Dissipation of naphthenic acids mixtures by lake biofilms

Abstract

The dissipation (combined sorption and biodegradation) of naphthenic acids (C(n)H(2n+z)O(2)) by lake biofilms with no previous adaptation to oil sands acids was investigated using rotating annular bioreactors. The dissipation by the biofilm was dependent on the chemical composition of the naphthenic acids mixture. There were 2 distinct groups of Fluka naphthenic acids which dissipated with pseudo first order kinetics: (a) t(1/2)= 7 days, r(2)= 0.984 and (b) components which were less readily dissipated with t(1/2)= 134 days, r(2)= 0.618. In contrast to the results observed for Fluka naphthenic acids, no dissipation was evident for lake biofilm exposed to Athabasca oil sands naphthenic acids. The differences in dissipation observed for the systems investigated are attributed to the combination of 3 key factors: (i) molecular structure and (ii) molecular mass of the naphthenic acids; along with (iii) inhibition by some components (containing elements of S and/or N acids). The later are more prevalent in oil sands naphthenic acids compared to Fluka naphthenic acids.

Culturing oil sands microbes as mixed species communities enhances ex situ model naphthenic acid degradation

“…Aside from even numbered carboxylic acid functional groups, studies have shown that alkyl side chain branching hinders NA degradation ( Herman et al, 1993 ; Smith et al, 2008 ; Johnson et al, 2011 ; Huang et al, 2012 ), as well as an increase the degree of cyclicity (ring cleavage is energetically costly) and molecular weight ( Scott et al, 2005 ; Han et al, 2008 ; Toor et al, 2013 ; Misiti et al, 2014 ). Other recalcitrant NAs include non-classical NAs, such as those containing elements of S or N ( Headley et al, 2010 ).…”

“…The biodegradability of NAs by OSPW microorganisms has been explored and reviewed extensively ( Clemente and Fedorak, 2005 ; Quagraine et al, 2005 ; Allen, 2008b ; Kannel and Gan, 2012 ), but no one particular method to harness the naturally occurring microbes for use in ex situ NA treatment has been established and put into practice. One potential strategy that has been proposed and evaluated in a limited number of studies is the use of microbial biofilms in ex situ bioreactors targeting NA bioremediation ( Headley et al, 2010 ; Huang et al, 2012 ; Gunawan et al, 2014 ; McKenzie et al, 2014 ).…”

The impact of various ozone pretreatment doses on the performance of endogenous microbial communities for the remediation of oil sands process-affected water

“…The presence of recalcitrant compounds could be one of the main factors inhibiting further biodegradation (Taylor and Trudgill, 1978;Rontani and Bonin, 1992;Quagraine et al, 2005b). In addition, current research indicated that the performance of biodegradation could be improved by increasing biomass concentration and microbial activity (Headley et al, 2010;Misiti et al, 2013). Therefore, besides carbon source, inorganic macronutrients such as nitrogen (N) and phosphorus (P) are also needed to facilitate bacterial growth.…”

Treatment of oil sands process-affected water using moving bed biofilm reactors: With and without ozone pretreatment

“…Headley et al (2010) applied rotating annular bioreactors with lake biofilm and no dissipation was evident when exposing to OSPW naphthenic acids. However, commercial NAs (Fluka naphthenic acids) could be found with dissipation.…”

“…Headley et al (2010) evaluated the potential of biofilm development in a rotating annular bioreactor using lake water. However, little impact on the degradation of OSPW NAs was achieved.…”