Effectiveness of Ozonation Treatment in Eliminating Toxicity of Oil Sands Process-Affected Water to Chironomus dilutus

Abstract

Water soluble organic compounds (OCs), including naphthenic acids (NAs), are potentially toxic constituents of oil sands process-affected water (OSPW) that is generated during extraction of bitumen from Alberta oil sands. Ozonation can decrease concentrations of OCs in OSPW. However, effects of ozonated-OSPW on multicellular organisms are unknown. A 10-day and a chronic exposure of Chironomus dilutus to OSPW were conducted to assess effects on survival, growth, development, and behavior. Two separate batches of OSPW were treated with 30 or 80 mg ozone (O(3))/L. Wet body masses of larvae exposed to OSPW were 64 to 77% less than their respective controls (p < 0.001). However, both levels of ozonation significantly attenuated effects of OSPW on growth. Similarly, chronic exposure to untreated OSPW resulted in significantly less pupation than in the controls, with 31% and 71% less pupation of larvae exposed to the two batches of OSPW (p < 0.05). Emergence was significantly less for larvae exposed to OSPW, with 13% and 8% of larvae emerging, compared to 81% in controls (p < 0.0001). Both levels of ozonation of OSPW attenuated effects on emergence. These results suggest that OCs degraded by ozonation causes toxicity of OSPW toward C. dilutus, and that ozonation attenuates toxicity of OSPW.

Impact of ozonation pre-treatment of oil sands process-affected water on the operational performance of a GAC-fluidized bed biofilm reactor

“…Fluid wastes generated from bitumen extraction, known as oil sands process-affected water (OSPW), are currently retained in large tailings ponds because of its known toxicity to aquatic organisms including fish (He et al 2012), bacteria (Gamal El-Din et al 2011), benthic invertebrates (Anderson et al 2012) and mammalian species (Garcia-Garcia et al 2011). The primary toxicity of OSPW has been attributed to the organic acids collectively known as naphthenic acids (NAs) (Anderson et al 2012).…”

“…Fluid wastes generated from bitumen extraction, known as oil sands process-affected water (OSPW), are currently retained in large tailings ponds because of its known toxicity to aquatic organisms including fish (He et al 2012), bacteria (Gamal El-Din et al 2011), benthic invertebrates (Anderson et al 2012) and mammalian species (Garcia-Garcia et al 2011). The primary toxicity of OSPW has been attributed to the organic acids collectively known as naphthenic acids (NAs) (Anderson et al 2012). The NAs are alicyclic or noncyclic alkyl-substituted carboxylic acids that have a general chemical formula C n H 2n?Z O x , where n is the carbon number, Z is zero or a negative even integer, and x represents the total oxygen atoms (classical NAs are x = 2; oxidized NAs are x = 3-5) (Barrow et al 2010;Grewer et al 2010;Wang et al 2013).…”

Next-Generation Pyrosequencing Analysis of Microbial Biofilm Communities on Granular Activated Carbon in Treatment of Oil Sands Process-Affected Water

“…The bitumen is extracted from the sands using the Clark hot-water process, in which 1 m 3 of bitumen extracted from oil sands generates 4 m 3 of oil sands process-affected water (OSPW) (1)(2)(3). Over a billion cubic meters of this generated OSPW is currently stored in tailing ponds given the no-release policy for OSPW followed by the oil sands companies (4,5).…”

“…Over a billion cubic meters of this generated OSPW is currently stored in tailing ponds given the no-release policy for OSPW followed by the oil sands companies (4,5). This volume of OSPW will continually increase as the oil sands bitumen extraction continues in the Athabasca region until suitable treatment technologies become available to allow for OSPW release (2). This OSPW is contaminated with a large number of inorganic and organic compounds during the extraction process that are known to be toxic to aquatic and terrestrial life (6).…”

“…Fresh OSPW has acute, subchronic, and chronic toxicities to aquatic organisms, and the majority of this toxicity has been previously attributed to naphthenic acids (NAs) (2,7). NAs are a mixture of organic surfactants containing carboxyl groups with a general chemical formula for classical NAs (containing two oxygen molecules) of C n H 2nϩZ O 2 , where n is the number of carbon atoms and Z is either zero or a negative even integer representing the number of hydrogen atoms lost due to ring formation (8,9).…”