Brine Discharge Research Articles

Power production from seawater and discharge brine of thermal desalination units by reverse electrodialysis

Direct discharge of brine with high concentration from desalination plants can deteriorate offshore ecology. Intensive treatment on the brine, such as salt production and precious metals extraction, will consume large amounts of energy and cost. Here, the reverse electrodialysis (RED) method is introduced to harvest the salinity gradient energy (SGE) between brine with high concentration (HS) and seawater (LS) for power production and alleviating the damage to marine ecology. Firstly, natural seawater with different concentrations is injected into a single-stage RED stack to verify the feasibility of harvesting this SGE. Secondly, performances of the stack are analyzed under different feed parameters, including concentration, feed temperature, and flow velocity. Finally, the multi-stage reverse electrodialysis (MS-RED) is proposed to harvest more SGE and make energy conversion more efficient. Experimental results show that the HS-LS combination has higher output power and a wider voltage range than the LS-freshwater combination. Concentration of brine is the most critical factor affecting performances of the RED stack, followed by feed velocity and temperature. Energy conversion efficiency increases to 18.0% with stages number increasing to 22. This study can give some suggestions for the capture of SGE between brine discharged from desalination plants and seawater.

Recovery of water and reusable salt solution from reverse osmosis brine in textile industry: A case study

Textile industry is one of the major water-consuming sectors; therefore, developing methods for reusing water is essential. Processes including reverse osmosis (RO) have gained momentum recently and been widely used. However, concentrated streams (brine) generated from RO must be managed properly. In this study, a pilot-scale brine treatment system containing ozone oxidation, nanofiltration (NF), RO and ion exchange (IEX) was developed and operated to recover a high quality process water and salt solution to be reused in dyeing processes. It was revealed that 77% of the water and 66% of the salt solution (as NaCl) can be recovered and brine discharge can be reduced. With full-scale operation for one year, it is possible to achieve cost-savings by 176,256 USD with 115,000 m3 reused water and by 37,000 USD with 680 tons of recovered NaCl. Recovery of brine makes it possible to achieve sustainable production and zero liquid discharge concepts.

Wintertime Brine Discharge at the Surface of a Cold Polar Glacier and the Unexpected Absence of Associated Seismicity

AbstractA subglacial groundwater system beneath Taylor Glacier, Antarctica, discharges hypersaline, iron‐rich brine episodically at the glacier surface to create Blood Falls. However, the triggering mechanism for these brine release events is not yet understood. Identifying which fracture processes are observed seismically can help us better characterize the hydrological system at Taylor Glacier, and more generally, provide us with a broader understanding of englacial hydrologic activity in cold glaciers. We document wintertime brine discharge using time‐lapse photography. Subfreezing air temperatures during the brine discharge indicate that surface melt‐induced hydrofracture is an unlikely trigger for brine release. Further, we analyze local seismic data to test a hypothesis that fracturing generates elevated surface wave energy preceding and/or coinciding with brine release events. Our results show no discernible elevated Rayleigh wave activity prior to or during Blood Falls brine release. Instead, we find a pattern of seismic events dominated by a seasonal signal, with more Rayleigh events occurring in the summer than the winter from the Blood Falls source area. We calculate that the volumetric opening of cracks that would generate Rayleigh waves at our detection limits are of similar size to myriad cracks in glacier ice, lake ice, and frozen sediment in the terminus area. We therefore propose that any fracturing coincident with brine release activity likely consists of a series of smaller opening events that are masked by other seismicity in the local environment.

Laboratory study to quantify lower boundary influences on desalination discharges

Brine discharges from desalination facilities represent an important environmental consideration surrounding the use of desalination technologies. These discharges are typically released through a series of subsurface discharge ports, and the ability to quantify their flow behaviour is critical to mitigating adverse environmental effects. Previous experimental studies on desalination discharges or Inclined Negatively Buoyant Jets have highlighted discrepancies in the dilution measurements reported in the literature. These discrepancies are potentially due to the inconsistent treatment of the lower boundary in the experimental setup, which in practice represents the seabed. This issue is investigated through a series of experiments using the Laser Induced Fluorescence method. Three discharge angles (300, 450 and 600) are tested and the non-dimensional source height above the boundary (H/F0d) is varied between 0.06 and 1.84 (termed the bed proximity parameter). The results illustrate a relationship between dilutions measured at common reference points near the boundary and the bed proximity parameter. Dilutions are also shown to decrease by up to 30% compared to experiments without lower boundary influence. The outcomes from this study provide valuable insight into the previously reported discrepancies and enable the lower boundary to be incorporated into the design of desalination discharge systems.

Janus Fibrous Mats Based Suspended Type Evaporator for Salt Resistant Solar Desalination and Salt Recovery.

Solar desalination has been recognized as an emerging strategy for solving the pressing global freshwater crisis. However, salt crystallization at the photothermal interface frequently causes evaporator failure. In addition, arbitrary discharge of concentrated brine produced during desalination results in potential ecological impacts as well as wastage of valuable minerals. In the present work, a suspended-type evaporator (STEs) constructed using Janus fibrous mats is reported. The fibrous structure wicks brine to the evaporation layer and the salt gets confined in the evaporation layer until crystallization for zero liquid discharge due to the suspended design. Enhanced evaporation is observed because STEs have an additional low-resistance vapor escape path directly from the evaporation layer to the atmosphere compared to traditional floating Janus evaporators. Moreover, owing to the drastically different wettability on both sides, the evaporator allows salt crystallization only on the hydrophilic bottom layer, thus eliminating salt accumulation at the hydrophobic photothermal interface. With this unique structural design, the proposed evaporator not only maintains a high evaporation rate of 1.94kg m-2 h-1 , but also demonstrates zero liquid discharged salt resistance and ideal recovery of the mineral in brine.

Integrated MED and HDH desalination systems for an energy-efficient zero liquid discharge (ZLD) system

The Persian Gulf hosts densely located desalination plants that represent 50% of the global seawater desalination. The salinity levels in this gulf, especially in Qatar, are very high because of constant brine discharge and the shallow seawater (∼35 m depth). With the growing population, more desalination plants need to be installed to meet freshwater demands. The rising salinity levels and the ambient and sweater temperature will raise the specific energy consumption to produce a unit distillate because of climate change. Furthermore, the brine discharge affects the marine ecosystem and deteriorates the soil and groundwater quality. Thus, it is imperative to design and innovate a low or zero liquid discharge (LLD or ZLD) desalination system to mitigate climate change impacts and guarantee a safe marine environment. One such ZLD system is proposed and assessed in this study. The multi-effect desalination (MED) with higher top brine temperature (75 °C) is integrated with humidification dehumidification (HDH) system for brine concentration. In the final stage, the salts are removed via an evaporative crystallizer using thermal energy. The performance ratio (PR) with top brine temperature and temperature difference across each evaporator is evaluated and discussed. Finally, the specific energy consumption of the ZLD system is analyzed for different operating conditions.

Sustainable Use of Brine Water in Concrete Cement Mixes Alter Compression-Bending Strengths

Freshwater resources are limited and many regions worldwide are suffering from water shortage due to the rapid increase in population, industrialization and urbanization. Concrete production has shown to consume a substantial amount of water for mixing and curing, and this large consumption has sparked concerted efforts to find sustainable and environmental friendly alternatives for replacing freshwater in order to lower the pressure on water resources. The use of hypersaline by-product brine water discharged from desalination plant has been tested in cement mortar production in order to lower the pressure on water resources and reduce the environmental impact resulted from discharging this effluent to surrounding streams. Discharge brine water to surrounding stream can deteriorate physicochemical and ecological properties of receiving streams as well as accelerate degassing process of dissolved greenhouse gases by lowering solubility coefficient. Compression and Bending strength of cement mortar specimens have been tested after adding different percentages of brine water and with/without Alkali-Resistance Glass Fiber (ARGF). Samples have been cured for 7, 14, 21 and 28 days in 50.5mm×50.5mm×50.5mm cubes and tested using compression testing machine. Adding 3% ARGF to cement mortar mixes has increased 28 curing days bending strength (3 times) and has decreased compression strength 30%. It has been observed that using brine water with ARGF in cement mortar mixes will lower compression strength on the average of 22%±2 and will increase bending strength values 2.7 times. The results show that using ARGF and brine water in cement mortar production seems promising in improving environmental conditions and enhancing the mechanical property in many applications.

Thermodynamics of solvent-driven water extraction from hypersaline brines using dimethyl ether

Solvent-driven water extraction (SDWE) has promising applications in hypersaline brine desalination, including zero-liquid discharge processing for industrial wastewaters, and resource recovery, such as the extraction of lithium and rare earth elements from solution mining leachates. In this study, we develop a computational thermodynamic framework to analyze the liquid–liquid extraction of water from hypersaline brines using dimethyl ether (DME), an aprotic solvent that is partially miscible with water. The high volatility of DME enables its rapid separation from water–DME mixtures after water absorption, while its low polarity minimizes the organic-phase solubility of electrolytes, such as sodium chloride (NaCl). We first build a thermodynamic model based on the LIQUAC excess Gibbs free energy model for water–DME–NaCl mixtures. Maximum likelihood estimators for water–DME–NaCl interaction parameters are calculated through the nonlinear regression of fluid phase equilibrium and osmotic coefficient data using metaheuristic global optimization techniques. A multistage counter-current liquid–liquid separator (LLS) model is then developed to explore the water recovery and brine concentration ratios achievable as a function of feed molality and DME to feed water flow rate ratio. For a saline feed with a molality of 2.0molkg−1 (over three times the salinity of seawater) our analysis demonstrates that a one-stage LLS can achieve a water recovery ratio of 0.51 with an initial DME to saline feed molar flow rate ratio of 4.0, rising to 0.63 with a second equilibrium stage. We conclude by quantifying the amount of DME required to reach zero-liquid discharge brine salinities and analyzing the impact of staging and temperature on separation performance. Our thermodynamic model enables the rapid evaluation of SDWE systems for emerging hypersaline brine desalination and valorization applications.

Simulation study of the interaction between brine discharge and catchment water of a desalination plant in Tenes, Algeria under various hydrodynamic conditions

Simulation study of the interaction between brine discharge and catchment water of a desalination plant in Tenes, Algeria under various hydrodynamic conditions

Forward osmosis (FO)-reverse osmosis (RO) hybrid process incorporated with hollow fiber FO

Currently, desalination is limited by high energy consumption and high operational and maintenance costs. In this study, a new concept of a hollow fiber forward osmosis (HFFO)-based infinity desalination process with minor environmental impacts (free-energy intake and no pretreatment or brine discharge) is suggested. To evaluate the concept, an element-scale HFFO was conducted in both conventional FO and pressure-assisted FO modes, simulating a submerged HFFO operation. In the HFFO test, the impacts of several operating conditions on the performance of the HFFO were investigated to select the best case. Based on these results, the energy costs were calculated and compared with those of a hybrid FO–seawater reverse osmosis (SWRO) process. The HFFO showed a high dilution rate of the draw solution (up to approximately 400%), allowing the downstream SWRO process to operate at 25 bar with the same permeate volume production (recovery rate of 60%). Consequently, the HFFO-based infinity desalination process has an annual energy revenue of 183.83 million USD, compared with a stand-alone two-stage RO process based on a 100,000 m3/day plant.

Numerical analysis of the transport of brine in the Odra River downstream of a mine's discharge

Abstract The mining of underground deposits causes the inflow of water to workings and the necessity of pumping them to the surface. The mining plant of KGHM Polska Miedź S.A. extracts copper ore in plant branches with different hydrogeological conditions. The inflowing water into the workings is characterised by variable mineralisation, which depends on the location of the branch. In the south-western part of the deposit, a low-mineralised stream with a relatively high flow rate can be observed, while the outflow of highly saline waters occurs in the north-eastern branch. Despite the activities undertaken that aim at using the pumped-off mine waters industrially, it is necessary to deposit them into the Odra River. Reducing the environmental impact on the Odra River is one of KGHM's goals, which is being implemented by stabilising its salt concentration at a safe level. The paper presents the results of a 3D simulation of brine plume propagation based on a numerical model of advection–diffusion and turbulent flow. Bathymetric data from a section of the river approximately 500 m long and point data from an Odra water quality test were used to develop and validate the model. The paper discusses the types of factors that minimise the impact of brine discharge. The developed model will be used in the future to propose solutions that accelerate the mixing of mine waters with the waters of the Odra River.

Study and evaluation of the characteristics of saline wastewater (brine) produced by desalination and industrial plants.

Desalination and industrial plants all around the world generate large amounts of saline wastewater (brine). The discharge of brine from facilities poses a severe environmental threat, while at the same time, the opportunity to recover resources is being lost as discharged brine is rich in valuable metals that could be recovered as salts/minerals. To this aim, this study presents and analyzes for the first time the characteristics of different brine effluents (from industries such as desalination, oil and gas production, petrochemical, aquaculture, pharmaceutical, textile) to prevent environmental pollution and to recover valuable resources (i.e., salts, minerals, metals, chemicals) enabling the concept of waste-to-resource (circular water economy model). The results revealed that the common salinity values in brine effluents range from 0.5 to 150 g/L, while the only exception is the produced water from the oil and gas industry (up to 400 g/L). Brine effluents from all sectors contain sodium, chloride, calcium, and potassium ions in high concentrations, while the production of common salts such as NaCl, CaCl2, and MgCl2 from brine can be economically profitable. Besides common ions, precious metals such as lithium, rubidium, and cesium are present in low concentrations (<25 mg/L); however, their extraction from brine effluents can be significantly profitable due to their very high sale price. The treatment and valorization of brine can be implemented by the hybridization of membrane-based, chemical, biological, and thermal-based technologies/processes in minimal and zero liquid discharge (MLD/ZLD) systems.

Sea Ice Dynamics Drive Benthic Microbial Communities in McMurdo Sound, Antarctica.

Climate change is driving dramatic variability in sea ice dynamics, a key driver in polar marine ecosystems. Projected changes in Antarctica suggest that regional warming will force dramatic shifts in sea ice thickness and persistence, altering sea ice-associated primary production and deposition to the seafloor. To improve our understanding of the impacts of sea ice change on benthic ecosystems, we directly compared the benthic microbial communities underlying first-year sea ice (FYI) and multi-year sea ice (MYI). Using two tractable coastal habitats in McMurdo Sound, Antarctica, where FYI (Cape Evans) and MYI (New Harbour) prevail, we show that the structure and composition of the benthic microbial communities reflect the legacy of sea ice dynamics. At Cape Evans, an enrichment of known heterotrophic algal polysaccharide degrading taxa (e.g., Flavobacteriaceae, unclassified Gammaproteobacteria, and Rubritaleaceae) and sulfate-reducing bacteria (e.g., Desulfocapsaceae) correlated with comparatively higher chlorophyll a (14.2±0.8μgg−1) and total organic carbon content (0.33%±0.04), reflecting increased productivity and seafloor deposition beneath FYI. Conversely, at New Harbour, an enrichment of known archaeal (e.g., Nitrosopumilaceae) and bacterial (e.g., Woeseiaceae and Nitrospiraceae) chemoautotrophs was common in sediments with considerably lower chlorophyll a (1.0±0.24μgg−1) and total organic carbon content (0.17%±0.01), reflecting restricted productivity beneath MYI. We also report evidence of a submarine discharge of sub-permafrost brine from Taylor Valley into New Harbour. By comparing our two study sites, we show that under current climate-warming scenarios, changes to sea ice productivity and seafloor deposition are likely to initiate major shifts in benthic microbial communities, with heterotrophic organic matter degradation processes becoming increasingly important. This study provides the first assessment of how legacy sea ice conditions influence benthic microbial communities in Antarctica, contributing insight into sea ice–benthic coupling and ecosystem functioning in a polar environment.

ECONOMICAL AND ENVIRONMENTAL BENEFITS OF POINT-OF-USE NaCl BRINE REUSE BY NEW MEMBRANE TECHNOLOGY

Cation exchange water softening is one of the most widely used technologies of water treatment. However, its environmental impact related to discharge of highly concentrated regeneration brine draws more attention as overall quality and availability of water resources decreases. Bearing in mind high levels of reusable NaCl in brine discharge, technology that will reduce the environmental impact and help reuse brine is required. To develop such technology composition of spent brine solution from Na-cation exchanger was investigated and conditioning of such solution with use of nanofiltration membranes of different types under different temperatures, pressures and recovery values was tested. Results show that optimal conditions for NaCl recovery include usage of DuPont (Dow) Filmtec Fortilife XC-N membrane elements at temperature 23-27 °С, pressure of 23-25 bar and recovery of 55-60 %. Under these conditions purity of NaCl in permeate over 90 % and productivity by NaCl of 13.1 kg/h were achieved. Principal technological scheme of the process of membrane conditioning of the spent regeneration solution was proposed that allows achieving reduction of NaCl consumption by 40 % and reduction of NaCl discharge into sewage by 72 % with corresponding economic and environmental benefits.

Brine reject dilution with treated wastewater for indirect desalination

The forward osmosis (FO) process was suggested as a pretreatment to a multi-stage flashing (MSF) plant to reduce the environmental impact of brine discharge and the chemicals used. Yet, there is no study investigating the performance of the FO process pretreatment to the MSF plant using tertiary sewage effluent (TSE) as a feed solution. Combining MSF brine with the TSE generates a considerable permeation flux, reducing the membrane area and capital cost. This study evaluated the performance of the FO process for indirect desalination of the MSF brine, considering membrane fouling, cleaning, required membrane area and the specific power consumption. The FO process used a thin-film composite (TFC) membrane to dilute the brine reject from the MSF plant by the TSE and hence converting waste solutions into a feasible water resource. A considerable high water flux (±35 L/m2h) was generated and slightly decreased throughout each experiment's 4 cycles. An enhancement in the water permeability was observed in the FO tests with a prefiltration of the brine reject and the wastewater with 20 μm and an osmotic backwash cleaning of the used membrane. The prefiltration of the draw and feed solutions was effective in minimizing the impact of fouling. Maximum power consumption of 0.007 kWh/m³ was consumed in the forward osmosis process without prefiltration and decreased to 0.006 kWh/m³ in the FO process. The proposed FO system successfully diluted the brine reject’ divalent ions, reducing their concentration to 43% in some cases. Depending on the FO membrane orientation, the TSE feed solution resulted in a 276%–473% reduction in the number of FO elements required in the FO process compared to the seawater feed solution.

Study of the salinity and pH dilution pattern of discharged brine of the Konarak desalination plant into the Chabahar bay: a case study

This research aims to study the salinity and pH dilution pattern of discharged brine of the Konarak desalination plant into the Chabahar bay, their relation on coastal environment, and type of its brine discharge. Due to the shallow water depth of the coast and type of brine discharge, evaluating the salinity and pH was done with a sampling of surface seawater. The type of brine disposal is a direct surface discharge of negatively buoyant flow in the coastal environment of Chabahar bay. The brine discharge mechanism is a shore-attached surface jet, which is most likely influenced by the cross-flow deflection, dynamic shoreline interaction, and more minor by bottom attachment factors. The laboratory simulations using actual brine and seawater and either satellite pictures support the finding dilution pattern. The zone of initial dilution is under 50 m which, in the long run, can affect the quality of water of intake seawater pool of the plant.

Developing a reclamation strategy for softening nanofiltration brine: A scaling-free conversion approach via continuous two-stage electrodialysis metathesis

A significant amount of concentrated, scaling-prone brine can be generated during the conversion of unconventional water resources to freshwater, thus necessitating the zero discharge of concentrated brine to meet environmental and resource requirements. In this study, a two-stage feed-and-bleed electrodialysis metathesis (FB-EDM) process was implemented to reclaim softening nanofiltration (SNF) brine. To determine the optimized process parameters, experiments were conducted with various initial diluate to concentrate volume ratios (VD:VC), applied voltages, replenishment flow rates (Qrp), and initial diluate compartment concentration ratios (CD1:CD2). The results indicated that these parameters (except for the initial volume ratio) significantly influenced the FB-EDM process. The optimized conditions included a VD:VC of 2:1, voltage of 1.5 V per repeating unit, Qrp of 4 L/h, and CD1:CD2 of 1.5:1. The two-stage FB-EDM process operating under the optimized conditions achieved an energy consumption of <0.9 kWh/kg salt, and the total dissolved solids (TDS) in terms of Cl-type and Na-type salts reached 199.1 and 224.4 g/L, respectively; the corresponding overflow rates were 1.17 and 1.14 L/h, respectively. The developed system thus demonstrated approximately 85% TDS removal and ionic conversion of the brine; additionally, the self-crystallization of CaSO4·2H2O was realized by blending the Cl-type and Na-type salts. This process therefore represents a suitable method for converting SNF brine into highly-concentrated liquid salts, and provides a reclamation strategy for miscellaneous salts.

Chemical and Energy Recovery Alternatives in SWRO Desalination through Electro-Membrane Technologies

Electro-membrane technologies are versatile processes that could contribute towards more sustainable seawater reverse osmosis (SWRO) desalination in both freshwater production and brine management, facilitating the recovery of materials and energy and driving the introduction of the circular economy paradigm in the desalination industry. Besides the potential possibilities, the implementation of electro-membrane technologies remains a challenge. The aim of this work is to present and evaluate different alternatives for harvesting renewable energy and the recovery of chemicals on an SWRO facility by means of electro-membrane technology. Acid and base self-supply by means of electrodialysis with bipolar membranes is considered, together with salinity gradient energy harvesting by means of reverse electrodialysis and pH gradient energy by means of reverse electrodialysis with bipolar membranes. The potential benefits of the proposed alternatives rely on environmental impact reduction is three-fold: (a) water bodies protection, as direct brine discharge is avoided, (b) improvements in the climate change indicator, as the recovery of renewable energy reduces the indirect emissions related to energy production, and (c) reduction of raw material consumption, as the main chemicals used in the facility are produced in-situ. Moreover, further development towards an increase in their technology readiness level (TRL) and cost reduction are the main challenges to face.

An assessment of the effects of oil field brine discharges on sediment and water of Forcardos River, Niger Delta, Nigeria

An assessment of the effects of oil field brine discharges on sediment and water of Forcardos River, Niger Delta, Nigeria

Techno-economic analysis of sustainability and externality costs of water desalination production

Increase in economic activities and population growth have resulted in the high energy and water demands which made them top priorities for many countries around the globe. This led to exploring new sources for producing fresh water including desalination. Estimating the true cost of desalinated water production should include both internal and externality costs. The objective of this paper is to calculate the externality costs that are associated with desalination water production in United Arab Emirates. The study examines and quantifies the environmental, economical and social costs of thermal desalination plants for both Multi-Effect Distillation (MED) and Multi-Stage Flash (MSF) technologies using Analytical Hierarchy Process model. For this purpose, various desalination sustainability criteria that are considered include CO2 emissions, brine discharge, chemicals pollutants, land area, employment rate, desalinated water quality and water availability. Results show that the true cost of desalinated water production almost doubled when the externality costs are included. Results indicated that the externality costs for the MED technology ranged between 0.297$/m3 and 0.702 $/m3 leading to an average increase of 65.8%. For the MSF technology, the externality costs ranged between 0.548$/m3 and 1.174$/m3 leading to an average increase is of 81.9%.