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The cost of treatment of produced water prior to disposal forms a significant percentage of the total economic impact of pollutants in crude oil production. The treatment of produced water involves the removal of toxic compounds contained in the fluid to a level where it is considered safe before the water can be disposed, discharged or reused in the environment. Production chemicals have been identified as one of the sources through which these toxic compounds enter the produced water and therefore the need to evaluate the influence of these chemicals at their various injection rates on the quality of the produced water from the production process. This research study is a part of an on-going project on the application of environmental process engineering for pollutant reduction and energy savings in crude oil production. The study has found that the introduction of scale inhibitor, paraffin inhibitor, demulsifier, biocides and corrosion inhibitor at the rates of 10 ppm, 200 ppm, 15 ppm, 500 ppm and 10 ppm, respectively, yields a corresponding increase in the concentrations of ammonia, hydrocarbons, salinity, phosphates and nitrates in the produced water by 242%, 53%, 12.5%, 300% and −4.8%, respectively. The knowledge provided by this project will educate the oil and gas sector across the globe, aid engineers and operators understanding of produced water pollution mechanism during oil and gas production processes. The results of this research will also be useful in the design of crude oil production and produced water treatment processes in avoiding negative environmental impacts from the final effluent composition of produced water.

This work reports a novel carrier flotation protocol for removing scaling cations from an oilfield produced water source which significantly reduces the collector consumption by employing natural minerals such as quartz, montmorillonite and talcum as the scaling cations carriers. The scaling cations uptake onto all carrier minerals exhibited homogeneous and monolayer adsorption, which was mainly dominated by physisorption. After adding oleate collector, the scaling cations removal rate was further enhanced, which was attributed to its high affinity with the scaling cations. Notably, the talcum flotation process simultaneously offered a high scaling cations removal rate (76.1%) and mineral recovery rate (98.3%), which achieved a sediment yield reduction of 72.2%. By summarizing the characterization results, the scaling cations removal mechanisms were also proposed. Moreover, high regeneration efficiencies (86.1% and 84.8% for quartz and talcum regeneration within three cycles) were achieved by the proposed regeneration protocol. This carrier flotation protocol with its low collector consumption offered technical promise for scaling cations removal from oilfield produced water. HIGHLIGHTS Novel carrier flotation protocol to remove scaling cations from produced water.; Outstanding scaling inhibition and carrier mineral recycle efficiencies simultaneously achieved.; Comprehensive removal mechanisms of scaling cations are explored.; Spent carrier minerals could be effectively regenerated.;

Oilfield-produced water (PW) can be cleaned using a variety of techniques. However, traditional methods are often expensive and can generate secondary waste that pollutes the environment. In addition, PWs contain highly stable micronized dispersed oil, which makes conventional treatment ineffective in meeting regulatory requirements. As a result of their unique properties, magnetized nanoparticles can effectively remove emulsified and dissolved oil from PW. This study aims to evaluate the residual oil removal efficiency of bare maghemite (γ-Fe2O3) nanoparticles in treating oilfield-produced water (produced water).Several techniques for manufacturing maghemite nanoparticles were evaluated to select one that is both cost-effective and produces high-quality nanoparticles. After manufacturing nanoparticles with the selected method, the mineral composition and properties of the nanoparticles were determined. Subsequent experiments used synthetic and commercial nanoparticles to treat samples of PWs derived from oil and gas wells. By measuring the oil content of PW before and after treatment, the removal efficiencies of the nanoparticles were determined. Nanoparticles were recovered from treated PW samples, washed, and reused. Over ten times, they were recycled. The recycling potential of nanoparticles is evaluated by assessing the reduction in oil removal efficiency after recycling. Using fresh nanoparticles, over 98% of residual oil can be removed. Even after recycling more than 11 times, the oil content of treated PW samples was below the disposal limit. However, a slight reduction in the efficiency of the nanoparticles was observed. The reduction could be attributed to their dissolution in water and carryover during the treatment/demulsification operation.

The adsorption capacity of coconut shell activated carbon as adsorbent for the removal of total hydrocarbon from produced water was investigated. The physico-chemical properties of the produced water were determined and the adsorbent was characterized in terms of pH and other surface characteristics. The effects of adsorption process variables on the adsorption capacity of the activated carbon for the the removal of total hydrocarbon was evaluated and optimized using the response surface methodology. The adsorption process variables considered and their range of values are adsorbent dosage of 0.4 to 1.0 g, contact time of 20 to 60 mins and temperature of 30 to 50. The physicochemical properties of the produced water before treatment revealed that produced water was contaminated with a high concentration of hydrocarbon and other contaminants. Elemental composition showed that the adsorbent contained predominantly CaO (73.22%) and P2O5 (20.59%). The BET surface area, pore volume and pore size of the adsorbent were found to be 689.406 m2.g-1, 0.266 cm3.g-1 and 2.153 nm respectively. The maximum amount of THC adsorbed in the adsorption process was found to be 1,068,451.73 mg.g-1. This maximum was achieved using an adsorbent dosage of 0.40 g, a contact time of 60 mins at a temperature of 30. The high and close R-squared values of the experimental and predicted values of the THC adsorption indicate reasonable agreement. The high amount of THC adsorbed showed that coconut shell activated carbon is efficient for the treatment of wastewater streams laden with hydrocarbon.

Removal of organic pollutants and metal ions from produced water by adsorption, using prepared activated carbon (AC) from sewage sludge, with chemical activations using NaOH, KOH and ZnCl2 separately and pyrolysis at different temperatures (500, 600 and 700 °C). Pure sludge and prepared ACs were analyzed using FTIR and XRD. The results showed 18% crystallinity compared to that of commercial AC, which has 44% crystallinity. The results of FTIR demonstrate that the properties of the post-treated affect the final products depending on the method used and that it contains similar functional groups to those present in the commercial AC, but at a higher peak intensity. Adsorption treatments were carried out at 25, 35 and 45 °C solution temperatures. The results showed that the removal of pollutants from produced water using prepared AC with all types of chemical activations reached 99.5%, such as commercial AC with 0.06 g dosage of adsorbent at pyrolysis temperatures of 500 and 600 °C and a solution temperature of 25 °C. The obtained results refer to the mechanism of exothermic reaction and physical adsorption. It was observed that despite the lower dosage of adsorbent of 0.01 g, a sufficient treatment of pollutants was achieved. This reveals the effectiveness of using sewage sludge as a cheap adsorbent. Also, using pure sewage sludge, the adsorption data showed a 95.2% removal of the pollutants. This result indicated that pure sludge has an efficient adsorption capacity and can be utilized as a cheap and environmentally friendly material. For the removal of manganese and cadmium metal ions from the produced water, the resultant data showed that more than 90% of manganese was adsorbed and more than 97% of cadmium was adsorbed, especially when using pure sewage sludge and prepared activated carbon with NaOH chemical activation at pyrolysis temperatures of 500 °C and 600 °C.

Produced water (PW) from the Cuban oil industry is a source of oil and chemicals into the sea. This kind of wastewater is a complex mixture of organic and inorganic compounds. The high salinity, metals and sediment could pose severe environmental impacts upon inadequate disposal. This study is based on the treatment proposal of this kind of wastewater used nature zeolite (N-Z) taking into account the deposits of this material across the island. Results suggest that, significant changes between a doses in terms of the adsorption of organic compounds were not found evaluated by UV-Vis at 295nm, the behavior was for the basic pH of the solution and the textural characteristics of the N-Z such as low surface area of 35 m2/g. Differents doses of N-Z vs. CL were studied, the best to carry out the adsorption process was 0,5 g of zeolite per 50mL of clear liquid (CL)according to the evaluation of the solid phase by ICP-OES(Inductively coupled plasma - optical emission spectrometry) the higher doses increase the compounds that are part of the zeolite structure. On the other hand the evaluation of the liquid phase with the Spectrophotometer at 295nm were no observed significant changes, demonstrating the non-adsorption of organic compounds. At the best doses the selectivity of the zeolite of heavy metal was Zn2+> Fe2+> Cu2+> Mn2+ and the ion exchange occurring by Al2O3 and CaO, also was evaluated by TGA (Thermogravimetry) analysis detecting a small difference in ash content between the virgin and exhausted zeolite that confirm the adsorption of inorganic compounds. [ABSTRACT FROM AUTHOR]

When assessing the environmental risks of offshore produced water discharges, it is key to properly assess the toxicity of this complex mixture. Toxicity can be assessed either through the application of whole‐effluent toxicity (WET) testing or based on its substance‐based chemical composition or both. In the present study, the toxicity assessed based on WET and substance‐based was compared for 25 offshore produced water effluents collected for the Norwegian implementation of the Oslo–Paris convention risk‐based assessment program. The objectives were, firstly, to examine the concurrence between toxicity estimates derived from these two lines of evidence; and, secondly, to evaluate whether toxicity of produced water discharges predicted from substance‐based data is adequately addressed in comparison with ground truth reflected by WET. For both approaches, 50% hazardous concentrations (HC50s) were calculated. For at least 80% of the effluents the HC50s for the two approaches differed by less than a factor of 5. Differences found between the two approaches can be attributed to the uncertainty in the estimation of the concentration of production chemicals that strongly influences the substance‐based estimated toxicity. By evaluating effluents on a case‐by‐case basis, additional causes were hypothesized. Risk management will particularly benefit from the strength of risk endpoints from both approaches by monitoring them periodically in conjunction over time. This way (in)consistencies in trends of both indicators can be evaluated and addressed. Environ Toxicol Chem 2022;41:2285–2304. © 2022 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC. [ABSTRACT FROM AUTHOR]

Produced water is the main residue from the petroleum extraction industry. Other critical factor in this sector is carbon dioxide emissions. This work presents a solution proposal for both problems throughout the development of an apparatus which allows the synthesis of salts dissolved in produced water with CO2 capture. The experimental unit developed in this work was based on the Solvay process, to convert sodium chloride (NaCl) into sodium bicarbonate (NaHCO3) from synthetic produced water and carbon dioxide (CO2). No previous work used the combination of produced water and CO2 aiming at the synthesis of new products. Four steps were made with different experimental setups. The best outcome for the reaction of bicarbonate attained a conversion of 44.5% of sodium chloride into sodium bicarbonate and capture of 250,000 tons of carbon dioxide per year. A preliminary financial analysis indicates an annual revenue of US$ 126,607,292.31 in sodium bicarbonate and ammonium chloride and US$ 2,862,897.23 in carbon credits per year. The studied methodology can be used as a starting point for new experimental works that have the purpose to obtain salts from produced water and can help for better understanding its potential as carbon capture agent and a source of valuable products, contributing to the reduction of the environmental impact and adding value to the production chain. [ABSTRACT FROM AUTHOR]

Produced water contaminated with oil has adverse effects on human health and aquatic life. Providing an efficient method for the removal of oil from produced water is a challenging task. In this study, the effects of carbon chain length and the cation nature of ionic liquids (ILs) on the removal efficiency of oil from produced water were investigated. For this purpose, seven ILs containing the bis (trifluoromethylsulfonyl) imide (NTf2) anion, and various cations such as imidazolium, pyridinium, phosphonium, and ammonium, were employed for the removal of oil from produced water via liquid–liquid extraction. The effects of process parameters such as the initial concentration of oil in produced water, contact time, pH, salinity, phase ratio, and temperature on the removal efficiency of oil were studied and optimized. 1-Decyl-3-methyl-imidazolium bis(trifluoromethylsulfonyl)imide ([C10mim][NTf2]) (IL4) was found to give the highest oil extraction efficiency of 92.8% under optimum conditions. The extraction efficiency was found to increase with increasing cation alkyl chain length from C2 to C10. The extraction efficiency of ILs based on cations follows the order imidazolium > ammonium > phosphonium > anpyridinium. Fourier Transform infrared spectroscopy (FTIR) was used to explore the ILs interaction with oil using [C10mim][NTf2] as a model. In addition, 1H and 13C NMR spectra were recorded to obtain a better understanding of the molecular structure of IL and to investigate the peak shifts in H and C atoms. Moreover, the cell viability of the most efficient IL, [C10mim][NTf2], in human cells was investigated. It has been concluded that this IL exhibited minimal cytotoxic effects at lower concentrations against human cell lines and is effective for the extraction of oil from aqueous media. [ABSTRACT FROM AUTHOR]

This research addresses a gap in the produced water management (PWM) literature by providing a conceptual framework to describe the connections of PWM to regional water budgets. We use southeastern New Mexico as a case study, because the region is facing looming shortfalls in water availability, and oil and gas production generate high volumes of produced water in the region. The framework was developed through expert interviews, analysis of industry data, and information gained at industry meetings; it is supported by detailed descriptions of material flows, information flows, and PWM decisions. Produced water management decisions may be connected to regional water budgets through dynamic complexities; however, modeling efforts exploring PWM often do not capture this complexity. Instead, PWM is most often based on the least expensive management and disposal alternatives, without considering short and long-term impacts to the regional water budget. On the other hand, regional water budgets do not include treated produced water as a potential resource, thus missing opportunities for exploring the impact of potential beneficial reuse. This is particularly important when there is a need to address water shortages in chronically water-short regions of the United States. At the same time, oil and gas production in the western United States is challenged by the need to dispose of large volumes of produced water. The framework is useful for developing improved models of PWM to identify the impact of alternative management decisions on regional water budgets. [ABSTRACT FROM AUTHOR]

The rapid development of unconventional oil and gas (O&G) extraction around the world produces a significant amount of wastewater that requires appropriate management and disposal. Produced water (PW) is primarily disposed of through saltwater disposal wells, and other reuse/disposal methods include using PW for hydraulic fracturing, enhanced oil recovery, well drilling, evaporation ponds or seepage pits within the O&G field, and transferring PW offsite for management or reuse. Currently, 1–2% of PW in the U.S. is used outside the O&G field after treatment. With the considerable interest in PW reuse to reduce environmental implications and alleviate regional water scarcity, it is imperative to analyze the current regulatory framework for PW management and reuse. In the U.S., PW is subject to a complex set of federal, state, and sometimes local regulations to address the wide range of PW management, construction, and operation practices. Under the supervision of the U.S. Environment Protection Agency (U.S. EPA), different states have their own regulatory agencies and requirements based on state-specific practices and laws. This study analyzed the regulatory framework in major O&G-producing regions surrounding the management of PW, including relevant laws and jurisdictional illustrations of water rules and responsibilities, water quality standards, and PW disposal and current/potential beneficial reuse up to early 2022. The selected eastern states (based on the 98th meridian designated by the U.S. EPA as a tool to separate discharge permitting) include the Appalachian Basin (Marcellus and Utica shale areas of Pennsylvania, Ohio, and West Virginia), Oklahoma, and Texas; and the western states include California, Colorado, New Mexico, and Wyoming. These regions represent different regulations; climates; water quantities; quality diversities; and geologic, geographic, and hydrologic conditions. This review is particularly focused on the water quality standards, reuse practices and scenarios, risks assessment, knowledge gaps, and research needs for the potential reuse of treated PW outside of O&G fields. Given the complexity surrounding PW regulations and rules, this study is intended as preliminary guidance for PW management, and for identifying the knowledge gaps and research needs to reduce the potential impacts of treated PW reuse on the environment and public health. The regulations and experiences learned from these case studies would significantly benefit other states and countries with O&G sources for the protection of their environment and public health. [ABSTRACT FROM AUTHOR]

In recent years, environmental concerns have urged companies in the energy sector to modify their industrial activities to facilitate greater environmental stewardship. For example, the practice of unconventional oil and gas extraction has drawn the ire of regulators and various environmental groups due to its reliance on millions of barrels of fresh water—which is generally drawn from natural sources and public water supplies—for hydraulic fracturing well stimulation. Additionally, this process generates two substantial waste streams, which are collectively characterized as flowback and produced water. Whereas flowback water is comprised of various chemical additives that are used during hydraulic fracturing; produced water is a complex mixture of microbiota, inorganic and organic constituents derived from the petroliferous strata. This review will discuss the obstacles of managing and treating flowback and produced waters, concentrating on the hardest constituents to remove by current technologies and their effect on the environment if left untreated. Additionally, this work will address the opportunities associated with repurposing produced water for various applications as an alternative to subsurface injection, which has a number of environmental concerns. This review also uses lithium to evaluate the feasibility of extracting valuable metals from produced water using commercially available technologies. [ABSTRACT FROM AUTHOR]

Saudi Aramco conducted comprehensive a field-testing program of produced water desalination technologies primarily targeted for produced water reuse as process/utility water and other industrial purposes with low total dissolved solids (TDS) (<1,000 mg/L). The main driver for the produced water re-use program was due to, firstly transition from linear model of economic growth, which is based on "take-make-dispose", which is not sustainable to circular economy model supporting "closing the loop" of recovering value from produced water considered waste stream and secondly the conservation of Saudi Arabia's precious non-renewable ground water resources which are currently used for crude washing in desalting across Saudi Aramco. The program will reuse produced water in its oil operations, with potential ground water savings up to several billion gallons annually post implementation and also enable circularity sustainably in its oil operations. The objectives of the program were to evaluate the produced water desalination with minimum 70% recovery factor as performance for two different configurations, that is, desalination of low salinity (TDS) produced water (<15,000 mg/L) and high salinity (TDS) produced water (<120,000 mg/L). A US patent 10,703,989 was also granted for the concept of produced water reuse. Produced water desalination testing was conducted at two different produced water streams in Arab Light crude oil at two different sites with gravities of 36-41 API, to determine the desalination performance and challenges with pre-treatment. Variation in feed conditions such as flow rate, temperature, inlet oil in water concentration and H2S in water, recovery factor were introduced to establish operating envelopes for the produced water desalination systems. The performance of two field produced water desalination technologies was evaluated by determining the salinity (TDS) and oil in water concentration at different operating conditions. Prior to piloting the laboratory bench test were conducted at lab scale to characterize the performance of produced water. The lab test helped identify the challenges during pilot testing and demonstrated that produced water desalination for sustained flow conditions. This paper presents the key results of produced water re-use program along with two field tests as well as the path forward to deployment of these technologies to unlock the value for produced water as resource in circular economy. The implications of this program success extend beyond Saudi Aramco. By increasing produced water reuse in the oil and gas processing, more groundwater will be available for non-industrial applications in Saudi Arabia, which reduces reliance on seawater desalination. [ABSTRACT FROM AUTHOR]

In this study, boron carbon nitride (BCN) nanostructures were used as a photocatalyst which was synthesized in a chemical vapor deposition reactor. Photoelectrocatalysis was used for degradation organic pollutants from produced water. BCN nanostructures were coated on a coil-type copper wire to act as anode electrode in the photoelectrocatalytic process. The effect of different parameters on chemical oxygen demand (COD) removal efficiency from produced water was investigated by a central composite design (CCD) to maximize photoelectrocatalysis influence as one of the most used methods of wastewater treatment. A 12 run Plackett–Burman design was used for screening of the parameters (initial COD, electrical conductivity, applied cell voltage, UV lamp wavelength, H2O2 concentration, residence time, and initial pH) which led to the selection of residence time and initial pH as effective parameters. Since the core goal of this study was to maximize the COD removal efficiency, the steepest ascent method was used to propel these two parameters to the optimum region. Finally, CCD showed that applying photoelectrocatalysis could lead to 88.79% of the COD removal efficiency which would be an optimum value at a residence time of 15.85 min and a pH value of 3.3. Ultimately, this result was confirmed by experimentation at those conditions. HIGHLIGHTS Boron carbon nitride nanomaterials were synthesized as photocatalyst.; A Plackett–Burman design was used for screening of the effective parameters.; Chemical oxygen demand (COD) of produced water was decreased by photoelectrocatalysis.; A central composite design was used for the optimization of COD removal efficiency.;

In this study, a combined lab-scale purification system was set up to treat wastewater from the National Iranian Oil Company. The combined system was composed of three main sections: pre-filtration using activated carbon filter (ACF), electrocoagulation (EC) system, and a filtration section (MF followed by RO). The performance of the treatment system was evaluated by measuring heavy metals, BOD, COD, TDS, TSS, and O&G. The results showed that pre-filtration using ACF could lead to the removal of the BOD, COD, TDS, TSS, and O&G by 24.6%, 21.12%, 31.07%, 36.9% and 8.49%, respectively; the heavy metals were removed significantly. In the EC section, heavy metals were rejected by more than 98% using both the Al and Fe electrode, except for the Cr ions that were mostly removed with Fe electrodes. The removal of BOD, COD, TDS, TSS, and O&G using the Al and Fe electrode was 95.6%, 96%, 91%, 76.6%, and 98.6% and 93.2%, 92.1%, 76%, 83% and 99%, respectively. EC followed by MF/RO filtration led to a remarkable purification performance, and the rejection rate of all pollutants was obtained over 99% after this section. The experimental results indicated that the optimum time for ACF and EC processes were 20 and 50 minutes.

We consider the design and operation of water networks simultaneously. Water network problems can be divided into two categories: the design problem and the operation problem. The design problem involves determining the appropriate pipe sizing and placements of pump stations, while the operation problem involves scheduling pump stations over multiple time periods to account for changes in supply and demand. Our focus is on networks that involve water co-produced with oil and gas. While solving the optimization formulation for such networks, we found that obtaining a primal (feasible) solution is more challenging than obtaining dual bounds using off-the-shelf mixed-integer nonlinear programming solvers. Therefore, we propose two methods to obtain good primal solutions. One method involves a decomposition framework that utilizes a convex reformulation, while the other is based on time decomposition. To test our proposed methods, we conduct computational experiments on a network derived from the PARETO case study. • Obtaining feasible solutions for water network problems is very challenging for MINLP solvers.. • We developed two methods for finding feasible solutions for water network problems. • We applied the proposed methodology to the PARETO case study. [ABSTRACT FROM AUTHOR]

Chemical additives used for hydraulic fracturing and matrix acidizing of oil reservoirs were reviewed and priority chemicals of concern needing further environmental risk assessment, treatment demonstration, or evaluation of occupational hazards were identified. We evaluated chemical additives used for well stimulation in California, the third largest oil producing state in the USA, by the mass and frequency of use, as well as toxicity. The most frequently used chemical additives in oil development were gelling agents, cross-linkers, breakers, clay control agents, iron and scale control agents, corrosion inhibitors, biocides, and various impurities and product stabilizers used as part of commercial mixtures. Hydrochloric and hydrofluoric acids, used for matrix acidizing and other purposes, were reported infrequently. A large number and mass of solvents and surface active agents were used, including quaternary ammonia compounds (QACs) and nonionic surfactants. Acute toxicity was evaluated and many chemicals with low hazard to mammals were identified as potentially hazardous to aquatic environments. Based on an analysis of quantities used, toxicity, and lack of adequate hazard evaluation, QACs, biocides, and corrosion inhibitors were identified as priority chemicals of concern that deserve further investigation.

Treatment and subsequent re-use of wastewater from shale gas extraction is a feasible strategy to ensure sustainability and reduce the environmental impact of the process. Here we demonstrate the photocatalytic benefits of improved three-dimensional graphitic carbon nitride (3D g-C3N4) during the degradation of organic contaminants. We show that precursor ratio (melamine to cyanuric acid) affects both the properties of 3D g-C3N4 as well as catalytic performance. When optimized, 3D g-C3N4 displayed the highest organics removal rate in brine-free solutions, achieving 99% conversion within 240 min. Significantly, the 3D g-C3N4 materials improved photocatalytic activity even in simulated shale gas brine solutions.

This paper explores the possibility and plausibility of developing a hybrid simulation method combining agent-based (AB) and system dynamics (SD) modeling to address the case study of produced water management (PWM). In southeastern New Mexico, the oil and gas industry generates large volumes of produced water, while at the same time, freshwater resources are scarce. Single-method models are unable to capture the dynamic impacts of PWM on the water budget at both the local and regional levels, hence the need for a more complex hybrid approach. We used the literature, information characterizing produced water in New Mexico, and our preliminary interviews with subject matter experts to develop this framework. We then conducted a systematic literature review to summarize state-of-the-art of hybrid modeling methodologies and techniques. Our research revealed that there is a small but growing volume of hybrid modeling research that could provide some foundational support for modelers interested in hybrid modeling approaches for complex natural resource management issues. We categorized these efforts into four classes based on their approaches to hybrid modeling. It appears that, among these classes, PWM requires the most sophisticated approach, indicating that PWM modelers will need to face serious challenges and break new ground in this realm.

This study reports a novel approach of resource recovery from co-managing two geographically co-located and chemically complementary wastewaters using a pilot-scale treatment process. Designed to treat flue gas desulfurized (FGD) effluent from combustion powerplants and produced water (PW) from energy industries, the process consists of soda-ash softening, nanofiltration (NF), and reverse osmosis (RO). Recovered products are barite, calcite, and low-salinity water. Using field-collected waters, the results show that softening at pH ≈ 8.5 produces calcite (yield: ~ 30 kg/m3 treated water), a chemical used as SO₂ (g) scrubbers. NF treatment under an applied pressure of ~ 3.5 MPa yields a permeate stream laden with monovalent ions (water recovery ~ 60 %) and a concentrate stream with a sulfate concentration ~ 1.8 times of the feedwater concentration. Mixing the NF concentrate and PW at a volumetric ratio of 1.0 precipitates a high-density barite material (4.1 g/cm3, yield: ~ 7.5 kg/m3 mixture) – a critical mineral commonly used as a weighting agent in drilling. The RO treatment recovers >64 % water as the permeate, which can be readily used as cooling make-up water at the powerplants. The RO concentrate stream can be further processed in a thermal evaporative system for additional water recovery and brine production. [Display omitted] • FGD effluent and PW have complimentary chemistries for critical mineral recovery. • FGD and PW co-treatment recovered barite, calcite, and low-salinity water. • Successful pilot-scale operation demonstrated feasibility of the co-treatment approach. [ABSTRACT FROM AUTHOR]

Oil and gas activities are sources of marine microplastics (MPs) but have received less attention globally. This study assessed the distribution characteristics and ecological risks of MPs in 31 sediment samples and effluent samples of 5 oil and gas platforms related to offshore oil and gas activities in the Bohai Sea. The results showed that the mean abundance of MPs in sediment, produced water, and domestic sewage was 205.7 ± 151.5 items/kg d.w., 18 ± 11 items/L, and 26 ± 39 items/L, respectively. The MPs in sediments and effluents were dominated by transparent, rayon, and fibers <1 mm. Oil and gas activities may influence the abundance of MPs in the sediments. The sediments in the area were at a low level of risk, but some samples exhibited indexes beyond low levels. The mass of MPs carried by the effluents from oil and gas platforms in the Bohai Sea was less than that of other sources. [Display omitted] • Oil and gas activities may somewhat impact on the abundance of MPs in sediments. • Annual loads of MPs from effluents were much less than those from other sources. • Some sediment and effluent samples exceeded the low level of risk. • Regional ecological risk assessment of MPs in sediments was at a low risk level. [ABSTRACT FROM AUTHOR]

Membrane technology presents an effective solution for treating oily wastewater, a significant environmental hazard stemming from industries such as food processing, metalworking, and oil extraction. Compared to polymeric membranes, ceramic ones exhibit superior mechanical, chemical, and thermal stability, enabling more effective oil removal and easier cleaning. Despite their advantages, membrane fouling remains a challenge, impacting the efficiency of oily wastewater treatment. This review explores oily wastewater characteristics and ceramic membrane applications in treatment processes. It examines the factors influencing ceramic membrane fouling, including wastewater properties (e.g., oil concentration, pH), membrane characteristics (e.g., surface hydrophilicity, charge), and operational parameters (e.g., cross-flow velocity, permeate flux). Strategies to mitigate fouling, such as pretreatment, backpulsing/backwashing for sustained operation, and chemical cleaning for fouling removal, are discussed. By using pretreatment, membrane fouling can be reduced. Backpulsing/backwashing is effective to maintain a long-term operation. Chemical cleaning is effective in removing irreversible fouling and restoring the performance of the ceramic membranes. Moreover, membrane modification techniques that enhance performance are highlighted. Ultimately, the review identifies that effective fouling control is crucial for optimizing ceramic membrane use in oily wastewater treatment, underscoring the need for ongoing research in this area. • Ceramic membrane technology is promising for oily wastewater treatment. • The factors affecting ceramic membrane fouling during oily wastewater separation are discussed. • The commonly used strategies for fouling control of ceramic membranes are reviewed. • Opportunities for improved fouling control are identified. [ABSTRACT FROM AUTHOR]

As worldwide reliance on the petroleum industry persists, environmental concerns associated with offshore oilfield operations continue to present a critical challenge for sustainable management. This study develops and tests a novel life cycle assessment (LCA)-based framework to examine strategies for produced water (PW) management from offshore oilfield operations. The framework encompasses experimental designs under a dynamic modelling system coupled with stepwise linear regression, multi-criteria decision analysis (MCDA), and fluctuating scenarios in Enhanced Oil Recovery (EOR) and other internal reuse options including cooling systems, drilling operations, and utility services. Two strategies for treatment train technologies were tested with various PW compositions, sludge management options, and variable EOR demands. When comparing conventional (corrugated plate interceptor, hydrocylone and nutshell filter) with recent treatment/disposal technologies (tubular separation, combined fiber coalescence and mechanical vapor compression), the LCA revealed that the latter increased operational efficiency (14%), reduced cost (6.5%) and the overall environmental impact categories (66%). The scenario that exhibited the lowest emissions incorporated recent treatment technologies and land application for sludge management. This configuration demonstrated considerable environmental advantages, evidenced by significant reductions in key impact indicators including freshwater eutrophication (74%), global warming (64%), marine ecotoxicity (58%), and stratospheric ozone depletion (44%) when compared to the baseline scenario with conventional treatment-disposal methods. The system dynamics model revealed that the internal reuse options exploited 23%–47% of PW inflow, indicating a significant annual surplus of unused PW that presents an opportunity for external applications to enhance sustainability. In closure, we argue that the proposed framework offers a valuable tool for waste management practitioners, facilitating the identification and selection of strategies with minimal environmental impacts for PW management. [Display omitted] • Developed an LCA-based framework for produced water (PW) management in offshore oilfields. • Integrated dynamic modeling, linear regression, and decision analysis for PW management strategies. • Compared environmental impacts of conventional and recent PW treatment technologies. • Emphasized operational efficiency, cost, and environmental impacts in diverse PW scenarios. • Demonstrated the framework's enhancement of PW management evaluation. [ABSTRACT FROM AUTHOR]

[Display omitted] • An advanced strategy for enhancing lithium extraction was investigated by modifying LDH with PAA. • The enhancement was driven by charge transfer and the increased electron cloud density. • This new adsorbent demonstrated excellent cyclic application performance. This study presents an advanced strategy for developing a novel poly(acrylic) acid-modified layered double hydroxide (PAA@LDH) for enhanced lithium adsorption. The optimal modification conditions include the use of a 2.5 % PAA solution in deionized water, an LDH powder dosage of 90 mL/g, and direct mixing at 333 K. Under these conditions, additional negatively charged functional groups were introduced into the material structure, thereby improving charge transfer, increasing electron cloud density, and lowering equipotential charge, as determined by DFT calculations. Consequently, the modified adsorbent exhibited a substantial rise in lithium adsorption capacity, increasing from 2.08 mg/g to 3.41 mg/g in produced water with low lithium concentration. Adsorption kinetics were rapid, reaching equilibrium within 40 min, and the adsorption behavior conformed to the Langmuir isotherm model. Besides, the adsorbent exhibited excellent selectivity for Li+ ions and maintained its performance at approximately 3.40 mg/g over seven cycles when regenerated under neutral conditions. The findings establish a robust framework for designing innovative adsorbent systems for lithium recovery from aqueous sources like produced water. [ABSTRACT FROM AUTHOR]

We analyze the use of excess natural gas (currently flared/vented) to instead treat oilfield-produced water via reverse osmosis (RO) to generate ultrapure electrolysis-grade water (Total Dissolved Solids (TDS): 0.028‐0.5 ppm) for green hydrogen production. We combine an analytical ε-MTU model and C Pavg model to predict average permeate concentration, to obtain improved estimates of electrolysis-grade water production from RO systems. The theoretical upper limit of the recovery of a RO system (similar to Carnot efficiency of heat engines) is established. Analysis is conducted for conditions corresponding to Niobrara Shale field (TDS: 29.1 g/L), as well as for brackish water (TDS: 5-15 g/kg) and seawater (TDS: 35–45 g/kg) feeds. Results show that electrolysis-grade water production can be as high as 0.75 m3 per cubic meter of water treated, with 1.38 m3 of natural gas providing the required energy. This translates to hydrogen production of 74.6 kg per cubic meter of produced water treated. Relatively low volumes of gas can treat large water volumes (<4 % of excess gas in Niobrara Shale can treat the entire quantity of produced water). These numbers highlight the benefits of our approach of utilizing two waste streams to create a high-value commodity, critical for decarbonization. [Display omitted] • Waste-to-value conversion: Oilfield produced water to electrolysis-grade water. • Reverse osmosis-based treatment using flared natural gas as energy source. • 1 m3 produced water can yield upto 0.75 m3 of electrolysis-grade water. • < 4 % of excess gas in Niobrara Shale can treat entire quantity of produced water. • Analytical model developed and theoretical upper limit of performance established. [ABSTRACT FROM AUTHOR]

Wastewaters generated by crude oil extraction processes, called "produced waters" (PWs), are complex solutions that contain organic compounds, mainly hydrocarbons, and often exhibit high salinity. The large amounts of PWs represent a global issue because of their environmental impact. An approach widely used in the oil industry is the reinjection of this wastewater into the extraction wells after a suitable treatment. The high salt concentration of such solutions may be used in salinity gradient technologies to produce green electricity. Among these technologies, reverse electrodialysis (RED) is one of the most promising. In this work, the application of RED for energy generation from two different real oil industry brines was investigated. An experimental campaign was performed by testing 10 × 10 cm2 units in long-run continuous operations, monitoring the performance for more than 25 days. Fouling phenomena, occurring during the continuous operation, decrease the unit performance and several anti-fouling strategies were adopted to tackle this issue. As a result, a positive net power density for up to 18 days of continuous operation was obtained. A maximum power density of about 2.5 W/m2 was observed, demonstrating how the RED technology could be an important strategy to harvest energy from an industrial waste. [ABSTRACT FROM AUTHOR]

The produced water is considered one of the largest waste streams in the oil and gas industries. Untreated produced water discharge damages the environment. Forward osmosis utilizes a dilute solution to concentrate contaminated streams to treat produced water. This paper tried to shed some light on forward osmosis's potential in treating produced water, measuring forward osmosis commercial membrane's effectiveness in treating produced water feed taken from two different points in an oil and gas facility in Malaysia. The rejection for chemical oxygen demand and boron was greater than 80 %, and a considerable decrease in forward osmosis flux was observed. The corrugated plate interceptor's inlet feed decreased by 73 % relative to the initial flux, while it decreased by 52.5 % for equalization tank feed. Design expert® was used to optimize the process using a one‐factor experimental design. The regression models indicated a good fit of model. The R2 was 0.9393 and 0.9888 for corrugated plate interceptor's inlet, and the equalization tank produced water, respectively. The optimization results concluded a 20 % draw solution concentration with the desirability of 0.927 and 0.987 for two feed waters. [ABSTRACT FROM AUTHOR]

The failure of the outlet pipeline and its accessories of high-pressure pump in oil field has great harm. Taking the fracture accident of pressure gauge joint at the outlet of produced water reinj ection pump in an oil field as an example, this paper studied the causes of fracture failure of the joint, experimentally detected and analyzed the chemical composition, hardness, metallographic structure and inclusions of the fracture joint, observed and analyzed the macro morphology of the fracture, and observed the micro morphology of the fracture by scanning electron microscope and energy spectrum analysis, The structure and service conditions of the joint are studied. The results showed that the fracture of the joint was caused by chloride stress corrosion cracking. The presence of H2S in the medium played a certain role in promoting the corrosion cracking. There was no fillet transition at the joint between the external thread undercut and the nut, resulting in stress concentration, which made the joint fracture at this place. It is recommended to test such pipe fittings in service in the same environment to eliminate potential safety hazards of the pipeline. [ABSTRACT FROM AUTHOR]

Produced water (PW) and crude glycerin (CG) are compounds overproduced by the oil and biodiesel industry and significant scientific efforts are being applied for properly recycling them. The aim of this research is to combine such industrial byproducts for sustaining the production of xanthan by Xanthomonas campestris. Xanthan yields and viscosity on distinct PW ratios (0, 10, 15, 25, 50, 100) and on 100% dialyzed PW (DPW) in shaker batch testing identified DPW treatment as the best approach for further bioreactor experiments. Such experiments showed a xanthan yield of 17.3 g/L within 54 h and a viscosity of 512 mPa s. Physical‐chemical characterization (energy dispersive X‐ray spectroscopy, scanning electron microscopy and Raman spectroscopy) showed similarities between the produced gum and the experimental control. This research shows a clear alternative for upcycling high salinity PW and CG for the generation of a valued bioproduct for the oil industry. [ABSTRACT FROM AUTHOR]

In this study, chitosan/ZnO nanocomposite was synthesized and employed for the first time as a selective adsorbent in produced water (PW) for the chemical oxygen demand (COD). Physical characteristics were studied using XRD, SEM, FTIR, BET, TGA, and XPS. Results showed that ZnO nanoparticles mobilized onto chitosan. The COD adsorption followed Langmuir isotherm with maximum monolayer adsorption. With a high coefficient of determination (0.98), COD adsorption followed the pseudo-second-order kinetics model. Furthermore, central composite design (CCD) in response surface methodology (RSM) was employed to assess different parameters' impact on COD adsorption. The parameters analyzed contain; solution pH, nanocomposite dose, and contact time. The COD removal efficiency was reported to be as high as 94.56%. The experimental results were in good accord with the model's predictions, demonstrating the value of the RSM technique in terms of optimization. Based on the present findings, it is possible to conclude that chitosan/ZnO nanocomposite, as a biocompatible, environmentally benign, and cost-effective material, can be a viable option for adsorption of organic pollutants and a way forward to a sustainable environment. [ABSTRACT FROM AUTHOR]

The treatment of produced water, associated with oil & gas production, is envisioned to gain more significant attention in the coming years due to increasing energy demand and growing interests to promote sustainable developments. This review presents innovative practical solutions for oil/water separation, desalination, and purification of polluted water sources using a combination of porous membranes and plasma treatment technologies. Both these technologies can be used to treat produced water separately, but their combination results in a significant synergistic impact. The membranes functionalized by plasma show a remarkable increase in their efficiency characterized by enhanced oil rejection capability and reusability, while plasma treatment of water combined with membranes and/or adsorbents could be used to soften water and achieve high purity. [ABSTRACT FROM AUTHOR]

A comprehensive study using a novel aluminum oxide microfiltration (MF) membrane and a thorough analysis of the effects of various operating conditions on the treatment of produced water were carried out. To set up the experiments and optimize the process parameters, an L9 orthogonal array of the Taguchi method and the larger-the-better target group analysis method was used. The impacts on filtrate flux and fouling control of operating conditions such as pH, temperature, crossflow velocity (CFV), and transmembrane pressure (TMP) were examined. Optimum operating conditions were determined to be 50°C, 1.8 bar, 1.8 m/s , and a pH of 5 and allowing for a maximum flux of 975 L/h·m2. The microfiltration (MF) membrane showed an oil-rejection rate of 98.25%, and the CFV was considered to be the most significant operating variable contributing to the regulation of the flux. Furthermore, 97% recovery was achieved with a mixture of cleaning solutions combining NaOH and HNO3. Two flux decline models were used to interpret the data including the Hermia and an artificial neural network (ANN). Hermia's cake-forming process had the average highest correlation with permeate flux decline data for the nine experiments (R2=0.83). Using ANN simulation, the best results were obtained with two hidden layers and 25 neurons in each layer. Its performance in terms of the mean squared error as a percentage of the maximum flux was 0.4%. [ABSTRACT FROM AUTHOR]

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Produced water is a significant waste stream that can be treated and reused; however, the removal of production chemicals-such as those added in hydraulic fracturing-must be addressed. One motivation for treating and reusing produced water is that current disposal methods-typically consisting of deep well injection and percolation in infiltration pits-are being limited. Furthermore, oil and gas production often occurs in arid regions where there is demand for new water sources. In this paper, hydraulic fracturing chemical additive data from California are used as a case study where physical-chemical and biodegradation data are summarized and used to screen for appropriate produced water treatment technologies. The data indicate that hydraulic fracturing chemicals are largely treatable; however, data are missing for 24 of the 193 chemical additives identified. More than one-third of organic chemicals have data indicating biodegradability, suggesting biological treatment would be effective. Adsorption-based methods and partitioning of chemicals into oil for subsequent separation is expected to be effective for approximately one-third of chemicals. Volatilization-based treatment methods (e.g. air stripping) will only be effective for approximately 10% of chemicals. Reverse osmosis is a good catch-all with over 70% of organic chemicals expected to be removed efficiently. Other technologies such as electrocoagulation and advanced oxidation are promising but lack demonstration. Chemicals of most concern due to prevalence, toxicity, and lack of data include propargyl alcohol, 2-mercaptoethyl alcohol, tetrakis hydroxymethyl-phosphonium sulfate, thioglycolic acid, 2-bromo-3-nitrilopropionamide, formaldehyde polymers, polymers of acrylic acid, quaternary ammonium compounds, and surfactants (e.g. ethoxylated alcohols). Future studies should examine the fate of hydraulic fracturing chemicals in produced water treatment trains to demonstrate removal and clarify interactions between upstream and downstream processes.