The topic of my graduate thesis is bioremediation of benzalkonium chloride, a cyclic aromatic hydrocarbon that serves as a biocide and a cationic surfactant. It is used in laundry detergents and fabric softeners. Bioremediation is any process that uses microorganisms for the purpose of restoring the environment to a natural state before pollution or contamination from an anthropogenic source occured. The aim of my graduate thesis is to determine whether benzalkonium chloride can be degraded by native bacteria from Lake Jarun and lake in botanical garden or specifically grown bacteria from activated sludge, wastewater, soils and suspensions of Pseudomonas fluorescens and Pseudomonas aeruginosa. It was not on bacterial agar plates any bacterial colonies of P. aeruginosa and P. fluorescens, meaning that these bacteria did not break down benzalkonium chloride. Native bacteria from Jarun lake and lake in the botanical garden did not degrade benzalkonium chloride either. Bacteria from the waste water, the activated sludge and the soil we isolated in the laboratory degraded the benzalkonium chloride completely. Bacteria identified as benzalkonium chloride degraders were Agrobacterium radiobacter, Stenotrophomonas maltophilia and Bacillus cereus.