Combined treatment method for shale gas fracturing flowback wastewater

A treatment method and technology for wastewater, applied in water/sewage treatment, oxidized water/sewage treatment, water/sewage multi-stage treatment, etc., can solve the problems of slow reaction speed, fast indirect oxidation reaction speed and high efficiency, and reduce pollution. , the effect of alleviating water shortage

Inactive Publication Date: 2013-12-25
CHONGQING INST OF GEOLOGY & MINERAL RESOURCES +2
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Ozone reacts with organic matter in water mainly in two ways: one is a direct oxidation reaction in which only ozone molecules participate in the degradation of organic matter, which is selective and has a slower reaction speed; the other is the decomposition of ozone molecules under alkaline conditions The highly active and strong oxidizing hydroxyl radicals ( OH ) produced have an indirect oxidation reaction with organic substances in water, and the indirect oxidation reaction is fast, efficient and non-selective

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  • Combined treatment method for shale gas fracturing flowback wastewater

Examples

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Comparison scheme
Effect test

Embodiment 1

[0033] Example 1: Under stirring conditions, a mixture of ferrous sulfate and PFS was dropped into the shale gas fracturing flowback wastewater, the mass ratio of which was 1:1, and the total dosage was 15000mg / L, and the wastewater was adjusted with an alkalizing agent at the same time The pH value is 9.5, then add polymer NSG coagulant 60mg / L, stir rapidly, and stop stirring after a large number of alum flowers are formed; take the effluent after coagulation treatment for electrolytic oxidation treatment, and add ferrous sulfate and Sodium persulfate, its consumption is respectively 4g / L and 5g / L, adjusts the pH value of waste water with alkalizing agent to be 9.0, and the current density of electrolytic oxidation is 50mA / cm 2 , the reaction time is 1.0 hour; carry out secondary coagulation to the wastewater after electrolytic oxidation treatment, add 3000mg / L coagulant ferrous sulfate under stirring conditions, and adjust the pH value of wastewater to 9.0 with an alkalizing ...

Embodiment 2

[0034] Embodiment 2: Under the condition of stirring, drop into the mixture of ferrous sulfate and ferric sulfate in the shale gas fracturing flowback wastewater, its mass ratio is 2:1, the total dosage is 20000mg / L, adjust with alkalizing agent at the same time The pH value of the wastewater is 10.0, then add polyacrylamide coagulant 70mg / L, stir quickly, stop stirring after a large number of alum flowers are formed; take the effluent after coagulation treatment for electrolytic oxidation treatment, and add ferrous sulfate at the same time and sodium persulfate, the dosage is 3g / L and 5g / L respectively, the pH value of wastewater is adjusted to 10.0 with alkalizing agent, and the current density of electrolytic oxidation is 150mA / cm 2 , the reaction time is 1.2 hours; carry out secondary coagulation to the wastewater after electrolytic oxidation treatment, add 4000 mg / L coagulant aluminum sulfate under stirring conditions, and adjust the pH value of the wastewater to 10.0 with...

Embodiment 3

[0035] Example 3: Under stirring conditions, ferrous sulfate was added to the shale gas fracturing flowback wastewater at a dosage of 18,000 mg / L. At the same time, the pH value of the wastewater was adjusted to 9.3 with an alkalizing agent, and then polyacrylamide was added to aid coagulation 65mg / L, stirring quickly, stop stirring after a large amount of alum flowers are formed; take the effluent after coagulation treatment for electrolytic oxidation treatment, and add ferrous sulfate and sodium persulfate at the same time, the dosage is 4g / L and 6g respectively / L, adjust the pH value of wastewater to 9.5 with alkalizing agent, and the current density of electrolytic oxidation is 200mA / cm 2 , the reaction time is 0.8 hours; carry out secondary coagulation to the wastewater after electrolytic oxidation treatment, add 2500 mg / L coagulant ferrous sulfate under stirring conditions, and adjust the pH value of the wastewater to 9.5 with an alkalizing agent at the same time, and th...

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Abstract

The invention relates to a combined treatment method for shale gas fracturing flowback wastewater. The method comprises the following steps that (1) firstly, coagulants, alkalizers and coagulant aids are sequentially added into the shale gas fracturing flowback wastewater for carrying out coagulation treatment; (2) the wastewater subjected to the coagulation treatment is subjected to electrolytic oxidation treatment, meanwhile, ferrous sulfate and persulfate or hydrogen sulfide are added; (3) the wastewater subjected to electrolytic oxidation is subjected to secondary coagulation treatment, and in addition, the coagulants, the alkalizers and the coagulant aids are sequentially added; (4) the wastewater subjected to the secondary coagulation treatment is subjected to ozone deep oxidation, and meanwhile, catalysts are added; and (5) system sedimentation sludge is dewatered by a filter press, filtrate is subjected to ozone deep oxidation treatment, and filter cake is subjected to curing treatment or bioremediation treatment. When the combined treatment method is adopted for treating the shale gas fracturing flowback wastewater, and the outlet water quality can reach first level discharge standards of national sewage comprehensive discharge or reinjection goals. The method belongs to an effective method for treating the shale gas fracturing flowback wastewater.

Description

1. Technical field [0001] The invention relates to a shale gas wastewater treatment technology, in particular to a combined treatment method for shale gas fracturing flowback wastewater. 2. Background technology [0002] Shale gas is mainly located in dark mud shale or high-carbon mud shale, and exists in mudstone, high-carbon mudstone, shale and silty rock in the state of adsorption (about 50%) or free phase (about 50%) In the class mezzanine. Different from conventional reservoir gas pools, shale is not only the source rock for natural gas generation, but also the reservoir and caprock for accumulating and preserving natural gas. The reservoirs of shale gas reservoirs are generally characterized by low porosity, low permeability, and thin thickness. The resistance to gas flow is greater than that of conventional natural gas. Reservoir fracturing is required to achieve effective production. [0003] At present, the most commonly used shale gas fracturing technology is mai...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C02F9/04C02F11/12C02F1/52C02F1/461C02F1/78
Inventor 杨德敏袁建梅
Owner CHONGQING INST OF GEOLOGY & MINERAL RESOURCES
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