Propylene glycol (PG), classed as alcohol, has been used in many industrial additives. Leaching PG in aquatic environments would cause a significant decrease in dissolved oxygen, and this is the main reason for treatment of runoffs and wastewater contaminated with this pollutant. Previous researches on PG removal from wastewater indicate that biological methods are more economically suitable. Therefore, a new biological reactor was introduced and used for the treatment of wastewater containing PG. Two main approaches for increasing removal efficiency in presented research are utilizing two serial lab-scale Sequencing Batch Reactors and feed backward connection between these reactors. This novel reactor was named Feed Backward Serial Sequencing Batch Reactor. Moreover, response surface method was used for modeling of PG treatment and investigation of interactions and simultaneous effects of independent parameters. Retention time, influent COD, and flow recirculation percentage were considered as independent variables, where COD removal efficiency was the dependent variable. According to the results, the best COD removal efficiency was 47%, and it was achieved in 3.52 h retention time, 1667.76 mg/L influent COD, and 23.33% flow recirculation percentage. Based on the results of the presented research, PG treatment with the presented reactor is feasible.