The present study evaluates the sequential integration of two advanced biological treatment methods viz., sequencing batch reactor (SBR) and bioelectrochemical treatment systems (BET) for the treatment of real-field petrochemical wastewater (PCW). Initially two SBR reactors were operated in aerobic (SBRAe) and anoxic (SBRAx) microenvironments with an organic loading rate (OLR) of 9.68kg COD/m3-day. Relatively, SBRAx showed higher substrate degradation (3.34kg COD/m3-day) compared to SBRAe (2.9kg COD/m3-day). To further improve treatment efficiency, the effluents from SBR process were fed to BET reactors. BETAx depicted higher SDR (1.92kg COD/m3-day) with simultaneous power generation (17.12mW/m2) followed by BETAe (1.80kg COD/m3-day; 14.25mW/m2). Integrating both the processes documented significant improvement in COD removal efficiency due to the flexibility of combining multiple microenvironments sequentially. Results were supported with GC-MS and FTIR, which confirmed the increment in biodegradability of wastewater. © 2015 Elsevier Ltd.