A device and method for removing ammonia nitrogen in wastewater

Abstract

The invention relates to a device and a method for removing ammonia-nitrogen in wastewater. Ammonia is used as a nitrogen source for growth of microalgae. Ammonia-nitrogen in wastewater is removed, and microalgae cell biomass is obtained. By replacing a traditional chemical absorption liquid with a microalgae solution, defects of existing chemical absorption methods can be overcome, operational difficulty is reduced, potential safety hazard is eliminated, a processing device is simplified, and maintenance cost is reduced. By isolating wastewater from a microalgae solution through a membrane contactor, the two solutions can be respectively and separately operated without contacting with each other, defects of existing ammonia-nitrogen removal technologies by the use of microalgae are overcome, noxious materials in wastewater are prevented from inhibiting growth of microalgae, and ammonia-nitrogen removal efficiency is raised. On the other hand, large surface area of the membrane contactor is beneficial to transmembrane transport of ammonia molecules, and ammonia-nitrogen removal rate and processible ammonia-nitrogen concentration are enhanced. By the device, repeated use of microalgae cells during the process of removing ammonia-nitrogen in wastewater can be realized.

Description

technical field [0001] The invention relates to a method for removing ammonia nitrogen in wastewater, in particular to using a membrane contactor to separate ammonia nitrogen in wastewater, and using ammonia as a nitrogen source for promoting the growth of oil-rich microalgae. Microalgal cell biomass was obtained. Background technique [0002] The membrane contactor uses a microporous hollow fiber hydrophobic membrane as a separation medium, allowing only volatile components or gases in the solution on one side of the membrane to pass through the separation membrane, and chemical / physical methods on the other side of the membrane. Gas is collected. Commonly used hollow fiber membrane materials include polypropylene (PP), polyvinylidene fluoride (PVDF), and polytetrafluoroethylene (PTFE). According to the different properties of the two-phase fluid on both sides of the membrane, membrane contactors can be divided into gas-liquid, liquid-gas and liquid-liquid membrane contac...

AI Technical Summary

Problems solved by technology

However, the concentration of ammonia nitrogen that can be treated by this patent is low, only 20ppm; although it can completely remove ammonia nitrogen in sewage, the treatment time is longer (at least 6 days)

In addition, the gel beads formed by sodium alginate and calcium chloride contain other metal ions (such as Mg 2+ ) in sewage, Ca 2+ It will be gradually replaced by other ions (about 2 days), so that the strength of the microalgal balls will decrease, and then rupture

At the same time, the microalgae cells in the ball will continue to divide and grow, affecting the internal structure of the microalgae ball, making it impossible to use repeatedly for a long time

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