Salt-resistant polymer-containing oily sewage treatment process

Abstract

The invention provides a salt-resistant polymer-containing oily sewage treatment process and relates to the technical field of oilfield sewage treatment. A main process successively includes: an air-floatation process; an advanced oxidization treatment process, wherein the sewage enters from the top, flows out from the lower part and ozone gas enters from the lower part and is in reverse contact with liquid. , and meanwhile, under the action of a concentric-square-shaped partition plate, the hydraulic retention time is prolonged, the contact area of ozone and the liquid is increased, and the oxidation effect is improved; a microbiological treatment process; and an MBR biological reaction process. . Oil and water are separated by utilizing a flotation technology, and the advanced oxidationtreatment process section is mainly used for deep degradation of organic pollutants in salt-resistant polymer-containing oily sewage; therefore, the viscosity of raw water is effectively reduced, residual emulsified oil removed by a microbiological treatment process, MBR biological reaction process effluent suspended solids and turbidity are almost zero, the treated water quality is good and stable. According to the invention, it is guaranteed that the effluent quality meets the requirements of oilfield low-permeability reservoir reinjection water standards or redistribution standards.

Description

Technical field: [0001] The invention relates to the technical field of oilfield sewage treatment, in particular to a process for treating salt-resistant, poly-containing and oily sewage. Background technique: [0002] A commonly used technological process for reinjection water biological treatment of oily and polymer-containing sewage in oilfields is: oilfield produced water → subsidence air flotation → biological treatment → solid-liquid separation → primary filtration → reinjection. In recent years, polymer flooding in oilfields has gradually begun to be used Salt-resistant polymer flooding, salt-resistant polymers are added salt-resistant functional groups to the original ordinary polymer chains, mainly sulfonic acid groups, and the polymer can reach a molecular weight of 25 million, forming a structure similar to that containing polymers and A kind of water quality situation of the binary sewage of the surfactant, the polymer after adding the anti-salt group can use the...

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Problems solved by technology

[0002] A commonly used technological process for reinjection water biological treatment of oily and polymer-containing sewage in oilfields is: oilfield produced water → subsidence air flotation → biological treatment → solid-liquid separation → primary filtration → reinjection. In recent years, polymer flooding in oilfields has gradually begun to be used Salt-resistant polymer flooding, salt-resistant polymers are added salt-resistant functional groups to the original ordinary polymer chains, mainly sulfonic acid groups, and the polymer can reach a molecular weight of 25 million, forming a structure similar to that containing polymers and A kind of water quality situation of the binary sewage of the surfactant, the polymer after adding the anti-salt group can use the sulfonic acid group to capture a large amount of calcium and magnesium ions in the combined water, and reduce the hydroxyl group on the polymer that plays a role in viscosity Therefore, the use of salt-resistant polymer formulations can be used for sewage mixing, reducing the impact of salinity on viscosity loss, but also increasing demulsification. and the difficulty of flocculation of suspended solids. It is difficult to meet the "5.5.2" water quality index required by oilfield reflooding and utilization by using the existing biological process to treat the oily and polymeric sewage produced by salt-resistant polymer flooding.

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