I will be conducting an experiment to see if wastewater can be treated using various chemicals. I want to know how can I prevent oxygen from interfering with my experiment. I tried searching various methods to remove oxygen from a sample, and some of the techniques include Nitrogen purging, boiling at 1 atm, boiling under reduced pressure, and sonication under reduced pressure.

I'm aware that nitrogen purging is the best method but I do not have a nitrogen cylinder in the lab and want to know any alternatives to this.

Any help is appreciated.