Acrylonitrile Removal from Synthetic Wastewater Using a Lab Scale ASFFR

Acrylonitrile is widely used as the main raw material in the production of acrylonitrile butadiene styrene resin (ABS) in the petrochemical industry and other industrial and commercial processes. Acrylonitrile is not easily decomposed by conventional treatment systems due to its toxic characteristics. If it’s not treated properly, it may cause profound damage to the environment. In this study, the performance of an aerated submerged fixed-film reactor (ASFFR) has been studied for the removal of acrylonitrile from synthetic ABS wastewater. The experiments were conducted using a bioreactor in laboratory scale with 44.2 L capacity operated at different hydraulic and organic loading rates. The specific surface area and porosity of polypropylene media were 324 m2/m3 and 87% respectively. The reactor was loaded to provide hydraulic retention time (HRT) of 9, 7, 5 and 4 hr and soluble COD of 300 mg/L. The experiments were continued with the constant HRT 4 hr and variable COD concentrations of 350, 400 and 450 mg/L. The reactor demonstrated 95-99% removal efficiencies of SCOD and exhibited efficient and stable performance at organic loadings of 0.8-2.4 kg.AN/m3.day. When the organic and surface loadings were increased to 2.7 kg. AN/m3.day and 23.16 g. AN/m2.day respectively, the COD removal efficiency was decreased to 66% and the system became unstable. Also, different sorts of equations were set to show the relationships between organic loading rates as independent variables and different dependent parameters such as effluent SCOD and VSS concentrations. According to the experimental results, the ASFF reactor was determined as suitable approaches for the treatment of petrochemical effluents contain acrylonitrile.