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Copyright of Industrial Water Treatment is the property of CNOOC Tianjin Chemical Research & Design Institute and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Applied Chemical Industry is the property of Shaanxi Research Design Insitute of Petroleum & Chemical Industry and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this study, we synthesized a novel electrode for electrocatalytic adsorption by fabricating ACF‐TiO2 via the sol‐gel method and binding it with IrO2‐TaO2. The electrode's effectiveness in treating oilfield produced water (OPW) was evaluated using batch techniques. Comprehensive characterization, including scanning electron microscopy (SEM), energy‐dispersive spectrometry (EDS), Brunauer‐Emmett‐Teller (BET) analysis, and Fourier‐transform infrared (FTIR) spectroscopy, confirmed uniform TiO2 loading onto the ACF surface, preserving structural integrity. BET analysis indicated increased mesopore volume and enhanced organic adsorption capacity without compromising microporous structure. Additionally, FTIR analysis revealed the emergence of functional groups conducive to adsorption and catalytic reactions. Freundlich isotherms and pseudo‐first‐order kinetics best fit the adsorption data. Remarkably, even after five cycles, the electrode maintained high removal efficiencies for chemical oxygen demand (COD) and oil content at 91.35 % and 91.12 %, respectively. We further investigated the complex phenomena of material adsorption, electrochemical oxidation, and desorption during electrocatalytic adsorption, highlighting the importance of solid‐phase adsorption and liquid‐phase electrocatalytic oxidative decomposition in OPW treatment. Comparison with similar electrodes and DSA electrodes demonstrated the superior performance and practicality of the IrO2‐TaO2‐ACF(TiO2) electrode. Its cost‐effectiveness and regeneration method further enhance its applicability in real‐world scenarios, emphasizing its potential in water treatment. [ABSTRACT FROM AUTHOR]

In this study, a flat sheet ceramic membrane experimental device was constructed, and the thermodynamics of membrane fouling interface was studied for oilfield produced water. The flux of ceramic membrane in three kinds of model solutions were measured with time, as well as the surface tension, contact Angle and Zeta potential of solid. The thermodynamic mechanism of membrane fouling interface combined with XDLVO theory were explored for three kinds of model solutions. The thermodynamic study of the interface of ceramic plate membrane shows that the total interaction energy between membrane and oil droplets decreases with the increase of the distance between two interfaces at initial stage of membrane fouling, and finally transforms from the mutual attraction to the mutual repulsion. The total interaction energy between reservoir and oil droplet is shown as mutual attraction, and the total interaction energy decreases with the increase of the distance between reservoir and oil droplet interface. The zeta potential of crude oil was affected by salinity to some extent. The electrostatic shielding effect of the salt ions leads to a decrease in the ζ-potential of the three solutions. They are in the order: model solution A > model solution B > model solution C. This leads to a decrease in the electrostatic interaction (EL). And since the oil layer has the same composition as the oil droplets, the EL interactions in the three solutions can behave as mutual repulsion. [ABSTRACT FROM AUTHOR]

Oilfield Produced Water (OPW) has been identified as a viable solution to mitigate water scarcity in California's Central Valley. However, consumer perception on the use of OPW outside of the oil and gas industry remains unknown and poses a hurdle for large-scale adoption. This paper, based on 134 randomly selected residents of Kern County (California's largest oil-producing county and top agricultural region), examined attitudes towards OPW reuse. In the survey, more than half (52.3%) of participants said that they have heard about oilfield-produced water and other reclaimed waters. Findings also suggest that participants mostly preferred rain and stormwater, and interestingly scored OPW higher than industrial and black waters for irrigation purposes. Around 67% of the participants supported the use of oilfield-produced water for irrigating crops. Younger people (18–29 years) expressed greater concern about using OPW compared to the older residents. Given the drought conditions in Central Valley, policymakers might need to focus on a circular economy and mandate the use of OPW in Central Valley considering that this region's economy lies at the nexus of the O&G and agriculture industries. [ABSTRACT FROM AUTHOR]

Biofilm formation can help to mitigate the stress placed on organisms during biological treatment of high-salinity wastewaters, such as "produced water" resulting from oil and gas extraction. This study investigated the implementation of two different biofilm-based biological reactors, activated carbon as an adsorptive biofilm surface (Bio-GAC) and aerobic granular sludge (AGS), and a conventional activated sludge (CAS) reactor for the treatment of synthetic produced water (PW) under hypersaline conditions (85,000 mg/L NaCl). A mixture of benzyl alcohol, o-cresol, and phenol were used as a carbon source with concentrations of 100, 100, and 250 mg/L, respectively. The performance of Bio-GAC was higher than AGS, with overall removal efficiencies for aromatic compounds of 100% and 93%. The presence of catechol in all three reactors during the reaction cycle confirmed that biodegradation was occurring. The performance of CAS was significantly lower in terms of removal efficiency for aromatic compounds (73%) and resilience to high salinity. Scanning electron microscopy showed that biofilm-based biosystems establish stronger biofilm texture. Microbial community analysis showed that carbon source and biosystem type played a crucial role in selecting for microbiome structure. These findings show that biofilm reactors can be used to successfully biodegrade toxic organic contaminants in a high-salinity environment, and that the hybrid Bio-GAC process is particularly promising for treating PW. [ABSTRACT FROM AUTHOR]

Copyright of Electroplating & Finishing is the property of Electroplating & Finishing Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The corrosion behavior of Q235B carbon steel is investigated in water, LB medium, and oilfield produced water adding Pseudomonas fluorescens FSYZ01. After immersion at 30 °C for 13 days, the weight loss of carbon steel with this strain decreased by 32.23%, 54.07%, and 78.34%, respectively. X-ray diffraction (XRD) results show that P. fluorescens FSYZ01 inhibited conversion of iron oxides by hindering oxygen from approaching metal surface. Fourier transform infrared (FT-IR) and X-ray photoelectron spectrometer (XPS) results show that specific functional groups and bonds reacted with Fe(II/III) to form a dense and stable chelate-oxide protective layer, thereby inhibiting corrosion. Pyrolysis gas chromatography-mass spectrometer (Py-GCMS) results demonstrate the bacteria degraded C12 to C20 alkanes in oil. The inhibitory mechanism of crude oil-degrading bacteria P. fluorescens FSYZ01 on the carbon steel corrosion was proposed, so as to slow corrosion of oilfield produced water system pipeline and prolong its service life, helping to comprehend the microbial corrosion in the actual environment. [ABSTRACT FROM AUTHOR]

In order to predict the corrosion trendency of X100 pipeline steel in flowing oilfield produced water, the effect of flow rate on the corrosion behavior of X100 pipeline steel was studied under general dynamic condition and simulated real working condition at the flow rate of 0.2, 0.4, and 0.6 m·s−1. Potentiodynamic polarization curves and electrochemical impedance spectroscopy were used to study the corrosion behavior of X100 steel. Energy dispersive spectroscopy, X-ray diffraction and scanning electron microscopy were used to analyze corrosion product composition and micromorphology. The experimental results show that the corrosion is more serious under simulated real working conditions than that under the general dynamic conditions. In any case the corrosion current density increases with the increase of the flow rate, and the total impedance value decreases. The corrosion products include Fe3O4, Fe2O3, and FeOOH. The mass transfer and electrochemistry were simulated by flow coupled in COMSOL software. The multiphysical field coupling simulation results are closer to the engineering practice than the single flow field simulation, and similar results from the experiments were obtained. Both experimental and simulation results reveal that the higher flow rate is, the more serious corrosion appear and the more corrosion products accumulate. By combining experimental and COMSOL simulation data, the corrosion process model of X100 steel was proposed. [ABSTRACT FROM AUTHOR]

Reuse of oilfield‐produced water (OPW) for crop irrigation has the potential to make a critical difference in the water budgets of highly productive but drought‐stressed agricultural watersheds. This is the first peer‐reviewed study to evaluate how trace metals in OPW used to irrigate California crops may affect human health. We modeled and quantified risks associated with consuming foods irrigated with OPW using available concentration data. The probabilistic risk assessment simulated OPW metal concentrations, crop uptake, human exposures, and potential noncancer and carcinogenic health effects. Overall, our findings indicate that there is a low risk of ingesting toxic amounts of metals from the consumption of tree nuts, citrus, grapes, and root vegetables irrigated with low‐saline OPW. Results show increased arsenic cancer risk (at 10−6) for adult vegetarians, assuming higher consumption of multiple foods irrigated with OPW that contain high arsenic concentrations. All other cancer risks are below levels of concern and all noncancer hazards are far below levels of concern. Arsenic risk concerns could be mitigated by practices such as blending high‐arsenic OPW. Future risk assessment research should model the risks of organic compounds in OPW, as our study focused on inorganic compounds. Nevertheless, our findings indicate that low‐saline OPW may provide a safe and sustainable alternative irrigation water source if water quality is adequately monitored and blended as needed prior to irrigation. [ABSTRACT FROM AUTHOR]

A molecularly imprinted polymer (MIP) sensor was successfully constructed on glassy carbon electrode for the determination of 1‐naphthol (1‐Nph). The sensor was constructed by electropolymerization on bare GCE in the presence of the target molecule. The recognition of 1‐Nph was conducted indirectly using [Fe(CN)6]3−/4− as redox probe. The MIP sensor presented wide linear working range and limit of detection of 1.5×10−9 mol L−1. The MIP sensor was applied for the determination of 1‐Nph in oilfield produced water. The results obtained showed good selectivity and sensitivity of the proposed sensor in terms of 1‐Nph quantification. [ABSTRACT FROM AUTHOR]

Copyright of Energy Chemical Industry is the property of Energy Chemical Industry Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Ni-WS2 composite coating was electroplated on the surface of X100 pipeline steel to improve its corrosion resistance. The corrosion behaviors of X100 pipeline steel before and after being immersed in artificial oilfield produced water saturated with CO2 at 60 °C within 24 hours were studied. The surface morphology and thickness of the composite coating before and after corrosion were observed using scanning electron microscope (SEM), and its phase structure was analyzed using X-ray diffractometer (XRD). The corrosion resistance of X100 pipeline steel with and without Ni-WS2 composite coating was tested by potentiodynamic polarization (PDP) measurement and electrochemical impedance spectroscopy (EIS). The results showed that the surface of Ni-WS2 composite coating was still compact and uniform after corrosion, and the corrosion products were mainly Fe3C and FeOOH. The X100 pipeline steel with a Ni-WS2 composite coating showed better corrosion resistance than the blank substrate in oilfield produced water saturated with CO2 within 24 hours. [ABSTRACT FROM AUTHOR]

During the oil production process, oily waste water is coproduced at a rate several times that of oil. This water is known as produced water. Treatment levels and technologies are selected based on disposal method or reutilization objectives, environmental impacts, economics, and other such factors. For the treatment of produced water, the treatment system equipped with nitrogen microbubble flotation in conjunction with anthracite filtration and activated carbon adsorption was designed and examined. Polymer flooding is being used as an enhanced oil recovery (EOR) method in Oman. The quality of polymer flood produced water (PFPW) is different from produced water (PW) without polymer, it was clarified that aluminum sulfate (AS) is more effective than poly-aluminum chloride (PAC) as a flocculant. Based on the examination results, a 50 m3/day capacity pilot plant was designed, fabricated, and utilized to conduct produced water treatment trials, good oil removal was confirmed in all tests. It was also confirmed that this accompanied water treatment water could be used as irrigation water for agriculture by performing necessary higher order treatment. As a result, it was considered that the development as a new water source in the Middle East, where water resources are scarce, could be expected. [ABSTRACT FROM AUTHOR]

This study focused on resolving the query "which is the most beneficial clay system for the petroleum industry, intercalated or exfoliated"? Dimethyl sulfoxide (DMSO) and ethylenediaminetetraacetate ions (EDTA2-) were used as well-known agents in the tailoring of intercalated- and exfoliated-organoclays, respectively. Both systems were characterized by X-ray diffraction, Fourier-transform infrared spectroscopy, dynamic light scattering, N2-physisorption, transmission electron microscopy, and atomic force microscopy techniques, and examined in treating oilfield produced water. EDTA-clay exhibited long-term ordered, uniformly negatively charged, and high swellable tactoids of hexagon shapes with enhanced pore structure. The lamellar structure of DMSO-clay was highly degenerated and roughened conducting uneven highly charged particles of poor surface features. EDTA-clay was preferentially managed in the petroleum industry as a perfectly safe and efficient agent for (i) long-lasting removal of scale-forming cations (Fe3+, Mg2+, Ca2+, and Sr2+) from oilfield produced water with high adsorption rates yielding performances ≥85% within excellent six repeating regeneration/reuse runs, (ii) corrosion protection of steel pipelines, and (iii) killing of sulfate-reducing bacteria (near 100%). Increased demand for exploration of multidiscipline materials for the petroleum industry will revitalize clay intercalation systems to a magnificent renaissance. [ABSTRACT FROM AUTHOR]

To improve the separation efficiency of oil field-produced water, a novel oil-water separation apparatus is developed. The high-efficiency cyclone separation apparatus could meet the continued increase of oil field-produced water and comply with the improvements in emission standards. Effectivity of the self-designed apparatus in oil removal was determined in laboratory and field tests. The effects of inlet flow, oil concentration and aeration amount were determined through laboratory tests. The particle size distribution of the influent and effluent oil-produced water was presented also. Results show that under optimal process conditions, i.e., the inlet flow rate is 2.0 m3/h, imported oil concentration is 1189 mg/L, and aeration rate is 0.6 L/min, effective separation can reach 93.1%. The oil removal rate is generally above 90% and the range of influent concentration is 900-1200 mg/L in the field test. Compared to the traditional oilfield produced water treatment device, the self-designed apparatus can combine both air flotation separation and cyclonic separation. The joint effect of the two kinds of separation, can promote the collision adsorption probability of micro bubbles and oil droplets, and effectively improve the separation efficient. [ABSTRACT FROM AUTHOR]

Determining a representative microbial signature from any given location is dependent on robust sample collection and handling. Different sampling locations and hence sample properties can vary widely; for example, soil would be collected and handled differently compared to liquid samples. In the event that sample material has a low concentration of biomass, large quantities need to be collected for microbial community analysis. This is certainly the case when investigating the microbiology of oilfield systems, wherein produced water (PW) is one of the most common sources for microbial sampling. As the detrimental effects of microbial metabolism within these industrial milieus are becoming increasingly well-established, the characterization of microbial community composition using molecular biological analyses is becoming more commonplace for accurate monitoring. As this field continues to develop, the importance for standardized operating protocols cannot be understated, so that industry can make the most informed operational decisions possible. Accurately identifying oilfield microbial communities is paramount, as improper preservation and storage following sample collection is known to lead to erroneous microbial identifications. Preserving oilfield PW can be challenging, as many locations are remote, requiring lengthy periods of time before samples can be processed and analyzed. While previous studies have characterized the effects of various preservatives on concentrated, filtered, or purified microbial samples, to the best of our knowledge, no such study has been undertaken on low biomass liquid samples. To this end, we investigated the effectiveness of nine different preservation conditions on PW collected from the same sampling location within a heavy-oil producing field, and monitored how the microbial community changed over the period of a month. Our results reveal that the choice of preservative drastically affects microbial community, and should be selected with careful consideration before sampling occurs. [ABSTRACT FROM AUTHOR]

The presence of carbon dioxide (CO2) in oilfield produced water, which could be natural or intentionally injected component in oil and gas production, is extremely corrosive to pipelines and tubings. Oilfield produced water is mainly brine solution comprising organic acids, purely condensed water as well as aggressive ions like SO42−, Cl− and dissolved acid gases (like CO2). CO2 induced corrosion in this media is more detrimental than corrosion induced by HCl. This study critically unveiled the CO2 corrosion behavior of steel in oilfield produced water. The subjects covered include the chemistry of CO2 in water, supercritical CO2 condition, computational fluid dynamics (CFD) and corrosion control. Corrosion resistant alloy has been proved to exhibit remarkable corrosion resistance due to formation of strong protective film that can prevent localized corrosion. Moreover, the use of viable surface-active compounds, which are constituents of crude oil is a promising strategy for pipeline steel corrosion mitigation. [ABSTRACT FROM AUTHOR]

This review discusses bioreactor-based methods for industrial hydrocarbon-containing wastewater treatment using different (e.g., stirred-tank, membrane, packed-bed and fluidized-bed) constructions. Aerobic, anaerobic and hybrid bioreactors are becoming increasingly popular in the field of oily wastewater treatment, while high concentrations of petroleum hydrocarbons usually require physico-chemical pre-treatments. Most efficient bioreactor techniques employ immobilized cultures of hydrocarbon-oxidizing microorganisms, either defined consortia or mixed natural populations. Some advantages of fluidized-bed bioreactors over other types of reactors are shown, such as large biofilm–liquid interfacial area, high immobilized biomass concentration and improved mass transfer characteristics. Several limitations, including low nutrient content and the presence of heavy metals or toxicants, as well as fouling and contamination with nuisance microorganisms, can be overcome using effective inocula and advanced bioreactor designs. The examples of laboratory studies and few successful pilot/full-scale applications are given relating to the biotreatment of oilfield wastewater, fuel-contaminated water and refinery effluents. [ABSTRACT FROM AUTHOR]

The corrosion performances of X100 steels in the oilfield produced water with different temperature (30°C, 40°C, 60°C) under the simulated working conditions were studied by potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS) test. Energy dispersive spectroscopy (EDS) was used to measure the element composition of the sample after corrosion. The phase and chemical compositions of the specimens were analyzed by X-ray diffraction (XRD) and Raman spectrometry. The electrochemical results showed that the corrosion resistance of the specimen exposed for 24 hours increased with the increase of the testing temperature, indicating the better protective effect due to the corrosion product film formed under high temperature despite the impact of turbulence. The corrosion products consist of Fe3O4, Fe2O3, α-FeOOH, and γ-FeOOH. The corrosion mechanism model of X100 steel was established and the corrosion behavior was analyzed under simulated working conditions. [ABSTRACT FROM AUTHOR]

Purpose The purpose of this paper is to study the corrosion rate for X52, X60, X65, X70 and X80 steel immersed in Mexican oilfield produced water. For the electrochemical characterization of the five steels rotating disk electrodes, 20°C, 30°C and 45°C of experimental temperature and 0, 500, 1,000 and 2,000 rpm of rotation speed were taken into account. The temperature dependence was analyzed using Arrhenius law. Thus, Rct values obtained from EIS data in comparison with the corrosion rate obtained from polarization curves data were taken into account. Hydrodynamic effects were analyzed by Rct and corrosion rate data.Design/methodology/approach Electrochemical impedance spectroscopy and potentiodynamic polarization techniques were used to assess the electrochemical behavior for five pipe steels steel immersed in a natural solution.Findings The resistance and corrosion rate taken from electrochemical tests decreased as temperature and hydrodynamic condition also decreased. In addition, the Arrhenius parameter revealed that the natural solution increased the corrosion rate as the activation energy decreased. Typical branches related to reduction-oxidation reaction (dissolution-activation process or corrosion products dissolution) on steel surface were discussed. Optical images analysis shows that corrosion products for X65 steel exposed to oilfield produced water can be attributed to more susceptibility to corrosion damage for this steel grade (Quej-Ake et al., 2018), which is increased with the temperature and rotation speed of the working electrode.Originality/value Corrosion process of the five steels exposed to oilfield produced water could be perceptive when Arrhenius analysis is taken into account. This is because oilfield produced water is the most aggressive condition (brine reservoir and sour water) for internal pipelines walls and storage tanks (brine tanks). Thus, stagnant condition was considered as a more extreme corrosive condition because produced water is stored in atmospheric stationary tanks as well as it is transported under laminar condition in zones where oilfield produced water is maintaining in the bottom of the pipe during the production, transporting and storing of the crude oil. In addition, a brief operational process for Reynolds number and the flowrate of the stock tank barrel per day (Q in STBD) using field and Reynolds number data is discussed. [ABSTRACT FROM AUTHOR]

Copyright of Research & Exploration in Laboratory is the property of Research & Exploration in Laboratory and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In general, the oil industry has been searching for ways to alleviate the abundant disposal of oilfield produced water, which contains dissolved hard-removal and highly toxic organic compounds. Advanced oxidative processes (AOPs) have revealed to be effective in the degradation of organic compounds, because they generate hydroxyl radicals with high oxidizing potential which are capable of degrading these compounds. The present study has demonstrated the degradation efficiency of effluents containing organic compounds although the photo-Fenton process using a tubular photochemical reactor under different energy sources. This reactor allowed the use and evaluation of two ultraviolet irradiation sources, the sun and black light lamps, besides other relevant variables to the process, such as reagents concentration and the irradiated area, using a model effluent containing phenol. A sample of oilfield produced water was photochemically degraded through the optimum experimental conditions found for the phenol degradation. Solar irradiation was more efficient than lamplight, and it corresponds an important factor for the reduction of operating costs of this process. The solar reaction system applied to the oilfield produced water showed a removal of organic components up to 76%. [ABSTRACT FROM AUTHOR]

In this study, novel coagulant poly(silicate aluminum)/Fe3O4 nanoparticles (PFeNPs) were prepared via magnetic iron oxide nanoparticles (FeNPs) modified by poly(silicate aluminum) (PSA). The physiochemical properties of the PFeNPs were investigated with Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, and ζ-potential metric analysis. The effect of the aging time on the Al distribution of the PFeNPs was analyzed by the Al-Ferron timed complex colorimetric method. Oilfield-produced water was used for the assessment of the coagulation performances. The fractal dimensions, formation, breakage, and regrowth of the flocs were studied in turn. The experimental results show that the PFeNPs exhibited a porous layer of a net structure, and the PSA grafted onto the PFeNPs via Si--O--Fe enhanced the positive charge of the FeNPs. Meanwhile, the coagulation performance of the PFeNPs on total organic carbon, the turbidity, and the calcium removal were beyond 98%. In addition, the moisture content of the flocs derived from the PFeNPs was 68.7% (it is normally >98%). We found that the compactness of the flocs derived from the PFeNPs was far greater than those of PSA. This will provide new sight into the preparation of magnetic singlephase inorganic polymer coagulants. VC [ABSTRACT FROM AUTHOR]

The removal process of Hg(II) and MeHg(II) from aqueous solution by surface modified agrowaste biomass (AWB) was studied. The surface modifications were carried out by methods of mercerization, oxidative delignification, acid treatment, and biological treatment using laccase. The modifications promoted disruption of AWB structural surfaces and thus changed their physical and chemical properties as well as Hg(II) and MeHg(II) adsorption performances. The adsorption efficiency of Hg(II) was higher than MeHg(II) for all AWB adsorbents. The adsorption capacity of Hg(II) and MeHg(II) for AWB-Pure was 0.97 and 0.17 mmol/g, respectively. The highest adsorption capacity of Hg(II) and MeHg(II) was respectively observed for the AWB-Laccase (0.98 ± 0.04 mmol/g) and AWB-NaOCl/NaOH (0.40 ± 0.07 mmol/g). The adsorption selectivity of modified AWB adsorbents towards Hg(II) and MeHg(II) studied using oilfield produced water and natural gas condensate samples was found to be lower as compared to AWB-Pure, but higher selectivity was observed for other metals. The renewability studies show that the pure and modified AWB adsorbents had similar adsorption performance characteristics. The high Hg(II) adsorption efficiency (η > 90 %) was observed up to the third adsorption cycle, while for the MeHg(II), it decreased after each adsorption–desorption cycle. [ABSTRACT FROM AUTHOR]

The objective of this study was to develop a pH sensor for monitoring hydrogen ion activity in situ in oilfield-produced water under subsurface conditions. An iridium oxide film was prepared, and the performance of the iridium oxide film was evaluated in produced water using a series of high salinities, temperatures, and pressures. Scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and X-ray photoelectron spectroscopy (XPS) were employed to assess the morphology and oxidation state of the iridium oxide film. A series of open-circuit potential (OCP) measurements were performed to access the sensitivity and stability of the iridium oxide film electrode in produced water. Research results indicated that the pH sensor exhibits a very high sensitivity in the environment with varied interference ions, including Na, Mg, Ca, Cl, and SO, and the existence of sodium chloride in produced water made a slight positive shift of potential. The iridium oxide film-based pH sensor exhibited a near-Nernstian response at −57.9 mV/pH in produced water. An increase in temperature from 24 to 80 °C decreased the pH potential. Compared with the theoretical Nernst equation, the iridium oxide sensor showed fair Nernstian behavior at high temperatures. The iridium oxide pH sensor was accurately investigated under high pressure; the sensor seems independent of pressure, and the slope is the same at different potentials under a wide range of pressures. [ABSTRACT FROM AUTHOR]

The feasibility of the application of the catalytic wet air oxidation (CWAO) in two produced water containing refractory organic pollutants [total organic carbon (TOC) content 1,249 and 1,442 mg L] were studied. The produced waters were oxidized in a batch reactor using a (4 wt%) Cu/Mn-Ce-O catalyst, prepared by the co-precipitation of manganese and ceria nitrates, followed by wet impregnation of copper acetate. The efficiency of the CWAO of oilfield produced water was determined by TOC removal of the tested wastewater, the Pseudomonas putida growth inhibition test was also accomplished. Approximately 80 % in TOC reduction was achieved during wet oxidation over the catalyst at 433 K and an oxygen partial pressure of 1.0 MPa. No leaching of Cu or Mn was detected. [ABSTRACT FROM AUTHOR]

A study of the anaerobic biodegradability of the three categories of water separated from extracted crude oil (Venezuelan oilfields) - light, medium or heavy crude - was carried out at laboratory scale using UASB reactors working at mesophilic conditions. Chemical oxygen demand (COD) removal in a low loaded UASB reactor fed with water separated from extracted light crude was high, with an average 87 % purification efficiency. The remaining COD was made up of the non-biodegradable and the very slowly biodegradable fractions of the organic matter in the water. Owing a second period, the hydraulic retention time was reduced in stages, thus increasing the loading rate. In the experimental conditions used, COD concentration at the outlet remained below the Venezuelan standard limit for discharge into the environment (350mg COD 1-1) when the hydraulic retention lime (HRT) was above 10 hours and the OLR under 3 g COD 1-1 d-1. For URT less than 10 hours, or organic loading rate (OLR) greater than 3 g COD 1-1 d-1, COD at the outlet of the reactor rose as a consequence both of increased volatile fatty acids (VFA) concentrations (indicating an overloading of the methanogenic population) and, also, of the increase in the non-VFA COD (indicating a decease in the acidification efficiency). On the other hand, results with UASB reactors operated at a low loading rate and fed with water separated from extracted medium and heavy crude oil showed that purification efficiency was low with only 20 % and 37% COD removal respectively. Continuing the operation of the UASB reactor fed with water separated from medium oil over a prolonged period did not bring any improvement, indicating that no adaptation of the sludge occurred. [ABSTRACT FROM AUTHOR]

Freshwater scarcity is a highly pressing and accelerating issue facing our planet. Therefore, there is a great incentive to develop sustainable solutions by reusing wastewater or produced water (PW), especially in places where it is generated abundantly. PW represents the water produced as a by-product during oil and gas extraction operations in the petroleum industry. It is the largest wastewater stream within the industry, with hundreds of millions of produced water barrels per day worldwide. This research investigates a reuse opportunity for PW to replace freshwater utilization in well stimulation applications. Introducing an environmentally friendly chelating agent (GLDA) allowed formulating a PW-based fluid system that has similar rheological properties in fresh water. This work aims at evaluating the rheological properties of the developed stimulation fluid. The thickening profile of the fluid was controlled by chelation chemistry and varying different design parameters. The experiments were carried out using a high-pressure, high-temperature (HPHT) viscometer. Variables such as polymer concentration and pH have a great impact on the viscosity, while temperature and concentration of the chelating agents are shown to control the thickening profile, as well as its stability and breakage behaviors. Furthermore, 50 pptg of carboxymethyl hydroxypropyl guar (CMHPG) polymer in 20 wt.% chelating solution was shown to sustain 172 cP viscosity for nearly 2.5 h at 150 °F and 100 S−1 shear rate. The newly developed fluid system, solely based on polymer, chelating agent, and PW, showed great rheological capabilities to replace the conventional stimulation fluids based on fresh water. The newly developed fluid can also have economic value realization due to fewer additives, compared with conventional fluids. [ABSTRACT FROM AUTHOR]

This experimental paper deals with the development of a hybrid biological reactor for the treatment of a synthetic oilfield produced water under an increase in total dissolved solids (TDS) concentration. To comply with strengthening regulations concerning produced water discharge and peculiar produced water compositions, a moving bed biofilm reactor (MBBR) consisting in a combination of free activated sludge and moving biofilm supports was compared to a fixed bed hybrid biological reactor (FBHBR) consisting in a combination of free activated sludge and a fixed biofilm support. After a 216 days experimental period, the MBBR and the FBHBR were efficient to treat a synthetic produced water with chemical oxygen demand (COD) removal rate above 90% under an increase in TDS concentrations from 1.5 to 20 g·L−1. Ecotoxicity measurements on freshwater and marine microorganisms revealed an absence of toxicity on treated waters. A decrease in bacterial diversity indices with respect to the inoculum was observed in both bioreactors. This suggests that the increase in TDS concentrations caused the predominance of a low number of bacterial species. [ABSTRACT FROM AUTHOR]

Kuwait is a desert country with scarce water resources and increasing population, which means that more water sources should be tapped, not only for irrigation but also to provide for the citizens of the country. Oilfield waters are produced at increasing levels in Kuwait, being a foremost oil producer in the gulf region. It contains lots of contaminants that, if left untreated, will pollute the surrounding areas when disposed of improperly. This paper examines the possibility of treating oilfield water to be used as an additional resource for irrigation and for improving its treatment prior to proper disposal. The water treatment concept being introduced was performed through several treatment stages including biological treatment combined with nitrification and denitrification (sedimentation), chemical treatment (flocculation and coagulation), reverse osmosis, and disinfection using ultraviolet process as the final treatment process. This was accomplished through the combination of conventional and membrane technology process. After the treatment, the water samples were tested and compared with the parameters set by the Kuwait Environment Public Authority (KEPA) for irrigation, as well as disposal. The results indicated that the treatment methods are efficient in treating oilfield water as the treated samples showed significant reduction in original concentration, such as to name a few, total suspended solids, total dissolved solids, ammonia, total Kjeldahl nitrogen, sulfide, turbidity, phosphate and biological oxygen demand with a reduction percentage of 94.23%, 95.86%, 76.47%, 80.39%, 94.59%, 98.0%, 54.54%, 80.19%, respectively. Grease, oil and chemical oxygen demand level can be lowered from the treated water by further treatment. Oilfield water can, therefore, be utilized for irrigation and eventual allowable discharge to sewage network conventional wastewater treatment methods combined with membrane technology. [ABSTRACT FROM AUTHOR]

Despite a declining trend, California remains a significant oil-producing state. For every barrel of crude oil, an average of 15 barrels of oilfield produced water (OPW) is generated, some of which is used to boost freshwater sources for crop irrigation in the agriculturally important Central Valley. OPW is known to contain salts, metals, hydrocarbons, alkylphenols, naturally radioactive materials, biocides, and other compounds from drilling and production processes. Less is known about the potential uptake and accumulation of these compounds in crops and soil irrigated with OPW. In this study, 23 potted mandarin orange plants were irrigated two to three times weekly (depending on season) with water containing three different concentrations of the known OPW heavy metals barium, chromium, lead, and silver. Seven sets of samples of soil and leaves and 11 fruits were collected and processed using microwave-assisted digestion (EPA Method 3051A). Processed samples were analyzed using inductively coupled plasma-optical emission spectroscopy (ICP-OES). Analysis of variance (ANOVA) and covariance (ANCOVA) coupled with Tukey’s honest significant difference test were used to examine the effects of metal concentrations in the irrigation water and number of watering days, respectively, on the metal concentrations in the soil, leaf, and fruit samples. Accumulation of barium in soil and leaves was strongly positively associated with sample and number of watering days, increasing nearly 2000-fold. Lead also showed an upward trend, increasing up to 560-fold over the baseline level. Total chromium showed an increase in the soil that tapered off, but less consistent results in the leaves and fruit. The silver results were more volatile, but also indicated at least some level of accumulation in the tested media. The smallest absolute accumulation was observed for chromium. Concentrations in the fruit were highest in the peel, followed by pith and juice. Accumulation of all heavy metals was generally highest in the soil and plants that received the highest irrigation water concentration. Considering the potential for adverse human health effects associated with ingesting soluble barium contained in food and drinking water, and to a lesser extent chromium and lead, the study signals that it is important to conduct further research into the accessibility and bioavailability of the tested heavy metals in the soil and whether they pose risks to consumers. [ABSTRACT FROM AUTHOR]