Evaporation Ponds Research Articles

Wastewater desalination for irrigation in inland regions

ABSTRACT Desalination using membrane processes is increasingly being implemented in coastal regions of the world to meet the water needs of the growing population. The use of this water treatment option to meet the growing water needs in inland regions, however, is impeded by the cost and regulatory challenges associated with responsible disposal of the concentrate brine. For inland regions of Australia, the use of evaporation ponds (EPs) is the only available brine management option. The high cost associated with construction and the high land requirements for EPs necessitates low waste brine volume production. This desktop study investigated the feasibility of achieving very high water recoveries and very low waste brine volumes in the reverse osmosis desalination of municipal wastewater for irrigation of crops near the inland town of Horsham, Victoria, Australia. Interstage lime and soda ash softening was selected as the means of removal of the scalants that prevent the achievement of high water recovery. It is hoped that this study will provide valuable information to aid in the planning of water reclamation operations for agricultural applications in inland areas at a time of increasing demand for water for food production and forecasts of population growth and climate change.

Land Use and Land Cover Change in East Java Indonesia from 1972 to 2021: Learning from Landsat

This study analyses land use and land cover (LULC) changes during the last five decades (1970–2021) in East Java Province, Indonesia. The changes are analysed by comparing four maps interpreted from Landsat images (MSS 1972, TM 1997, OLI 2013, and OLI 2021). The main research procedures consist of (1) data collection, (2) field survey, (3) image classification, and (4) LULC change interpretation. The classification uses the maximum likelihood algorithm, achieving an overall kappa accuracy of > 75%. The classification produces eight classes, i.e., built-up land (BU), heterogeneous agricultural land (HAL), bare soil (BS), paddy fields (PF), open water (OW), vegetation (VG), shrubland (SH), and wetlands (WL). The analysis shows a significant shift in land use from 1972 to 2021, with HAL declining by 46%, SH by 91%, and BS by 88%. In contrast, PF has increased by 105%, VG (forest and plantation) by 64%, and built-up areas by a remarkable 366%. These changes show a significant shift from dryland agriculture, shrublands, and barren lands to irrigated regions, vegetated areas, and urban growth. Furthermore, there are increases in water bodies due to the construction of several reservoirs to support water availability. In coastal regions, the development of inland aquaculture leads to a proliferation of wetlands (salt evaporation ponds, fish ponds, and rice-fish integrated farming).

Mechanical Behavior of Soils Polluted by Olive Mill Wastewater – Case Bouladhieb Evaporation Pond Site, Sfax, Tunisia

Mechanical Behavior of Soils Polluted by Olive Mill Wastewater – Case Bouladhieb Evaporation Pond Site, Sfax, Tunisia

Energy conversion for water surface evaporation in evaporation ponds with different depths and improvement of Dalton model

The accurate quantification of water surface evaporation can provide decision support for lake water scheduling and water resources management. However, water surface evaporation models rarely take into account the effect of water depth directly. Four evaporation ponds with water depths of 30 cm, 60 cm, 150 cm and 200 cm were set up. And the driving factors of energy and vapor pressure deficit were analyzed by using the measured data of daily meteorology, water temperature and evaporation for seven consecutive months. And an evaporation model including water depth was built based on Dalton model. The results showed that water surface evaporation decreased with the increase of water depth from April to August, the evaporation of 30 cm evaporation pond was 2.4 %, 4.9 % and 8.9 % higher than that of 60 cm, 150 cm and 200 cm evaporation ponds from April to May, respectively, and was 5.0 %, 9.7 % and 11.4 % from June to August; and water surface evaporation increased with the increase of water depth from September to October, the evaporation of 30 cm evaporation pond was 5.0 %, 9.5 % and 13.6 % lower than that of 60 cm, 150 cm and 200 cm evaporation ponds, respectively. In summer and autumn, the influence of water depth on evaporation was greater than that in spring because of the energy difference caused by water depth was larger. Water surface evaporation divided by vapor pressure deficit and water depth showed a logarithmic relationship, the aerodynamic evaporation model including water depth based on this can be used well on daily scale and can reflect the effect of water depth on water surface evaporation better. This study provides a basis for calculating evaporation from water surface by considering the influence of water depth.

Evaluation of environmental geochemical signatures due to RO rejects on arid agricultural farms and tangible solutions

The impact of reverse osmosis (RO) rejects in the groundwater presents a significant challenge in arid regions. This study collected groundwater samples, product water, and reverse osmosis brine (ROB) from evaporation ponds and analyzed them for major ions and trace elements. Test boreholes were drilled near the ROB site along the flow direction, and borehole sediment samples were collected. The samples were predominantly gravelly sand, and the depth to water level fluctuated around 30 m below ground level (bgl), with minerals mainly consisting of calcite, gypsum, and Quartz. Data loggers reflected a rise in water level (<22 m bgl) corresponding to higher electrical conductivity (>16 mS/Cm) during the cropping period in many locations, confirming the impact of ROB in groundwater. The results were further supported by enriched signatures of δ18O (∼ +1.5‰) and δ2H (∼ +15‰). The saturation index of the minerals reflected that carbonate minerals (Calcite > Dolomite) were saturated in the ROB relative to the groundwater. The vertical variation of mineral assemblages in the boreholes indicated gypsum precipitation in the capillary zone along with calcite and dolomite. The assemblage varies as the groundwater moves from the disposal site. The speciation of different compounds along the groundwater path indicated higher carbonate and sulfate species (CaCO3 > CaHCO3> CaSO4 > NaSO4 > MgSO4) near the disposal site, with variations along the flow direction. Considering the significant variation in temperature in the region (5 to 50 ℃), the water sample composition was modeled using PHREEQC, suggesting that the increase in temperature led to supersaturation of Epsomite and Gypsum compositions. The ROB was theoretically mixed with groundwater and product water in different proportions, and an optimum composition (10:90) for safe disposal was derived and tested fit for reuse in agriculture.

Demonstration of ultra-high-water recovery and brine concentration in a prototype evaporation unit: Towards zero liquid discharge desalination

The availability of water is still one of the most important factors affecting the sustainable growth of a country. Although many countries have free access to an inexhaustible source of water, the sea, this source cannot be used for human purposes as it is. To face this problem, desalination has been proposed for freshwater production but the generation of a waste brine effluent poses some issues of actual sustainability. In this work, the operation results of a Multiple Effect Distillation (MED) demo plant, designed for stable operation at high brine concentrations and operated as a brine concentrator, are presented. To this purpose, the integration with NanoFiltration (NF) has been implemented to minimize scaling risks, by removing bivalent ions from the feed stream. The 2-effects MED pilot unit, with a capacity of 1.7 m3/h, has been installed as part of the treatment chain of the WATER-MINING project, within the premises of the power station of the island of Lampedusa (Sicily, Italy) and is fully powered by waste heat at 70–80 °C from diesel engines. A vapor temperature of 40–50 °C allowed a perfect coupling with the low temperature waste heat source, demonstrating the possibility to produce distilled water with a conductivity between 15 and 25 μs/cm. Among the several operating conditions investigated, a recovery ratio above 80 % has been achieved and an effluent brine conductivity of 240 mS/cm was produced, very close to saturation in NaCl, thus being excellent for food-grade sea salt production in evaporative ponds. For the first time, it has been demonstrated on a pilot scale how a MED unit, supplied with waste heat, can be used efficiently as a brine concentrator, obtaining a brine concentration 8 times higher than the input concentration without any scaling problem.

(Invited) Electroflow: Sustainable Electrochemical Lithium Chemical Production

The demand for lithium has soared in recent years as the adoption of electric vehicles has grown rapidly, and lithium supply will need to grow another ~5x from current day to meet projected demand for lithium in 2030. To keep pace with this exponentially growing demand, novel methods of lithium sourcing are needed. Direct lithium extraction (DLE) from saltwater brines holds promise to unlock the lithium resources needed to power the electric vehicle revolution.Lithium is traditionally sourced via two methods. Open pit hard rock mining is the method which many are familiar with. In this method, rocks are excavated, roasted with sulfuric acid, and the eluent is processed to produce a pure lithium product. This is well known to be environmentally destructive, and it produces larges amounts of waste products. The second method employed to produce lithium chemicals is brine evaporation ponds. In this method, brine is pumped to a surface pond, often multiple acres across, and solar evaporation concentrates the lithium in the brine to the point that it can undergo further processing. This method is extremely land and water intensive, and local residents adjacent to such ponds are increasingly worried about the effects of such methods on local water tables.Electroflow employs a DLE process to convert brine directly into pure, battery grade lithium chemicals via a sustainable electrochemical process. Our electrochemical cell design enables extraction from dilute lithium brine resources with as low as 10 ppm Li, which unlocks huge swaths of new lithium resources across the globe, and specifically in North America. We use lithium-selective electrode materials as the basis for lithium separation from brine solutions, and this allows a new paradigm of DLE processes that have not yet been thoroughly studied. This talk will describe the operation of our technology and explore the impact that it could have at scale.

THE EFFECT OF VARIATION IN THE NUMBER OF SPRAYS AND DISCHARGE ON THE TECHNOLOGY SPRAY FOR EVAPORATION

Spray technology is an innovative salt production process technology that is able to increase seawater salinity and accelerate the salt production process. This study aims to determine the effect of variations in the amount of spray and discharge in spray technology on increasing seawater salinity. The experimental method was carried out by varying the spray and water discharge amount in spray technology according to the variables. This research has been successfully carried out to increase the salinity of synthetic seawater where to increase from the initial seawater salinity of 2.5 °Be to 24 °Be. It takes 16 hours taken in 3 days using the number of sprays as much as 5 sprays with a seawater flow rate of 0.2424 m³/hour in an evaporation pond of 15í—7 m. The use of the spray method proved effective in accelerating the rate of increase in salinity of synthetic seawater, which was tested to increase the salinity of synthetic seawater from 2.5 °Be to 12 °Be with an evaporation time in traditional methods of 15 days to only 11 hours. This can also happen because the temperature, humidity and wind speed were relatively stable when the research took place.

Salt production by ignition during the prehistory in the Iberian Peninsula with special focus on the archaeological site of Espartinas (Ciempozuelos, Spain)

One of the prehistoric techniques of salt production consisted of using ceramic vessels, known as briquetage, for the artificial evaporation of salt water. This paper summarizes all the archaeological sites throughout the Iberinan Peninsula where briquetage has been described to date, with special focus on the well-studied archaeological site of Espartinas saltworks. At Espartinas we found the use of two different kinds of ceramics, which points to a two-step process also involving halfah or esparto grass, which may well have been used for transport or/and as an insulating layer between the vessels walls and the mass of salt to facilitate the extraction of whole salt cakes. Palaeoenvironmental conditions at Espartinas have also been described based on local and regional pollen records and compared with the dry conditions associated to the so-called “4.2 cal kyr BP abrupt climatic event”. Despite the reduced amount of radiocarbon dating, the briquetage appears have been present in the studied region from the Late Neolithic to at least the Bronze Age. However, we cannot discard the fact that it might have reached the early Roman period, when salt evaporation ponds replaced this laborious technique. Moreover, briquetage distribution has been compared with evaporite outcrops throughout the Iberian Peninsula and it has been observed a characteristic pattern with a preference for peripheral, near to coast regions, with the exception of from Aranjuez-Getafe lower-Miocene lacustrine evaporites in central Iberia. Briquetage spread also shows a marked correlation with sites characterized by the presence of Atlantic halberds the first true metal weapon ever made in Western Europe and part of the warrior panoply of Late Copper Age/Early Bronze Age elites. At least during this period, these findings suggest that briquetage was used to obtain solid salt cakes easily transportable to medium and large distances by Atlantic and intra-Iberian trade exchange networks, which confirms previous studies that associate Bell Beaker phenomenon with salt circulation.

A comprehensive assessment of the economic and technical viability of a zero liquid discharge (ZLD) hybrid desalination system for water and salt recovery

Brine, a by-product of desalination and industrial facilities, is becoming more and more of an environmental issue. This comprehensive techno-economic assessment (TEA), focusing on the technical and economic aspects, investigates the performance and viability of a novel hybrid desalination brine treatment system known as zero liquid discharge (ZLD). Notably, this research represents the first instance of evaluating the feasibility and effectiveness of integrating three distinct desalination processes, namely brine concentrator (BC), high-pressure reverse osmosis (HPRO), and membrane-promoted crystallization (MPC), within a ZLD framework. The findings of this study demonstrate an exceptional water recovery rate of 97.04%, while the energy requirements stand at a reasonable level of 17.53 kWh/m3. Financially, the ZLD system proves to be at least 3.28 times more cost-effective than conventional evaporation ponds and offers comparable cost efficiency to alternatives such as land application and deep-well injection. Moreover, the ZLD system exhibits profitability potential by marketing both drinking water and solid salt or solely desalinated water. The daily profit from the sale of generated water varies from US$194.08 to US$281.41, with Greece and Cyprus attaining the lowest and highest profit, respectively. When considering the sale of both salt and water, the profit rises by 8% across all locations.

Pioneering minimum liquid discharge desalination: A pilot study in Lampedusa Island

Minimum Liquid Discharge (MLD) and Zero Liquid Discharge (ZLD) schemes have been widely proposed in the recent scientific literature not only as a possible solution to brine disposal but also as a non-conventional sustainable source of raw materials. Nevertheless, very few works have pushed the idea towards a real demonstration activity, and this somehow limits the reliability that such schemes have with respect to the real implementation potential at the industrial scale. In this work, for the first time in the literature, an integrated treatment chain for the sustainable production of freshwater and minerals has been demonstrated at a pre-industrial scale, in the island of Lampedusa (Italy). The treatment chain included a Nanofiltration (NF) step to separate monovalent and bivalent ions, followed by a Multi-Effect Distillation (MED) unit, powered by waste heat from a Thermal Power plant, generating high-quality water (<30 μS/cm) and an ultra-concentrated brine. The latter was treated in Evaporation Ponds (EPs) to generate high purity NaCl (>99 %). On the other side, the NF retentate was treated to selectively recover magnesium and calcium hydroxides (Mg(OH)2 purity up to 98 %) in a novel Multiple Feed-Plug Flow Reactor (MF-PFR). The resulting brine fed an ElectroDialysis with Bipolar Membranes unit (EDBM), generating in-situ alkaline and acidic solutions: chemicals needed for internal usage in the plant. All units were successfully tested, reaching satisfactory performance indicators. Furthermore, the stability of each unit during the daily operational run was assessed and successfully achieved, demonstrating not only the technical feasibility of the proposed demo plant, but also the feasibility of MLD as a sustainable alternative for minerals recovery.

Comparison of waterbird communities in a Mediterranean salina – saltmarsh complex

Coastal wetlands provide habitat for large numbers and many species of waterbirds. Man-made salinas are a particu-lar habitat type often found in such wetlands. This study is an initiative to understand the differences in bird communities between a salina (including evaporation ponds and prebasin) and a saltmarsh. Bird counts and nest surveys took place in the wetlands of Angelochori, Thessaloniki, Greece, in 1991, when the salina was inactive, and in 1997, 2000-01 when it was active. Counts in evaporation ponds were richer in species, abundance and nests compared to the prebasin and the saltmarsh. These three wetland types supported different bird communities. Similarities among bird communities depended on the inundation of the salina with seawater. Evaporation ponds in their inactive period presented low similarity with the communities of the prebasin and the saltmarsh ; in the active period this was observed only for the saltmarsh. Species showing clear selection for the evaporation ponds were Charadrius alexandrinus, Calidris alpina, Calidris minuta, Recurvirostra avosetta, Sterna hirundo, Sternula albifrons, Sterna sandvicensis and Haematopus ostralegus; the prebasin was preferred by Phoenicopterus roseus and Anas platyrhynchos, and the saltmarsh by Anas querquedula, Anas clypeata, Plegadis falcinellus, Tringa totanus, Tringa glareola, Tringa stagnatilis and Himantopus himantopus.

Total Resource Circulation of Desalination Brine: A Review

AbstractDesalination brine is a concentrated stream that is generated during the desalination process. Brine commonly has high salinity and TDS (total dissolved ions), which contains ions such as Na+, K+, Ca2+, Mg2+, Cl−, SO42−, HCO3−, PO43−, and some critical elements. Currently, the brine treatment mainly applies direct disposal, like surface water discharge, sewer discharge, deep‐well injection, and evaporation ponds. However, these methods can cause harm to marine ecosystems, soil, and groundwater. Therefore, brine can be regarded as a resource to be reutilized. This work then aims to highlight the novel developments of brine application. For example, Na, Ca, and Mg in brine can be employed for carbon capture and utilization with ammonia, amines, and alkaline substances. With slight adjustment, brine can also be directly used as irrigation water, aquaculture water, and the activation of biochar. Furthermore, brine holds a higher concentration of critical elements, which makes many countries and scholars start to conduct element extraction, reducing the amount of ore exploitation. At last, the major obstacles related to these advancements in sustainability, expenses, and technological aspects are outlined, and promising research trends of brine reutilization are also suggested.

Assessment of occupational external radiation exposure of workers in the Southwest of Libya using portable NaI detector

In this study, gamma dose rates generated from the naturally occurring radioactive materials (NORM) were measured in the waste streams of a large scale and sludge onshore petroleum operations. Measurements conducted in this work involved: sludge recovery from separation tanks, sludge forming, NORM storage, scaling in oil tubulars, scaling in gas production and sedimentation in produced water evaporation ponds. Field work was carried out in many places of different terrain of an operation oil exploration and production in Murzuq basin in the Southwest of Libya. The radiation dose rates were measured using portable InSpector-1000. A total of 400 dose rates were acquired. The highest dose rate was 70 μSv/h acquired in sludge stored in barrels. The estimated mean annual equivalent doses in this field were in the range of 0.2–2.8 mSv/y in the first scenario, while in the second scenario the calculated mean annual equivalent doses were in the range of 0.04–0.68 mSv/y. It is assumed that workers may face various exposures in the field where measurements took place, considering the total annual effective dose to be 1.53 mSv/y. The main radioisotopes detected in these samples indicated by the display of the measuring device were 226Ra and 228Ra but detecting both radioisotopes in the same run is not achievable by using the display of the screen.

Delineation of the proper locations for wastewater disposal in arid regions using TEM and ERT techniques: A case study at Rubiki industrial zone, Badr City, Egypt

Proper wastewater disposal is crucial for the sustainable development of rapidly growing megacities worldwide. The emergence of waterlogging near evaporation ponds (EVP) and in desert areas surrounding these cities poses a significant environmental threat. This study employs an integrated approach, combining transient electromagnetic (TEM) and 2D-electrical resistivity tomography (2D-ERT) methods with remote sensing techniques, to understand wastewater flow patterns around EVPs and identify suitable disposal sites. The research focuses on a complex subsurface structure in the Cairo-Suez district, characterized by extensive surface waterlogging. Initial monitoring relies on satellite imagery and land use-land cover maps. TEM provides an overview of subsurface layer distribution, while 2D-ERT offers detailed insights into near-surface flow paths. To address the limitations of geoelectrical methods in locating conductive layers, advanced inversion techniques (AIS) are applied. The findings reveal a four-layer subsurface composition, with waterlogging primarily attributed to the argillaceous limestone layer interbedded with shale. This layer is shallower in the eastern and northwest areas, correlating with higher instances of waterlogging. Moving northward, the argillaceous limestone layer deepens, and the upper clastic layer thickens, resulting in reduced waterlogging. The study underscores the influence of subsurface structure on near-surface layer distribution. Based on these findings, optimal wastewater disposal sites are recommended, with a focus on the northern region where the argillaceous limestone layer is deeper and the upper clastic layer is thicker. To mitigate waterlogging, the installation of disposal wells is highly advised, leveraging the insights derived from this research. This study offers a versatile and reproducible approach suitable for both pre-project planning and post-project phases in desert regions.

Comparison of simple and active solar stills for freshwater recovery during lithium brine mining

Lithium mining from brines raise environmental issues due to huge volumes of both saline and freshwater being constantly pumped in desertic environments. Data indicating the slow depletion of both underground water levels and lagoon surfaces in the regions where large lithium brine mining exploitations are located have recently being disclosed. Amongst different direct lithium extraction methodologies, DLE, for more sustainable lithium recovery, a few proposals aim at the recovery of freshwater from the high salinity brines. About 900 kg of freshwater could potentially be recovered per cubic meter of processed native brine. The water evaporation and freshwater production capabilities of a simple and an active solar still are compared in this work. These are two simple and relatively low-cost technologies that could be adapted to existing solar evaporation ponds. The two systems were thermodynamically modelled. Equations were derived which were fed with real meteorological data from the Olaroz salt lake location and brine properties derived from the Pitzer model for the said brine. Analysis of the heat fluxes show that the behavior of both systems is relatively similar with large heat losses that are responsible for neither of the systems reaching the evaporation rate of the evaporation ponds.

Soil-geochemical assessment of salinization of the territory adjacent to the Kuchuk salt deposit (Altai Krai)

A soil geochemical analysis was conducted to assess the impact of the exploitation of the Lake Kuchuk salt deposit on the salinization of the soils in the adjacent areas. The specific characteristic of the soil forming in the Kulunda steppe is the wide distribution of salinization processes. Solonetzes soils are distributed in the impact zone of the deposit exploitation; therefore, as background soils, we considered also Solonetzes. Background soils are located at a considerable distance (2–10 km) from industrial facilities. The results of the chemical analysis of the soil-water extracts showed that the area of the most intense salinization is concentrated in the eastern and southeastern parts of the depression of the former lake. Nowadays, a salt evaporation pond and an open salt storage, which are the main industrial sources of sodium sulfate dust, occupy the bottom of the lake. The maximum salt content (over 1%) was found in these parts of the basin and is associated with the prevailing wind direction in the study area. With an increase in the hypsometric level of the surfaces and the distance from the open technological sources of dust, as well as on the opposite slope of the basin, there was a sharp (2–3 times) decrease in the salt content. The total salt content in the background soils ranged from 0.3 to 0.6%. The specificity of the chemistry of soil salinization in the impact zone was the dominance of sulfates and sodium in the composition of the soil-water extract, and thenardite, which is a dehydration product of mirabilite, in the composition of salt crust minerals and salt efflorescences. In the background Solonetzes, the participation of soda in the chemical composition became more noticeable, which is a natural halogen geochemical feature of the Kulunda steppe. In the surface salt crusts in the background areas, a greater variety of minerals were noted, among which there were typical minerals of the evaporite association (gypsum, halite, calcite, dolomite, mirabilite) and their rare species (konyaite, wedellit).

Installation of geomembrane panels in low heights slopes

We understand that one of Engineering's main services, in addition to following good construction techniques, is also allowing customers to low down costs, such as installation speed (shorter the time required to complete the work usually means lower costs). As a manufacturer of waterproofing geomembranes, we rarely participate in defining what kind of geomembrane is used for each job, but we are required to produce the geomembrane to the meet the necessary specifications. Sometimes, when we are asked to produce panels, we follow modulation requirements. This work was developed based on projects executed in mining areas, mainly in evaporation ponds to obtain potassium and lithium, located in the Atacama Desert, in Chile and in ponds of the same purpose located in the Uyuni Desert, in Bolivia. However, although we did not project, due to our experience as supplier participating in many projects and different works, this experience enable us to observe certain aspects of many projects we got in contact. One of these aspects, which we want to draw attention to here, was the installation of geomembranes in small lagoons with 2.00 m height, where the placement of panels reached a high speed coupled with also high security in the installation.

Photothermal self-floating aerogels based on chitosan functionalized with polydopamine and carbon nanotubes for removal of arsenic from wastewater

Although wastewater disposal in evaporation ponds may be a cost-effective strategy for wastewater management, it overlooks water recycling and can possibly pose significant threats to the surrounding environment. The development of photothermal materials with functional groups capable of adsorbing toxic contaminants offers a promising opportunity for detoxification and potentially solar-driven recycling of wastewater disposed in evaporation ponds. In this study, ultralight aerogels based on chitosan (Ch), a natural biodegradable polymer, functionalized with mussel-inspired polydopamine (PDA) and carbon nanotubes (CNT) were fabricated through a facile approach and examined for the removal of arsenic from water. Three aerogels, namely chitosan, CNT/Ch, and PDA@CNT/Ch were fabricated and characterized using SEM, FTIR, TGA, XPS, and BET surface area analysis. Adsorption isotherms, thermodynamics, and kinetics were systematically investigated, revealing the feasibility of the fabricated aerogels for arsenic removal from aqueous solutions. The UV–Vis and photothermal analysis indicated excellent light-absorption and light-to-heat conversion performance of the functionalized aerogels. Arsenic adsorption by aerogels occurred rapidly and reached equilibrium within 30 to 60 min and was well-fitted by pseudo second-order kinetics model. The Langmuir model well described the adsorption isotherm, and the maximum adsorption capacities were found to be 31.5, 36.6, and 38.7 mg/g at neutral pH for chitosan, CNT/Ch, and PDA@CNT/Ch, respectively. The adsorption mechanism was studied by FTIR and XPS analysis and the adsorption pathway was evaluated using intraparticle diffusion model. This study broadens the scope of utilizing aerogels for the detoxification and potential recycling of wastewater from diverse sources and effluents disposed in evaporation ponds.

Concentrate circularity: A comparative techno-economic analysis of membrane distillation and conventional inland concentrate management technologies

Inland desalination with reverse osmosis (RO) offers a promising alternative to increase potable water resources. However, large volumes of concentrated brine are generated as a byproduct of the process. Concentrate disposal for inland regions displaces valuable water resources and can make up to 33 % of the total cost of desalination. Conventional disposal systems are limited by location, hydrogeology, climate, and policies, and few place value on resource recovery, thus limiting the implementation of desalination facilities in water-stressed regions. Membrane distillation (MD) is an alternative technology that can minimize disposal volume while maximizing water recovery for beneficial reuse. MD uses thermal energy gradients to desalinate the concentrate stream achieving near zero-liquid discharge. Furthermore, several MD configurations include heat recovery, making MD an energy-efficient alternative. A techno-economic assessment (TEA) of air-gap MD (AGMD) for RO concentrate management was performed and compared to three conventional concentrate management systems: evaporation ponds, deep-well injection (DWI), and concentration-crystallization. TEA results indicate that compared to DWI at 1.09 $/m3, evaporation ponds at 1.47 $/m3, and concentrators at 6.2 $/m3, respectively, AGMD is a competitive concentrate management technology producing water at 0.90 $/m3 when operating conditions are optimized and low-grade heat is available. When operating at high salinity (>70 g/L) the selection of operating conditions, specifically module length and circulating flowrate, is critical. Results of this study support the economic viability of AGMD in contrast to current industry standards and highlight the importance of resource recovery to promote a circular water-energy economy for regions relying on reuse and desalination.