Anaerobic Biodegradation of Methyl Tert-Butyl Ether and Tert-Butyl Alcohol in Petrochemical Wastewater Publisher Pubmed



Ghasemian M¹ ; Amin MM² ; Morgenroth E³ ; Jaafarzadeh N⁴
Source: Environmental Technology (United Kingdom) Published:2012

Abstract

A laboratory-scale anaerobic sequencing batch reactor was used to evaluate treatment of a synthetic substrate mixture representing petrochemical wastewater containing methyl tert-butyl ether (MTBE), ethanol and acetic acid. Influent MTBE concentrations were 5, 10 and 50mg/l (corresponding to MTBE loading rates of 0.2, 0.4 and 2mg/l.d) with overall organic loading rates (OLRs) of 1.51, 3.23 and 3.25g COD/l.d, respectively. These OLRs resulted in removal efficiencies for MTBE of 78%, 98% and 88%. Removal efficiencies for chemical oxygen demand were 85% and 90% with influent MTBE concentrations of 5 and 10mg/l, but were significantly reduced to 72% with influent MTBE concentrations of 50mg/l. During all reactor runs, effluent concentrations of tert-butyl alcohol (TBA) were below the detection limit. Batch degradation of the organic substrate mixture demonstrated initial inhibitory effects when exposed to MTBE concentrations of 50mg/l and complete inhibition with MTBE concentrations above 2000mg/l. It is interesting to note that in batch tests using MTBE as the sole organic substrate (initial MTBE concentrations of 50, 100 and 200mg/l), the specific methanogenic activity decreased to below detection within the first 96 hours, but following a 72-hour lag phase the methane production increased again. Based on low volatile fatty acid (VFA) concentration, disappearance of TBA peaks and no findings of any other intermediate via gas chromatography/mass spectrometry, while the MTBE concentration is still high, it can be suggested that during the batch tests the breakdown of gas production and the following lag phase were the direct effect of higher MTBE concentrations (more than 50mg/l) and not because of the TBA or VFA accumulations. © 2012 Copyright Taylor and Francis Group, LLC.