Method for purifying undiluted anaerobic fermentation tail liquid by growing microalgae in carbon dioxide environment

Abstract

The invention relates to purification of organic pollutants in wastewater, and provides a method for purifying undiluted anaerobic fermentation tail liquid by growing microalgae in a carbon dioxide environment. The method comprises the steps of centrifuging the anaerobic fermentation tail liquid, taking supernate as the tail liquid raw material, sterilizing the tail liquid raw material, regulating the pH value of the tail liquid raw material, and then conducting alga species inoculation; controlling temperature and illumination, and introducing carbon dioxide to the inoculated tail liquid raw material for 7-14 days of culture; obtaining microalgae biomass through centrifugal separation after microalgae culture is ended, so that purification of the anaerobic fermentation tail liquid is achieved. Optimal regulation is achieved by growing microalgae in the high-concentration carbon dioxide environment, anaerobic fermentation tail liquid purification and microalgae growth are combined, and organic pollutants in the undiluted pig manure anaerobic fermentation tail liquid can be effectively purified.

Description

technical field [0001] The invention relates to the field of purifying waste water organic pollutants, in particular to a method for purifying undiluted anaerobic fermentation tail liquid by growing microalgae under carbon dioxide. Background technique [0002] Biogas production by anaerobic fermentation is a widely used technology in rural areas, providing people with cheap and clean fuel. The by-products of fermentation, biogas slurry and residue, are usually discharged directly into water bodies or landfilled. The biogas fermentation process can remove a large amount of soluble organic matter in raw materials, but inorganic components such as ammonia nitrogen cannot be effectively removed (Parketal., 2010), and the tail liquid after fermentation still contains high COD, total nitrogen, total phosphorus and a large number of microorganisms , if discharged directly, it will cause eutrophication of water body and cause secondary pollution (Parketal., 2010). Large and mediu...

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Problems solved by technology

[0006] Due to the high turbidity of the high-concentration anaerobic fermentation tail liquid is not conducive to the progress of photosynthesis, and the high ammonia nitrogen content is also toxic to a certain extent, the direct cultivation of microalgae without dilution is likely to inhibit the growth of algae, so large Most studies use wastewater that has been diluted to varying degrees, and dilution of wastewater means that the amount of wastewater to be treated increases and the volume of the reactor required increases, which is not conducive to engineering applications

[0007] In order to solve the problem of tail liquid discharge after biogas fermentation and the cost of microalgae cultivation, a method that can not only purify the tail liquid but also obtain higher biomass quality of microalgae has broad application prospects

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