Interaction Effects of Metals and Salinity on Biodegradation of a Complex Hydrocarbon Waste

Abstract

The presence of high levels of salts because of produced brine water disposal at flare pits and the presence of metals at sufficient concentrations to impact microbial activity are of concern to bioremediation of flare pit waste in the upstream oil and gas industry. Two slurry-phase biotreatment experiments based on three-level factorial statistical experimental design were conducted with a flare pit waste. The experiments separately studied the primary effect of cadmium [Cd(II)] and interaction effect between Cd(II) and salinity and the primary effect of zinc [Zn(II)] and interaction effect between Zn(II) and salinity on hydrocarbon biodegradation. The results showed 42-52.5% hydrocarbon removal in slurries spiked with Cd and 47-62.5% in the slurries spiked with Zn. The analysis of variance showed that the primary effects of Cd and Cd-salinity interaction were statistically significant on hydrocarbon degradation. The primary effects of Zn and the Zn-salinity interaction were statistically insignificant, whereas the quadratic effect of Zn was highly significant on hydrocarbon degradation. The study on effects of metallic chloro-complexes showed that the total aqueous concentration of Cd or Zn does not give a reliable indication of overall toxicity to the microbial activity in the presence of high salinity levels.

Static and dynamic sorption of phenanthrene in mangrove sediment slurry

“…The solubility of high molecular weight PAHs such as benzo[a]pyrene was also sensitive to small changes in salinity [40]. Amatya et al [41] found that with increases in salinity, the ionic strength would rise and induced more PAH sorption. The present study showed that the high salinity (20 ppt) enhanced the Phe sorption onto sediment and decreased the bioavailability of Phe in the aqueous phase but salinity effect was not obvious at salinity lower than 20 ppt.…”

The effect of heavy metals on thiocyanate biodegradation by an autotrophic microbial consortium enriched from mine tailings

“…Like most other organisms, microorganisms are susceptible to high concentrations of heavy metals (Giller et al 1998 ; Mattila et al 2007 ). The effects of heavy metals on biodegradation of environmental pollutants have been studied, mostly for separate hydrocarbons (Ma et al 2018 ), mixtures of hydrocarbons (Amatya et al 2006 ), diesel oil (Sprocati et al 2012 ), polychlorinated biphenyls (PCBs), perchloroethene (PCE) (Lu et al 2020 ), and phenanthrene (Wong et al 2005 ). The effects of operational conditions such as pH, temperature, loading, phosphate amendment, and light, on SCN − biodegradation, have also been investigated (Kantor et al 2015 , 2017 ; Lay-Son and Drakides 2008 ; van Zyl et al 2017 ; Watts et al 2017a , 2019 ).…”