The present work attempts to solve pollution problems in watery surroundings by aromatic compounds such as the phenol and the benzoic acid. Several ways of elimination of these compounds were the object of different research among which is the use of bacteria. In this framework, Pseudomonas aeruginosa bacterium is used to eliminate phenol and the benzoic acid. This made it possible to isolate the Pseudomonas aeruginosa bacterium directly on the nourishing environment containing phenol and benzoic acid as source of energy then the bacteria is incubated at 37℃ during a minimal duration of four days. Furthermore, we studied the influence of the Pseudomonas aeruginosa bacterium on the deterioration of an area exposed to a phenol and the benzoic acid concentration. Results obtained at the time of the different experimentations clearly show that phenol and the benzoic acid were eliminated by the Pseudomonas aeruginosa bacterium. However, it was noted that during the various investigations the bacterium Pseudomonas aeruginosa develops better in a phenol milieu and therefore degrades phenol more than benzoic acid.