Performance Evaluation of Membrane-Aerated Biofilm Reactor for Acetonitrile Wastewater Treatment

Abstract

Biological treatment for volatile organic compound (VOC)–contaminated wastewater with conventional aeration methods causes significant stripping loss of pollutants due to its high volatility. To overcome this problem, the membrane-aerated biofilm reactor (MABR) was developed. The aim of this study was to reduce acetonitrile (ACN) stripping loss during the aeration process and to evaluate MABR performance under different hydraulic retention times (HRTs) and ACN surface loading rates. The MABR was operated with an inlet ACN concentration of 300 mg/L at four HRT conditions—4, 6, 9, and 12 h. Experimental results indicated that nearly 49% of ACN was stripped due to mechanical aeration, whereas stripping loss due to MABR was approximately 0.1%. A HRT of 6 h was found to be the optimum condition with removal efficiencies of ACN, total organic carbon (TOC), chemical oxygen demand (COD), and total nitrogen (TN) at 98%, 87%, 84%, and 69%, respectively. This MABR could achieve removal of ACN with a maximum surface loading rate and removal capacity of 3.75 and 3.63 g/m2·day, respectively. This study therefore established improved MABR efficiency with shorter HRT requirements.