Emission patterns of acrylonitrile and styrene around an industrial wastewater treatment plant in Iran

Abstract

The uncontrolled releases of volatile organic compounds (VOCs) from wastewater treatment plants (WWTPs) have been highly concerned due to the associated public health risks. In petrochemical industries, WWTPs are responsible for various organic compound emissions into the atmosphere, which can considered as the main source of VOCs emission in such industries. The typical high-strength petrochemical wastewater is generated from an acrylonitrile-butadiene-styrene (ABS) resin manufacturing plant that usually needs pretreatment before discharging to the main WWTP. The objective of this study was to investigate the emissions and fates of acrylonitrile (ACN) and styrene (STM) through wastewater pretreatment units operated in an ABS manufacturing plant. In this study, the emission rates of ACN and STM were estimated by means of EPA's Water9 emission model. Subsequently, the emission rates were used as the input data of AERMOD model to simulate the atmospheric behaviors of emitted ACN and STM. The results of Water9 model showed that 57 and 81 % of influent ACN and STM are emitted to the air through pretreatment units, respectively. For both of them, the equalization basin had the major portion of emission to the atmosphere. The concentration distribution profiles of ACN and STM resulted from AERMOD model indicted that the concentration of STM was lower than EPA reference concentration (RfC); however, the higher concentration of ACN (higher than RfC) occurred near the WWTP as well as the neighbor ambient.