Large volumes of oil sands process water (OSPW) are generated during the extraction of bitumen from the mined oil sands ores in northern Alberta. The treatment of OSPW is currently considered a serious challenge facing the oil sands industry in the region. Among the different constituents in OSPW, naphthenic acids (NAs) are considered the most abundant and problematic organic pollutants. Enormous efforts have been implemented towards the development of strategies for OSPW treatment. However,

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... hly effective and cost-efficient treatment approaches have not been found so far. The main objective of this study was to investigate the effectiveness of applying electrooxidation (EO) at low current densities as a treatment option for OSPW treatment. Combining EO with aerobic biodegradation was proposed as an effective and cost-efficient treatment train for OSPW. The study investigated the performance of EO by graphite anode for NAs degradation, biodegradability enhancement, and toxicity reduction. The degradation kinetics and structure-reactivity relation for NAs during EO by graphite anode were also investigated. The performance of EO by graphite anode for the degradation of organics in real OSPW was evaluated and compared with that by dimensionally stable Ti-RuO2/IrO2 anode (DSA). The effectiveness of EO for improving the biodegradability of NAs in OSPW was also evaluated. In the first set of investigations, EO by graphite anode was applied for the degradation of a commercial NA mixture in water samples. At current densities of 0.5, 2.5, and 5 mA/cm 2 , acid extractable fraction (AEF) was removed by 42.2%, 57.0% and 67.9%, respectively, while classical NAs were degraded by 76.9%, 77.6% and 82.4%, respectively. Oxidized NAs were also degraded effectively during EO. The biodegradability of the NA mixture was improved by up to