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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]

Bromate is a potentially carcinogenic disinfection by-product of potential concern in desalinated waters, where bromide derived from seawater can be converted to bromate by the oxidising species used for disinfection. Historically, it has been difficult to maintain complete adherence to national standards of no more than 10 ppb for bromate at all locations served with desalinated seawater by the Saline Water Conversion Corporation (SWCC) in the Kingdom of Saudi Arabia. In this full-scale study, the addition of 100–200 ppb of ammonia to the produced water of a Multi-Stage Flash Desalination plant effectively controlled the formation of bromate in the transmission system supplying inland centres in the Makkah Province of the Kingdom of Saudi Arabia (Arafa, Taif) on a time scale sufficient for the distribution of water to the consumer, even when the bromide content of the produced water was artificially enhanced (up to 132 ppb) via the addition of seawater. [ABSTRACT FROM AUTHOR]

Hyper-saline water streams, such as the produced water from the oil industry, cannot be treated via the conventional desalination method, such as reverse osmosis (RO), due to the extreme required pressure to overcome the osmotic pressure. This research investigates the effect of oil fouling and cleaning behaviors when the forward osmosis (FO) process is applied to treat hyper-saline-produced water. Synthetic produced water with total dissolved solids (TDS) concentration of 240 g/l (contained Na, Ca, Mg, Fe, Cl, SO4, and CO3 ions) and oil content of 100 ppm was used as a feed solution. Also, two draw solutions, namely: ammonium bicarbonate (NH4HCO3) and magnesium chloride (MgCl2) of concentrations 6 M and 4.8 M, respectively, were utilized for the FO operation. Results showed that the MgCl2 draw solution provided significantly higher water flux than NH4HCO3 due to MgCl2's high osmotic pressure and low scaling influence. Furthermore, the individual impact of oil was found to be low on the FO's water flux. However, a synergistic effect between the oil and inorganic scaling was noticed. SEM technique was used to comprehend the observation and analyze the fouling content. Although the feed was a highly polluted stream, it was found that osmotic backwashing can recover more than 90% of the initial flux. [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]

The flexibility of membrane contactors (MCs) is highlighted for a reverse osmosis (RO) desalination plant. MCs are applied as pre-treatment for the oxygen removal and the pH reduction of seawater, also as post-treatment for the pH increase of the RO permeate and the reduction of the RO brine volume. A decrease of the seawater pH down to neutral values, as needed when coagulation is used in the pre-treatment line of RO, together with an increase of the RO permeate pH up to 7.58, matching the target of produced water, can be obtained without the use of chemicals. Direct Contact Membrane Distillation (DCMD) and Vacuum Membrane Distillation (VMD) are investigated as function of the feed concentration (ranging from 40 g/L to 80 g/L) and temperature (40 °C–80° C). Their performance is compared at parity of operating conditions and in terms of applied driving force. Both distillation systems are able to efficiently reject salts (rejection > 99.99%), while higher distillate fluxes are obtained when a vacuum is applied at the permeate side (15 kg/m2h vs. 6.6 kg/m2h for the 80 g/L feed). [ABSTRACT FROM AUTHOR]

The treatment and disposal of hypersaline produced water remains a challenge, particularly for oil and gas producers in the Permian basin where production wells generate significant amounts of wastewater, and the traditional method of injecting wastewater into disposal wells is coming under increasing scrutiny. Here we investigate the viability of using solar energy to power a multi-stage, surface heated, vacuum membrane distillation (SHVMD) with energy recovery to treat hypersaline produced wastewater from Midland, Texas. Membrane distillation is a process that can desalinate waters with high total dissolved solids concentration, and when incorporated into a system with surface heating and energy recovery can achieve high water recovery rates. Model results show that a 6-stage SHVMD system with a 54.4 % water recovery rate and a gained output ratio (GOR) of 3.28 has the potential to be economically viable when used to treat hypersaline produced water in the Permian basin. Assuming energy costs of $0.03/kWh thermal and $0.12kWh electric , we estimate a project net present value (NPV) of $225,525 and an internal rate of return (IRR) of 13.5 % when an air cooled condensor is used to cool the distillate and a NPV of $570,791 and IRR of 24.52 % when a liquid coooling source is available. This work presents a comprehensive economic assessment of utilizing a surface-heated membrane distillation system with heat recovery to treat hypersaline produced well water. • An economic analysis of surface-heated membrane distillation process for the treatment of hypersaline brine was performed • Under certain conditions, the process is economically viable compared to deep-well injection • Process economics are sensitive to the availability of liquid cooling, sunlight, and the cost of solar-thermal energy [ABSTRACT FROM AUTHOR]

Optimal management and desalination of produced water is a major challenge for U.S. oil and gas development. Integrating rigorous desalination models into multi-period produced water network optimization problems presents several hurdles, which need to be tackled using advanced optimization strategies. In this work, a novel multi-period produced water network formulation with separate solid and liquid flows is introduced to avoid singularities at zero flows. Rigorous steady state desalination models based on mechanical vapor recompression are embedded at the desalination sites in the network model. An integrated optimization formulation is developed to co-optimize the design of desalination units along with the operation of the network. Furthermore, a more robust approach based on the trust region filter method is developed to efficiently integrate complex desalination models into the multi-period planning problem. Both optimization approaches are demonstrated on a produced water network from the PARETO library (Drouven et al., 2022) using thermal desalination units. Our results show that while the TRF and integrated approaches have comparable solve times, the TRF approach has better performance reliability in terms of solver convergence. Furthermore, the optimal solution obtained by embedding rigorous models into the network is significantly different than when desalination costs are approximated using simple cost models, which motivates further research in this field. • Produced water network models developed with recycle and treatment facilities. • Multi-period optimization network formulation developed with separate solid and liquid flows. • Rigorous steady state desalination models based on mechanical vapor recompression are incorporated. • Robust trust region filter strategy implemented to co-optimize network desalination models. [ABSTRACT FROM AUTHOR]

Although the freezing-melting process is not widely used commercially, perhaps the most significant potential advantage of desalination by freezing is the very low energy required compared with other desalination processes. Five seawater samples of 3,000 mL each were collected from different locations at the Gaza Strip beach. The physicochemical characteristics of the raw seawater samples were tested. The seawater samples were poured into an identical flask connected directly to an external stainless steel single-phase freezer (thermally protected-Sichuan Dandy Co. Ltd. 220 Volt, 50 Hz) with an energy consumption of 0.1 kW/h to be crystallized by direct freezing (at -20°C). Then the physicochemical analysis was undertaken on the water produced from three repeated freezingmelting (FM) cycles for each seawater sample. The average water mineral reduction percentages ranged from 39.0% to 45.5%, (49.7%-52.8%), and (56.0%-59.0%) for the 1st, 2nd, and 3rd FM cycles, respectively. The overall average removal percentage of dissolved minerals and constituents after the 3rd FM cycle for North Gaza, Gaza, Middle area, Khan Younis, and Rafah seawater samples was 84.7%, 85.6%, 87.3%, 86.4%, and 87.6%, respectively. The time of crystallization in the 1st, 2nd, and 3rd freezing cycles was 80, 50, and 30 min, respectively. The consumed energy for produced water after the three cycles of freezing was 0.018, 0.022, 0.018, 0.023, and 0.021 kW/L for the North Gaza, Gaza, Middle Area, Khan Younis, and Rafah seawater samples, respectively. The FM technique could be used as a pretreatment method for other methods of desalination. [ABSTRACT FROM AUTHOR]

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

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

Solar interfacial water evaporation is an environmentally friendly and potential approach to producing fresh water. Herein, a PAN/CNTs-foam (PCF) evaporator with high porosity, hierarchical pore structure, and excellent solar absorption was successfully prepared by the vacuum casting method. The PCF prepared with a CNTs content of 17 % and NaCl particle size of 150–300 μm possessed an evaporation rate of 2.04 kg m−2 h−1 for pure water under 1 sun illumination. The PCF-2 showed a maximum evaporation rate of 5.60 kg m−2 h−1 for real seawater in outdoor experiments, and the quality of the produced clean water was also demonstrated. The purification ability of PCF for organic dyes further confirmed the potential usage in wastewater treatment. Particularly, the PCF-2 exhibited efficient and stable desalination performance for hypersaline water even in 25 wt% simulated brine due to the hierarchical interconnected channels. Our work offers a robust method for the construction of a 3D foam evaporator with hierarchical interconnected channels for efficient and sustainable hypersaline water desalination. [Display omitted] • A 3D PCF evaporator with hierarchical pore structure and controllable pore size was successfully prepared by the vacuum casting method. • The prepared PCF-2 evaporator showed a high evaporation rate and evaporation efficiency. • The PCF-2 evaporator possesses excellent salt resistance and can be for the treatment of hypersaline water. [ABSTRACT FROM AUTHOR]

In this study, four zero liquid discharge thermal desalination processes were technoeconomically investigated to select the most efficient and economic process for the treatment of the brine rejected from desalination units. These processes were (1) evaporation/crystallization, (2) evaporation/spray drying, (3) membrane distillation/crystallization, and (4) membrane distillation/spray drying. To harmonize the economic assessment conditions in this technoeconomic study, the feed concentration and feed flow rate of all processes were considered to be 80,000 ppm and 1500 m3/day, respectively. The results showed that the specific water production costs for Processes 1–4 were 8.1, 22.1, 8.4, and 20.7 $/m3, respectively. Therefore, the produced water from Processes 1 and 3 had the lowest specific production cost. In addition, these processes had the lowest total fixed capital investment. On the other hand, although the specific production cost and the equivalent thermal gained output ratio of Processes 1 and 3 were almost the same, Process 1 can produce demineralized water. Therefore, Process 1 was considered as the most economic option due to the high economic value of demineralized water. [ABSTRACT FROM AUTHOR]

Solar steam generation (SSG) is promising for clean water production owing to low cost, simple operation, and green technology. This work investigates the fabrication of bioinspired photothermal (BIPT) material by sputtering a copper layer on Phanera purpurea (PP) leaf for application in SSG systems. It is observed that the light absorbance of the BIPT material exceeds 92% in the wavelength region of 300–2500 nm. This is due to the light trapping effect caused by multi‐internal reflection inside the Cu‐coated leaf nanostructure. The BIPT material exhibits a low thermal conductivity and easy cleaning properties as a result of PP leaf surface features. A novel strategy in this work is the design of the BIPT material‐based SSG system to recycle the radiative heat loss for evaporation. The developed SSG system results in a solar steam efficiency of 83.7% and a water evaporation rate of 1.45 kg m−2 h−1 under 1 sun. It is also applied in seawater desalination and the produced water satisfies the WHO standards for ion concentrations in clean water. Because of the simple procedure and low cost, the sputtering Cu on the PP leaf can be potentially used in the mass production of BIPT material for seawater desalination. [ABSTRACT FROM AUTHOR]

Membrane-based technologies have a tremendous role in water purification and desalination. Inspired by biological proteins, artificial water channels (AWCs) have been proposed to overcome the permeability/selectivity trade-off of desalination processes. Promising strategies exploiting the AWC with angstrom-scale selectivity have revealed their impressive performances when embedded in bilayer membranes. Herein, we demonstrate that self-assembled imidazole-quartet (I-quartet) AWCs are macroscopically incorporated within industrially relevant reverse osmosis membranes. In particular, we explore the best combination between I-quartet AWC and m-phenylenediamine (MPD) monomer to achieve a seamless incorporation of AWC in a defect-free polyamide membrane. The performance of the membranes is evaluated by crossflow filtration under real reverse osmosis conditions (15 to 20 bar of applied pressure) by filtration of brackish feed streams. The optimized bioinspired membranes achieve an unprecedented improvement, resulting in more than twice (up to 6.9 L·m-2·h-1·bar-1) water permeance of analogous commercial membranes, while maintaining excellent NaCl rejection (>99.5%). They show also excellent performance in the purification of low-salinity water under low-pressure conditions (6 bar of applied pressure) with fluxes up to 35 L·m-2·h-1 and 97.5 to 99.3% observed rejection. [ABSTRACT FROM AUTHOR]

[Display omitted] • We looked into the potential applications of hydrate-based desalination (HBD) • HBD process treats produced water with a concentration 2.8 wt% • CO 2 as guest gas produced a water recovery of 45.55% • The desalination efficiency is strongly dependent on the ionic radii and strength of the ionic charge. This paper emphasizes sustainable development goal 6 and accepts that social progress and economic prosperity depend on the appropriate management of produced water. Produced water being the largest source of wastewater, several conventional desalination methods (thermal, membrane and freeze–thaw), are applied to obtain treated water. Nevertheless, the methods are highly energy intensive. Prospective utilization of hydrate-based desalination was proposed with a novel filter-based apparatus design to separate hydrate crystals from residual water and enhance the gas–liquid contact with all the unit operations (hydrate formation, and dissociation) occurring inside a single reactor. Experimentations were implemented to obtain the optimum conditions for CO 2 hydrate formation and compared with pure water. CO 2 hydrate formation kinetics revealed induction time, moles consumed, water-to-hydrate conversion, and water recovery were 57 mins, 1.28 mol, 27.72 %, and 50.65 % at optimum conditions of 500 ml, 3.0 MPa, 450 rpm, and 275.15 K for purification of produced water. A desalination efficiency of 62–80 % is achieved with each of the metal ions in the sequence K+>Na+>Mg2+>Ca2+, and anions SO 4 2- > Cl- without any pre and post-treatment. Also, demonstrated that the ionic charge and size have a significant impact on the ion rejection mechanism. The findings disclosed that with an upsurge in the temperature to 277.15 K the desalination efficiency enhanced nevertheless the volume of formed hydrate is less resulting in less driving force. The total dissolved solids and electrical conductivity results indicate that the treated water meets Malaysia's water quality standards for irrigation purposes. This showcases the execution of the hydrate-based desalination process, investigating salt rejection and yield with our custom reactor design. The proposed reactor design may be utilized for the effective separation of hydrate and effectively desalinating waters of higher salinities. Hydrate-based desalination integrated with membrane reactors could lead to a sustainable source of clean water by treating produced water. [ABSTRACT FROM AUTHOR]

Fluoride is one of those ions that cause acute human health problems among the inhabitants of southern Algeria. Naturally occurring high levels of fluoride are closely linked to interactions between groundwater and volcanic rocks. Among the water treatment techniques applied to remove fluoride, nanofiltration (NF) was studied in this work. Fluoride removal operations were carried out on NaF 10–3 and 10–2 M model solutions and on natural groundwater (Kouinine) in a pilot cross-flow filtration unit at different pressures. The performance of two commercial NF composite thin-film membranes (NF90 and NF270) was evaluated in terms of productivity, desalination efficiency and energy consumption. The results showed that NF90 had the highest retention efficiency while NF270 had the highest permeate flow rate. However, it was observed that the NF90 membrane retained more than 88% of the fluoride ions of a complex natural matrix (Kouinine), while NF270 can retain 79%. The fluoride content of the permeate (0.35 and 0.62 mg L–1) was well below the World Health Organization (WHO) threshold and Algerian standards. The water recovery rate (γ) has a strong impact on salt rejection and energy consumption. The best compromise was obtained by using NF90 with a quality of produced water that complies with the requirements of the WHO and the Algerian standards. [ABSTRACT FROM AUTHOR]

Brackish water desalination is widely used to supply fresh water; reverse osmosis (RO) desalination units are considered as the most widespread technology used for this purpose due to the advantage of low power consumption. On the other hand, renewable energy resource integration into the power systems is an important trend, which serves energy supply especially in rural areas and non-stable power supply places. RO units powered from Photovoltaic (PV) systems are considered one of the reliable solutions in places where both water and energy demands are issues to be improved. In this research, the idea of storing energy in water salinity is introduced and discussed to reduce conventional battery storage banks. This concept depends on changing the pressure of the RO unit based on solar profiles to get high distilled water at high solar radiation times (high pressure applied) and low distilled water at low radiation times (low pressure values). Then, the produced water is mixed to get an acceptable salinity in the produced water. This research was applied on a small-scale RO testing unit with a pressure that changed from 40 to 60 bar, and, as a result, the water conductivity changed from 1.7 to 1.1 mS/cm. This was the base line to investigate the possibility of curtailing the battery storage system of the selected plant. Following the variable pressure scenarios, energy storage capacity was reduced by a factor of 20%. [ABSTRACT FROM AUTHOR]

Flaring is a major concern in the oil and gas industry as it wastes valuable raw materials/energy and emits a substantial amount of air pollutants. The produced water treatment during oil and gas production is very troublesome due to its large processing volume, high salinity, and expensive disposal cost. Thus, the on‐site integration of the flaring gas recovery (FGR) and desalination processes for handling the produced water could not only monetize flare emission sources but could also generate freshwater for versatile usages. Here, a novel process was developed integrating the ejector‐based FGR (EFGR) process with the thermal vapor compression (TVC)‐based desalination process. The newly developed EFGR‐TVC process is shown to be technically viable and cost‐effective under normal operating conditions. [ABSTRACT FROM AUTHOR]

The increase of salts both in soils and water for irrigation purposes is a growing problem for farmlands. Waster stress in arid and semi-arid regions encourages the use of non-conventional water sources, such as wastewater reuse. Current wastewater treatment plants (WWTPs) are unable to reduce salinity because they are designed to remove the organic fraction from the wastewater. Hence, effluent contains high amount of salts which adversely affect farmlands. This work addresses the desalination of the effluent from WWTPs with a dual purpose: irrigation and the leaching of salts in soils. The desalination of WWTPs effluent has an environmental impact (there will be environmental cost savings related to not spilling salts) and an economic impact (water will be available for irrigation of farmlands). This study assesses the feasibility of desalination in the effluent of a WWTP sample considering the internalization of environmental externalities. Using the shadow prices methodology, the environmental avoided cost of reducing the salinity of the effluent of WWTPs is quantified as 62 € per kg of salt which is reduced. The feasibility study of effluent desalination has been modelled for growing vegetables, taking into account the 272 hectares/year that can be irrigated with the available volume of desalinated effluents. This modelling confirms that the reduction in the effluent's salinity makes it possible to reduce the environmental impact in soils with salinity problems, and also, from an economic point of view, allows farmers to generate an income. [ABSTRACT FROM AUTHOR]

Due to the lack of drinking water people have been forced to obtain fresh and renewable water sources. For this reason, desalination systems are being developed around the world. Ultrasound technology is one of the most recent technologies in the desalination industry which improves the evaporation and distillation processes by increasing the mass and heat transfer that causes a reduction in energy consumption. This technology can help to maintain the health and safety of people because of avoiding the use of chemical material. In this study, an ultrasonic desalting system was evaluated in terms of salinity and the amount of produced water through response surface methodology (RSM). It was found that the salinity of incoming water had the highest impact on the produced water salinity level. By raising the temperature of incoming hot air the level of salinity decreased while by increasing the power of ultrasound the amount of produced water increased. The value of optimal experimental variables was obtained by RSM for the desalination system's operation for one hour, which yielded 200.737 ml water with a salinity level of 545 ppm. In addition to that, the economic analysis of this system was also investigated and it was proved that the operational and energy costs of this system were lower than those of the conventional methods such as RO and MSF. The salinity level in produced water by the desalination system was analyzed and the results matched with the WHO guidelines for drinking water quality. The results revealed that this system is practical and can be scaled up for testing industrial saline water desalination systems. [ABSTRACT FROM AUTHOR]

Produced water (PW) is the subsurface water brought to the surface during oil and gas production. PW is primarily disposed of by deep well injection, but it can be treated for beneficial use applications. However, efficient technologies for treating hypersaline PW with complex water chemistry are limited. This study developed an innovative, multifunctional photocatalytic membrane distillation (PMD) technology using hydrophobically modified tubular ceramic membranes coated with TiO 2 nanoparticles as photocatalysts for treating unconventional PW. The effects of membrane modifications were characterized in terms of membrane morphology, pore size, chemical functionality, zeta potential, hydrophobicity, liquid entry pressure, water production, permeate water quality, and membrane fouling and scaling propensity. The desalination performance of the PMD technology was demonstrated using unconventional PW with total dissolved solids concentrations of 135,000 mg/L and 175,000 mg/L, and NH 3 -N concentrations of 1551 mg/L and 613 mg/L, respectively. The novel PMD concept provides a promising technology for hypersaline PW treatment, and TiO 2 coating significantly reduced membrane fouling and scaling, improved distillate quality, and maintained stable permeate flux. The photocatalyst activation by ultraviolet-light emitting diodes (UV-LED) light further increased the permeate flux and enhanced the total organic carbon removal from 82.0% (without UV-LED) to 89.7% (with UV-LED). UV-LED irradiation did not affect ammonia and metals removal in PMD, reaching 99.4% and > 99.99% removal, respectively. [Display omitted] • Photocatalytic membrane distillation (PMD) was developed using TiO 2 -coated ceramic membrane. • PMD effectively treated hypersaline produced water (PW) with salinity 13.5% and 17.5%. • PMD achieved high removal of > 99.99% metals and 89.7% organics from PW. • PMD significantly reduced fouling and maintained a stable operation of PW treatment. • Ammonia in PW permeated to membrane distillate and requires further treatment. [ABSTRACT FROM AUTHOR]

Freezing desalination has gained interest due to its potential to reduce energy use. The freezing process faces challenges that limit its wide use. Washing product ice causes a large mass loss. Most freezing processes involve crushing to generate the appropriate ice form, limiting large-scale production. A vacuum pump and pressing piston are experimentally utilized to collect brine during melting to avoid washing and crushing ice. Five brine separation processes are needed to produce 2 %-salinity water. The studies used salinity-varying feed water. From the results, utilizing a vacuum pump and piston for brine separation during melting and a relatively small number of separation steps has considerably enhanced the quality of the produced water without causing significant mass loss. It is observed that 1000 ml of 15,000 ppm feed water produces freshwater with salinity and volume equal to 114 ppm and 185 ml, respectively. Results indicate that when the COP varied from 4 to 6, the system performance ratio increased from 31.74 to 47.62 and 7.94 to 11.90, with a recovery ratio equal to 0.9 and 0.6, respectively. Compared to previously described freeze desalination, MSF, MED, and MD desalination systems, the specific energy consumption increases by 71.5 %, 66.4 %, 54.5 %, and 36.1 %. • Crushing and washing free, freezing desalination technology • A technique that involves brine extraction by vacuum • Experimental investigation at different feed salinities • System performance ratio ranged from 31.74 to 47.62. [ABSTRACT FROM AUTHOR]

The lithium extraction from emerging unconventional oil and gas (UOG) field brine by β -diketone synergic system was established and systematically studied for the first time. A synergistic system consisting of dibenzoylmethane (DBM) and trioctylphosphine oxide (TOPO) was screened for lithium extraction through high-precise DFT calculation, and the synergistic effects were revealed by FT-IR analysis. A state-of-the-art Li+-Mg2+-Ca2+ co-extraction and Li+ selective stripping (CESS) process was proposed to achieve high lithium recovery efficiency. The effects of saponification, phase ratio, extractant composition and stripping acidity on extraction efficiency were systemically studied using real UOG field brine. After three-stage countercurrent extraction, the lithium extraction efficiency reached 98.1 % with the DBM concentration of 0.25 mol/L, TOPO concentration of 0.25 mol/L, and saponification of 70 %. After selective stripping and scrubbing with gradient HCl concentrations, Li+ was further separated from Na+, Mg2+ and Ca2+. The mass ratio of Mg2+/Li+ was reduced by 49.7 times, Na+/Li+ was reduced by 102.4 times. This work bridged the gap in the solvent extraction of lithium resources from UOG field brines and provided ideas for UOG field resource exploit and comprehensive utilization. [Display omitted] • Solvent extraction of lithium from actual unconventional oil and gas field brine was studied for the first time. • A state-of-the-art Li+-Mg2+-Ca2+ co-extraction and Li+ selective stripping process was established. • A synergistic system consisting of DBM and TOPO was selected for lithium extraction through DFT calculation. • 98.1 % of lithium was extracted after three-stage countercurrent extraction. [ABSTRACT FROM AUTHOR]

Increasing disposal costs and environmental concerns have encouraged desalination projects in the Permian basin to cut down produced water (PW) volumes and improve the handling. This study aims to demonstrate performance of membrane-distillation (MD) for desalinating high-salinity PW. Prior to MD, electrocoagulation (EC) and microfiltration (MF) are used as primary and secondary pretreatments, respectively. These pretreatment steps are necessary to remove constituents such as suspended solids, oil, and grease. The integrated EC-MF process was followed by vacuum MD (VMD) to recover water and concentrate the brine stream. To improve latent heat recovery, vapor compression is integrated into the vacuum membrane distillation (VMD). Our EC-MF-VMD PW treatment process can treat 1000 L of PW per day, with water recoveries in the range of 30–70 %. Suspended solids and turbidity removal of 90 % and total organic carbon (TOC) removal of 60 % were achieved with EC-MF pretreatments, which effectively mitigated PW fouling potential. A custom-designed plate-and-frame VMD module was established which enabled unparalleled service flexibility to change membrane replacement and active area. Results from our systematic evaluation revealed that the flux of the commercial membranes in our VMD module varied from 5 to 66 Lm−2 h−1. The intensified VMD performance achieved by vapor compression led to remarkable improvement in energy efficiency in terms of gained output ratio (GOR = 2.7) and energy consumption per unit of water production (248 kWh m−3). This study demonstrates the capability of the MD process for PW treatment, revealing the reasonable potential for PW reuse and recycling. Although this process might be of interest for unique applications that justifies the cost, further improvements in energy consumption are required to make this technology feasible for commercialized desalination of oilfield produced waters. • MD prototype demonstrated for treating hypersaline produced water. • Hybridizing EC and MF resulted in superior pretreatment performance. • Custom-designed plate-and-frame MD module exhibited fluxes up to 66 Lm−2 h−1. • Long-term operation demonstrated excellent water recovery and GOR > 2.7. [ABSTRACT FROM AUTHOR]

A novel multipurpose seawater desalination process is presented that integrates a Lithium Bromide (LiBr) absorption chiller, humidification-dehumidification (HDH), multi-effect evaporator, and mechanical vapor recompression (MVR) to improve the energy effectiveness of conventional desalination processes. The proposed process uses the LiBr absorption chiller cycle to preheat the seawater prior to the steam generation in the multi-effect evaporators while the MVR system activates the LiBr cycle. The integration of HDH further allows to recover the excess water in the process stream and concentrates the brine effluent for zero liquid discharge processing. A stand-alone HDH desalination is comparatively studied with the integrated system to quantify their respective performances over several metrics. Technoeconomic analysis is also performed to assess the economic feasibility and a sensitivity analysis is carried out to observe the effects of changing process variables on the overall performance of these systems. The results show that the proposed process design achieves several times higher gain-output ratio compared to a conventional HDH system of equal capacity, with a levelized water production cost of $ 8.4 / m 3 and 6 kW of cooling capacity that can be used for air conditioning. [Display omitted] • A multipurpose desalination plant is designed and analyzed. • The LiBr absorption cycle is activated by mechanical vapor recompression. • The levelized cost of produced water is $8.4/m3 with a cooling capacity of 6 kW. • NaCl composition in the brine effluent is 21 wt%. • A recovery ratio of 81 % is achieved in the proposed process. [ABSTRACT FROM AUTHOR]

Room-temperature ionic liquids (RTILs) have been promoted as "green" chemicals that can be used as alternatives to conventional volatile organic solvents. In addition to low volatilities, hydrophobicity for organic liquids and hydrophilicity for ions in RTILs lead to a wide spectrum of applications. ILs have recently been considered as alternative solvents to carboxylic acids and amines used for solvent extraction desalination (SED). RTILs are used in pairs of cations and anions that can significantly influence SED potentials. This study aimed to find an optimal combination of cationic and anionic RTIL as a desalination solvent through theoretical, experimental, and computational approaches. SED potentials in terms of water absorption and salt rejection were investigated for ten pairs of RTILs using different combinations of imidazolium and phosphonium cations with various anions. SED potentials were highly dependent on the anion type, with Tf2N showing the most promising SED potential. Imidazolium based RTILs exhibited better SED performances than phosphonium based RTILs in experiments. [BMIM][Tf 2 N] was recommended as a candidate SED-IL material, showing a water absorption and salt rejection of 1.73 % and 93.7 %, respectively. Molecular dynamics (MDs) simulation was implemented in parallel in order to examine and analyze intermolecular interactions that led to particular experimental observations. [Display omitted] • Cation-anion RTIL combinations for solvent extraction desalination were investigated. • Solubility parameter (HSP) of RTIL pair was related to SED potentials. • Selection of anion IL was more important for SED. • Molecular interactions between ILs and water were simulated and analyzed through MD. • Experiments and MD simulation for RTIL-SED were well matched. [ABSTRACT FROM AUTHOR]

• An integrated system for produced water treatment in onshore oilfields is presented. • A superstructure-based optimisation model is developed for integrated system. • Performance of MED and MVC for hypersaline produced water are investigated. • Injection and internal reuse of produced water are considered as two scenarios. Produced water (PW), water extracted along with oil, can cause important environmental challenges due to its high volume and salinity and is considered a key factor in the economic exploitation of oil fields. Therefore, making use of a cost-effective integrated system of wastewater treatment is a fundamental requirement in oil and gas industries. In this paper, the integrated PW treatment system is presented using superstructure-based mathematical optimisation methodology which is aimed at minimising the total annual cost. Two distinct scenarios of injection and reuse in industrial scale are considered to propose an efficient and optimal integrated system. The results show that, despite the emergence of new technologies, the traditional ones such as gravity separation, hydrocyclone, and media filters, with a cost of $0.509 per cubic meter, are selected as the optimum solution for treating PW for injection purpose. Because of the poor quality of PW in Iran, reuse options are limited, and the efficient available technologies are few. Mechanical Vapor Compression (MVC) and Multi Effective Desalination (MED) technologies are investigated as two desalination options. According to the findings, a treatment system composed of MVC with appropriate pretreatment is capable of recovering 50% of the PW, which is the optimal water recycling option with a total treatment cost of 3.808 $/m3. In cases of increasing the volume of PW with time, it is concluded that utilising advanced treatment system to recover a part of PW, decreases the annual cost up to 20% in comparison with the case which increases the PW injection capacity. This can be considered as a more viable management strategy for PW management in future. [ABSTRACT FROM AUTHOR]

This paper presents a steady state analysis of a multi-effect thermal vapor compression desalination plant (MED-TVC) installed in the Tunisian Chemical Group (GCT) factory. A thermodynamic model includes mass and energy balances of the system are presented. An economic model is developed to estimate the cost of produced water ($/m³). The proposed models to minimize the total annualized cost (TAC) of the desalination unit are based on a combination between the process simulator Aspen HYSYS and Matlab. The effects of the operating parameters variations on the system’s performance were studied. The simulation results show a good agreement with the industrial data of the pilot unit. [ABSTRACT FROM AUTHOR]

Thermodynamic data of multicomponent brines are needed to properly treat brines from oil/gas and CO 2 sequestration operations. Joule-heating treatment of hypersaline brine is a unique methodology that allows for direct heating of brines without the need of external heating, potentially simplifying operation and reducing process footprint. The thermodynamic properties of multicomponent hypersaline brine (> 3.5 wt%) are unknown and limited to estimations based on single component brine data. Experimental data for multicomponent brines at elevated temperatures and pressures do not exist due to operating conditions above the pseudocritical point of pure water. This study combines experimental results for multicomponent brines using a Joule- heated desalinator at pressures of 230 to 280 bar and temperatures of 387 to 406 °C with thermodynamic models previously created for single component NaCl brines to identify the deviations resulting from the additional species. In addition, a comparison between an Aspen Plus® v9 simulation using the ELECTNRTL model with experimental results is provided. [ABSTRACT FROM AUTHOR]

Global water scarcity is an imminent problem caused by the increasing water demand arising from population and economic growth. Against this background, technologies for water resource management and treatment have been developed steadily to meet the water demand targets. However, further advances are necessary for securing environmental and economic sustainability. The management of saline water and wastewater is one of the focus areas to tackle the problems of water scarcity and sustainability in the context of water desalination. Hybrid desalination is one of the most practical and efficient technologies that can afford environmental and economic sustainability. Hybridization of multiple processes maximizes the advantages of individual technologies and minimizes their drawbacks. The overall research on desalination and research on hybrid desalination, in particular, increased by a compound annual growth rate of 16.6% and 21.8%, respectively, from 2011 to 2020. Meanwhile, in 2020, 10.7% of scientific articles and reviews dealt with hybrid technologies. Moreover, the advances in hybrid technology are not limited to academic research; they have been widely implemented in the desalination industry. Reverse osmosis-multistage flash (RO-MSF) hybrid technology has been adopted for the largest desalination plant in the world, with a total water production of 1,036,000 m3/d in Ras Al-Khair, Saudi Arabia. The synergetic impacts of hybridization have various benefits depending on the desalination processes selected. In an RO-MSF system, the hybridization leads to additional water production with higher water recovery compared to a standalone RO system. Improvement in energy efficiency is another advantage of hybrid technologies as observed in the case of membrane distillation-adsorption (MD-AD) hybrid system. However, the challenges of hybrid desalination technologies are the complexity of process design, optimization, and operations. In this paper, the case of a forward osmosis-membrane distillation (FO-MD) hybrid system is presented to identify the challenges and potential solutions for hybrid desalination technologies. An FO process is driven by the osmotic pressure difference between two streams and produces water across a hydrophilic polymeric membrane. By using a saline solution, known as the draw solution, freshwater may be recovered from a targeted feed solution stream with relatively lower salinity. MD is a thermal membrane process that makes use of the difference in vapor pressure between hot and cold streams to transport water vapor across the membrane to a cold permeate solution. These two membrane processes (FO and MD) are selected to treat the produced water, which is a by-product in the oil and gas industry; produced water has extremely high salinity and complex organic composition and hence is one of the most challenging wastewater streams for water treatment. Since FO and MD employ two different energy potentials (i.e., osmotic and thermal energies, respectively), hybridization allows maximizing the use of available energy in target streams (i.e., produced water). To solve the challenge of complexity of hybridization, a novel integrated membrane module was developed for an FO-MD hybrid system. To evaluate the performance of the FO-MD hybrid system for produced water treatment, synthetic produced water streams were prepared according to water quality references from a conventional oil and gas production facility. Separate FO and MD experiments were conducted to study the membrane-fouling phenomena of different produced water qualities. In addition, the FO-MD hybrid system is operated with varied combinations of produced water streams for sustainability evaluation. The experimental results demonstrate the great potential of the FO-MD hybrid system for sustainable produced water treatment. Long-term operation of the hybrid system and experiments with real produced water samples are necessary for scaling up and optimizing the technology. Investigating the water-energy nexus related to the desalination technologies integrated with renewable energy is one approach to broaden the applications of hybrid desalination technologies. Such a study will emphasize the advantages of hybridization despite the complex challenges. The benefits of hybrid technologies in terms of greater water production, higher recovery, and cleaner water quality will be synergized with less energy consumption by their integration with renewable energy. Meanwhile, artificial intelligence (AI)-based process design, optimization, and control will be an important tool to address the complexity of hybrid desalination technologies and will provide a comprehensive understanding of the challenges, for which the conventional experimental and theoretical studies are still limited. AI algorithms, such as machine learning and artificial neural network algorithms, are the leading approaches to the advancement of AI-assisted smart desalination. [ABSTRACT FROM AUTHOR]

Rag-e-Safid desalting unit No. 1 produces 3,126 barrels per day (bbl/d) of wastewater from oil processing in Rag-e-Safid oil field. This much wastewater, due to the high amount of minerals and total dissolved solids (TDS) is injected to disposal well – A through a 6-inch, 20-km pipeline. Injection of this wastewater into disposal well has had great damage and incurred high costs to Iranian oil company due to inorganic scales and corrosion damage in wastewater injection pipelines, wellhead and downwell equipment, the need for work over the well, and acidizing operations to remove scales. This article presents the predicting scale tendency and scale precipitation at different pressures, temperature, and mixing ratios of injection wastewater with formation water in disposal well – A of Iranian oil field. The experimentally measured chemical analyses of formation water and injection water were used by Scale Soft Pitzer software to determine the formation of these scales. This software has been applied to investigate the potential of scale formation in disposal wells of oil fields. [ABSTRACT FROM AUTHOR]

Produced water is the largest volume byproduct stream in oil and gas production, and has an adverse environmental impact due to its complex composition and high disposal costs. Membrane fouling due to hydrocarbons limits purification of produced water by reverse osmosis (RO). A novel hybrid adsorption/ion exchange (IEX)/RO process is developed in which the adsorber removes dissolved hydrocarbons, IEX removes scale causing precursors, and RO desalinates the water. A part of the hydrocarbon free liquid from the adsorber is pressurized to 6.2 bar, heated to 160 °C and used to regenerate the adsorber, which resulted in an improvement in water recovery (to 86%), and translated into a predicted 22.8% decrease in costs amounting to US$ 27 million annual savings. The new high water recovery processes delineated in this work provide an array of novel options for removing hydrocarbons and desalination under different conditions. Experimental studies are needed to verify the assumptions made in this analysis. [ABSTRACT FROM AUTHOR]

Gravity-Driven Membrane (GDM) is considered an emerging seawater reverse osmosis desalination pretreatment. The objective of this study was to assess the GDM process performance under different operating conditions and to evaluate the impact of membrane biofilm on the produced water quantity and quality. Three lab-scale submerged GDM systems (UF 12h , UF 24h and MF 24h) were tested under different conditions of Hydraulic Retention Time (HRT) (12 h/24 h) and membrane pore size (Microfiltration/Ultrafiltration). The best water quality in terms of Assimilable Organic Carbon (AOC) was achieved with the longer HRT (24 h), where significant AOC was removed by the biofilm developed on the membrane. The next generation sequencing indicated that a longer HRT increased the abundance of Proteobacteria and Planctomycetes in the biofilm, which due to their biodegradation capability yielded to the highest AOC removal (~50–55 %). Furthermore, the use of microfiltration led to the highest water production (9.1 L/m2/h) due to larger membrane pore size, and a less dense biofilm. These findings indicate that employing a microfiltration membrane and 24 h HRT provides the best performance in terms of water quantity and AOC-removal. This study demonstrates that controlling GDM design and operation enabled manipulation of the biofilm proprieties yielding to high water production and high AOC-removal. [Display omitted] • GDM for SWRO pretreatment was tested under different HRT and membrane pore sizes. • GDM operating conditions impacted biofilm morphology and composition. • Permeate water quality improved by the GDM biofilm development. • Longer HRT led to higher Assimilable Organic Carbon (AOC) removal from the seawater. • AOC removal was enhanced by the abundance of specific bacteria in the biofilm. [ABSTRACT FROM AUTHOR]

Steam-assisted gravity drainage (SAGD) is a thermally enhanced heavy oil recovery method which is widely practiced for the bitumen extraction from the oil sands in Alberta, Canada. This study is the first application of forward osmosis (FO) for the treatment of SAGD produced water with the intent to reuse the treated water. The effects of temperature, flow rate, and pH of the feed water (produced water) and concentration and flow rate of the draw solution (salt solution) on the water flux as well as undesired diffusion of organic matter toward the draw solution were studied. Since no interaction between parameters is predicted, a fully saturated L16Taguchi design was used to investigate these five parameters each at four levels. It was found that increasing the feed water temperature and the draw solution concentration enhanced the water flux. The change in feed pH did not have any significant effect on water flux. Increasing the flow rate of both the BFW and the draw solution reduced the concentration polarization layer on both sides, thus increased the efficiency of the separation process. Analysis of variance showed that the feed water temperature and the draw solution concentration were the most influential parameters. This study provides valuable insights regarding the feasibility of the FO process for the treatment of oil sands produced water. [ABSTRACT FROM PUBLISHER]

Unconventional oil and gas production raises concerns regarding sustainable management of high salinity wastewaters generated in this process. Membrane distillation (MD) is a thermal desalination process capable of treating hypersaline brines such as produced water. The low single pass recovery in MD systems operated in a single stage requires a large recycle stream to achieve the desired recovery, resulting in high energy consumption and operating cost. Multistage configurations in continuous recirculation operation mode offer the potential to reduce the energy intensity of MD systems. However, rigorous analysis is needed to assess the performance of MD configurations when operating in multi-stage mode. We present an optimization-based comparison of economic and energetic performance for five configurations of MD (including DCMD, AGMD, PGMD, CGMD, and VMD) operating in multi-stage continuous recirculation mode. Our findings demonstrate that multistage operation reduces the treatment cost and energy intensity of all MD configurations compared to single stage MD, with the greatest benefit for VMD and PGMD. AGMD with five stages outperforms other configurations with 3.58 $/m3 feed treatment cost, followed by VMD, CGMD, DCMD, and PGMD with 3.8, 4.2, 5.4, and 9.06 $/m3 feed treatment costs corresponding to twelve, eight, eight, and sixteen stages, respectively. • Developed an optimization framework for comparing five multistage MD configurations. • Continuous recirculation mode is analyzed for produced water treatment. • Treatment cost and energy intensity are compared for the five MD configurations. • Multistage MD offers energy and economic benefits over single stage MD. • AGMD outperforms all other configurations with lowest treatment cost. [ABSTRACT FROM AUTHOR]

• A new type of MOF-based solar steam generator with a layered architecture, in which a hydrophilic MOF membrane serves the water sorbent and Ti 2 O 3 @PEDOT-OH as a solar absorber. • This new architecture creates a transmembrane temperature gradient, which maximizes water adsorption and desorption during desalination. • The device achieves the highest average evaporation rate of 2.20 kg.m−2.h−1 and produces water with ion concentrations lower than the drinkable water standard suggested by WHO by three orders of magnitudes. To develop an efficient solar steam generation platform based on the hydrophilic metal-organic framework for producing potable water from seawater or wastewater. Solar steam generation and desalination membranes have attracted much attention due to their intrinsic advantages of energy consumption entirely from solar irradiation and no pollutants produced. Ti 2 O 3 nanoparticles blended with poly(hydroxymethyl EDOT) (Ti 2 O 3 @PEDOT-OH) as photothermal conversion nanocomposites are coated on synthesized CAU-10-H membranes This architecture creates a transmembrane temperature gradient, which optimizes water adsorption and desorption efficiency. The device with CAU-10-H in 13 μm of thickness achieves the highest average evaporation rate of 2.20 kg.m−2.h−1 and evaporation efficiency of 98%. Also, the ion concentrations of the produced water are lower than the drinkable water standard. [Display omitted] [ABSTRACT FROM AUTHOR]

Electrodialysis (ED) is suitable for brackish water desalination due to its unique electro-demineralizing mechanism. However, the role of typical factors in pilot-scale ED desalination performance has not been illustrated systematically. In this study, a pilot-scale energy-efficient ED system was manufactured for the desalination of seawater nanofiltration permeate which could be considered as a typical brackish water, and its influencing mechanisms of typical factors were investigated in detail. The factors included ion exchange membrane (IEM) type, water recovery (WR), temperature, and feed concentration. The results show that the permselectivity of IEMs, which is related to the leakage of co-ions, played an important role in ED desalination performance. Furthermore, the salinity of produced water increased 3-fold times with the WR increasing from 53 % to 67 % due to the intensification of ionic back diffusion. Besides, the SEC increased 37.7 % with similar salt removal ratio when temperature increased from 7 to 29 °C, which is attributed to the changes of IEM structures and solution chemical properties. Finally, the fluctuation in the feed concentration had significant influence on produced water quality and SEC due to continuous operation mode. This study provides insights into, and guidance for, the large-scale BWED desalination process. [Display omitted] • Membrane permselectivity affected co-ion leakage and caused energy consumption increase. • Water recovery had a great impact on concentration polarization and produced water quality. • Temperature greatly influenced the reverse ion diffusion and made energy consumption increase. • BWED performance was closely related to feed concentration fluctuation. [ABSTRACT FROM AUTHOR]

[Display omitted] • Adsorption equilibrium and kinetics of the materials are presented and compared. • Advanced working cycles and strategies are summarized and discussed. • Innovative design approaches of the adsorber are reported. • Influence factors on performance indicators are discussed. • Possible future investigation directions are given based on the current studies. Adsorption desalination is considered as a promising alternative to solve the problem of water scarcity, owing to the remarkable advantages of energy-saving, low cost, limited environmental effect and high-quality produced water driven by renewable low-temperature thermal energy. However, this technology is still in the early laboratory research stage, further endeavor is required to facilitate the marketization based on a comprehensive summary of the current investigation achievements. Herein, this review summarizes the main achievements of adsorption desalination technology, involving sorption materials, system configurations and operation performances. So far, physical adsorbents, salt hydrates and composite adsorbents have been adopted, and, according to the most recent findings, composite adsorbents showed better thermodynamic desalination performance. Several advanced working cycles and strategies have been proposed and validated through experimental testing and simulations, like heat and mass recovery and multi-stage cycle, they contribute to improving the performance of the system by increasing the water production, broadening the working conditions or enhancing the output delivering power. Furthermore, the most recent innovative design approaches of the adsorber have been reported. Finally, the influence of operating conditions, like heat source temperature and cycle time, on specific daily water production, specific cooling power and coefficient of performance derived from the experiment and simulation results were discussed. Market aspects and the implementation of the different solutions in terms of cost and engineering complexity were also discussed. Possible future investigation directions include developing high-performance adsorbents with low desorption temperature (<50 °C), designing reactors with less heat and mass transfer resistance, using seawater or brine water in testing prototypes and validating the operation of real-scale prototypes under real operating conditions. [ABSTRACT FROM AUTHOR]

Produced water management is one of the key challenges faced by the oil and gas industry globally. Specifically, the gas industry in Qatar is challenged to minimize the produced/process water (PPW) volumes injected into disposal wells to ensure long term sustainability of the reservoirs. This research evaluated a novel application of forward osmosis (FO) to reduce the volumes of PPW disposed of by deep well injection using brine from thermal desalination plants or seawater as draw solutions. In the case of brines, this process also provides some environmentally beneficial dilution before discharge. In order to verify the PPW volume reduction concept, bench-scale FO experiments were carried out using commercial flat sheet membranes. FO performance was evaluated using PPW with and without pretreatment and results confirm that pretreatment is key to the successful implementation of FO for the treatment of PPW. Experimental results indicate that FO is effective in achieving 50% volume reduction of pretreated PPW with stable flux of 12 LMH. Lab analyses show that the TOC in the diluted draw solution was below the detection limit indicating that the TOC from the feed did not appear in the draw solution and hence would not be discharged to the environment. [ABSTRACT FROM AUTHOR]

The focus of this study was on the development and application of ceramic hollow fiber membrane (CHFM) technology for the treatment of oilfield produced water (PW) prior to disposal/discharge into the environment. PW refers to any fossil water that is brought to the surface along with crude oil or natural gas. It is a complex mixture of dispersed oil, dissolved organic compounds, suspended solids, production chemicals, heavy metals, and natural radioactive minerals. PW is difficult to handle/treat and represents the largest volume of waste associated with the oil and gas industry. It can have different potential impacts on offshore or onshore environments depending on where it is discharged. Therefore, the development of effective treatment technologies for PW is essential from both ecological and economic standpoints. The first stage of any treatment process for PW consists of a significant reduction in the level of dispersed hydrocarbons and suspended solids. In a second and often in a third stage, the oil and total carbon (TC) content is reduced by hydrocyclones and by micro- and ultrafiltration using membrane technologies. Due to legal requirements, final oil contents below 10 ppm are required in some regions before PW disposal to the environment. CHFMs represent a new generation in the development of inorganic membranes by offering the advantages of one membrane consisting of both inorganic material and hollow fiber geometry. In this study, the effect of cross-flow velocity on the CHFM performance at a low trans-membrane pressure of 0.5 bar, as well as the permeate quantity and quality, was investigated in terms of fouling behavior and efficiency of oil and TC removal. In the filtration system presented here, using ceramic hollow fiber ultrafiltration (UF) membranes with ad90pore diameter of 40 nm, the removal of oil and TC from samples of tank dewatering produced water and oily model systems, was successfully demonstrated with a remarkable decontamination efficiency of >99.5% (oil) and 61–94% (TC), respectively. [ABSTRACT FROM PUBLISHER]

• A novel VMD process for the desalination of high salinity wastewater. • Thermal carriers to conduct heat to membrane surface and along the channel length. • A physics-based process model to estimate process performance of full-scale modules. • Enhanced water recovery by effective heat delivery. • Improvement in specific energy consumption due to reduced temperature polarization. Membrane distillation (MD) is an emerging thermal desalination technology capable of desalinating waters of any salinity. During typical MD processes, the saline feedwater is heated and acts as the thermal energy carrier; however, temperature polarization (as well as thermal energy loss) contributes to low distillate fluxes, low single-pass water recovery and poor thermal efficiency. An alternative approach is to integrate an extra thermal energy carrier as part of the membrane and/or module assembly, which can channel externally provided heat directly to the membrane-feedwater interface and/or along the feed channel length. This direct-heat delivery has been demonstrated to increase single-pass water recovery and enhance the overall thermal efficiency. We developed a bench-scale direct-heated vacuum MD (DHVMD) process to desalinate pre-treated oil and gas "produced water" with an initial total dissolved solids of 115,500 ppm at a feed temperature ranging between 24 and 32 °C. We evaluated both water flux and specific energy consumption (SEC) as a function of water recovery. The system achieved a 50% water recovery without significant scaling, with an average flux >6 kg m–2 hr–1 and a SEC as low as 2,530 kJ kg−1. The major species of mineral scales (i.e., NaCl, CaSO 4 , and SrSO 4) that limited the water recovery to 68% were modeled in terms of thermodynamics and identified by scanning electron microscopy and energy-dispersive X-ray spectroscopy. In addition, we further developed and employed a physics-based process model to estimate temperature, salinity, water transport and energy flows for full-scale vacuum MD and DHVMD modules. Model results show that a direct-heat input rate of 3,600 W can increase single-pass water recovery from 2.1% to 3.1% while lowering the thermal SEC from 7,800 kJ kg−1 to 6,517 kJ kg−1 in an unoptimized module. Finally, the scaling up potential of DHVMD process is briefly discussed. [Display omitted] [ABSTRACT FROM AUTHOR]

Produced water generated from oil and gas operations contains significant quantities of environmentally hazardous hydrocarbons, organic chemicals, and inorganic salts. Environmental regulations with impaired water disposal mandates produced water treatment and desalination. Industry standard desalination technologies are energy-intensive and mandate extensive produced water pre-treatment including removal of hydrocarbons constituents for efficient operations. This study investigates a novel process intensification approach integrating supercritical water oxidation (SCWO) unit operation with a supercritical water desalination (SCWD) process for energy efficient produced water treatment and desalination. The coupled SCWD-SCWO process is found to be very energy-efficient and cost effective than existing industry standard desalination technologies. For energy efficient operation, the heat generated from the SCWO of hydrocarbons present in the produced water is used for power generation using a high efficiency and low-cost re-heat Rankine cycle process. The cost of treating produced water with proposed SCWO-SCWD process is independent of the salt concentration. The proposed process has the potential to offer step-change improvements over conventional processes in both the efficiency and cost of produced water treatment: for example, a cost and energy saving of 70% and 100% is calculated for the treatment of produced water containing 250 g/l salt and 10.6 g/l hydrocarbon. [Display omitted] • Novel approach to produced water treatment • Net zero energy consumption, with 70% lower cost • Treatment cost independent of produced water salt concentration • Using organics energy to generate power and desalinate the feed [ABSTRACT FROM AUTHOR]

Indigenous microalgae consortia present in domestic wastewater, were acclimatized to three real produced water (PW) samples collected from different oil fields. PW, a byproduct of oil mining and extraction, is hypersaline and toxic. Therefore, progressive adaptation mechanism was applied for acclimatization in a steadily decreasing dilutions of PW. After acclimatization, algae consortia were used for biodesalination and treatment of PW. The acclimatization lag phase was longer when the dilutions were reduced. The predominant species present in the consortia were Chlorella. One PW sample (onshore with largest initial salinity) showed the earliest adaptation (13 days) at lowest dilution. Chloride and salinity removal efficiencies of 25% and 22% were achieved, respectively, along with significant decrease in total dissolved solids (TDS) and conductivity in the different samples. The same PW sample showed highest removal of chloride (25%, from initial 53 g/L to final 40 g/L) and COD (44%). Another PW sample showed highest removal of salinity (22%), electrical conductivity (9%), TDS (20%) and total organic carbon (26%), as well as highest increase in alkalinity (86%). Removal efficiencies were minimum in the last PW sample which also showed less adaptability to the same dilution ratio of other two PW samples. [Display omitted] • Acclimatized algae consortia used for desalination and treatment of three different produced water samples. • Progressive adaptation mechanism adopted for acclimatization in steadily decreasing dilutions of PW. • Raw hypersaline PW without pretreatment used with very minimal inputs of nutrients supplements • Significant removal efficiencies of chloride (25%) and salinity (22%) along with 44% COD removal were achieved. [ABSTRACT FROM AUTHOR]

In the existing nuclear power plants, almost 60 to 70% of produced heat in the reactor is released to the ambient through the condenser, which can be used as the feedwater of reverse osmosis (RO) desalination plants. Although increasing the temperature of RO feedwater improves the overall performance, the quality of produced water decreases. This difficulty can be solved by blending the high-quality water produced by thermal desalination plants (DPs) with RO products. However, supplying the required energy for driving the thermal DP needs to consume a huge amount of fossil fuel, which is contrary to net zero-emission goals. In this study, three different scenarios, based on the solar plant (SP) (scenario 1), small modular reactor (SMR) (scenario 2), and the hybrid SMR-SP (scenario 3) for supplying the required energy of DP have been suggested. According to the techno-economic evaluation conducted in this study, using the SMR as the auxiliary heat source of the SP in the third scenario can be considered as a promising technology, which is associated with several benefits. However, the average water cost in scenario 2 is 66 cent m 3 , which almost 8.5 and 5% is less than scenarios 1 and 3, respectively. • The effects of using the rejected water of NPP's condenser as the feedwater of the desalination plan • Developing three different schemes based on SMR-Solar cogeneration plant equipped with modular PCM storage system • Developing a new program based on the Fortran language to simulate various components of the schemes • A general techno-economic comparison of SMR-Solar cogeneration schemes for desalination [ABSTRACT FROM AUTHOR]

A fully corrosion-resistant direct contact membrane distillation system has been built to test the viability of desalinating oil field produced water using fluorinated polyoxadiazole (F-POD) hollow fiber membranes. This highly hydrophobic membrane material was designed to endure the harsh conditions of Arabian oil field produced waters. These waters have high salinity, and the presence of dissolved organic compounds and gases - including hydrogen sulfide (H 2 S). The hazards associated with H 2 S require special safety controls. In this paper, the desalination of sour produced water with membrane distillation is compared with Gulf Sea water from the East Coast of Saudi Arabia. The effect of the produced water on the efficiency of the membrane distillation was evaluated in terms of distillation flux and salt rejection. The high salinity, the presence of H 2 S, and volatile organic compounds (VOC) are found to negatively impact the flux and salt rejection. [Display omitted] • Sour oilfield produced water tested in corrosion-proof membrane distillation system. • Comparison between seawater and oilfield membrane distillation performances. • Polymer swelling from volatile organic compounds reduces the distilled water flux. • Decomposition of fluorinated polyoxadiazole due to hydrogen sulfide was detected. [ABSTRACT FROM AUTHOR]

Volume reduction has been suggested as a novel method to tackle the various challenges associated with produced water. The present solution offers an economical and environmentally friendly solution to treat a large bulk of produced water that may overwhelm conventional water treatment methods. The current study provides a review of the various volume reduction technologies including freeze concentration, reverse osmosis, and humidification and dehumidification desalination systems. Focus is concentrated on the general HDH technologies in addition to its integration with refrigeration cycles for conditioned air production, and the power cycles for power generation. The GOR, freshwater yield, and efficiencies of the integrated HDH systems were reviewed. Lastly, innovation in the HDH desalination technology is discussed with emphasis on its incorporation with the MVC process. [ABSTRACT FROM AUTHOR]

Abstract: The risk associated with storage of carbon dioxide in the subsurface can be reduced by removal of a comparable volume of existing brines (e.g. ). In order to avoid high costs for disposal, the brines should be processed into useful forms such as fresh and low-hardness water. We have carried out a cost analysis of treatment of typical subsurface saline waters found in sedimentary basins, compared with conventional seawater desalination. We have also accounted for some cost savings by utilization of potential well-head pressures at brine production wells, which may be present in some fields due to CO2 injection, to drive desalination using reverse osmosis. Predicted desalination costs for brines having salinities equal to seawater are about half the cost of conventional seawater desalination when we assume the energy can be obtained from excess pressure at the well head. These costs range from 32 to 40¢ per m3 permeate produced. Without well-head energy recovery, the costs are from 60 to 80¢ per m3 permeate. These costs do not include the cost of any brine production or brine reinjection wells, or pipelines to the well field, or other site-dependent factors. [Copyright &y& Elsevier]