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Reverse osmosis is a widely known technology used to produce fresh water from brackish waters. However, the reject brine from desalination plants poses a serious threat to the environment due to soil and groundwater salinization. The aim of this study was to investigate the potential of Atriplex nummularia to extract salts from a soil irrigated with reverse osmosis brine, at varying moisture levels. A field experiment was conducted in a split-plot design, with randomized complete blocks replicated four times. Treatments consisted of irrigation with reject brine in the main plots, with four relative percentages of the soil moisture at field capacity (100, 85, 70, and 50%), and two levels of organic fertilization in the subplots (0 and 1.5 L plant−1 of goat manure). The mineral composition of leaves and stems indicated that the highest salt extraction by plants occurred when soil moisture was maintained at 100% field capacity. The salt extraction capacity of A. nummularia indicates a high potential for phytoremediation of soils affected by brine disposal from reverse osmosis plants.

ABSTRACT: Rural communities located in the Brazilian Northeast, especially in the semiarid zone, live with water shortages resulting from erratic rainfall. This work proposes the cultivation of saltbush (Atriplex nummularia) in the Rural Settlement Project of Boa Fé, Mossoró/RN as alternative to the disposal of reject brine from desalination plant on yield of forage. The statistical design was a split-plot design, being four treatments at the plots, related to irrigation with reject brine water, at different levels of soil moisture by moisture from Field Capacity (FC) (100, 85, 70 and 50% of FC) and in subplots and two levels of organic manure (without fertilized and fertilized) with four replications. The variables of yield and forage quality of saltbush were analyzed. It was observed that saltbush has a great production capacity in terms of fresh matter and drought for saltbush under a level of 85% soil moisture in relation to the field capacity of soil, presenting minimal loss of yield; however, this proved to be productive even with the dry soil. The total yield was satisfactory, showing its viability for forage production.

Feasibility of salt production from inland RO desalination plant reject brine: A case study

In a context of growing global water demands, plus climate change affecting water resources availability, non-conventional water sources (like reclaimed water and desalinated seawater) are emerging as promising water supply alternatives. Given that agriculture is the major contributor to water withdrawals, this study analyzes if the use of non-conventional water for irrigation leads to a better performance of irrigation communities (ICs). To do so, the research includes several ICs from the Segura River Basin (southeast of Spain), a region with structural water deficit, which is pioneer regarding the use of non-conventional water; as well as ICs from the Apulia region (southeast of Italy), which also suffers from water scarcity problems, but is less experienced regarding the use of non-conventional water. A benchmarking analysis was carried out, based on a set of Key Performance Indicators (KPIs), such as irrigation efficiency, guarantee of water supply, energy costs or gross margin, among others. This methodology has been previously used in the framework of the water and drainage sector. Also, a Principal Component Analysis and Clustering Analysis were applied to explore potential dissimilarities between the studied ICs and their causes. Finally, a regression analysis was carried out to observe if the use of non-conventional water has any effects on the performance of the studied ICs. The results of this research may help to increase knowledge regarding the pros and cons of using these non-conventional water resources, depending on the socioeconomic, environmental and geographical context. This way, this study would contribute to promoting the use of non-conventional water in other regions, leaning towards a more sustainable use of water resources and, consequently, protecting and preserving water ecosystems.

Desalination has been growing rapidly as an industry and as a field of research that combines engineering and science to develop innovative and economical means for water desalting. Many countries in the world, especially in the Middle East, depend heavily on seawater desalination as a major source of drinking water and have invested considerable efforts and financial resources in desalination research and training. Desalination plants have seen considerable expansion during the past decade as the need for potable water increases with population growth. It is estimated that the world production of desalination water exceeds 30 million cubic meters per day and the desalination market worldwide is expected to reach $ 30 billion by 2015. One of the major economical and environmental challenges to the desalination industry, especially in those countries that depend on desalination for potable water, is the handling of reject brine, which is the highly concentrated waste by-product of the desalination process. It is estimated that for every 1 m3 of desalinated water, an equivalent amount is generated as reject brine. The common practice in dealing with these huge amounts of brine is to discharge it back into the sea, where it could result, in the long run, in detrimental effects on the aquatic life as well as the quality of the seawater available for desalination in the area. Although technological advances have resulted in the development of new and highly efficient desalination processes, little improvements have been reported in the management and handling of the major by-product waste of most desalination plants, namely reject brine. The disposal or management of desalination brine (concentrate) represents major environmental challenges to most plants, and it is becoming more costly. In spite of the scale of this economical and environmental problem, the options for brine management for inland plants have been rather limited. These options include: discharge to surface water or wastewater treatment plants; deep well injection; land disposal; evaporation ponds; and mechanical/thermal evaporation. Reject brine contains variable concentrations of different chemicals such as anti-scale additives and inorganic salts that could have negative impacts on soil and groundwater. This chapter highlights the main concerns as well as the environmental and economical challenges associated with the generation of large amounts of reject brine as a by-product of the desalination process. The chapter also outlines and compares the most common options for the treatment or disposal of reject brine. The chapter focuses on a novel approach to the management of reject brine that involves chemical reactions with carbon dioxide in the

Percolation columns constructed in the Laboratory can predict the degree of contamination in soil due to reject brine disposal and can be a tool for reducing environmental impacts. This study aim to evaluate the mobilization of ions in reject brine from desalination process by reverse osmosis. The mobilization of the contaminant ions in the saline waste was studied in glass percolation columns, which were filled with soil of contrasting textures (eutrophic CAMBISOL, typic dystrophic Red OXISOL, ENTISOL Quartzipsamment). Experiments ware repeated three times each, and the initial and final concentrations of the ion contaminants were analyzed. The pollution potential of this wastewater was determined by the retardation factor and dispersion-diffusion coefficient of K+, Cl- and Na+ for each studied soil. The differences in the displacement curves of the ions present in the saline waste among various soil types were analyzed. The Entisol Quartzipsamment showed a higher forward speed of the ions K+ and Cl- (greater retardation factor, i.e., greater power of the subsurface contamination for these ions). In typic dystrophic Red OXISOL, the ions move with greater ease and therefore produced greater groundwater contamination. In eutrophic CAMBISOL, the low coefficient of diffusion-dispersion in all ions was evaluated (i.e., reduced ion mobility is directly influenced by their exchangeable levels).

Combining green manure and cattle manure to improve biomass, essential oil, and thymol production in Thymus vulgaris L.

Use of evaporation ponds for brine disposal in desalination plants

Desalination is becoming crucial to meet the increasing global demand for potable water. Despite its benefits, desalination produces reject brine, a highly concentrated saline byproduct, which poses substantial environmental risks if not managed properly. It contains high levels of salts and other potentially harmful compounds, which, when discharged into oceans or land, can disrupt habitats, degrade soil quality, and harm biodiversity, creating serious environmental challenges. In response to these challenges, this study investigated various uses for reject brine, aiming to reduce its environmental footprint and explore its potential applications. This review paper synthesizes findings from previous studies on the disposal, management, and applications of reject brine in fields such as concrete production, road construction, and ground stabilization. In addition, this review highlights the potential cost savings and resource efficiency resulting from the utilization of reject brine, as well as the mitigation of environmental impacts associated with traditional disposal methods. This paper also provides a comprehensive overview of existing technologies and approaches used to utilize reject brine in various industries, including construction. This review contributes to the growing body of knowledge on environmentally friendly solutions for reject brine, emphasizing its potential role in supporting sustainable development goals through resource reutilization and waste minimization. The study also highlights current research gaps that are still unaddressed, hindering the complete realization of the full potential of reject brine as a sustainable resource.

After drought, salinity is the second most important hindrance to sustain agriculture in the semiarid. Subterranean waters extracted from wells are often high in salts and, during dry years, this dependency on saline ground water precludes water and food security for small farmers and their families. Water desalination offers a potential solution to this problem, but the process results in a reject brine that needs to be properly disposed of to prevent increasing soil salinity and environmental degradation. This chapter considers desalination of naturally saline well waters as a potential solution to water and food security when used in conjunction with an integrated production system involving reject brine for farm-raised fish and the use of fish pond water to grow organic salt-tolerant vegetables and forage crops for small ruminants. We present results on the recovery of desalination systems in different small communities in the Brazilian northeast and chemical analyses of the saline water input, of the desalinized water, of the resulting reject brine, and of soils that received the desalinized water. Our results indicate that the use of desalination reject brine in family agricultural production is technically, economically, and socio-environmentally feasible, especially when using integrated and sustainable production systems.

Treated wastewater (TWW) is a major source of water for agriculture in Israel; however, recent reports indicate a marked yield loss in TWW-irrigated avocado and citrus orchards planted in clayey soils. The association of the yield loss with clayey soils rather than sandy soils suggests that it is associated with conditions in the root zone, and specifically poor aeration. A three-year study (2012–2015) was conducted in an avocado orchard planted in clayey soil, comparing the oxygen and redox conditions in the root zone of TWW-irrigated plots with fresh water (FW)-irrigated plots, together with the physiological status of the trees. Soil parameters included: continuous in-situ measurement of soil-water tension (SWT), soil oxygen, and soil redox potential, and periodic measurements of soil solution composition. Physiological parameters included: mineral composition of plant tissue from the leaves, trunk xylem and roots, root growth, yield, fruit setting, plant volume, and yield. TWW-irrigated plots were found to endure longer periods of low SWT indicating higher water content, accompanied by lower oxygen levels and more reduced conditions in comparison to FW-irrigated plots. The differences in these soil parameters between treatments were greater during the irrigation season than during the rainy period. The more reduced conditions in the TWW plots did not lead to significant differences in Fe or Mn concentrations in the soil solution or in plant leaves. TWW soil solution had significantly higher Na levels compared with FW. This did not affect the leaf Na content, but was expressed in substantially higher Na content in the root and trunk xylem, with up to seven times more trunk xylem Na in TWW-irrigated plants compared with FW-irrigated plants. Root growth was significantly hindered in TWW-irrigated plots compared with FW-irrigated plots. A negative correlation was found between root growth and the duration of hypoxic conditions, and similarly between root growth and the Na levels in the roots. TWW-irrigated plants had greater fruitlet numbers at the initial fruit-setting stage, but had a smaller number of fruit and a lower yield at harvest. The yield (kg/tree) negatively correlated with the duration of hypoxic conditions in the root zone but not with the Na levels in the roots or xylem. Our findings point towards a substantial role of oxygen deprivation as a major factor leading to the damage to TWW-irrigated orchards in clayey soils. Based on the assimilation of data, we suggest that a downward cascade is instigated in the TWW-irrigated orchards by increased input of Na into the soil, leading to degradation of soil hydraulic properties and reduced aeration. Impaired physiological functioning of the roots due to limited oxygen supply results in less roots growth, lower water uptake and impaired selectivity against Na uptake, thus imposing a negative feedback to increase soil water content, reduce aeration and root-zone oxygen availability for the roots, and further impair plant resistance to the high Na levels.

Three species of saltbush (A. amnicola, A. nummularia and A. undulata) and bluebush were collected from five sites in Western Australia (Dalwallinu, Meckering, Tammin, Katanning and Lake Grace) that had previously been established to saline pastures, although not all species were present at all 5 sites. Five individual plants of each species were randomly selected from within a 2500 m 2 area for the collection of leaf material. The leaf material was analysed for the following attributes; in vitro and in sacco digestibility of the organic matter in the dry matter (DOMD), ash and insoluble ash content, acid detergent fibre (ADF), neutral detergent fibre (NDF) and nitrogen (N) content. In vitro digestibility was determined using a modified Klein and Baker (1993) pepsin-cellulase procedure. These in vitro measurements were not calibrated for in vivo digestibility due to a lack of reliable calibration standards from diets containing high salt. Since not all species were present at each site, an analysis of variance using unbalanced treatments was used. Table 1 provides data on the nutritional attributes of the 4 halophytes. Bluebush tended to accumulate more ash and insoluble ash than the 3 saltbush species. Atriplex nummularia contained higher concentrations of N and was more digestible than the other species. However, A. amnicola and A. undulata had higher ADF and NDF concentrations. Considering the standard deviations, it was apparent that there was variability within the 4 species of halophytes, with A. amnicola and A. undulata showing greatest differences in both in vitro and in sacco digestibility, and ash content. However, the reasons for such differences could not be determined. Table 1. Nutritional attributes (means (% of DM) ± s.d.) of 4 halophytes (see the text for details).

Managing forest plantation landscapes for water conservation

Impact of land disposal of reject brine from desalination plants on soil and groundwater

“When the well is dry, we know the worth of water.” Benjamin Franklin, (1706-1790), Poor Richard's Almanac, 1746 Fast depletion of groundwater reserves, coupled with severe water pollution, has put governments all over the world in a difficult position to provide sufficient fresh water for our daily use. Ismail Serageldin vice president of World Bank in 1995 predicted that “if the wars of this century were fought over oil, the wars of the next century will be fought for water”. Thus it signifies the role water is going to play in the current century we live in. At the same time, the need for sustained food production to feed the hungry mouths of the ever increasing population is apparent. In many arid and semi-arid countries since water is becoming increasingly scarce resource and planners are forced to consider alternate sources of water which might be used economically and effectively. The use of wastewater (WW) for crop irrigation as an alternative for effluent water disposal and for freshwater (FW) usage is common worldwide in countries in which water is scarce. Disposal of wastewater is also a problem of increasing importance throughout the world including India. Both the need to conserve fresh water and to safe and economically dispose of wastewater makes its use in agriculture a very feasible option. Furthermore, wastewater reuse may reduce fertilizer rates in addition to low cost source of irrigation water. In many parts of the world, treated municipal wastewater and raw sewage wastewater and even industrial wastewater has been successfully used for the irrigation of various crops (Asano and Tchobanoglous 1987, Adriel et al., 2007; Tak et al., 2010). It is well known that the enteric diseases, anaemia and gastrointestinal illnesses are high among sewage wastewater farmers. In addition, the consumers of vegetable crops which are eaten uncooked and grown without any treatment are also at risk. This chapter particularly envisages the review on the safe and quality parameters of wastewater for sustainable use in agriculture. The use of sewage effluents for agricultural irrigation is an old and popular practice in agriculture (Feigin et al., 1984). Irrigation with wastewater has been used for three purposes: i. complementary treatment method for wastewater (Bouwer & Chaney, 1974); ii. use of marginal water as an available water source for agriculture (Al-Jaloud et al., 1995; Tanji, 1997) – a sector demanding ~ 70% of the consumptive water use.