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The problems existing in the preparation of produced water with high salinity arc rcncwcd, thc influence mrchanism of produced water with high salinity on the performance of conventional frarhiring fluid system is analyzed, aml the performance charartrristics ami application of watrr-basrd fracturing fluid system with high salinity resistance in recent years arc summarized, and put forward that the slick water instant soluble powder drag reducer system is an important research direction tor high salinity resistant fracturing fluid in the fuhirc. [ABSTRACT FROM AUTHOR]

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]

ABSTRACTA substantial amount of wastewater is generated during the extraction of oil and gas. Wastewater that is generated as a result of oil and gas extraction activities is known as produced water (PW), and managing PW is one of the greatest challenges faced by the oil and gas industry. Effective management of PW requires an understanding of the complex impact it may have on both oil production and water treatment operations. Here, a numerical model has been applied to a real-world case study, that of Kuwait Oil Company (KOC), to examine the relationships among various input and output factors in PW supply chain management. Specifically, the numerical model is a multi-objective optimisation model for the management of PW supply chains that takes into account economic as well as environmental objectives. A global sensitivity analysis has also been performed to assess the economic and operational factors that can influence the management of PW in KOC. The findings of this study show that the operational costs, treatment costs and environmental impacts can be assessed and used to guide the management of the PW supply chain in KOC.

Abstract Produced water (PW) from oil and gas exploration adversely affects aquatic life and living organisms, necessitating treatment before discharge to meet effluent permissible limits. This study first used activated sludge to pretreat PW in a sequential batch reactor (SBR). The pretreated PW then entered a 13 L photobioreactor (PBR) containing Scenedesmus obliquus microalgae culture. Initially, 10% of the PW mixed with 90% microalgae culture in the PBR. After the exponential growth of the microalgae, an additional 25% of PW was added to the PBR without extra nutrients. This study reported the growth performance of microalgae in the PBR as well as the reduction in effluent’s total organic carbon (TOC), total dissolved solids (TDS), electrical conductivity (EC), and heavy metals content. The results demonstrated removal efficiencies of 64% for TOC, 49.8% for TDS, and 49.1% for EC. The results also showed reductions in barium, iron, and manganese in the effluent by 95, 76, and 52%, respectively.

Quaternary ammonium compounds (QACs) are active ingredients in hundreds of disinfectants for controlling the epidemic of infectious diseases like SARS-CoV-2 (COVID-19), and are also widely used in shale gas exploitation. The occurrence of QAC-resistant bacteria in the environment could enlarge the risk of sterilization failure, which is not fully understood. In this study, QAC-resistant bacteria were enumerated and characterized in 25 soils collected from shale gas exploitation areas. Total counts of QAC-resistant bacteria ranged from 6.81 × 103 to 4.48 × 105 cfu/g, accounting for 1.59% to 29.13% of the total bacteria. In total, 29 strains were further purified and identified as Lysinibacillus, Bacillus, and Klebsiella genus. There, bacteria covering many pathogenic bacteria showed different QACs tolerance with MIC (minimum inhibition concentration) varying from 4 mg/L to 64 mg/L and almost 58.6% of isolates have not previously been found to tolerate QACs. Meanwhile, the QAC-resistant strains in the produced water of shale gas were also identified. Phylogenetic trees showed that the resistant species in soil and produced water are distinctly different. That is the first time the distribution and characterization of QAC-resistant bacteria in the soil environment has been analyzed. [ABSTRACT FROM AUTHOR]

Herein, we report a facile method to fabricate thermo-mechanically reinforced polymer nanocomposite aerogel for oil-field-generated water treatment applications. Polystyrene-graphene (PS-G) aerogel was prepared using solvent crystallization-induced phase separation through flash-freezing route. The fabricated polymer nanocomposite aerogel was characterized using Fourier-Transform Infra-Red spectroscopy (FT-IR), X-ray diffraction (XRD), Differential scanning calorimetry (DSC), Field-Emission Scanning Electron Microscopy (FE-SEM), and Brunauer-Emmet-Teller (BET) surface area, and nano-indentation test. The PS-G nanocomposite aerogel showed 3D-interpenetrating network structures with high specific surface area (~ 300 m2/g) and high porosity. Notably, the PS-G aerogel exhibits a reinforced compression strength of 152 kPa compared to that of PS aerogel (124 kPa). The PS-Graphene aerogel showed Tg value as high as 101.4 oC. The PS-G nanocomposite aerogel was found to be a potential absorbent for the rapid removal of oil from produced water samples. Interestingly, the PS-G nanocomposite aerogel exhibited an oil absorption capacity of 50 g/g and reached saturation within 20 min. Furthermore, the aerogel nanocomposite absorbent can be easily regenerated by simple squeezing or washing with methanol and was found to be efficiently recycled up to 10 cycles with only a negligible reduction in oil absorption efficiency. [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.)

Naphthenic acids (NA) are organic compounds commonly found in crude oil and produced water, known for their recalcitrance and toxicity. This study introduces a new adsorbent, a polymer derived from spent coffee grounds (SCGs), through a straightforward cross-linking method for removing cyclohexane carboxylic acid as representative NA. The adsorption kinetics followed a pseudo-second-order model for the data (0.007 g min−1 mg−1), while the equilibrium data fitted the Sips model ( q m = 140.55 mg g−1). The process's thermodynamics indicated that the target NA's adsorption was spontaneous and exothermic. The localized sterical and energetic aspects were investigated through statistical physical modeling, which corroborated that the adsorption occurred indeed in monolayer, as suggested by the Sips model, but revealed the contribution of two energies per site ( n 1 ; n 2 ). The number of molecules adsorbed per site (n ) was highly influenced by the temperature as n 1 decreased with increasing temperature and n 2 increased. These results were experimentally demonstrated within the pH range between 4 and 6, where both C6H11COO−(aq.) and C6H11COOH(aq.) species coexisted and were adsorbed by different energy sites. The polymer produced was naturally porous and amorphous, with a low surface area of 20 to 30 m2 g−1 that presented more energetically accessible sites than other adsorbents with much higher surface areas. Thus, this study shows that the relation between surface area and high adsorption efficiency depends on the compatibility between the energetic states of the receptor sites, the speciation of the adsorbate molecules, and the temperature range studied. [ABSTRACT FROM AUTHOR]

The inability of most photocatalysts to continue the catalytic process after the removal of light irradiation is one of their major drawbacks. In this work, a ternary nanocomposite of titanium oxide (TiO 2) supported with tungsten oxide (WO 3) and hybridized with graphene oxide (GO) (TiO 2 -WO 3 @GO) photocatalyst with electron energy storage properties was synthesized for oilfield-produced water (OPW) treatment under visible light and in dark conditions. WO 3 addition extended the light absorption range of TiO 2 into the visible light while also serving as an electron storage material for dark catalysis (memory catalysis). The GO serves as an efficient electron acceptor and transporter to prevent charge carrier recombination, thereby enhancing interfacial electron transfer within the photocatalyst system. 2.5 wt%, 5 wt%, and 10 wt% of WO 3 precursors were reacted with TiO 2 precursor and GO was further added to synthesize the nanocomposites via a modified sol-gel and solution-based approach for the first time. The properties of the nanocomposite were assessed using a wide range of characterization. The nanocomposite containing 5 wt% WO 3 showed the best photocatalytic activity with the total organic content (TOC) degradation of 27.7% within 4 h of photodegradation in visible light, which is better than 22 % in 5 h under UV light so far reported in the literature. The nanocomposite also exhibited electron energy storage properties for dark catalysis after pre-illumination, i.e., 16.6% TOC degradation in 3 h in dark conditions. This low % TOC degradation in the dark could be attributed to the complex nature of OPW. This work has further confirmed the possibility of the use of photocatalysts for dark catalysis. [ABSTRACT FROM AUTHOR]

Produced water (PW) from oil and gas exploration adversely affects aquatic life and living organisms, necessitating treatment before discharge to meet effluent permissible limits. This study first used activated sludge to pretreat PW in a sequential batch reactor (SBR). The pretreated PW then entered a 13 L photobioreactor (PBR) containing Scenedesmus obliquus microalgae culture. Initially, 10% of the PW mixed with 90% microalgae culture in the PBR. After the exponential growth of the microalgae, an additional 25% of PW was added to the PBR without extra nutrients. This study reported the growth performance of microalgae in the PBR as well as the reduction in effluent's total organic carbon (TOC), total dissolved solids (TDS), electrical conductivity (EC), and heavy metals content. The results demonstrated removal efficiencies of 64% for TOC, 49.8% for TDS, and 49.1% for EC. The results also showed reductions in barium, iron, and manganese in the effluent by 95, 76, and 52%, respectively. [ABSTRACT FROM AUTHOR]

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]

Abstract 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 $$\mathrm{\mu m}$$ 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.

Membrane distillation (MD) has emerged as a highly promising method for the treatment of intricate and heavily contaminated water sources, such as those containing oily wastewater. The present study endeavors to advance the field by designing and evaluating a novel nanocomposite membrane comprised polyvinylidene fluoride (PVDF) and Bentonite (BNT) for application in vacuum membrane distillation (VMD) processes targeted at treating oily wastewater. A series of five nanocomposite flat sheet membranes were meticulously fabricated, incorporating varying quantities of bentonite (ranging from 0 to 0.8 g). Systematic characterizations were meticulously undertaken to comprehensively elucidate the influence of BNT incorporation on the structural and functional attributes of the developed membranes. These encompassed an array of analytical techniques, including Fourier Transform Infrared Spectroscopy (FTIR), atomic Force Microscopy (AFM), X-Ray diffraction (XRD), field emission scanning electron microscopy (FESEM), contact angle measurements (CA), as well as assessments of membrane thickness, porosity, pore size, and pore size distribution. The findings distinctly showcased the successful integration of BNT within the PVDF matrix, which correspondingly led to discernable augmentations in membrane surface roughness, hydrophobicity, and porosity. Employing consistent operational conditions involving a feed temperature of 50°C, a vacuum pressure of 30 kPa, and a NaCl solution with a concentration of 14.75 g/L, VMD experiments were systematically conducted. The empirical outcomes revealed that the incorporation of BNT notably conferred substantial enhancements upon the nanocomposite membrane's performance. The pinnacle achievement was evidenced in a flux rate of 34 L/m2.h and a remarkable NaCl rejection rate of 99.92%, a result achieved by the nanocomposite membrane incorporating the highest content of BNT additives. [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]

This work explores the potential of three hypersaline native microalgae strains from Oklahoma, Geitlerinema carotinosum, Pseudanabaena sp., and Picochlorum oklahomensis, for simultaneous treatment of flowback (FW) and produced wastewater (PW) and the production of algal biomass. The quality of wastewater before and after treatment with these microalgae strains was evaluated and a characterization of algal biomass in terms of moisture, volatile matter, fixed carbon, and ash contents was assessed. The experimental results indicated how all the microalgae strains were able to grow in both FW and PW, revealing their potential for wastewater treatment. Although algal biomass production was limited by nutrient availability both in PW and FW, a maximum biomass concentration higher than 1.35 g L−1 were achieved by the three strains in two of the PWs and one of the FWs tested, with Pseudanabaena sp. reaching nearly 2 g L−1. Interestingly, higher specific growth rates were obtained by the two cyanobacteria strains G. carotinosum and Pseudanabaena sp. when cultivated in both PW and FW, compared to P. oklahomensis. The harvested algal biomass contained a significant amount of energy, even though it was significantly reduced by the very high salt content. The energy content fell within the recommended range of 16–17 MJ kg−1 for biomass as feedstock for biofuels. The algal treatment resulted in the complete removal of ammonia from the wastewater and a significant reduction in contaminants, such as nitrate, phosphate, boron, and micronutrients like zinc, manganese, and iron. [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]

Water production from petroleum (oil and natural gas) wells is a topic of increasing environmental and economic importance, yet quantification efforts have been limited to date, and patterns between and within petroleum plays are largely unscrutinized. Additionally, classification of reservoirs as "unconventional" (also known as "continuous") carries scientific and regulatory importance, but in some cases the distinction from "conventional" wells is unclear. Using water, oil, and gas production data, we calculated a set of quantitative metrics that elucidate trends in the water-to-petroleum ratio over the life of each producing well. The percent growth of the water-to-petroleum ratio quantifies the degree to which a well "waters out" over time; values calculated for 153,900 wells in 18 oil and gas plays show generally much higher values for conventional wells than for continuous/unconventional wells. Analysis of the percent growth along with the slope and median metrics reveals greater variation between conventional plays and between continuous (unconventional) plays than previously recognized. Further, an example from the Bakken Formation in the Williston Basin, USA, illustrates that, within a single play, the metrics provide insight into spatial variation of water production trends, as influenced by geology and reservoir characteristics. By quantifying the variability of water production trends within individual plays and between plays, including differences between conventional and continuous (unconventional) plays, these results provide a more nuanced view of water production from oil and gas wells than has previously been possible and they illustrate the degree to which water management considerations vary spatially and temporally. [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]

This study deals with removing crude oil droplets from colloidal oil in water emulsions. The target was the development of efficient adsorbents for the tertiary treatment of industrial-produced water (PW). The novel adsorbent was designed from recycled low-density polyethylene (LDPE) powder grafted by the cationic polymer. The cationic polymer was synthesized directly on the LDPE surface by plasma-induced radical polymerization. A positively charged adsorbent was chosen due to the negative character of oily droplets to enhance separation efficiency in treating oil-water emulsions. The separation was performed in both batch and filtration modes. Absorption/adsorption uptake capacities showed a sigmoidal S-shape that was analyzed using the Sips model and compared with the newly developed empirical model. Both models showed a remarkable coincidence in the description of experimental data. The separation efficiency of the novel adsorbent was also tested in a filtration mode mimicking a commonly used deep-bed filtration technology. The comparison of the separation efficiency for various sorbents indicated a supreme performance of novel adsorbent. This study demonstrates the potential of a relatively cheap, prepared commodity-based adsorbent for the purification of emulsified oily polluted water in both batch and filtration configurations. This study also contributes to the recycling of polyethylene waste because LDPE attracts meager interest in recycled LLDPE due to many obstacles to reusing LDPE waste for its reprocessing as packaging materials. [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]

It was tested the production of a viscous exopolysaccharide (EPS) by Lelliottia amnigena using different concentrations (10, 15, 25, 50 and 100%) of produced water (PW) and Dialyzed PW (DPW) at 100% concentration, with a nutrient medium based on glycerin and sucrose as carbon sources in 44 h batches. There was an increase in EPS recovery when used PW up to a concentration of 25%. The viscosity of the EPS solutions was maintained with DPW and up to 15% of PW, such a condition resulted in 9.34 gL− 1 of EPS, representing an increase of 84.9% compared to the control (P < 0.0001). The PW 15% increased the viscosity per produced liter by 114.3% (P < 0.0001). Scanning electron microscopy and Energy-dispersive X-ray spectroscopy analysis showed that EPS adsorbed mineral constituents of the substrate and its characterization by Fourier Transform Infrared Spectroscopy was similar to an external control of a commercial EPS produced by an Enterobacter A47 strain. PW at 15% becomes an alternative to increase the EPS production process and can contribute to the mitigation of environmental damage through sustainable PW management in the oilfield chain. [ABSTRACT FROM AUTHOR]

To study the feasibility of using municipal sewage as a reserve water source for oilfield reinjection, the water sample treated by the municipal sewage treatment plant and the produced water of the Chang 2 reservoir were taken as the research objects. Through the analysis of water quality and compatibility, the optimal ratio of reinjection water samples was determined. At the same time, the clay swelling experiment and reservoir damage experiment were carried out. The experimental results show that the salinity of municipal sewage is low, and the content of scale ions is low. When the ratio of produced water to municipal sewage is 7:3, the scale formation amount can reach 42.5 mg.L-1, and when the scale inhibitor is added, the scale formation amount can be reduced to 10.4 mg.L-1. The mixed water sample will not cause clay expansion. Meanwhile, Chang 2 reservoir is moderately weak water sensitive and weak acid sensitive. The oil content, suspended solids content, and median particle size of the mixed water sample during reinjection should be controlled at 5 mg.L-1, 5 mg.L-1, and 5 µm to ensure that the reinjected water sample does not cause damage to the reservoir. [ABSTRACT FROM AUTHOR]

Relevance. The need to determine the permissible errors of hydraulic calculations of surface pipelines of the reservoir pressure maintenance system. This must be done, among other things, due to changes in the properties of produced water. As a result of the transition of most fields to the late stages of development, the water content of the extracted products increases, the composition and properties of reservoir waters change due to the breakthrough of the injected water. These circumstances can lead to significant changes in the mineralization, composition and Ph of water, which must be taken into account in numerical modeling. Aim. Creation of a nomogram for estimating the error in the course of changing the properties of produced water for numerical modeling of the operation of pressure pipelines of the reservoir pressure maintenance system. Methods. Hydraulic calculations in the engineering process simulator software, analysis of the properties of produced water samples in the laboratory, assessment of the density of produced water samples in the PVTSim 20 software product. Results. The studies were carried out on samples of produced water taken from seven wells. The value of salinity in the reservoir pressure maintenance system during the year varies from 247.85 to 327.79 g/dm3. The calculated density varies from 1188 to 1255 kg/m3. To calculate the pressure at the mouth of the injection well during water injection, samples with the highest, average and lowest density were taken. Analyzing the obtained data, a strong effect of water properties on the values of wellhead pressures is noticeable. On the basis of the conducted studies, a nomogram was created to determine the degree of influence of changes in water properties in the course of hydraulic calculation, taking into account the specific-injectivity index of injection wells and the length of pipelines. Conclusion. In the course of numerical modeling, it is quite difficult to take into account all the parameters that affect the accuracy of the calculations obtained. To do this, it is proposed to use the created nomogram, which allows estimating the permissible errors of hydraulic calculation taking into account the variability of the properties of water sent to the reservoir pressure maintenance system.

تعتبر المياه المصاحبة للنفط من أخطر أنواع التلوث على البيئة، لأنها تحتوي على العديد من الملوثات الضارة بالبيئة وصحة الإنسان مثل (النفط، المواد الصلبة العالقة، المواد الذائبة، والعديد من الملوثات الأخرى). يتناول هذا المقال عمليات الأكسدة المتقدمة (AOPs) التي تمت دراستها لتنقية المياه المنتجة من حقل الخباز النفطي الواقع في شمال العراق - محافظة كركوك من المحتوى النفطي. نظرًا لسهولة استخدام AOPs والأداء والسعر المنخفض، فهي طريقة شائعة لتنقية هذا النوع من مياه الصرف الصحي. في هذا العمل تم استخدام عمليات التحفيز الضوئي المتجانسة (Photo-Fenton (H2O2+Fe+2+UV)،) Fenton (H2O2+Fe+2، وUltra Violet (UV) فقط) في نظام الدفعات تحت أفضل الظروف (الزمن = 120 دقيقة، الرقم الهيدروجيني = 2.5، H2O2 = 20 مل في عملية فوتو فنتون، H2O2 = 80 مل في عملية فنتون، 2 مصباح UV (قدرة كل واحد = 8 وات) في عملية فوتو فنتون، 10 مصابيح UV في عملية UV مباشرة، و Fe+2=18 مجم في عمليات فوتو فنتون وفنتون). تم في هذا البحث دراسة تأثير جرعات H2O2 وFe+2 وزمن التشعيع وقيمة الرقم الهيدروجيني وشدة الأشعة فوق البنفسجية على فعالية إزالة النفط. حققت هذه الدراسة أعلى كفاءة في الفوتو-فنتون هي 85.68%، الفنتون= 75.01%، والتحليل الضوئي فوق البنفسجي المباشر= 56.64%. ونتيجة لذلك تم التوصل إلى أن عملية الفوتو فنتون هي أفضل طريقة لإزالة النفط من المياه المصاحبة للنفط.

Guizhou Province of China is rich in shale gas resources. In recent years, important progress has been made in the exploration and development of shale gas in the Upper Ordovician Wufeng Formation-Lower Silurian Longmaxi Formation in Zheng'an block in northern Guizhou, adjacent to Sichuan Basin. Due to the complex geological conditions and fragile ecological environment in the shale gas distribution area, serious environmental pollution risks may exist in shale gas exploitation. Therefore, this paper conducted element, hydrogen and oxygen isotope analyses for shale gas fracturing flowback/produced water of Well AY7-4 in Zheng'an block. The results showed that the contents of K, Na, Ca, Mg and NH4+ in the flowback/produced water of Well AY7-4 were very high, with an average of 118 mg/L, 7616 mg/L, 266 mg/L, 47 mg/L and 76 mg/L, respectively. The content of Na, Ca and Mg is similar to that of shale gas flowback/produced water in Weiyuan, but lower than that in Changning and Fuling. NH4+ content was similar to that in Changning, but much higher than that in Weiyuan. The average Cl content was 11605 mg/L, which was similar to that in Weiyuan, but lower than that in Changning and Fuling. The average Br content is 48 mg/L, slightly lower than that of Weiyuan, and about half of that of Changning and Fuling. Correspondingly, the Br/Cl value of Well AY7-4 is the lowest, reflecting its relatively low Br content. The average content of Li, B and Sr is 17 mg/L, 10 mg/L and 45 mg/L, respectively, which is similar to that of the Weiyuan, Changning and Fuling shale gas fields. The distribution model of Li and Sr is similar to that of Cl, Br and Na, but the B content and B/Cl value of Well AY7-4 are the lowest. The linear relationship between Br and Cl contents and between δD and δ18O of flowback/produced water of Well AY7-4, freshwater used for hydraulic fracturing and hydraulic fracturing injected fluid indicates that flowback/produced water of Well AY7-4 is mainly the mixed product between low salinity injected fracturing fluid and high salinity brine retained in shale formation. The hydrogen and oxygen isotopic compositions gradually become heavier over time, indicating that the proportion of high salt end formation brine in flowback/produced water is increasing. The contents of Cl, Br, Na and NH4+ in the flowback/produced water of Well AY7-4 are far higher than the allowable discharge value, which is a potential environmental pollution risk and cannot be discharged directly.

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]

The Permian Basin, underlying southeast New Mexico and west Texas, is one of the most productive oil and gas (OG) provinces in the United States. Oil and gas production yields large volumes of wastewater with complex chemistries, and the environmental health risks posed by these OG wastewaters on sensitive desert ecosystems are poorly understood. Starting in November 2017, 39 illegal dumps, as defined by federal and state regulations, of OG wastewater were identified in southeastern New Mexico, releasing ~600,000 L of fluid onto dryland soils. To evaluate the impacts of these releases, we analyzed changes in soil geochemistry and microbial community composition by comparing soils from within OG wastewater dump-affecte d samples to unaffected zones. We observed significant changes in soil geochemistry for all dump-affected compared with control samples, reflecting the residual salts and hydrocarbons from the OG-wastewater release (e.g., enriched in sodium, chloride, and bromide). Microbial community structure significantly (P < 0.01) differed between dump and control zones, with soils from dump areas having significantly (P < 0.01) lower alpha diversity and differences in phylogenetic composition. Dump-affected soil samples showed an increase in halophilic and halotolerant taxa, including members of the Marinobacteraceae, Halomonadaceae, and Halobacteroidaceae, suggesting that the high salinity of the dumped OG wastewater was exerting a strong selective pressure on microbial community structure. Taxa with high similarity to known hydrocarbon-degrading organisms were also detected in the dump-affected soil samples. Overall, this study demonstrates the potential for OG wastewater exposure to change the geochemistry and microbial community dynamics of arid soils. [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]

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Copyright of Oil Drilling & Production Technology / Shiyou Zuancai Gongyi is the property of Shiyou Zuancai Gongyi Bianjibu 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.)

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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]

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]

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Produced water (PW) from oil and gas production contains variable constituents that are difficult to remove with conventional treatment processes. The focus of this study was to explore the long-term performance of a membrane bioreactor (MBR) for the removal of organic constituents from PW and how performance and microbial community composition are affected by progressively increasing salinity and introduction of PW from different shale basins around the United States. Dissolved organic carbon removal from the PW remained consistent throughout the study, averaging 86% from the Denver-Julesburg basin PW and 66% removal from the Permian basin PW. Surfactant removal was less consistent, showing 87% removal of poly(ethylene glycols) (PEGs) at a total dissolved solid (TDS) concentration of 40 g/L but only 58% removal at a TDS concentration of 100 g/L. Diversity in the microbial community decreased during reactor establishment but increased at TDS concentrations above 80 g/L. The results of this study suggest that MBRs can be effective PW pretreatment processes even at high salinities.

Produced water is one of the most dangerous types of pollution for the environment, specifically the soil since it is full of oil, suspended particulates, dissolved compounds, and various other pollutants. This research describes the advanced oxidation process (AOPs) that were studied to purge the generated water from the Al Khabaz oilfield located in (Northern Iraq – Kirkuk governorate) of any oil content using two photocatalytic homogeneous and heterogeneous processes in the batch system under optimal conditions: homogeneous processes including Photo-Fenton (hydrogen peroxide, ferrous sulphates, and ultraviolet light), and Fenton process (hydrogen peroxide, and ferrous sulphates), and Direct-Photolysis (ultraviolet only) were used studied the effects of hydrogen peroxide (H2O2) & ferrous sulfate (Fe+2) dosages, irradiation time, pH value, and intensity of UV to the oil removal efficiency. This work investigated the maximum efficiency in Photo Fenton= 85.68%, in Fenton= 75.01%, and in direct UV photolysis= 56.64%. The heterogeneous photocatalytic process (TiO2/UV) studied the effect of titanium dioxide (TiO2) nanoparticles doses and UV intensity. The results show that the optimal efficiency achieved was 60.95%. X-ray Diffraction (XRD), scanning electron microscopy (SEM), and Fourier Transforms Infrared Spectroscopy (FT-IR) were used to look into the characteristics of the catalyst titanium dioxide nanoparticles. TiO2 nanoparticles seemed to be spherical in the SEM test, and their FT-IR analysis absorption values ranged from (424.77 - 3403.71 cm-1). Their sizes varied between 31.57 and 38.40 nm, and XRD revealed details regarding their chemical composition.