Biodegradation of Naturally Occurring Substances in Produced Water - Revision of data for the DREAM model

A literature review was conducted to obtain more reliable primary (biotransformation) and ultimate (biomineralization) biodegradation rates for compounds in produced water for the DREAM model, than the current biodegradation data. During the literature review, it became apparent that many compounds lacked quality ultimate biodegradation rates, which is preferred in the model. Therefore, ultimate biodegradation rates for these compounds were estimated based on their primary biodegradation rates and a FACTOR. These data and calculations are described in the report below. Calculated ultimate biodegradation rates are compared to rates found in the literature. This report also includes two separate Excel spreadsheets that summarize the prima ry and ultimate biodegradation data obtained during the literature review and their corresponding experimental details. A Q10 approach was applied to calculated ultimate biodegradation rates to display rates at three relevant temperatures (5, 13, and 20°(). The ultimate biodegradation rates included in this report will substantially improve the DREAM model, but the majority of these rates are extrapolated estimates. Additional biodegradation tests are recommended to correlate these calculations with laboratory experiments.StatoilpublishedVersio

Biodegradation of weathered crude oil by microbial communities in solid and melted sea ice.

Abstract Oil spilled in the Arctic may drift into ice-covered areas and become trapped until the ice melts. To determine if exposure to oil during freezing may have a priming effect on degradation of the oil, weathered dispersed oil (2-3 mg/L) was frozen into solid ice for 200 days at -10 °C, then melted and incubated for 64 days at 4 °C. No degradation was measured in oil frozen into ice prior to melting. Both total amount of oil and target compounds were biotransformed by the microbial community from the melted ice. However, oil released from melted ice was degraded at a slower rate than oil incubated in fresh seawater at the same temperature (4 °C), and by a different microbial community. These data suggest negligible biodegradation of oil frozen in sea ice, while oil-degrading bacteria surviving in the ice may contribute to biodegradation when the ice melts

Biodegradation in seawater of PAH and alkylphenols from produced water of a North Sea Platform

Operational planned discharges of produced water (PW) to the marine environment from offshore oil production installations, contain low concentrations of dispersed oil compounds, like polycyclic aromatic hydrocarbons (PAH) and alkylated phenols (APs). Biotransformation in natural seawater (SW) of naphthalene/PAH and phenol/AP in field-collected PW from a North Sea platform was investigated in this biodegradation study. The PW was diluted in SW from a Norwegian fjord, and the biodegradation study was performed in slowly rotating carousels at environmental conditions (13⁰C) over a period of 62 days. Naphthalene/PAH and phenol/AP biotransformation was determined by first-order rate kinetics, after normalization against the recalcitrant biomarker 17α(H),21β(H)-Hopane. The results from this study showed total biotransformation half-lives ranging from 10 to 19 days for groups of naphthalenes and PAH, while half-lives for APs (C0- to C9-alkylated) were 10 to 14 days. Biotransformation half-lives of single components ranged from 8 to >100 days for naphthalenes and PAHs (median 16 days), and from 6 to 72 days (median 15 days) for phenols and AP. Four of the tested PAHs (chrysene, benzo(b)fluoranthene, benzo(e)pyrene, benzo(g,h,i,)perylene) and one AP (4-tert-butylphenol) showed biotransformation half-lives >50 days. This is one of a few studies that has investigated the potential for biodegradation of PW in natural SW. Methods and data from this study may be used as a part of Risk Based Approaches (RBA) for assessments of environmental fate of PW released to the marine environment and as part of the persistence related to risk.acceptedVersio

Biodegradation-mediated alterations in acute toxicity of water-accommodated fraction and single crude oil components in cold seawater

Hydrocarbon biodegradation may be slower in cold Arctic than in temperate seawater, and this will affect the toxicity time window of the hydrocarbons. In this study, the acute toxicities of water-soluble phases of 1,3-dimethylnaphthalene, phenanthrene, fluoranthene, and low energy water-accommodated fractions (LE-WAFs) of an evaporated (200 °C+) crude oil, were screened by a Microtox bioassay during biodegradation in cold seawater (4–5 °C). The water-solubility of fluoranthene was too low to provoke a toxic response at any time, whereas the toxicity of 1,3-dimethylnaphthalene and phenanthrene decreased over time in relation to biotransformation of these compounds. In LE-WAFs, the Microtox EC50 was associated with biodegradation of the predominant hydrocarbons (naphthalenes, 2- to 3-ring PAH), as well as with phenol degradation products. The acute toxicities of single hydrocarbons and LE-WAFs persisted for a longer period in the cold seawater than previously shown at higher seawater temperatures. These results suggest implications for fate and effects assessment of hydrocarbons after oil spills in cold environments, like the Arctic. However, further biodegradation studies using Arctic seawater and relevant species for toxicity testing are needed for confirmation.acceptedVersio

Biodegradation of oil spill dispersant surfactants in cold seawater

While biodegradation of chemically dispersed oil has been well documented, only a few studies have focused on the degradation of the dispersant compounds themselves. The objective of this study was to determine the biodegradation of dispersant surfactants in cold seawater, relevant for deep sea or Arctic conditions. Biotransformation of the surfactants dioctyl-sodium sulfosuccinate (DOSS), Tween 80, Tween 85, and α/β-ethylhexylsulfosuccinate (EHSS, expected DOSS hydrolysis product) in the commercial dispersants Corexit 9500, Dasic Slickgone NS and Finasol OSR52 were determined. The biotransformation studies of the surfactants were performed in natural seawater at 5 °C over a period of 54 days without oil present. The surfactants were tested at concentrations of 1, 5, and 50 mg/L, the lower concentration being as close as possible to expected field concentrations. Experiments with dispersants concentrations of 1 mg/L resulted in rapid biotransformation of Tween 80 and Tween 85, with depletion after 8 days, while DOSS showed rapid biotransformation after a lag period of 16 days. The degradation half-life of DOSS increased from 4.1 days to >500 days as Corexit 9500 concentrations went from 1 mg/L to 50 mg/L, emphasizing the importance of performing experiments at dispersant concentrations as close as possible to environmentally relevant concentrations. EHSS showed limited degradation compared to other surfactants. This study shows that the surfactants DOSS, Tween 80 and Tween 85 in the three chemical dispersants studied are biodegradable in cold seawater, particularly in environmentally relevant concentrationsacceptedVersio

Preliminary Studies into the Environmental Fate of Nitrosamine and Nitramine Compounds in Aquatic Systems

AbstractPreliminary hydrolysis and photolysis data are presented for a suite of nitramines and nitrosamines relevant to post combustion CO2 capture using monoethanolamine solvent. Two nitramines (DMNA and MEA-NO2) and the nitrosamine NDELA were resistant to hydrolytic degradation at pH 4, 7 and 9. The nitrosamine NPz was hydrolytically stable at pH 4 and 9, but exhibited ∼30% degradation at pH 7. Nitrosamines appear highly susceptible to photolytic degradation, while nitramines are photolytically stable. The data form part of an ongoing study investigating the fate of nitrosamines and nitramines in terrestrial and aquatic environments

Biotransformation in water and soil of nitrosamines and nitramines potentially generated from amine-based CO2 capture technology

Nitrosamines (NSAs) and nitramines (NAs) are identified as possible degradation products from amine-based post-combustion CO2-capture (PCCC). Selected NSAs and NAs were subjected to aerobic and anaerobic biodegradation studies. In a screening study with 20 μg/L NSAs and NAs at 20 °C, only NSAs and NAs containing hydroxyl groups (alkanol compounds) exhibited aerobic biotransformation >10% after incubation in 28 days. Extending the biodegradation period to 56 days resulted in ≥80% biotransformation of the examined alkanol NSAs and NAs at 20 °C. Biotransformation (20 °C; 56 days) of the NSA NDELA at different concentrations (1–100 μg/L) did not differ significantly, but both water sources and temperatures affected biotransformation of the tested compounds. Anaerobic biotransformation (20 °C; 56 days) occurred rapidly  with alkanol NSAs and NAs, but not with alkyl compounds. Interestingly, 1st order rate coefficients and half-lives indicated comparable or even faster anaerobic than aerobic biotransformation at the same temperature. Predictions of biotransformation pathways suggested that the -OH substituent of alkanol NSAs and NAs was more susceptible to degradation than nitroso- and nitro-substituents.Biotransformation in water and soil of nitrosamines and nitramines potentially generated from amine-based CO2 capture technologyacceptedVersio

Attachment of APAM to mineral particles in seawater

Polymer injection is used in enhanced oil recovery (EOR) when an oil field ages and the pressure in the reservoir decreases, or for oil fields with heavy oil. By polymer injection, the viscosity of the water injected for pressure support is increased by mixing with a high concentration of a polymer solution. Polymers used in EOR operations are often high molecular weight polyacrylamides, including anionic polyacrylamide (APAM), which may subsequently enter the marine environment with produced water releases. Since seawater (SW) contains mineral particles (MPs) in low concentrations, and polymers like APAM are known to flocculate MPs, we investigated if APAM at different concentrations (0.5–10 mg/L) would attach and flocculate MPs, when these occurred in concentrations relevant for oceanic SW (1 mg/L). Two types of MPs, diatomaceous earth and kaolin, were exposed to fluorescence-tagged APAM (APAM-TAG). A low-energy carousel system with natural seawater (SW) was used for incubation of MPs and APAM-TAG at a temperature relevant for the Norwegian Continental Shelf (13 °C). Attachment to MPs and aggregates of these were analysed by fluorometry and fluorescence microscopy. Particle analyses showed that only minor fractions of the MPs aggregated. When samples were separated in steel filter with a mesh size of 20 μm, APAM-TAG was mainly measured in the flow-through fraction (<20 μm), and the results therefore showed that the polymer mainly remained in the water-phase, or was attached to small particles (<20 μm). For the small fraction of APAM attaching to aggregated MPs, attraction to kaolin was higher than to diatomaceous earth, and fluorescence microscopy analyses confirmed the presence of fluorescent particles at the higher APAM concentrations. MPs at concentrations relevant for oceanic SW are therefore not expected to significantly contribute to sedimentation of APAM dissolved in the water column.publishedVersio

Dual-polarized chipless humidity sensor tag

In this letter, a miniaturized, flexible and high data dense dual-polarized chipless radio frequency identification (RFID) tag is presented. The tag is designed within a minuscule footprint of 29 × 29 mm2 and has the ability to encode 38-bit data. The tag is analyzed for flexible substrates including Kapton® HN DuPont™ and HP photopaper. The humidity sensing phenomenon is demonstrated by mapping the tag design, using silver nano-particle based conductive ink on HP photopaper substrate. It is observed that with the increasing moisture, the humidity sensing behavior is exhibited in RF range of 4.1–17.76 GHz. The low-cost, bendable and directly printable humidity sensor tag can be deployed in a number of intelligent tracking applications

Modelling biodegradation of crude oil components at low temperatures

For oil spilled at sea, the main weathering processes are evaporation, emulsification, photo-oxidation, dispersion and biodegradation. Of these, only biodegradation may completely remove hydrocarbons from the environment in the long term, as the other processes only serve to transform and dilute the oil components. As petroleum development is moving north, the probability of Arctic oil spills increases. Hence, it is imperative to develop methods for comprehensive risk assessment of oil spills in cold and ice-covered waters. Accurate biodegradation rates are an essential part of this, as they are required to predict the long-term effects of marine oil spills. In this paper, we present experimentally determined biodegradation rates for the component groups which are used to represent oil in the OSCAR oil spill model. The experiments have been carried out at seawater temperatures of , , , and . We show that for the lighter and more soluble oil components, the changes in degradation rates between and are well captured by a constant scaling law. At lower temperatures, and for heavier and less soluble components, the rates are not well described by a constant , probably indicating that oil properties become important for the biodegradation rate.publishedVersio