Method for processing oilfield wastewater and fixing CO2 (carbon dioxide) by using microalgae

Abstract

The invention provides a method for processing oilfield wastewater and fixing CO2 (carbon dioxide) by using microalgae; the method comprises the following steps of: using oilfield wastewater in which the crude oil content is lower than 10mg / L, the TOC (total organic carbon) is lower than 40mg / L and the COD (chemical oxygen demand) is lower than 100mg / L for microalgae cultivation and carbon fixing, introducing CO2 directly into the wastewater, selecting the microalgae with high stress resistance, high oil content and high function in degrading petroleum hydrocarbon according to the water quality of the oilfield wastewater introduced with the CO2, combining the large-scale cultivation of the microalgae with the wastewater treatment, building a large-scale cultivation system by using five stepped microalgae processing ponds which are connected with each other, and then adjusting the water temperature to be 20 DEG C to 35 DEG C; a silicon carbide micro-filtration membrane is used for harvesting, and 10-20% of the harvested microalgae is used as algae seed for the algae liquid cultivation of the next batch and 70-90% of the harvested microalgae is used for preparing biodiesel. The wastewater temperature which is the most proper for the growth of the algae is controlled by controlling the content of fresh wastewater, and the full-year stable and continuous running of the oilfield wastewater processing and CO2 fixing system is achieved.

Description

Technical field [0001] The invention belongs to the field of sewage treatment technology and new-born material energy, and particularly relates to a method of using microalgae to treat oilfield sewage and fix CO 2 Methods. Background technique [0002] The greenhouse effect is the biggest environmental problem facing all mankind in the 21st century. Industrial development leads to large amounts of CO 2 Discharged into the atmosphere, only the maximum absorption and conversion of CO 2 In order to coordinate economic development and environmental issues. Current CO 2 The fixed emission reduction technologies can be divided into three categories: physical treatment, chemical treatment and biological fixation. Among them, in the biological fixation method, microalgae can use CO under photosynthesis. 2 Synthesize a large number of biological substances, such as protein, starch, vitamins and lipids. And microalgae have the advantages of high photosynthesis rate, fast reproduction, st...

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Problems solved by technology

[0004] CO using microalgae 2 Although gas fixed emission reduction has become increasingly mature in theory, and many enterprises and institutions have also carried out beneficial attempts, there are still many difficulties in realizing large-scale application, mainly because of the high cost and the limitation of large-scale breeding technology. immature

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