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In the present study, a bioelectrochemical reactor (BEC) was utilized to treat two types of real saline produced water (PW). BEC was designed based on the combination of electrocoagulation (EC) process with halophilic microorganisms, and it was assessed in terms of biodegradation of hydrocarbons. The effects of various operating parameters including the current density, electrical contact time (On/Off), hydraulic retention time (HRT), and total dissolved solids (TDS) at different levels on the chemical oxygen demand (COD) removal efficiency, settleability, and performance of isolated halophilic microorganisms were examined. Additionally, a novel neural network (ANN) approach modelling using adaptive factors was used to predict and optimize the effects and interactions between operating parameters during BEC process by predicting complicated mechanisms and variations associated with microorganisms. In addition, a new algorithm was developed for the sensitivity analysis to achieve the optimum operating conditions and obtain maximum efficiency in COD removal, sludge volume index (SVI), mixed liquor suspended solids (MLSS), and specific electrical energy consumption (SEEC), simultaneously. BEC was found to be significantly more effective at removing most hydrocarbons, particularly pristine and phytane. In addition, the results showed a significant improvement in settling ability of the biological flocs with average SVI of 91.5 mL/g and a size of 178.25 μm using BEC. Based on estimated operating costs and energy consumption, BEC was more cost-effective and efficient than other bioelectrochemical systems. [ABSTRACT FROM AUTHOR]

Considering that high-purity fresh water is employed in the green production of hydrogen via commercial water electrolyzers and that over 80% of the global population faces significant water safety risks, it is essential to explore alternative water sources. One such alternative is the use of produced water from oil extraction processes. Hence, the main objective of this study is to evaluate the effect of the oil content of oilfield production water on the production of green hydrogen by electrolysis in the presence of carbon quantum dots (CQDs). For this purpose, various electrochemical techniques, such as linear sweep voltammetry (LSV), cyclic voltammetry (CV), and potentiometry, were used to identify the effect of crude oil during hydrogen production. Thermogravimetric analysis (TGA), mass spectrometry (MS), and Fourier-transform infrared spectroscopy (FTIR) were employed to discern the adsorption of crude oil onto the electrodes, quantify the gas fractions generated during the process and identify the functional groups present after the procedure, respectively. Also, optical microscopy was employed to follow the droplet size in the emulsion. The results show that using CQDs affects the Faradaic efficiency, which increases from 77% to 83% with the incorporation of CQDs. In the presence of CQDs, the effects generated by the presence of the oil are inhibited at low oil concentrations. On the contrary, hydrogen production increases by 10.0% (0.1 mL/min) with a faradaic efficiency of 83% and a half-cell efficiency of 41%, compared to the record obtained with the maximum concentration of emulsified crude oil (400 mg/L). The mean size of the initial emulsion droplets was 3.4 μm. At the end of the test, there was evidence of complete breakage of the emulsion due to the effect of the applied electric field. No evidence of adsorption of crude oil on graphite electrodes during electrolysis is observed based on the tests. It has been shown that green hydrogen production from crude oil production water is feasible due to the proposed disruptive electrolytes in the produced water, which inhibit the effect of oil content in the O/W emulsion. This allows the implementation of a new green energy production initiative aligned with the global goal of achieving net zero emissions (NZE) by 2050. The current investigation presents a prospective alternative for harnessing the 18 kW electrical energy potential employed within emulsion-breaking processes within a Colombian field for treatment of around 1000 bpd. This alternative offers a theoretical potential for hydrogen production, approximating 7.36 kW, thus representing a promising opportunity for practical field deployment. • CQDs in electrolysis enhance green hydrogen production efficiency from oilfield-produced water due to their conductive properties. • CQDs significantly increases Faradaic efficiency, inhibiting crude oil's negative effects on hydrogen generation. • Optimized electrolysis with CQDs result in 10% higher hydrogen production at high concentrations of emulsified crude oil. • CQDs mitigate crude oil's negative effects on the system, such as reduced conductivity and electrode degradation. • Gas analysis demonstrates the feasibility of converting oilfield production water into a valuable resource for green energy. [ABSTRACT FROM AUTHOR]

Produced waters are often treated in open lagoons where hydrogen sulfide (H2S) can off gas, posing a risk to human health and the environment. The aim of this study was to optimize a treatment process using hydrogen peroxide (H2O2) to oxidize H2S while minimizing off gassing. Samples of produced water from West Texas and laboratory-prepared waters utilizing sodium sulfide (Na2S) or biogenic polysulfides were oxidized with H2O2 alone or in combination with copper or iron catalysts, sodium hydroxide (NaOH), or a commercial sulfide oxidizer, HydroPower Green™. Sulfur speciation was measured using Hach test kits for sulfide/sulfate/sulfite and Dräger tubes for headspace H2S. HydroPower Green™ (HPG) helped to reduce H2S in the headspace of water samples; some of this was pH related as NaOH also worked, but not as well as HPG. The dose of peroxide necessary to oxidize sulfides to sulfate is a function of the oxidation-reduction potential (Eh) of the water and total sulfide concentration as well as pH; approximately a 1–4:1 ratio of peroxide to sulfide concentration was needed to oxidize sulfidic waters of pH 7–10 with half-lives under 30 min. Both copper and iron catalysts reduce H2O2 demand and the half-life of H2S. Peracetic acid (PAA) and copper (II) sulfate pentahydrate (CuSO4, 5H2O) were explored as biocides for controlling sulfate-reducing bacteria (SRBs) that produce H2S. An AquaSnap (Hygenia) test kit was employed to monitor relative microbial activity in a wetland porewater containing H2S. Microbial regrowth occurred after a few days using the highest dose of PAA; these results showed that PAA was being used by bacteria as a carbon source even after the initial substantial reduction in the microbial activity. CuSO4, 5H2O at a dose of 1 ppm prevented microbial regrowth. The recommended treatment process from this research is determined by jar testing with H2O2, a base for pH control, a biocide, and possibly a metal catalyst or other co-oxidants in order to achieve oxidation of sulfides without H2S release or the precipitation of metal carbonates or oxides. [ABSTRACT FROM AUTHOR]

Almost all research on natural attenuation and phytoremediation of sites contaminated with briny produced water has been conducted in temperate climates, however, there is a dearth of information on the use of tropical species for this purpose. It is within this context, that we investigated a spontaneously growing hypersaline spikerush from a contaminated site in southeast Mexico, to determine its soil salinity limits, the relationship between soil organic matter and salinity, and for preliminary documentation of floristic succession with Typha sp. for phytoremediation o f brine s pills. Soil was sampled (0 cm–20 cm) three times between 2018–2021, focusing on the end of the dry season (most critical period). The species tentatively identified as Eleocharis mutata was tolerant to soil hypersalinity (Electrical Conductivity: 125 dS/m) and appeared to generate a cyclic process of succession to recover areas with soil salinity levels higher than it could otherwise tolerate. A salinity gradient was found between the most heavily contaminated part of the site (“kill zone”, > 212 dS/m), the first Eleocharis sp. individuals (125 dS/m), slowly advancing through the main spikerush stand, and finally into a cattail stand (< 8.02 dS/m). Similarly, an inverse relationship between Soil Organic Matter content and soil salinity was observed. This is the first time this species has been identified with a brine spill, its salinity limits determined, and investigated for use in phytoremediation of this kind. [ABSTRACT FROM AUTHOR]

The treatment of produced water is a major challenge faced by oil and gas industries worldwide. As a result of the increase in industrial activities, the generation of produced water has increased significantly. The most commonly used method for produced water oil–water separation is de-oiling hydrocyclone technology due to its simple construction, compact design, easy maintenance, and high efficiency. A wide breadth of scientific research studies has been carried out on performance evaluation, design optimisation, geometric parametrisation, external interventions, etc., to enhance the performance of hydrocyclones. These studies mostly rely on either experimental data obtained from the field, in laboratories under a controlled environment, or the application of numerical techniques for oil-in-water separation. Considering the extensive research studies published on hydrocyclone technology, this study aims to provide a comprehensive review of recent technological advancements in hydrocyclone technology in order to identify key areas where scientific research efforts should be concentrated. This will help make well-informed decisions for strategic investments in this wide area of research. Furthermore, it will widen the scope of applicability of hydrocyclones in the industrial sector. [ABSTRACT FROM AUTHOR]

Copyright of Tikrit Journal of Engineering Sciences is the property of Republic of Iraq Ministry of Higher Education & Scientific Research (MOHESR) 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.)

Gravity settling is a widely employed technology that removes oil from produced water in oilfields. However, with the transition of reservoir development to low-permeability reservoirs, conventional produced water settling tanks face limitations in the treatment efficiency and coagulant dosage. This study presents an innovative approach that optimizes sedimentation tank structures and integrates micro-vortex flow technology to enhance coagulation and flocculation. Through chemical dosage experiments, comparative experiments, and long-term observation, the micro-vortex flow reactor demonstrates a 9.4% increase in oil removal efficiency while reducing the coagulant dosage by 30.0%. The MOR equipment achieved a 20.5% higher oil removal efficiency than conventional methods while maintaining effluent oil and suspended solids below 20 mg/L. The long-term observation experiment of MOR equipment further highlights oil removal efficiency of 94.2% and the micro-vortex reactor's excellent anti-pollution performance. The MOR equipment significantly reduces the land occupancy area by over 50% compared to conventional methods, thanks to the implementation of micro-vortex flow technology that effectively addresses the limitations associated with traditional settling tanks. This study contributes to advancing efficient and sustainable practices in waterflooding reservoirs, particularly for meeting stringent standards of water injection in low-permeability oilfields. [ABSTRACT FROM AUTHOR]

The purpose of this work is to study the influence of oil and surfactant present in produced water on the membrane distillation and membrane crystallization performance. The latter is evaluated in terms of permeate flux, quality of permeate and sodium chloride crystallization kinetics. Polypropylene and Hyflon AD40H/PVDF composite membranes with 0.2 μ m pore size were used in the investigation. The tests were carried out in direct contact configuration using two synthetic feed solutions: the first one without oil and surfactant, and the second one with oil and surfactant. The achieved results showed a permeate flux reduction of 20 and 40% for PP and AD40H, respectively, in membrane distillation and of 35% in membrane crystallization. These results may be attributed to the interaction between the salts and surfactant, which led to the deterioration of the membrane performance. Despite this, high salt rejection factors greater than 99.9% and total carbon rejections ranging between 80 and 90% indicated the good potential of membrane distillation technology for the treatment of produced water. Moreover, good quality crystals and high total water recovery factor (97%) were achieved using the membrane crystallization process. Nevertheless, the presence of oil and surfactant in the feed caused an increase in the induction time compared to the system without oil and surfactant. In addition, in the performed experiments, simple physical cleaning with distillate water was sufficient to recover the initial trans-membrane flux of the membranes. [ABSTRACT FROM AUTHOR]

One of the most common problems encountered in the oil industry is the microbiologically induced corrosion (MIC) of steel equipment by the produced water (PW). In this aspect, PW sample, which is known to contain microorganisms, was taken from Adıyaman oil field and used in corrosion tests of N80 tubing steel. Two different laboratory scale systems, test (with non-sterile PW) and control (with sterile PW), were set up and operated at 70°C over 720 h. For corrosion analysis, the coupons were removed from the laboratory-scale systems at certain time intervals and, gravimetric and electrochemical analyses were carried out. The surface of the coupons was examined by scanning electron microscopy (SEM). The corrosion rates of the test coupons obtained from gravimetric analyses were higher than the control ones during the experiment, and the test coupons were 1.46 times more corroded at the end of the experiment. Additionally, it was determined that the current values of the test coupons were significantly higher than those in the control system (p<0.05). The results of corrosion analyses pointed out that N80 steel was corroded microbiologically. SEM analysis showed that microorganisms were present among the corrosion products. The corrosion data obtained from the control system also indicated that the PW was aggressive for N80 steel. [ABSTRACT FROM AUTHOR]

Two pilot-scale desalination systems employing carbon modified nano-sized, zero valent metals (n-ZVMs) were manufactured and tested to determine (1) the degree to which high-salt water (20 to 130 mS) could be desalinated and (2) if this degree of desalination could be maintained throughout an extended treatment period. The two pilot systems (referred to as Generation 1 and Generation 2) consisted of parallel lines of four individual reactors in series, a settling tank and an activated carbon cell at the end of each reactor line. The system capacity was 300 gal in Generation 1 and 600 gal in Generation 2 with a total hydraulic residence time of 6 h per reactor line (one hour per cell/tank). A slurry of n-ZVMs manufactured from mixtures of ferrous sulfate and green or black tea extract was introduced in the first reactor on each line to yield approximately 5 to 45 g of nano metal per 100 L of influent salt water based on dosing experiments required to achieve maximum salt removal at each of the three influent salt contents used, 28 mS, 44 mS and 123 mS. Once dosing was set, continuous runs (14 days, 23 days and 9 days) were carried out. The results demonstrated that maximum removal occurred with 10 g/100 L of salt for the 30 mS salt solution, 16 g/100 L of salt for the 40 mS influent water and 40 g/100 L for the 130 mS influent. Salt removal (expressed as Na+ and Cl− removed) approached 78% for the 30 mS influent and 41 mS influent, respectively, while removal for the highest concentration salt influent (130 mS) approached 81%. Continuous operation over the extended time-period showed no significant decrease in salt removal with a typical day to day variation of no more than 10%, suggesting that this approach to desalination could rapidly provide usable water from saline aquifers, seawater or even produced water. [ABSTRACT FROM AUTHOR]

Numerous treatment modalities have been employed over the years to eradicate bacterial communities in industrial wastewater. Oxidizing agents and chemical additives, such as ozone, permanganate, glutaraldehyde, and chlorine, are effective in treating microbial contaminants that are typically found in domestic wastewater. However, the chemical complexity of water produced from fracking requires novel approaches, because the microbes have developed mechanisms to overcome typical disinfectants. In this work, we test the effectiveness of bacteriophages for the eradication of two model bacteria from produced water: Pseudomonas aeruginosa and Bacillus megaterium. These bacteria were grown in low salinity produced water and exposed to their corresponding phage. Overall, the total inactivation of the P. aeruginosa population was achieved, as well as the inactivation of B. megaterium. These promising results provide a potentially useful tool for bacterial elimination in overall PW treatment, at an industrial scale. Particularly, since phage treatment is a rapid and cost-effective alternative. Moreover, these results fall within the objectives proposed as part of the sustainable development goals adopted worldwide. [ABSTRACT FROM AUTHOR]

Produced water is the main waste stream in the oil and gas sector, with significantly greater concentrations of hydrocarbons, heavy metals, and other contaminants. Several works and technologies were developed to reuse the produced water in many applications including drilling and completion fluids. However, in general, a pretreatment is required. According to our knowledge, the reuse of produced water in non-aqueous drilling is still not reported. Therefore, this work proposed the formulation of olefin-based drilling fluids containing between 20-40% of untreated produced water. Through factorial experimental design, the influence of produced water, emulsifier, and viscosifier on the properties of the formulated emulsions was investigated. Our results show that produced water without treatment can be used as an aqueous phase for olefin-based drilling fluids, with the best formulation being the test that has RO/A = 60/40, emulsifier concentration of 14.26 kg/m³ and viscosifier concentration of 2.85 kg/m³. The well-cleaning properties of the proposed formulation were evaluated through numerical simulation in a well with high inclination. The results showed that the hole cleaning was not affected by using untreated produced water in the fluid formulation. The results presented here open a new possibility to reuse produced water in drilling operations without performance loss. [ABSTRACT FROM AUTHOR]

The article studies the effect of nanosized agents on the chemical and radionuclide content of the produced water. It has been demonstrated that there is a correlation between the radionuclide content of oil and water produced from the oil and gas fields of the country and the total salinity of the produced water. To this end, the contents of the nanocomposites proposed are shared in this issue along with the established effect on the radionuclide content of the produced water. [ABSTRACT FROM AUTHOR]

Wastewater generated as a result of extracting oil and gas from subterranean reservoirs is known as produced water. There are suspended solids, dissolved solids, organic and inorganic compounds, emulsified oil, and other substances. Untreated produced water may have a harmful impact on the ecology. In this study, waste from Coronavirus Face Masks was used as an adsorbent dosage for produced water adsorption discharged from the south Oil Company – Basra. In each trial, a 250 ml beaker held 100 ml of generated water, temperature (25, 35 and 50)°C, adsorbent dosage (2, 5 and 10)g, Investigations were also conducted on contact duration (30, 60, and 90) minutes, pH at (2, 4, 6, and 8), and mixer rotational speed (200 rpm). The ideal parameters for removing 97 percent of the oil were determined to be 25°C, pH 8, 5 g of adsorbent, and 90 min of contact time using a generic model built from the experimental data. Other oil removal equilibrium isotherm models did not adequately account for the experimental results, as did the Langmuir equation. The most common type of adsorption used in kinetics research is pseudo-first-order adsorption. [ABSTRACT FROM AUTHOR]

Manganese-oxidizing bacteria (MOB) may be found in produced water (PW) due to its manganese (Mn) content and may survive by oxidizing Mn. Additionally, different Mn concentrations can alter the growth of MOB, their growth phases, and their ability to produce MnOx. To investigate these aspects, the presence of MOB was investigated in PW. The MOB isolate was identified by molecular and biochemical methods. Its ability to oxidize Mn was also evaluated using Mn-oxidation agar medium with different Mn concentrations (0.15, 0.5, 1, 2, and 3 g/L). The strain was identified as Bacillus zhangzhouensis. The results showed that the Mn concentrations affected both the strain's growth and its ability to oxidize Mn. Triauxic growth was observed at the concentrations of 0.5 g/L and 1 g/L where the bacterium showed the most intensive growth and Mn-oxidation. In contrast, the concentrations of 2 and 3 g/L inhibited bacterial growth. This is the first study reporting the isolation of Mn-oxidizing B. zhangzhouensis from oil environment. The oil industry should consider the presence of this bacterium as it might be a potential risk for microbiologically influenced corrosion. [ABSTRACT FROM AUTHOR]

The identification and assessment of plant stress using wetland satellite images is a major task in remote sensing. In this study, one of the largest constructed wetlands (CWs) in the world, located in the Sultanate of Oman, was examined, assessed, and evaluated using remote sensor data from Sentinel-2. This CW system treats produced water generated during oil exploration activities in a desert environment; thus, CW vegetation is subjected to stress induced by oil hydrocarbons and water salinity. This study examined the plant stress and detected changes between the years of 2017 and 2019. Sentinel satellite images were evaluated for vegetation status extraction. The Normalized Difference Vegetation Index (NDVI), Modified Soil-Adjusted Vegetation Index (MSAVI), and Normalized Difference Salinity Index (NDSI) were used to evaluate the vegetation change. The results showed a comprehensive mapping identification of the plant stress and water flow parameter factors including oil in water contamination (OIW), dissolved oxygen (DO), water temperature (WT), and water conductivity (COND). Among the three indices, it was found that the NDVI showed a very good correlation with all parameters in both years with average R2 = 0.78, 0.67, 0.75, and 0.60 for OIW, DO, WT, and COND, respectively. The same trend was found for MSAVI but with R2 = 0.59, 0.48, 0.55, and 0.56 for OIW, DO, WT, and COND, respectively. This shows that the NDVI performed better than the MSAVI in evaluating the water flow parameters. On the other hand, the NDSI showed a strong correlation with one flow parameter, that is, water conductivity, especially at the outlet cells of the CW with R2 = 0.86 and 0.82 for winter time and summer time, respectively. The synchronization and correlation between the water flow parameters and remote sensing vegetation indices in this study lead to a new approach to large-scale landscape wetland monitoring that improves and helps predict any degradation or stress on vegetation growth. Furthermore, the results of this work can help decision makers potentially modify the wetland design and water flow path to improve future expansion phases. The mapping of such a critical and massive industrial CW should consider the use of high spatial resolution sensors where identifications and classifications are further improved. In summary, this research demonstrates that it is feasible to estimate vegetation stress within the constructed wetland using remote sensing techniques across extensive regions when an ample dataset comprising field data, satellite imagery, and supporting information is accessible. [ABSTRACT FROM AUTHOR]

A variety of microorganisms grow in oil reservoirs, where they participate in the biodegradation of oil and lead to changes in oil quality. Today, our knowledge about microbial processes in oil reservoirs is largely limited, and among the urgent tasks for the oil industry, monitoring and controlling microbial activity (including the activity of microbes responsible for biocorrosion) are important. In this work, we aimed to characterize the bacterial community structure of the produced waters from oilfields in the south of the Republic of Tatarstan (Russian Federation) using cultural and molecular methods of analysis. Bacteria from produced water samples from various oil wells were enriched, and 16S rRNA gene amplicon sequencing was used to assess the phylogenetic diversity of the bacterial communities. Thus, analysis of the bacterial communities revealed the presence of various members within the genera Desulfotomaculum, Clostridium, Acetobacterium, Desulfovibrio, Dethiosulfovibrio, Desulfomicrobium, Fusibacter, Dethiosulfatibacter, Thermovirga, Sphaerochaeta, and Desulfoplanes, but in different produced water samples. The role of the bacterial associations in biocorrosion was separately assessed in experiments on monitoring and stimulating biocorrosion. The bacterial community receiving additional nutrition was shown to have a higher corrosion potential, and scanning electron microscopy analysis confirmed changes in the surface of the metal coupons during immersion testing. The practical value of this research lies in identifying the potential contribution of microbial communities to oil pipeline corrosion. [ABSTRACT FROM AUTHOR]

Copyright of LHB: Hydroscience Journal is the property of Taylor & Francis Ltd 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 petroleum industry produces a large amount of wastewater, known as produced water (PW), during oil production and processing. This PW contains hazardous organic and inorganic components that can harm the environment. Conventional treatment methods have been used to purify PW, but they do not meet environmental regulations, especially when the goal is to reuse the water. Therefore, further research is needed to find an effective technology for managing PW. This review focuses on the characteristics and management of PW originating from oil and gas fields. Firstly, we provide a detailed overview of PW production scenarios worldwide and in the US with detailed quantities and chemical compositions of organic, inorganic, and physicochemical characteristics. Secondly, challenges and environmental concerns associated with treating PW are discussed. Thirdly, all relevant treatment technologies for PW are systematically explored. In addition, this review highlights the management of PW and suggests treatment options and best practices for the industry, and finally, future research needs and opportunities for sustainable water treatment and effective reuse technologies are addressed. Because PW contains a variety of severe contaminants, single methods have not been effective in converting it to a reusable form or fulfilling disposal criteria. As a result, integrated technologies may provide a potential approach that not only meets regulatory standards but also provides chances to employ PW as a non-conventional water supply. Advances in PW management are critical and demand a defined framework and risk-based approach to determine and build the most efficient plan. [ABSTRACT FROM AUTHOR]

The multistage bio-contact oxidation reactor (MBCOR) has been extensively applicated in the oily wastewater treatment. Nonetheless, the underlying mechanisms, especially the fungal community information during the bioremediation of low-COD and high-salinity oilfield produced water is still poorly understood. In this study, the fungal community succession, and fungi-bacteria interactions of a MBCOR were investigated. The result of Illumina high-throughput sequencing showed that the chemical oxygen demand was the main variable in influencing the community structure within the first tank. Besides, the linear discriminant analysis effect size analysis disclosed the feature fungal taxa at different stages, revealing that the fungal community shift was driven by its functional needs. Additionally, network analysis revealed that fungal and bacterial communities were highly interconnected and possessed cooperative relationships. Furthermore, the equilibrium of fungal-bacterial communities was primarily influenced by species richness and diversity. This study provides a deeper insight into the role of fungi within MBCOR in treating oily wastewater. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Objective The study is aiming to explore the key corrosion bacteria in the production process of shale gas, and analyze the potential succession law of bacteria. Methods The 16S rRNA high-throughput sequencing analysis technology was used to sequence the bacterial flora in the fracturing fluid preparation water and produced water of a shale gas platform in Weiyuan area. Results The bacterial structure of fresh water is completely different from that of produced water and recycled flowback fluid, the richness and diversity of bacteria decreased after fracturing. The key corrosive bacteria include Arcobacter, Marinobacterium and Pseudomonas, etc. The bacterial community in the freash water is mainly composed of mesophilic, aerobic bacteria with weak functions such as sulfate reduction and acid production. While in the recycled flowback fluid, there are a large number of bacteria with functions of sulfur metabolism, acid production and biofilm production. After fracturing, in the produced water there are mainly facultative anaerobic, anaerobic or strictly anaerobic bacteria with functions such as sulfate reduction, sulfur reduction, sulfur oxidation, acid production, biofilm production, iron reduction, and some thermophilic bacteria were identified. Conclusion This provides theoretical and technical support for further research on bacterial corrosion of gathering and transportation pipelines and pipeline protection. [ABSTRACT FROM AUTHOR]

Co-production can improve coalbed methane (CBM) development efficiency under multi-coal seam conditions; however, differences in hydrodynamic conditions between coal seams lead to fluid interference and thus low gas production. Fluid interference identification is important to increase CBM co-production efficiency. In this study, produced water samples were collected from CBM wells in the Hancheng block and their ionic and isotopic compositions were tested to investigate their relationships with productivity and to identify their implications for hydrodynamic conditions and fluid interference in CBM co-production. The produced water samples (PWS) were dominated by Cl, HCO3, and Na, with water qualities of Na–HCO3 and Na–Cl. The PWS of Nos. 3, 5, and 11 coal seams exhibited increasingly enhanced marine influence successively. The PWS from Nos. 3 + 5 and Nos. 3 + 11 coal seams were characterized by continental influences, and the PWS from Nos. 5 + 11 coal seams were characterized by marine influence. The gas production tended to increase with increase in marine influence on produced water. Sensitive indicators and their critical values were extracted to identify the hydrodynamic conditions of the production layers, including Cl (1000 mg/L), Na (1000 mg/L), δD (− 78.72 %), δ18O (− 11 %) and Sr (5 mg/L). The Shanxi and Taiyuan Formations have different hydrodynamic conditions, resulting in poor CBM co-production compatibility. Nos. 5 and 11 coal seams had good co-production compatibility. The results will improve the method of identifying fluid interference during CBM co-production based on produced water analysis. [ABSTRACT FROM AUTHOR]

Produced water (PW) generated by oil companies is a highly impacting waste that contains chemicals such as metals and organic and inorganic compounds. Given its polluting potential, PW requires effective treatment before being discharged into the environment. Conventional treatments have limited efficiency in removing PW toxicity, so alternative approaches must be developed and standardized. In this context, treatment with adsorbent materials like magnetized vermiculite (VMT‐mag) is highlighted. This work aimed to evaluate the efficiency of treatment with VMT‐mag in reducing PW toxicity to aquatic biota. For this purpose, three aquatic species (the midge Chironomus riparius, the planarian Girardia tigrina, and the crustacean Daphnia magna) were exposed to untreated PW and to PW treated with VMT‐mag at laboratory conditions. The assessed endpoints included mortality, growth, emergence, and developmental time of C. riparius; mortality, locomotion, feeding, and head regeneration of G. tigrina; and intrinsic population growth rate (r) and reproductive output of D. magna. The results showed that all the species exposed to raw PW were impaired: C. riparius had delayed development, G. tigrina had reduced locomotor activity and delayed head regeneration, and D. magna had reduced reproduction and delayed intrinsic population growth rate (r). Most of the analyzed parameters showed that treatment with VMT‐mag diminished PW toxicity. Therefore, using VMT‐mag to treat PW may be the key to reducing the PW effects on aquatic organisms. Produced water (PW) generated by oil companies is a highly impacting waste. This work aimed to evaluate the treatment with VMT‐mag in reducing PW toxicity to aquatic biota with three aquatic species (Chironomus riparius, Girardia tigrina, and Daphnia magna). The results showed that all the species exposed to raw PW were impaired: C. riparius had delayed development, G. tigrina had reduced locomotor activity and delayed head regeneration, and D. magna had reduced reproduction and delayed intrinsic population growth rate. [ABSTRACT FROM AUTHOR]

This comprehensive review focuses on treatment technologies for produced water, with a particular emphasis on membrane-based systems. These systems offer significant advantages, including high contaminant removal efficiencies, compact design, and the potential for resource recovery. The review emphasizes the application of these technologies, their performance in meeting regulatory standards, and the challenges they face, such as operational efficiency and fouling. It highlights the need for further research and for the optimization of processes to enhance their efficiency. The integration of conventional methods with advanced treatment processes is also explored, with a vision toward developing hybrid systems for improved treatment efficiency. Overall, membrane-based systems show great promise for the treatment of produced water, but further advancements, sustainability considerations, and integration with other technologies are essential for their successful implementation in large-scale applications. [ABSTRACT FROM AUTHOR]

The petroleum industry produces thousands of barrels of oilfield waters from the initial stage driven by primary production mechanisms to the tertiary stage. These produced waters contain measurable amounts of oil-in-water emulsions, the exact amounts being determined by the chemistry of the crude oil. To meet strict environmental regulations governing the disposal of such produced waters, demulsification to regulatory permissible levels is required. Within the electric double layer theory, coupled with the analytical solutions to the Poisson–Boltzmann Equation, continuum electrostatics approaches can be used to describe the stability and electrokinetic properties of emulsions. In the literature, much of the surface charge density and zeta potential relationship to emulsion stability has been confined to systems with less salinity. In this paper, we have exploited the theoretical foundations of the electric double layer theory to carry out theoretical evaluations of emulsion salinity based on zeta potential and surface charge density calculations. Most importantly, our approaches have enabled us to extend such theoretical calculations to systems of the higher salinity characteristic of oil-in-water emulsions found in oilfield-produced waters, based on crude oil samples from the literature with varying surface chemistry. Moreover, based on the definition of acid crude oils, our choice of samples represents two distinct classes of crude oils. This approach enabled us to evaluate the stability of emulsions associated with these produced oilfield waters in addition to predicting the potential of demulsification using demulsifiers. Given that the salinity range of this study is that encountered with the vast majority of produced oilfield waters, the findings from our theoretical predictions are perfect guides as far as emulsion stability is concerned. [ABSTRACT FROM AUTHOR]

Strong alkali alkali-surfactant-polymer (ASP) flooding produced water is a byproduct of oil recovery, and it is a stable system composed of petroleum, polyacrylamide, surfactant, and inorganic salts. Efficient, green, and safe ASP produced water treatment technology is essential for oilfield exploitation and environmental protection. In this study, an anaerobic/anoxic/moving bed biofilm reactor with a microfiltration membrane was established and assessed for the real strong alkali ASP flooding produced water (pH 10.1-10.4) treatment. The results show that the average removal rates of COD, petroleum, suspended solids, polymers and surfactants in this process are 57, 99, 66, 40, and 44%, respectively. GC-MS results show that most of the organic compounds such as alkanes and olefins in the strong alkali ASP produced water are degraded. Microfiltration membrane can significantly improve the efficiency and stability of sewage treatment system. Paracoccus (AN), Synergistaceae (ANO) and Trichococcus (MBBR) are the main microorganisms involved in the degradation of pollutants. This study reveals the potential and adaptability of composite biofilm system in treating the produced water of strong alkali ASP produced water. [ABSTRACT FROM AUTHOR]

With the continuous increase of shale gas production in China, the associated water production is also increasing, which is the mixture of the water used for hydraulic fracturing and the brine retained in shale formation. During the treatment of produced water, valuable elements such as lithium, potassium and bromine are further enriched and concentrated. especially lithium. resources, which has broad prospects for development and utilization, and can alleviate the contradiction between supply and demand of strategic resource lithium in China. In this paper, the shale gas resources in Sichuan are introduced and summarized mainly. And the ion content in the produced water of shale gas in Weiyuan and Changning areas in southern Sichuan is listed respectively. At present, the produced water volume of each well in Weiyuan and Changning is 19 800 m³ and 15 293 m³ respectively, and the lithium content in most of the produced water is 10, 62-58, 96 mg/L, which has high economic utilization value. The reserves and prospects of lithium resources in the produced water of shale gas are predicted. The applicability of extraction method, membrane separation method and adsorption method to the extraction of lithium in shale gas produced water are summarized, which provides the reference for the comprehensive utilization of lithium resources from shale gas formation in southern Sichuan. [ABSTRACT FROM AUTHOR]

Produced water (PW) has been generated in a huge amount representing the largest volume waste stream. Membrane technology has found a leading ability in treating PW due to its significant advantages, such as lower cost, easy installation, and being environmentally friendly. Mixed matrix membranes (MMMs) have received significant research interest due to their flexibility, multifunctionality enhances the membrane performance with increasing selectivity, permeability, robustness, mechanical strength, and resistance to fouling. This mini‐review paper identifies the utilization of different membranes for treating PW. It also gives a review of different types of MMMs with specific fillers for the application of PW treatment. Lastly, some methods to enhance the performance of mixed matrix membranes have been highlighted. The issues and challenges in membranes are also discussed. Practitioner Points: Mixed matrix membranes (MMMs) are a potential membrane type for PW treatment.This mini‐review paper identifies the use of several membranes to treat PW. It also examined various types of MMMs containing specific fillers for the application of PW treatment.Methods for improving the performance of mixed matrix membranes have been highlighted, including the use of novel materials, surface modification, and cross‐linking.The issues and challenges in membranes are also discussed. [ABSTRACT FROM AUTHOR]

This work inspected the produced water discharged from the Amara oil field in (Misan-Iraq) to improve the quality of water before reuse and reinjection or disposal. The process of treatment included a pretreatment step using activated carbon and post-treatment using flat polymeric nanofiltration membrane (NF) (1.0 nm) and reverse osmosis membrane (RO) (0.3 nm), respectively. Therefore, activated carbon without aluminum oxide (Al2 O3 ) nanoparticles and with (Al2 O3 ) nanoparticles (20 nm) was used to examine the removal efficiency of the total organic compound (TOC). The height of the fixed bed of activated carbon and its diameter were 35 cm and 2.5 cm, respectively. The volumetric flow rates of the produced water flowing through the activated carbon column were taken as (25, 20, 15, 10 and 5)×10-4 m³ /h respectively, at transmembrane pressure (TMP) of 1.0 bar, pH equals 6, and the temperature of 25 °C. The TOC removal efficiencies attained using activated carbon without Al2 O3 nanoparticles were (52, 64, 77, 83 and 87%), respectively, and (65, 72.7, 83.4, 92.5 and 95.2%) with the use of Al2 O3 nanoparticles, respectively. Produced water effluent from the activated carbon column was treated by flat NF and RO membranes to reduce the total dissolved solids (TDS). The cross-flow rates through NF and RO membranes were 0.1 and 0.25 m³ /h, TMP (1–12 bar) and 60 bar, respectively. The removal efficiency of TDS was enhanced up to 40% and 99.67%, respectively. In addition, the TOC removal efficiency was 100% in the effluent of the RO membrane. [ABSTRACT FROM AUTHOR]

Microbiologically influenced corrosion (MIC) or biocorrosion is a complex biological and physicochemical process, Strategies for monitoring MIC are frequently based on microbial cultivation methods, while microbiological molecular methods (MMM) are not well-established in the oil industry in Brazil. Thus, there is a high demand for the development of effective protocols for monitoring biocorrosion with MMM. The main aim of our study was to analyze the physico-chemi- cal features of microbial communities occurring in produced water (PW) and in enrichment cultures in oil pipelines of the petroleum industry. In order to obtain strictly comparable results, the same samples were used for both culturing and metabarcoding. PW samples displayed higher phylogenetic diversity of bacteria and archaea whereas PW enrichments cultures showed higher dominance of bacterial MIC-associated genera. All samples had a core community composed of 19 distinct genera, with MIC-associated Desulfovibrio as the dominant genus. We observed significant associations between the PW and cultured PW samples, with a greater number of associations found between the cultured sulfate-reducing bacteria (SRB) samples and the uncultured PW samples. When evaluating the correlation between the physicochemical characteristics of the environment and the microbiota of the uncultivated samples, we suggest that the occurrence of anaerobic digestion metabolism can be characterized by well-defined phases. Therefore, the detection of microorganisms in uncultured PW by metabarcoding, along with physi-cochemical characterization, can be a more efficient method compared to the culturing method, as it is a less laborious and cost-effective method for monitoring MIC microbial agents in oil industry facilities. [ABSTRACT FROM AUTHOR]

We present a new experimental approach to further understand the injectivity impairment due to reinjection of produced water in an oilfield, containing residual oil and solids. A unique microfluidic setup with imposed flowrate is characterized by excellent reproducibility and allows one to determine the kinetics of external cake formation and the propagation of the damage inside the porous medium, similar to what happens at the injection wellbore. The growth rates of the external cake and that of the propagation of the internal damage exhibit discontinuities, likely related to a pressure buildup up to a threshold Laplace pressure above which the O/W Pickering droplets are pushed through, and which sets a limit to the cake growth. Finally, the external cake reaches a quasi-stationary thickness whose mechanisms are discussed below. Direct visualization readily achieved in microfluidic experiments, coupled with spatiotemporal image analysis, enables better spatial resolution than core flooding experiments and shows that the damage occurs in a small region close to the entry to the porous medium. These developments lead to the derivation of an analytical model of the damage formation. It appears that although very localized, this damage strongly decreases the global permeability of the whole porous medium. Finally, controlled temperature experiments permit to identify the variation of the viscosity of the oil droplets (or the viscosity ratio), as the primary mechanism by which temperature influences clogging. Clogging is slowed at high temperatures, but the final state is characterized by particle clogging and is thus irreversible. Article Highlights: Novel method to study PWRI, comprising a microfluidic setup with direct visualization, coupled with image analysis Analytical model derived for the damage propagation and the permeability decline during PWRI experiments with 3 different regions. Temperature impacts the clogging through variation of viscosity, with a qualitatively different final jammed state. [ABSTRACT FROM AUTHOR]

Polycyclic aromatic hydrocarbons (PAHs), due to their mutagenic, carcinogenic, and teratogenic potential, can lead to numerous chronic and fatal diseases. PAHs have been found in several wastewater streams, including "produced water," which is wastewater generated during the extraction of oil and gas. The PAHs' removal from produced water using physical, chemical, biological, and combined methods is crucial. Water is a vital ecosystem component and is extremely vulnerable to PAHs. This article reviews the current PAH situation, including their physical and chemical properties, types, characteristics, and removal methods from produced water. The mechanism of each method of removal of PAHs has been discussed. The current study results show that adsorption by nanoparticles and integrated methods are promising methods to meet the strict authoritarian limit with advanced increase potential in the direction of commercialization for the removal of PAHs and provide opportunities to use produced water as a source of water. The current study results can help the policy/decision makers in the efficient management of water resources. [ABSTRACT FROM AUTHOR]

The hazardous composition of produced water (PW) places it as a dangerous contamination agent, which must be treated to meet environmental and operational requirements before disposal, reuse, or reinjection. The current work evaluated an adsorption treatment using raw and pretreated corncob samples to remove total oil and grease (TOG) from PW. The influence of adsorbent dosage (1.0, 2.5, and 5.0 g), particle size (0.5, 1.0, and 2.0 mm), and contact time (60, 120, and 240 min) were tested in a batch system, showing that the lowest oil concentration was achieved with the smallest particle size (0.5 mm) and highest contact time (240 min) and adsorbent dosage (5.0 g). Using a 20 cm secondary partition in the fixed-bed column system was more efficient for TOG removal than a 10 cm one: the raw corncob removed 85.23% of TOG against 17.41% pretreated biomass. Comparative studies showed that the adsorption performance of untreated corncob was superior to that observed for walnut shells (69%), a widely used commercial absorbent. Results indicated corncob's environmental and economic potential as a natural and cost-effective adsorbent. [ABSTRACT FROM AUTHOR]

Accidental releases (i.e., spills) of produced water can occur at any point during oil and gas development operations, potentially resulting in chronic and/or catastrophic loadings of produced water to nearby ecosystems and exposures of human populations to toxic constituents including trace metals (e.g., arsenic), organic compounds (e.g., benzene), and/or radionuclides (e.g., radium). Despite California being one of the largest oil and gas producing states in the USA, no comprehensive reviews of produced water spills in the peer-reviewed literature have been published. To address this knowledge gap, produced water spill incident data contained within the California HazMat database were synthesized to elucidate trends in produced water spills in California. During the period of 2006–2020, a total of 1029 incidents involving produced water spills were reported. Despite the potential threat to environmental and human receptors, there are significant knowledge gaps concerning these incidents. Specifically, only ~ 6% of spill incidents contained geographic coordinates, greatly hindering assessments of the impacts of these events to public health and the environment. Moreover, updated spill volumes are not rapidly retrievable from the HazMat database, and during the years 2018–2020 volumes of produced water spilled were underreported in initial reports anywhere from 35–2750%. Further, it is unclear if groundwater monitoring is performed following spill events. This study highlights significant shortcomings in produced water spill reporting in California and recommends improvements to aid future investigations that assess the environmental and public health impacts of spill incidents. [ABSTRACT FROM AUTHOR]

As the amount of oilfield produced water (PW) keeps going up, highly efficient flotation agent is needed. In this paper, a series of surfactants (abbreviated as Q-PTEA-Cn) derived from polytriethanolamine were synthesized. Their surface activities and flotation performance were evaluated. The result showed that the Q-PTEA-Cns can effectively reduce the surface tension of water and interface tension of crude oil/water. The Q-PTEA-C12-1 had the best flotation performance and the rational flotation condition was recommended as follows: Q-PTEA-C12-1 dosage 100 mg/L, gas flow 3 L/min, and flotation time 20 minutes. At this condition, the oil removal efficiency of two commonly used flotation agents (FL-1 and FL-2) and Q-PTEA-C12-1 were 62.3%, 69.1%, and 83.6%, respectively. The flotation kinetic of Q-PTEA-C12-1 can be described by Maruyama's flotation model, which presented that there was adsorption of oil droplet adsorbed surfactant onto bubble. Floatation mechanism study confirmed that the Q-PTEA-C12-1 can absorb onto the oil droplet and showed that the Q-PTEA-C12-1 can enhance the bubble–drop attachment efficiency and the stability of bubble–drop agglomerates. [ABSTRACT FROM AUTHOR]

Electrochemical advanced oxidation processes are the most promising methods for destroying and degrading organic and inorganic pollutants present in produced water effluents. This study presents the electro‐oxidation process using graphite electrodes and electro‐Fenton process using iron electrodes for the treatment of real produced water. The effect of operating parameters such as current density on chemical oxygen demand (COD) removal efficiency was addressed. The result showed that electro‐Fenton process was more efficient than electro‐oxidation process where it gave 98% as maximum COD removal efficiency with energy consumption of 1.9 kWh/dm3 at H2O2 concentration of 12 mM, current density of 10 mA/cm2, temperature of 25°C, pH of 3, and treatment time of 80 min compared with 96.9% as maximum COD removal efficiency with energy consumption of 3 kWh/dm3 at pH of 6, current density of 10 mA/cm2, temperature of 40°C, and reaction time of 80 min when using electro‐oxidation process. These results demonstrated that electrochemical technologies are very promising methods for the treatment of produced water from oil/gas industry, so it can be safely disposed of or effectively reused for injection and irrigation. [ABSTRACT FROM AUTHOR]

Produced water (PW) is a by‐product and one of the major pollutants from the oil and gas industry. PW contains various pollutants and must be treated as per environmental regulations before its disposal or reuse. Thus, it presents a substantial economic and ecological problem in the oil and gas industry. Currently, there is ongoing research on various methods to treat PW efficiently. Hydrate‐based water desalination is one of the promising technologies. There is a continuing effort to identify a suitable hydrate former that can enhance the commercial feasibility of the process. This study investigates tetra‐n‐butyl ammonium chloride (TBAC) + methane as a potential clathrate former. The hydrate equilibrium temperatures of the mixed hydrates (TBAC + methane) are significantly higher at a given pressure than methane hydrates, suggesting the suitability of mixed hydrates for process development. There was a significant increase in the phase equilibrium temperature at 5 wt.% TBAC in the presence of PW compared to deionized water (DI), but the effect faded away as TBAC concentration increased in the solution. This can be attributed to a higher amount of chloride ions as the TBAC concentration is increased. These results elucidate the necessity to optimize the TBAC concentrations to develop an efficient hydrate desalination process for higher saline concentrations. [ABSTRACT FROM AUTHOR]

Hydraulic fracturing utilizes pressurized liquid typically consisting of water, proppants, and a multitude of chemical additives, in order to fracture petroliferous strata to extract natural gas and oil. In this process, a vast amount of wastewater is produced. This water is heavily contaminated, which renders it unusable outside of direct reuse, without extensive treatment being performed. Typically, various sophisticated analytical techniques are involved in the characterization of both waste and treated waters, increasing the cost and the complexity of the management efforts. The article discusses the constituents found in oilfield wastewater, the methods used to identify and quantify these constituents, and the present management methods. Additionally, we introduce total organic carbon and conductivity analyses as surrogate measurements of overall water quality. Total organic carbon and conductivity are established bulk measurements, which can be used to facilitate rapid decisions regarding the treatment and greater utilization of flowback and produced oilfield wastes. The application of the proposed surrogates could be used to streamline the current myriad of complex and expensive measurements. This would improve operational efficiency with respect to wastewater management in the energy sector. [ABSTRACT FROM AUTHOR]

Produced water are the main waste from the exploitation of conventional and unconventional oil and gas reservoirs and must be treated and disposed of properly to avoid contamination of environmental matrices. However, Colombian environmental regulations related to alternatives for managing this produced water are scattered and have gaps. The objective of this review is to analyze the alternatives for discharge and reuse of produced water, established in the regulations and specialized literature, propose options to fill the regulatory gaps and present treatment technologies for these waters. The results of the review of the regulations show gaps related to the discharge of produced water into the air by total or partial evaporation in lagoons, as well as gaps and contradictions regarding the discharge of produced water into aquifers through injector wells. Regarding the review of specialized literature, the results show reuse options different from those considered in the regulations and two alternatives emerge as the most common: enhanced recovery in conventional reservoirs and hydraulic fracturing operations in unconventional reservoirs. Likewise, the specialized literature presents a wide availability of treatment technologies for produced water; however, their selection depends on their characteristics and the maximum permissible limits of contaminants according to the discharge and reuse alternative. As contributions, this review discusses the main problems associated with the disposal of produced water through injector wells, or its reuse in producer wells, which could cause contamination of aquifers and soils: loss of formation injectivity and corrosion of pipelines. Additionally, it proposes parameters for the characterization of formation waters and raw and treated production waters, together with possible compatibility tests in order to avoid the problems discussed. [ABSTRACT FROM AUTHOR]

Produced water (PW) generated by the oil and gas industries is deemed the largest waste stream and contains a high toxic pollutant concentration. Hence, it is essential to eliminate or reduce its concentration to an acceptable level before discharge. The present study aims to optimize the reaction conditions in response surface methodology (RSM) via central composite design (CCD) for lead removal from synthetic PW using commercially available chitosan as an adsorbent. A statistically significant model was developed for lead removal through regression analysis (R2 = 0.99). The highest predicted Pb(II) removal value at optimal conditions was 89.12%. The Pb(II) adsorption optimal values were at the following conditions; an adsorbent dose of 1.9 g/L, 4.5 pH, 4 mg/L of concentration, and 76 min of contact time. The results of adsorption isotherms and kinetics showed that data fitted well to Langmuir's and kinetics Pseudo-second-order model (R2 = 0.99). The CCD based on RSM employed for the optimization via adsorption ensured maximum Pb(II) removal. This study could suggest a successful use of eco-friendly and cost-effective adsorbents for real PW treatment. [ABSTRACT FROM AUTHOR]

Improving the produced fluid yield is an effective measure for realizing the crude oil production capacity of offshore platforms. However, for offshore platforms employed in production, using the narrow space of the platform to expand the produced water treatment system is a significant problem. In this study, a highly efficient pre-treatment core tube was coupled with the main cavity and secondary cavities (MCSCs) based on a vane-type tubular separator and a cub-mother cyclone. The optimal inlet Reynolds number and processing capacity were determined according to the structure size of the MCSC, and the MCSC was applied to achieve highly efficient pre-treatment of produced water in a heavy oilfield in the Bohai Sea. The comprehensive evaluation indicators FA and FV were better than those used by current technology. When the influent oil content fluctuated around 2000 mg/L (average of 1772.81 mg/L), the oil content in the effluent was stable and below 200 mg/L (average of 106.44 mg/L), and the separation efficiency was nearly 94%. Compared to those of the current corrugated plate interceptor on the platform, the floor space was reduced by more than 60% and the separation efficiency increased by up to 65%. [ABSTRACT FROM AUTHOR]

A green magnetic nanocomposite based on kaolin clay and two-dimension graphene oxide (Fe3 O4 @ GO@Ka) was prepared using natural, economic, and available raw materials for oil removal from produced water. The preparation was carried out through a two-step hydrothermal carbonization method followed by a modified co-precipitation method in the presence of a kaolin clay matrix. Fourier-transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, high-resolution transmission electron microscopy, Brunauer–Emmett–Teller, and vibrating-sample magnetometer, were used to characterize Fe3 O4 @GO@Ka. The batch experiments results revealed that the oil removal efficiency reached its maximum with contact time = 60.0 min, pH = 7.0, initial oil concentration = 25.0 mg/L, the composite quantity = 5.0 mg, and T = 35°C. Theoretical models were applied to examine and assess the adsorption kinetics and isotherm. The adsorption kinetic was found to follow the pseudo-second-order, implying that the emulsified oil adsorption mechanism is chemisorption. The isothermal results closely matched the Freundlich isotherm model, meaning that the adsorption occurs in multilayers on a heterogeneous surface. Thermodynamic studies indicated that the adsorption process was spontaneous and endothermic. The prepared nanocomposite was regenerated using ethanol and reused four times without a significant decrease in its oil removal efficiency. These results indicated that Fe3 O4 @GO@Ka could be a promising, eco-friendly adsorbent for removing emulsified oil droplets. [ABSTRACT FROM AUTHOR]

Polymers, such as partially hydrolyzed polyacrylamide (HPAM), are widely used in oil fields to enhance or improve the recovery of crude oil from the reservoirs. It works by increasing the viscosity of the injected water, thus improving its mobility and oil recovery. However, during such enhanced oil recovery (EOR) operations, it also produces a huge quantity of water alongside oil. Depending on the age and the stage of the oil reserve, the oil field produces ~ 7–10 times more water than oil. Such water contains various types of toxic components, such as traces of crude oil, heavy metals, and different types of chemicals (used during EOR operations such as HPAM). Thus, a huge quantity of HPAM containing produced water generated worldwide requires proper treatment and usage. The possible toxicity of HPAM is still ambiguous, but its natural decomposition product, acrylamide, threatens humans' health and ecological environments. Therefore, the main challenge is the removal or degradation of HPAM in an environmentally safe manner from the produced water before proper disposal. Several chemical and thermal techniques are employed for the removal of HPAM, but they are not so environmentally friendly and somewhat expensive. Among different types of treatments, biodegradation with the aid of individual or mixed microbes (as biofilms) is touted to be an efficient and environmentally friendly way to solve the problem without harmful side effects. Many researchers have explored and reported the potential of such bioremediation technology with a variable removal efficiency of HPAM from the oil field produced water, both in lab scale and field scale studies. The current review is in line with United Nations Sustainability Goals, related to water security–UNSDG 6. It highlights the scale of such HPAM-based EOR applications, the challenge of produced water treatment, current possible solutions, and future possibilities to reuse such treated water sources for other applications. [ABSTRACT FROM AUTHOR]

The geochemical characteristics of water produced from coalbed methane (CBM) wells contain rich information about the associated geology, environment, and production. This study was conducted in the Southern Qinshui Basin, where produced water samples were collected from 10 typical CBM wells and their ionic compositions and water quality parameters were tested. The differences in the chemical characteristics of the produced water between different producing coal seams and between single-seam production wells (SPWs) and multi-seam co-production wells (MCWs) were compared, and the geochemical formation process of the produced water was revealed. The following conclusions were obtained: (1) the water produced samples that were mainly Na-HCO3-type and were generally weakly alkaline and moderately mineralized. The water produced from No. 15 coal seam was more enriched in SO4, Ca, and Mg compared to that of No. 3 coal seam, and the variations were more intense, reflecting a more complex water chemistry formation. (2) The ionic data of the water produced from MCWs do not lie between the coal seams of SPWs, nor do they satisfy the linear relationship between the ionic compositions of SPWs, reflecting the differences in the water sources between MCWs and SPWs. Water from MCWs tends to communicate with active water sources outside the coal seams, and the produced water contains small amounts of Cl and total dissolved solids, thus inhibiting the pressure reduction efficiency and limiting the effect of CBM co-production. (3) Based on a principal component analysis of the ionic compositions, two characteristic components were extracted, and these represented two types of hydrochemical formation processes. The first type is pyrite oxidation and carbonate dissolution, and its opposite represents sulfate reduction. The second type reflects the groundwater retention and confinement characteristics, and its opposite represents active groundwater or stronger recharge conditions. (4) A geochemical formation model of the water produced from CBM wells in the study area was constructed. Cation exchange adsorption and sulfate reduction were found to be the main water–rock interactions in the coal measure, and they determine the overall water quality of the produced water. Recharge has a relatively significant influence on water produced from MCWs. Pyrite oxidation exists in the water produced from No. 15 coal seam of the Taiyuan Formation, and the higher sulfur content in the coal contributes to this reaction. The results of the study will assist in deepening our understanding of the geochemical formation mechanisms of water produced from CBM wells, and they provide the main reasons for the poor CBM co-production effect from the Shanxi and Taiyuan Formations. [ABSTRACT FROM AUTHOR]

Produced water (PW) generated from the petroleum industry, during the extraction of oil and gas, has harmful impacts on human health and aquatic life, due to its complex nature. Therefore, it is necessary to treat it before discharging it into the environment in order to avoid serious environmental concerns. In this research, oil adsorption from PW was investigated using clay-alginate beads loaded with ionic liquids (ILs), as the adsorbent material. The effects of several process parameters, such as the initial concentration of oil, contact time, pH, and temperature on the removal efficiency of the beads, were analyzed and optimized. Different characterization methods, such as the Fourier transform infrared spectrophotometer (FTIR), scanning electron microscopy (SEM), energy dispersive X-ray (EDX), and thermal gravimetric analysis (TGA), were used to investigate the surface morphology, the chemical bond structure and functional group, and the thermal stability of the ILs-based beads. The results revealed that the clay-alginate-ILs beads indicated a removal efficiency of 71.8% at the optimum conditions (600 ppm initial oil concentration, 70 min contact time, 10 pH, and at room temperature) with an adsorption capacity of 431 mg/g. The FTIR analysis confirmed the successful chemical bond interaction of the oil with the beads. The SEM analysis verified that the beads have a porous and rough surface, which is appropriate for the adsorption of oil onto the bead's surface. The TGA analysis provides the thermal degradation profile for the clay-alginate-ILs. The beads used in the adsorption process were regenerated and used for up to four cycles. [ABSTRACT FROM AUTHOR]

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]

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]

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]