佑军
徐泸军
徐伟姗
邓婷婷
黄伟聪
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Guangdong Wteya Environmental Technology Co ltd
Original Assignee
Guangdong Wteya Environmental Technology Co ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Guangdong Wteya Environmental Technology Co ltd filed Critical Guangdong Wteya Environmental Technology Co ltd
Priority to CN202310892496.7A priority Critical patent/CN116891320A/en
Publication of CN116891320A publication Critical patent/CN116891320A/en
Pending legal-status Critical Current

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F9/00—Multistage treatment of water, waste water or sewage
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D36/00—Filter circuits or combinations of filters with other separating devices
    • B01D36/04—Combinations of filters with settling tanks
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/30—Treatment of water, waste water, or sewage by irradiation
    • C02F1/32—Treatment of water, waste water, or sewage by irradiation with ultraviolet light
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/52—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities
    • C02F1/54—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities using organic material
    • C02F1/56—Macromolecular compounds
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/66—Treatment of water, waste water, or sewage by neutralisation; pH adjustment
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/72—Treatment of water, waste water, or sewage by oxidation
    • C02F1/722—Oxidation by peroxides
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/72—Treatment of water, waste water, or sewage by oxidation
    • C02F1/725—Treatment of water, waste water, or sewage by oxidation by catalytic oxidation
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F7/00—Aeration of stretches of water
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F2001/007—Processes including a sedimentation step
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2103/00—Nature of the water, waste water, sewage or sludge to be treated
    • C02F2103/10—Nature of the water, waste water, sewage or sludge to be treated from quarries or from mining activities

Landscapes

  • Chemical & Material Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Hydrology & Water Resources (AREA)
  • Engineering & Computer Science (AREA)
  • Environmental & Geological Engineering (AREA)
  • Water Supply & Treatment (AREA)
  • Organic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Health & Medical Sciences (AREA)
  • Toxicology (AREA)
  • Physical Water Treatments (AREA)

Abstract

The application relates to the technical field of sewage treatment, and discloses a method for degrading pollutants in shale gas exploitation fracturing flow-back wastewater, which aims to effectively reduce the treatment cost of high-salt, especially high-chloride ion oil and gas field exploitation wastewater. The pollutant degradation method for the shale gas exploitation fracturing flow-back wastewater can realize pollutant degradation of the shale gas exploitation fracturing flow-back wastewater, the pollutant index of the shale gas exploitation fracturing flow-back wastewater treated by the method meets the emission requirement specified by the water pollutant special emission limit specified in the emission standard (second solicitation opinion manuscript) of the land petroleum gas exploitation industry in Table 2, no toxic and harmful gas is generated in the treatment process, the addition amount of ferrous sulfate in the process can be reduced, the final sludge amount is reduced, and the treatment cost is lower than that of the traditional method due to the combination of UV/Fenton and ECO.

Description

Shale gas exploitation fracturing flow-back wastewater pollutant degradation method
Technical Field
The application relates to the technical field of sewage treatment, in particular to a method for degrading pollutants in shale gas exploitation fracturing flow-back wastewater.
Background
Shale gas is usually mined by adopting a hydraulic fracturing method, a large amount of high-salt flowback wastewater is generated while a large amount of fresh water resources are consumed, and the wastewater also contains various organic matters, oils, volatile phenols and the like, so that the shale gas has strong toxicity and high treatment difficulty. And a large amount of wastewater flows to the ground surface when shale gas back-discharge wastewater adopts gas well back injection. Such wastewater, whether returned to the ground or to the surface, if left untreated, can cause serious contamination of the ground or ground.
For such waste water treatment, methods such as high temperature evaporation are generally employed, which are costly and the evaporated water requires additional treatment. The COD (chemical oxygen demand ) value of the final wastewater is still relatively high by combining treatment and discharge methods such as electric flocculation and the like, and the local discharge standard of each province and city is not met. Traditional biochemical treatment methods are not suitable for such high salt wastewater. The reasonable method for treating the wastewater is to pre-treat the wastewater so as to reduce various pollutants in the wastewater as much as possible, and finally treat the wastewater by combining other methods so as to finally meet the water quality standard of the gas well re-filling water.
How to effectively reduce the treatment cost of the oil and gas field exploitation wastewater of high salt, especially high chloride ion, after treatment, the COD value is as low as possible, and finally, other treatment methods are used to meet the water quality standard of gas well reinjection water, thus the application provides a method for degrading pollutants in shale gas exploitation fracturing reinjection wastewater, which is a world problem in the oil and natural gas exploitation field.
Disclosure of Invention
(one) solving the technical problems
Aiming at the defects of the prior art, the application provides a method for degrading pollutants in shale gas exploitation fracturing flow-back wastewater, which can realize the pollutant degradation of the shale gas exploitation fracturing flow-back wastewater, and the pollutant index of the shale gas exploitation fracturing flow-back wastewater treated by the method meets the emission requirement specified by the water pollutant special emission limit specified in the national petroleum and natural gas exploitation industrial pollutant emission standard (second solicitation opinion manuscript) in Table 2, and no toxic and harmful gas is generated in the treatment process.
(II) technical scheme
In order to achieve the above purpose, the present application provides the following technical solutions: a method for degrading pollutants in shale gas exploitation fracturing flowback wastewater comprises the following steps:
1) After the collecting tank collects enough wastewater, the wastewater is discharged to the dosing tank, after the dosing tank collects enough wastewater, an aeration system is started, enough A is added into the dosing tank after the aeration system is started, and alkali is added into the dosing tank until the pH value of the wastewater in the dosing tank is above 6 after the addition of A is finished;
2) Adding a sufficient amount of PAM into the dosing tank after the alkali is added, and discharging the wastewater in the dosing tank into a primary sedimentation tank after the PAM is added, wherein the residence time of the wastewater in the primary sedimentation tank is 1-10h;
3) After the residence time of the wastewater in the primary sedimentation tank is finished, discharging supernatant to a primary UV/Fenton reaction vessel, and discharging lower sludge into a filter pressing system after the residence time of the wastewater in the primary sedimentation tank is finished;
4) After the first-stage UV/Fenton reaction vessel collects enough wastewater, an aeration system is started, enough ferrous sulfate is added into the first-stage UV/Fenton reaction vessel after the aeration system is started, and sulfuric acid is added into the first-stage UV/Fenton reaction vessel until the pH value of the wastewater in the first-stage UV/Fenton reaction vessel is between 1 and 7 after the addition of the ferrous sulfate is completed;
5) After the sulfuric acid is added, starting a first-stage UV lamp, adding enough hydrogen peroxide into the first-stage UV/Fenton reaction vessel after the first-stage UV lamp is started, and continuously reacting the wastewater in the first-stage UV/Fenton reaction vessel for 1-10h after the hydrogen peroxide in the first-stage UV/Fenton reaction vessel is added;
6) After the reaction time of the wastewater in the UV/Fenton reaction vessel is over, adding enough alkali into the first-stage UV/Fenton reaction vessel until the pH value of the wastewater in the UV/Fenton reaction vessel is between 6 and 12, and turning off the first-stage UV lamp after the residence time of the wastewater in the first-stage UV/Fenton reaction vessel is over;
7) After the primary UV lamp is turned off, the wastewater in the primary UV/Fenton reaction vessel is discharged to an ECO system, after the ECO system collects enough wastewater, an aeration system is turned on, after the aeration system is turned on, the ECO system is turned on, after the ECO system is turned on, the secondary UV lamp is turned on, and the total residence time of the wastewater in the ECO system is 1-24 hours;
8) After the residence time of the wastewater in the ECO system is finished, discharging the wastewater in the ECO system to a secondary UV/Fenton reaction vessel, starting an aeration system after the secondary UV/Fenton reaction vessel collects enough wastewater, starting a tertiary UV lamp system after the aeration system is started, and adding sulfuric acid into the secondary UV/Fenton reaction vessel after the tertiary UV lamp is started for 1-10 hours until the pH value of the wastewater in the secondary UV/Fenton reaction vessel is between 1 and 7;
9) After the sulfuric acid is added, starting a secondary UV lamp, after the tertiary UV lamp is started, adding a sufficient amount of hydrogen peroxide into the secondary UV/Fenton reaction vessel, and after the hydrogen peroxide is added, continuously staying the wastewater in the secondary UV/Fenton reaction vessel for 0.5-5h;
10 After the reaction of the wastewater in the secondary UV/Fenton reaction vessel is finished, the tertiary UV lamp is turned off, sufficient PAC is added into the secondary UV/Fenton reaction vessel after the tertiary UV lamp is turned off, and sufficient alkali is added into the secondary UV/Fenton reaction vessel until the pH value of the wastewater in the secondary UV/Fenton reaction vessel is between 5 and 10 after the PAC is added;
11 Adding a sufficient amount of PAM into the secondary UV/Fenton reaction vessel after the alkali addition in the secondary UV/Fenton reaction vessel is finished, discharging the wastewater in the secondary UV/Fenton reaction vessel to a second sedimentation tank after the PAM addition is finished, and keeping the residence time of the wastewater in the second sedimentation tank for 1-10h;
12 After the residence time of the wastewater in the second sedimentation tank is finished, the supernatant is discharged to a clean water tank, after the residence time of the wastewater in the second sedimentation tank is finished, the lower sludge is discharged to a filter pressing system, the filter pressing system is started after the filter pressing system collects enough sludge, the dry sludge filtered by the filter pressing system is additionally treated, and the clean water filtered by the filter pressing system is discharged to a first-stage UV/Fenton reaction container.
Preferably, the a is an inorganic salt.
Preferably, the pH value of the wastewater in the dosing tank after alkali is added is preferably 9-11, and the retention time of the wastewater in the primary sedimentation tank is preferably 2-4h.
Preferably, the pH value of the primary UV/Fenton reaction vessel after sulfuric acid is added is preferably 2-4, and the reaction time of the wastewater in the primary UV/Fenton reaction vessel is preferably 1-3h.
Preferably, the pH value of the wastewater in the primary UV/Fenton reaction vessel after alkali is added is preferably 9-11, and the residence time of the wastewater in the ECO system is preferably 2-5h.
Preferably, the pH value of the wastewater in the secondary UV/Fenton reaction vessel after sulfuric acid is added is preferably 2-5, and the total residence time of the wastewater in the secondary UV/Fenton reaction vessel is preferably 1.5-5h.
Preferably, the preferred value of the pH value of the wastewater after alkali is added into the secondary UV/Fenton reaction vessel is between 6 and 9, and the preferred value of the residence time of the wastewater in the second sedimentation tank is between 2 and 4 hours.
Another technical problem to be solved by the present application is to provide a system for implementing the above method, comprising a pretreatment system, a primary UV/Fenton treatment system, an ECO/UV treatment system, and a secondary UV/Fenton treatment system;
the pretreatment system comprises an aeration system, a collecting tank, an A storing tank, an alkali storing tank, a PAM (polyacrylamide) storing tank, a dosing tank, a first sedimentation tank and a filter pressing system;
the primary UV/Fenton treatment system comprises a ferrous sulfate storage tank, a sulfuric acid storage tank, a hydrogen peroxide storage tank, a primary UV/Fenton reaction container, a primary UV lamp and a filter pressing system;
the ECO/UV treatment system comprises an ECO system, a secondary UV lamp and a PAC storage tank;
the secondary UV/Fenton treatment system comprises a secondary UV/Fenton reaction vessel, a tertiary UV lamp, a PAC storage tank, an alkali storage tank, a PAM storage tank, a second sedimentation tank, a filter pressing system and a clean water tank.
(III) beneficial effects
Compared with the prior art, the application provides a method for degrading pollutants in shale gas exploitation fracturing flow-back wastewater, which has the following beneficial effects:
1. the treated wastewater has lower pollutant content, and can directly meet the discharge requirement specified by the special discharge limit of water pollutants specified in the discharge standard (second solicitation opinion manuscript) of the industrial pollutant emission of land petroleum and natural gas production, which is specified in the table 2;
2. the treatment cost is lower than that of the traditional method due to the combination of UV/Fenton and ECO;
3. because the shale gas exploitation wastewater has high salt content, the catalyst is prevented from being newly added in the ECO process, so that the treatment cost is reduced, the salt content in the wastewater is prevented from being newly added, the addition amount of ferrous sulfate in the process can be reduced by introducing the UV/Fenton method, and the final sludge amount is further reduced.
Drawings
FIG. 1 is a schematic flow chart of the present application.
Detailed Description
The technical solutions of the embodiments of the present application will be clearly and completely described below in conjunction with the embodiments of the present application, and it is apparent that the described embodiments are only some embodiments of the present application, not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the application without making any inventive effort, are intended to be within the scope of the application.
Referring to fig. 1, the application provides a method for degrading pollutants in shale gas exploitation fracturing flow-back wastewater, which aims to effectively reduce the treatment cost of high-salt, especially high-chloride ion oil and gas field exploitation wastewater, and the whole treatment process comprises pretreatment, primary UV/Fenton treatment, ECO/UV treatment and secondary UV/Fenton treatment.
In the pretreatment process, enough wastewater is collected by a collecting tank, the wastewater is discharged to a dosing tank, after the enough wastewater is collected by the dosing tank, an aeration system is started, enough A is added into the dosing tank after the aeration system is started, alkali is added into the dosing tank until the pH value of the wastewater in the dosing tank is above 6, and preferably, the pH value of the wastewater in the dosing tank after the alkali is added is preferably between 9 and 11.
It should be noted that a is a non-toxic, harmless, cheap and easily available inorganic salt, and does not negatively affect the wastewater treatment process, and a does not add pollutants after wastewater treatment.
After the alkali is added, adding a sufficient amount of PAM into the dosing tank, discharging the wastewater in the dosing tank to a primary sedimentation tank after the addition of the PAM is finished, wherein the retention time of the wastewater in the primary sedimentation tank is 1-10h, preferably, the retention time of the wastewater in the primary sedimentation tank is 2-4h.
In the primary UV/Fenton treatment process, after the residence time of the wastewater in the primary sedimentation tank is finished, the supernatant is discharged to the primary UV/Fenton reaction vessel, after the residence time of the wastewater in the primary sedimentation tank is finished, the lower sludge is discharged to the filter pressing system, after the primary UV/Fenton reaction vessel collects enough wastewater, an aeration system is started, sufficient ferrous sulfate is added into the primary UV/Fenton reaction vessel after the aeration system is started, sulfuric acid is added into the primary UV/Fenton reaction vessel until the pH value of the wastewater in the primary UV/Fenton reaction vessel is between 1 and 7, and preferably, the pH value of the wastewater after sulfuric acid is added into the primary UV/Fenton reaction vessel is between 2 and 4.
After the sulfuric acid is added, a first-stage UV lamp is started, enough hydrogen peroxide is added into the first-stage UV/Fenton reaction vessel after the first-stage UV lamp is started, the mass percentage content of the hydrogen peroxide is 27.5%, after the hydrogen peroxide is added into the first-stage UV/Fenton reaction vessel, the wastewater continuously reacts for 1-10h in the first-stage UV/Fenton reaction vessel, and the optimal value of the reaction time of the wastewater in the first-stage UV/Fenton reaction vessel is 1-3h.
After the reaction time of the wastewater in the UV/Fenton reaction vessel is over, adding enough alkali into the primary UV/Fenton reaction vessel until the pH value of the wastewater in the UV/Fenton reaction vessel is between 6 and 12, and after the residence time of the wastewater in the primary UV/Fenton reaction vessel is over, turning off the primary UV lamp, wherein the pH value of the wastewater in the primary UV/Fenton reaction vessel after adding alkali is preferably between 9 and 11.
In the ECO/UV treatment process, after the primary UV lamp is turned off, the waste water in the primary UV/Fenton reaction vessel is discharged to an ECO system, after the ECO system collects enough waste water, an aeration system is turned on, after the aeration system is turned on, the ECO system is turned on, after the ECO system is turned on, the secondary UV lamp is turned on, the total residence time of the waste water in the ECO system is 1-24h, preferably, the preferable residence time of the waste water in the ECO system is 2-5h.
After the residence time of the wastewater in the ECO system is finished, performing secondary UV/Fenton treatment, specifically, discharging the wastewater in the ECO system to a secondary UV/Fenton reaction vessel, starting an aeration system after the secondary UV/Fenton reaction vessel collects enough wastewater, starting a tertiary UV lamp system after the aeration system is started, and adding sulfuric acid into the secondary UV/Fenton reaction vessel after the tertiary UV lamp is started for 1-10h until the pH value of the wastewater in the secondary UV/Fenton reaction vessel is 1-7, wherein the preferable pH value of the wastewater in the secondary UV/Fenton reaction vessel after sulfuric acid is added is 2-5.
After the sulfuric acid is added, a secondary UV lamp is started, after the tertiary UV lamp is started, a sufficient amount of hydrogen peroxide is added into the secondary UV/Fenton reaction vessel, after the hydrogen peroxide is added, the wastewater continuously stays in the secondary UV/Fenton reaction vessel for 0.5-5h, preferably, the preferable value of the total residence time of the wastewater in the secondary UV/Fenton reaction vessel is 1.5-5h, after the wastewater is reacted in the secondary UV/Fenton reaction vessel, the tertiary UV lamp is turned off, after the tertiary UV lamp is turned off, a sufficient amount of PAC is added into the secondary UV/Fenton reaction vessel, after PAC is added, a sufficient amount of alkali is added into the secondary UV/Fenton reaction vessel until the pH value of the wastewater in the secondary UV/Fenton reaction vessel is 5-10, preferably, the preferable value of the pH value of the wastewater after alkali is added into the secondary UV/Fenton reaction vessel is 6-9.
After alkali addition in the secondary UV/Fenton reaction vessel is finished, adding a sufficient amount of PAM in the secondary UV/Fenton reaction vessel, discharging waste water in the secondary UV/Fenton reaction vessel to a second sedimentation tank after the PAM addition is finished, wherein the retention time of the waste water in the second sedimentation tank is 1-10h, preferably, the retention time of the waste water in the second sedimentation tank is 2-4h, the supernatant fluid is discharged to a clean water tank after the retention time of the waste water in the second sedimentation tank is finished, the lower sludge is discharged to a filter pressing system after the retention time of the waste water in the second sedimentation tank is finished, the filter pressing system is started after collecting enough sludge, the dry sludge filtered by the filter pressing system is additionally treated, and clear water filtered by the filter pressing system is discharged to the primary UV/Fenton reaction vessel.
The application also provides a system for implementing the method, which comprises a pretreatment system, a primary UV/Fenton treatment system, an ECO/UV treatment system and a secondary UV/Fenton treatment system.
Wherein, the pretreatment system comprises an aeration system, a collecting tank, an A storing tank, an alkali storing tank, a PAM (PAM) storing tank, a dosing tank, a first sedimentation tank and a filter pressing system; the primary UV/Fenton treatment system comprises a ferrous sulfate storage tank, a sulfuric acid storage tank, a hydrogen peroxide storage tank, a primary UV/Fenton reaction vessel, a primary UV lamp and a filter pressing system; the ECO/UV treatment system comprises an ECO system, a secondary UV lamp and a PAC storage pool; the secondary UV/Fenton treatment system comprises a secondary UV/Fenton reaction vessel, a tertiary UV lamp, a PAC storage tank, an alkali storage tank, a PAM storage tank, a second sedimentation tank, a filter pressing system and a clean water tank.
The method and the system for degrading pollutants in the shale gas exploitation fracturing flowback wastewater can realize the pollutant degradation of the shale gas exploitation fracturing flowback wastewater, and the pollutant index of the shale gas exploitation fracturing flowback wastewater treated by the method or the system meets the emission requirement specified by the water pollutant special emission limit value specified in the emission standard (second solicitation opinion manuscript) of the land petroleum and natural gas exploitation industry pollutant emission standard (Table 2), and no toxic and harmful gas is generated in the treatment process.
Experimental example:
certain shale gas project of China petrochemical Yuxi, and the daily water production of shale gas well is about 100m 3 The effective volume of the collecting tank is 10m 3 The effective volume of the first-stage UV/Fenton reaction vessel is 10m 3 The effective volume of the secondary UV/Fenton reaction vessel is 10m 3 The throughput of the ECO system was 10m 3 And/2 h, the power of the primary UV lamp system is 1.6kW, the power of the secondary UV lamp system is 1.2kW, and the power of the secondary UV lamp system is 3.2kW.
Each part needing sampling analysis in the processing system is automatically sampled and analyzed by an online monitoring system, and the part needing medicine adding in the system is automatically calculated and controlled to be added by an automatic control system according to the data transmitted by the online monitoring system.
The treatment process is as follows:
(1) After the collecting tank collects enough wastewater, the wastewater is discharged to the dosing tank, after the dosing tank collects enough wastewater, an aeration system is started, enough A is added into the dosing tank after the aeration system is started, and alkali is added into the dosing tank until the pH value of the wastewater in the dosing tank is above 6 after the addition of A is finished;
(2) Adding a sufficient amount of PAM into a dosing tank after the alkali is added, discharging wastewater in the dosing tank to a primary sedimentation tank after the PAM is added, wherein the retention time of the wastewater in the primary sedimentation tank is 2 hours, discharging supernatant to a primary UV/Fenton reaction vessel after the retention time of the wastewater in the primary sedimentation tank is finished, and discharging lower sludge into a filter pressing system after the retention time of the wastewater in the primary sedimentation tank is finished;
(3) After the first-stage UV/Fenton reaction vessel collects enough wastewater, an aeration system is started, 2.4kg of ferrous sulfate is added into the first-stage UV/Fenton reaction vessel after the aeration system is started, and sulfuric acid is added into the first-stage UV/Fenton reaction vessel until the pH value of the wastewater in the first-stage UV/Fenton reaction vessel is between 3 and 4 after the addition of ferrous sulfate is completed;
(4) After the sulfuric acid is added, starting a primary UV lamp, after the primary UV lamp is started, adding 223L of hydrogen peroxide with the mass content of 27.5% into a primary UV/Fenton reaction container, and after the hydrogen peroxide is added into the primary UV/Fenton reaction container, continuously reacting the wastewater in the primary UV/Fenton reaction container for 1.5 hours;
(5) After the reaction time of the wastewater in the UV/Fenton reaction vessel is over, adding enough alkali into the first-stage UV/Fenton reaction vessel until the pH value of the wastewater in the UV/Fenton reaction vessel is between 9 and 11, wherein the total residence time of the wastewater in the first-stage UV/Fenton reaction vessel is 2 hours;
(6) After the retention time of the wastewater in the first-stage UV/Fenton reaction vessel is over, turning off the first-stage UV lamp, and after the first-stage UV lamp is turned off, discharging the wastewater in the first-stage UV/Fenton reaction vessel to an ECO system;
(7) After the ECO system collects enough wastewater, an aeration system is started, after the aeration system is started, the ECO system is started, and after the ECO system is started, a secondary UV lamp is started, wherein the total residence time of the wastewater in the ECO system is 2 hours;
(8) After the residence time of the wastewater in the ECO system is over, the wastewater in the ECO system is discharged to a secondary UV/Fenton reaction container, an aeration system is started after the secondary UV/Fenton reaction container collects enough wastewater, and a tertiary UV lamp system is started after the aeration system is started;
(9) After the wastewater is irradiated in a three-stage UV lamp system for 2 hours, sulfuric acid is added into a second-stage UV/Fenton reaction vessel until the pH value of the wastewater in the second-stage UV/Fenton reaction vessel is 3-4, after the sulfuric acid is added, a three-stage UV lamp is started, and after the three-stage UV lamp is started, hydrogen peroxide 42L with the mass content of 27.5% is added into the second-stage UV/Fenton reaction vessel;
(10) After the hydrogen peroxide is added, the wastewater reacts in the secondary UV/Fenton reaction vessel for 1.5 hours, after the wastewater reacts in the secondary UV/Fenton reaction vessel, the tertiary UV lamp is turned off, after the tertiary UV lamp is turned off, sufficient PAC is added in the secondary UV/Fenton reaction vessel, and after the PAC is added, sufficient alkali is added in the secondary UV/Fenton reaction vessel until the pH value of the wastewater in the secondary UV/Fenton reaction vessel is between 6 and 9;
(11) After the alkali in the second-stage UV/Fenton reaction vessel is completely added, adding a sufficient amount of PAM in the second-stage UV/Fenton reaction vessel, discharging the wastewater in the second-stage UV/Fenton reaction vessel to a second sedimentation tank after the PAM is completely added, and keeping the wastewater in the second sedimentation tank for 2 hours;
(12) After the residence time of the wastewater in the second sedimentation tank is finished, the supernatant is discharged to a clean water tank, after the residence time of the wastewater in the second sedimentation tank is finished, the lower sludge is discharged to a filter pressing system, the filter pressing system is started after enough sludge is collected by the filter pressing system, the dry sludge filtered out by the filter pressing system is additionally treated, and the clean water filtered out by the filter pressing system is discharged to a first-stage UV/Fenton reaction container.
The wastewater in the clean water tank is analyzed and measured to determine the content of main pollutants, and the specific results are shown in the following table 1:
TABLE 1 COD before and after wastewater treatment 1，2 Value change
1 Chlorine correction method for measuring chemical oxygen demand of high chlorine wastewater (HJ/T70-2001)
2 Determination of the chemical oxygen demand of high chlorine wastewater Potassium iodide alkaline Potassium permanganate method (HJ/T132-2003)
According to measurement, the COD value of the wastewater in the clean water tank meets the limit requirement that the COD value specified in the table 2 is not higher than 60mg/L in the discharge standard (second solicitation opinion manuscript) of industrial pollutants for land petroleum and natural gas exploitation, and meets the requirement that the COD value of IV-class water quality specified in the table 1 is not higher than 30mg/L in the quality standard (GB 3838-2002) of surface water environment.
Although embodiments of the present application have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made therein without departing from the principles and spirit of the application, the scope of which is defined in the appended claims and their equivalents.

Claims (8)

1. The method for degrading pollutants in the shale gas exploitation fracturing flow-back wastewater is characterized by comprising the following steps of:
1) After the collecting tank collects enough wastewater, the wastewater is discharged to the dosing tank, after the dosing tank collects enough wastewater, an aeration system is started, enough A is added into the dosing tank after the aeration system is started, and alkali is added into the dosing tank until the pH value of the wastewater in the dosing tank is above 6 after the addition of A is finished;
2) Adding a sufficient amount of PAM into the dosing tank after the alkali is added, and discharging the wastewater in the dosing tank into a primary sedimentation tank after the PAM is added, wherein the residence time of the wastewater in the primary sedimentation tank is 1-10h;
3) After the residence time of the wastewater in the primary sedimentation tank is finished, discharging supernatant to a primary UV/Fenton reaction vessel, and discharging lower sludge into a filter pressing system after the residence time of the wastewater in the primary sedimentation tank is finished;
4) After the first-stage UV/Fenton reaction vessel collects enough wastewater, an aeration system is started, enough ferrous sulfate is added into the first-stage UV/Fenton reaction vessel after the aeration system is started, and sulfuric acid is added into the first-stage UV/Fenton reaction vessel until the pH value of the wastewater in the first-stage UV/Fenton reaction vessel is between 1 and 7 after the addition of the ferrous sulfate is completed;
5) After the sulfuric acid is added, starting a first-stage UV lamp, adding enough hydrogen peroxide into the first-stage UV/Fenton reaction vessel after the first-stage UV lamp is started, and continuously reacting the wastewater in the first-stage UV/Fenton reaction vessel for 1-10h after the hydrogen peroxide in the first-stage UV/Fenton reaction vessel is added;
6) After the reaction time of the wastewater in the UV/Fenton reaction vessel is over, adding enough alkali into the first-stage UV/Fenton reaction vessel until the pH value of the wastewater in the UV/Fenton reaction vessel is between 6 and 12, and turning off the first-stage UV lamp after the residence time of the wastewater in the first-stage UV/Fenton reaction vessel is over;
7) After the primary UV lamp is turned off, the wastewater in the primary UV/Fenton reaction vessel is discharged to an ECO system, after the ECO system collects enough wastewater, an aeration system is turned on, after the aeration system is turned on, the ECO system is turned on, after the ECO system is turned on, the secondary UV lamp is turned on, and the total residence time of the wastewater in the ECO system is 1-24 hours;
8) After the residence time of the wastewater in the ECO system is finished, discharging the wastewater in the ECO system to a secondary UV/Fenton reaction vessel, starting an aeration system after the secondary UV/Fenton reaction vessel collects enough wastewater, starting a tertiary UV lamp system after the aeration system is started, and adding sulfuric acid into the secondary UV/Fenton reaction vessel after the tertiary UV lamp is started for 1-10 hours until the pH value of the wastewater in the secondary UV/Fenton reaction vessel is between 1 and 7;
9) After the sulfuric acid is added, starting a secondary UV lamp, after the tertiary UV lamp is started, adding a sufficient amount of hydrogen peroxide into the secondary UV/Fenton reaction vessel, and after the hydrogen peroxide is added, continuously staying the wastewater in the secondary UV/Fenton reaction vessel for 0.5-5h;
10 After the reaction of the wastewater in the secondary UV/Fenton reaction vessel is finished, the tertiary UV lamp is turned off, sufficient PAC is added into the secondary UV/Fenton reaction vessel after the tertiary UV lamp is turned off, and sufficient alkali is added into the secondary UV/Fenton reaction vessel until the pH value of the wastewater in the secondary UV/Fenton reaction vessel is between 5 and 10 after the PAC is added;
11 Adding a sufficient amount of PAM into the secondary UV/Fenton reaction vessel after the alkali addition in the secondary UV/Fenton reaction vessel is finished, discharging the wastewater in the secondary UV/Fenton reaction vessel to a second sedimentation tank after the PAM addition is finished, and keeping the residence time of the wastewater in the second sedimentation tank for 1-10h;
12 After the residence time of the wastewater in the second sedimentation tank is finished, the supernatant is discharged to a clean water tank, after the residence time of the wastewater in the second sedimentation tank is finished, the lower sludge is discharged to a filter pressing system, the filter pressing system is started after the filter pressing system collects enough sludge, the dry sludge filtered by the filter pressing system is additionally treated, and the clean water filtered by the filter pressing system is discharged to a first-stage UV/Fenton reaction container.
2. The method for degrading pollutants in shale gas recovery fracturing flow-back wastewater of claim 1, wherein a is an inorganic salt.
3. The method for degrading pollutants in shale gas exploitation fracturing flow-back wastewater, which is characterized in that the pH value of the wastewater in the dosing tank after alkali is added is preferably 9-11, and the retention time of the wastewater in the primary sedimentation tank is preferably 2-4h.
4. The method for degrading pollutants in shale gas exploitation fracturing flow-back wastewater, which is characterized in that the pH value of the primary UV/Fenton reaction vessel after sulfuric acid is added is preferably 2-4, and the reaction time of the wastewater in the primary UV/Fenton reaction vessel is preferably 1-3h.
5. The method for degrading pollutants in shale gas exploitation fracturing flow-back wastewater, which is characterized in that the pH value of the wastewater in the primary UV/Fenton reaction vessel after alkali is added is preferably 9-11, and the retention time of the wastewater in the ECO system is preferably 2-5h.
6. The method for degrading pollutants in shale gas exploitation fracturing flow-back wastewater, which is characterized in that the pH value of the wastewater in the secondary UV/Fenton reaction vessel after sulfuric acid is added is preferably 2-5, and the total time of the wastewater in the secondary UV/Fenton reaction vessel is preferably 1.5-5h.
7. The method for degrading pollutants in shale gas exploitation fracturing flow-back wastewater, which is characterized in that the preferred value of the pH value of the wastewater after alkali is added in the secondary UV/Fenton reaction vessel is between 6 and 9, and the preferred value of the residence time of the wastewater in the second sedimentation tank is between 2 and 4 hours.
8. A system for carrying out the method of any one of claims 1 to 7, comprising a pretreatment system, a primary UV/Fenton treatment system, an ECO/UV treatment system, and a secondary UV/Fenton treatment system;
the pretreatment system comprises an aeration system, a collecting tank, an A storing tank, an alkali storing tank, a PAM (polyacrylamide) storing tank, a dosing tank, a first sedimentation tank and a filter pressing system;
the primary UV/Fenton treatment system comprises a ferrous sulfate storage tank, a sulfuric acid storage tank, hydrogen peroxide storage, a primary UV/Fenton reaction vessel, a primary UV lamp and a filter pressing system;
the ECO/UV treatment system comprises an ECO system, a secondary UV lamp and a PAC storage tank;
the secondary UV/Fenton treatment system comprises a secondary UV/Fenton reaction vessel, a tertiary UV lamp, a PAC storage tank, an alkali storage tank, a PAM storage tank, a second sedimentation tank, a filter pressing system and a clean water tank.
CN202310892496.7A 2023-07-20 2023-07-20 Shale gas exploitation fracturing flow-back wastewater pollutant degradation method Pending CN116891320A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202310892496.7A CN116891320A (en) 2023-07-20 2023-07-20 Shale gas exploitation fracturing flow-back wastewater pollutant degradation method

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202310892496.7A CN116891320A (en) 2023-07-20 2023-07-20 Shale gas exploitation fracturing flow-back wastewater pollutant degradation method

Publications (1)

Publication Number Publication Date
CN116891320A true CN116891320A (en) 2023-10-17

Family

ID=88310520

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202310892496.7A Pending CN116891320A (en) 2023-07-20 2023-07-20 Shale gas exploitation fracturing flow-back wastewater pollutant degradation method

Country Status (1)

Country Link
CN (1) CN116891320A (en)

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103787551A (en) * 2014-01-26 2014-05-14 广东威迪科技股份有限公司 Treatment method of printing ink wastewater generated in circuit board production
CN208883638U (en) * 2018-08-17 2019-05-21 广州市勃发环境科技有限公司 The system of PVA in a kind of degrading waste water
CN110040911A (en) * 2019-05-06 2019-07-23 孙鹏 A kind of processing method of cupric dyeing waste water with high salt
CN114906962A (en) * 2022-06-24 2022-08-16 深圳市清源宝科技有限公司 Photoelectric synergistic catalytic oxidation treatment system and method for high-concentration organic wastewater

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103787551A (en) * 2014-01-26 2014-05-14 广东威迪科技股份有限公司 Treatment method of printing ink wastewater generated in circuit board production
CN208883638U (en) * 2018-08-17 2019-05-21 广州市勃发环境科技有限公司 The system of PVA in a kind of degrading waste water
CN110040911A (en) * 2019-05-06 2019-07-23 孙鹏 A kind of processing method of cupric dyeing waste water with high salt
CN114906962A (en) * 2022-06-24 2022-08-16 深圳市清源宝科技有限公司 Photoelectric synergistic catalytic oxidation treatment system and method for high-concentration organic wastewater

Similar Documents

Publication Publication Date Title
Hashim et al. Effect of initial pH value on the removal of reactive black dye from water by electrocoagulation (EC) method
CN101817617B (en) Comprehensive treatment process for coking wastewater
CN103011347B (en) Method for carrying out electrolytic treatment on copper-containing electroplating wastewater and recycling copper
CN104445733A (en) Technology for removing thallium with lead and zinc smelting flue gas washing waste acid water
CN110921954A (en) Method and system for treating oilfield wastewater by combining iron-carbon micro-electrolysis and Fenton oxidation
US20130112617A1 (en) Redox wastewater biological nutrient removal treatment method
US20130153509A1 (en) Wastewater treatment comprising electrodissolution, flocculation and oxidation
CN107381892A (en) A kind of handling process of high-concentration ammonia nitrogenous wastewater
CN106219806A (en) A kind of processing method of heavy metal wastewater thereby
CN111470729A (en) Garbage leachate treatment system and method for garbage incineration power plant
CN112960819A (en) Double oxidation-electrochemical oxidation combined process for advanced treatment of landfill leachate
Sharma et al. A comparison of the sorbtive characteristics of leaf mould and activated carbon columns for the removal of hexavalent chromium
CN102344225A (en) Processing method of salty wastewater in cellulose ether production
CN111995181B (en) Treatment method of photovoltaic industrial wastewater
CN112919709A (en) Process for treating high-salt high-concentration organic wastewater
CN110550780B (en) Method for treating desulfurization wastewater of thermal power plant based on pretreatment and double-membrane method
CN116891320A (en) Shale gas exploitation fracturing flow-back wastewater pollutant degradation method
CN104556510B (en) Copper-containing wastewater recovery and processing system and copper-containing wastewater recovery and treatment method
Xu et al. Electrocoagulation: a new approach for the removal of boron containing wastes
CN113087295B (en) Shale gas fracturing flowback fluid standard discharge treatment process method and system
CN212356935U (en) Garbage leachate treatment system of garbage incineration power plant
CN111807496B (en) Method for deeply treating oil refining wastewater by using copper slag to activate persulfate
CN112919728A (en) Blue algae mud pressure filtrate treatment method
Vieira et al. Degradation potential and growth of anaerobic bacteria in produced water
CN111470622A (en) Method and device for treating nitrate nitrogen in high-concentration sulfate wastewater

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination