In this research, biological removal of phenol and orthonitrophenol (2NP) pollutants from wastewater by continuous moving bed sequencing batch reactor (MSBR) was studied. The experiments were conducted in various operational conditions to find out the optimum level of the significant parameters. Best performance for removal of Phenols was achieved when parameters were set as follows: pH=7, sludge volume=30%, influent volumetric flow rate=20 ml.min-1, number of carriers=150 and aeration flow rate= 12ml. min-1. At this optimum condition, 2NP concentration, Biochemical Oxygen Demand (BOD5) and Chemical Oxygen Demand (COD) indicators reduced 84/7%, 94/8%and94%, respectively. Cost analysis for this treatment method was also assessed and final cost for treatment of 24 L wastewater in each operation was evaluated as 4/46$/L. By increasing treatment sessions, fixed costs would reduce and after treatment of 500 L wastewater, break-even point would achieve, which would turn the final costs down to 2.4 $/L. پرونده مقاله