Shale gas wastewater treatment method and system

Abstract

The invention discloses a shale gas wastewater treatment method which comprises the following steps: step 1 of separating oil from water in shale gas wastewater; step 2 of performing fenton reaction on wastewater of which waste oil is separated, then adding a coagulant to precipitate, filtering and drying a precipitated solid flocculation product and sending filtered supernate into the next step; step 3 of artificially infiltrating liquid obtained in the step 2 and then filtering sequentially through a walnut shell filter and a modified fiber ball filter, wherein artificially infiltrating is that liquid sequentially passes through filter layers with different particle sizes. A shale gas wastewater treatment system comprises a wastewater collecting tank, an oil partitioning tank, a coagulating, oxidizing and sedimentation basin, an artificial infiltrating tank, a clean water temporary storage tank, the walnut shell filter and the modified fiber ball filter which are sequentially connected. The shale gas wastewater treatment method disclosed by the invention can effectively reduce the concentration of flocculate in the wastewater, the treated wastewater can meet a national related environmental requirement, shale gas exploit water can be directly drained outwards or recycled, and an obvious environment-friendly effect and economical benefit are achieved.

Description

technical field [0001] The invention belongs to the field of environmental protection and relates to wastewater treatment technology, in particular to a shale gas wastewater treatment method and system. Background technique [0002] Shale gas is natural gas extracted from shale formations. The main body is located in dark mud shale or high-carbon mud shale. Shale gas mainly exists in mudstone, high-carbon mudstone, shale and silt in an adsorbed or free state. Natural gas in sandy rock interlayers, which can be generated in various stages of organic origin, exists in free phase (about 50%) in fractures, pores and other storage spaces on the main body of natural gas, and in adsorption state (about 50%) It exists on the surface of kerogen, clay particles and pores, and a very small amount is stored in kerogen, asphaltene and petroleum in a dissolved state. Shale gas exploitation technologies mainly include horizontal well technology, multi-layer fracturing technology, clean wa...

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Problems solved by technology

[0003] The main pollutant of wastewater generated during shale gas exploitation is oil components, but when polymer flooding or fracturing is used, the produced water or fracturing flowback fluid contains a large amount of polymers, which greatly increases the viscosity of wastewater , small oil droplets are encapsulated by a large number of high molecular polymers, forming a large number of flocculated solids, which are difficult to eliminate and clean up in large quantities and quickly to meet the discharge or reuse standards

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