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Recycling salt and water from saline wastewater is crucial for environmental preservation, resource conservation, and social economy sustainability. The heat pump air circulation evaporating separation (HP-ACES) system for saline wastewater treatment is proposed. Nevertheless, it is discovered that the system evaporation efficiency (SEE) is low and solid crystalline salt does not precipitate during the experiment. Therefore, an established and validated mathematical model of the HP-ACES system is provided and the average relative errors of the system evaporation rate (SER) and SEE are 5.3 % and 7 %, respectively. The theoretical analysis of the non-optimized system indicates that the main cause of the low SEE of the HP-ACES system during the test is incorrect cooling water flow. Hence, the system optimization scheme is presented and the comparison of the HP-ACES system's performances before and after optimization is conducted. Results demonstrate that the SEE of the optimized HP-ACES system has been greatly improved (optimized system: 0.62–2.46 kg/kWh, non-optimized system: 0.77–0.91 kg/kWh). Additionally, there is almost no change in the yield and composition of the solid crystalline salt when the inlet air temperature of spray separation tower is above 90 °C.

Bisphenol A, a hazardous endocrine disruptor, poses significant environmental and human health threats, demanding efficient removal approaches. Traditional biological methods struggle to treat BPA wastewater with high chloride (Cl−) levels due to the toxicity of high Cl− to microorganisms. While persulfate-based advanced oxidation processes (PS-AOPs) have shown promise in removing BPA from high Cl− wastewater, their widespread application is always limited by the high energy and chemical usage costs. Here we show that peroxymonosulfate (PMS) degrades BPA in situ under high Cl− concentrations. BPA was completely removed in 30 min with 0.3 mM PMS and 60 mM Cl−. Non-radical reactive species, notably free chlorine species, including dissolved Cl2(l), HClO, and ClO− dominate the removal of BPA at temperatures ranging from 15 to 60 °C. Besides, free radicals, including •OH and Cl2•−, contribute minimally to BPA removal at 60 °C. Based on the elementary kinetic models, the production rate constant of Cl2(l) (32.5 M−1 s−1) is much higher than HClO (6.5 × 10−4 M−1 s−1), and its degradation rate with BPA (2 × 107 M−1 s−1) is also much faster than HClO (18 M−1 s−1). Furthermore, the degradation of BPA by Cl2(l) and HClO were enlarged by 10- and 18-fold at 60 °C compared to room temperature, suggesting waste heat utilization can enhance treatment performance. Overall, this research provides valuable insights into the effectiveness of direct PMS introduction for removing organic micropollutants from high Cl− wastewater. It further underscores the critical kinetics and mechanisms within the PMS/Cl⁻ system, presenting a cost-effective and environmentally sustainable alternative for wastewater treatment.

There is a gradual increase in the discharge of saline wastewater which is harmful to the environment and human health. A novel heat pump air circulation evaporating separation (HP-ACES) system for saline wastewater treatment is proposed and experimentally investigated. The results show that the system evaporation efficiency (SEE) initially decreases before increasing with the expansion valve opening at different refrigerant charges. However, the SER increases by 0.67 kg/h at 1.21 kg refrigerant charge while they descend and then rise at 1.53 and 1.86 kg refrigerant charges. Noted that the effects of expansion valve opening on the SER and SEE are lessened with refrigerant charge. Moreover, there exist the optimal values of total air flow and air flow proportion of packing concentration tower at which the SER and SEE peak, and both of the solution concentration and cooling water flow negatively affect the SER and SEE. Besides, compared with similar evaporating separation systems, the HP-ACES system has higher energy efficiency for treating high saline wastewater and the SEE ranges from 0.86 to 1.64 kg/kWh (5–25 % CaCl2 solution). However, the SEE is low, and it is necessary to reveal the cause and propose the optimization schemes in the future.

Electrocatalytic treatment of chemical saline wastewater showed great technical advantages due to its characteristics of simple operation, high catalytic efficiency and little secondary pollution. The review takes the classification and composition of titanium-based anodes as the starting point. Typical studies of wastewater treatment by electrocatalytic technology based on free radicals and non-free radicals were also discussed. Combined with the previous researches about electrocatalytic mechanisms in recent years, the mechanisms of titanium-based anodes were analyzed in terms of ·OH, active chlorine and others. The studies on titanium-based anodes in chemical wastewater containing different salt concentrations, such as dye wastewater, coal chemical wastewater, landfill leachate wastewater, fertilizer and pesticide production wastewater, etc., were thoroughly examined. According to the amount of electricity required for the removal of organic matter per unit, the energy consumption of titanium-based anodes for wastewater treatment by electrochemistry was described. The review would provide theoretical basis and technical support for electrocatalytic treatment of chemical saline wastewater.

In this research, the exit treated wastewater from the gravity filtration unit, mechanical and chemical treatment unit, biological treatment unit and finally UV disinfection treatment unit enters to a solar desalination unit. Wastewater evaporation process is performed in this unit. In this study, in order to increase the UV waves in solar energy, nano-flooring has been used on the floor of the solar pond. The laboratory results show that the average difference between the experimental data and the theoretical results for simple coating, coating made of zinc oxide nanoparticles and coating made of aluminum oxide nanoparticles is equal to 2%, 2.3% and 1.6%, respectively. Laboratory results show that the average temperature difference between theory and laboratory when simple coating, nano zinc oxide coating and nano aluminum oxide coating are used are 0.5%, 2.89% and 0.67%, respectively. The laboratory results show that the minimum and maximum average temperature of different layers of wastewater are related to the months of January and July, respectively. This research shows that the maximum and minimum temperature difference of the first layer and the last layer of wastewater are in April and March, respectively.

Solar driven air evaporating separation (AES) technology has extensive application in the field of saline wastewater treatment due to its energy saving and cleanliness. However, these current systems generally utilize solar collectors to heat working fluids (air and wastewater), and then pass these heat carrying fluids into the evaporator to complete the mass transfer evaporation process, so as to realize the separation of the wastewater. This conventional process inevitably leads to the mismatch between heat and mass transfer of two working fluids in evaporator, which limits the efficient utilization of the energy. Accordingly, a novel thermal collector–evaporator integrated unit, in which the collecting process and evaporating process are carried out at the meantime and the collected heat directly supplies the latent heat consumed by this evaporation process, is designed to couple with the solar air evaporating separation system for saline wastewater treatment in this paper. Meanwhile, the system thermodynamic simulation model is established and detailed system performance experimental investigations are carried out. The results show that this system is feasible, and this special design is indeed conducive to improve the system thermal utilization (compared with the traditional system, the average irradiation utilization efficiency ηican be increased by 21.2%). Furthermore, by comparing the experimental and simulation results, the thermodynamic model can effectively predict various system state parameters during operation (errors are all basically within ±10%). More importantly, from the system dynamic characteristic analysis results, the stored wastewater has the phenomenon of heat storage and heat release, which is beneficial to prolong the duration of maintaining high GOR, evaporation efficiency (EE) and system energy utilization efficiency (ηsys). Even under experimental conditions in winter, this system can still sustain high wastewater treatment performance and energy efficiency (When c=10%, three average indicator: GOR = 3.99, EE = 6.97 kg/kWh, ηsys=73.8%).

Fungal overgrowth in halophilic aerobic granular sludge (HAGS) is a severe problem, leading to granule disintegration. However, it is still mostly unclear how to control fungal overgrowth. This study explored the effects of carbon availability in saline wastewater with a salinity of 20 g/L on fungal and bacterial population sizes, community compositions, and network interactions in HAGS by manipulating different carbon-to‑nitrogen ratios (C/N). Bacterial population size increased from 6.42 × 10 6 copies/ng DNA to 8.67 × 10 6 copies/ng DNA as the C/N ratio increased from 4 to 20. In contrast, fungal population size decreased from 1.24 × 10 6 copies/ng DNA to 8.05 × 10 3 copies/ng DNA. The maximum removal rate of ammonia by fungi decreased from 5.02 ± 0.04 mg·L -1 ·h -1 to 1.72 ± 0.30 mg·L -1 ·h -1 . Nitrosomonas, Thauera, and Planktosalinus competed for nutrients with the dominant fungi Cosmospora, being in antagonism. Carbon availability in the saline wastewater could regulate the population of bacteria and fungi, laying a theoretical foundation for controlling HAGS disintegration., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

UV-E-chlorination/hematite nanoparticles (UV/E-Cl/HNs) as a heterogeneous photocatalytic activation of electrogenerated chlorine was assessed for the degradation of bisphenol A (BPA) as a new approach based on the generation of reactive chlorine and oxygen species. The prepared sample was characterized using multiple techniques, such as XRD, FTIR, FESEM, EDS, and BET-BJH. An excellent decontamination efficiency of 99.4% was achieved within 40 min of electrolysis under optimum conditions (pH of 5, HNs dosage 100 mg/L, current density of 20 mA/cm 2 , and NaCl concentration of 50 mM). The HOCl content was reduced more swiftly in the presence of ultraviolet (UV) irradiation and hematite, resulting in the production of oxidative radicals (i.e., • OH, Cl • , and Cl 2 •- ). The scavenging experiments also verified the vital role of these radicals in oxidative treatment. The UV/E-Cl/HNs process is readily supplied with hydroxyl radicals through several mechanisms. Bicarbonate ions showed a noticeable inhibitory impact, whereas nitrate and sulfate anions only slightly affected BPA degradation. The HNs were a recoverable and stable catalyst for six cycles. Furthermore, the ECOSAR program predicted that the UV/E-Cl/HNs can be labeled as an environmental-friendly process. Eventually, reasonable degradation pathways were proposed based on the identified by-products through experimental and theoretical approaches., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

The use of seawater to alleviate water shortages causes an increase of salinity in municipal pipe networks, posing challenges for biological wastewater treatment. The impacts of two compatible solutes on the anammox process under salt stress (20 g L -1 ) were compared here at the genetic and microbial levels. The findings revealed that both 0.3 mM glycine betaine (GB) and mannitol (MA) could alleviate the salt stress on anammox process, with GB exhibiting a better effect. Specifically, the addition of GB recovered the nitrogen removal efficiency (NRE) from 40 % to >80 % within 13 days. The addition of MA caused the reduction of the absolute abundance of hdh and hzsA, implying that 0.6 mM was not the optimal concentration. Moreover, salt stress induced an increase in the absolute abundance of nitrification functional genes and a decrease in the abundance of denitrification functional genes. Notably, compared with the initial level, the abundance of Candidatus Kuenenia increased by 7.1 % and 4.3 % after adding GB and MA, respectively. According to the network analysis, two compatible solutes promoted the bacterial interactions in anammox systems, which promoted the nitrogen circulation and further the nitrogen removal performance. This work provides a feasible strategy to relieve the salt stress on anammox process and then facilitates its application for treating saline wastewater., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

To improve the nitrogen removal (NR) capability of tidal flow constructed wetlands (TFCWs) for treatment of saline wastewater, biochar, produced from Cyperus alternifolius, was used to adsorb and immobilize a salt tolerant aerobic denitrifying bacteria (Zobellella sp. A63), and then was added as a substrate into the systems. Under low (2:1) or high (6:1) C/N ratio, the removal of NO 3 - -N and total nitrogen (TN) in the biochar immobilized bacteria (BIB) dosing system (TFCW3) was significantly higher (q < 0.05) than that in the untreated system (TFCW1) and the biochar dosing system (TFCW2). At low C/N ratio, the removal rates of NO 3 -N/TN was still nearly 10% and 5% higher than TFCW1 and TFCW2, respectively. Microbial community analysis showed that aerobic denitrifying bacteria, sulfate reducing bacteria and sulfur-driven denitrifiers (DNSOB) played the most important role of NR in TFCWs. Moreover, biochar bacterial agent significantly increased the abundances of genes involved in NR. The total copy numbers of bacterial 16S rRNA, nirS, nirK, drsA and drsB genes in the TFCW3 were 1.1- to 3.76-fold higher than those in the TFCW1; Especially at low C/N ratio, the copy number of drsA and drsB in the upper layer of TFCW3 were 85.5 and 455 times that of TFCW1, respectively. Thus, BIB provide a more feasible and effective amendment for constructed wetlands to improve the N removal of the saline wastewater by enhancing the microbial NR capacity mainly via aerobic and sulfur autotrophic denitrification.- -N, TN and chemical oxygen demand (COD) of TFCW3 were 68.2%, 72.6% and 82.5%, respectively, 15-20% higher than TFCW1 and 5-10% higher than TFCW2. When C/N ratio was further increased to 6, the pollutant removal rate of each system was greatly improved, but the removal rate of TFCW3 for NO 3 - -N/TN was still nearly 10% and 5% higher than TFCW1 and TFCW2, respectively. Microbial community analysis showed that aerobic denitrifying bacteria, sulfate reducing bacteria and sulfur-driven denitrifiers (DNSOB) played the most important role of NR in TFCWs. Moreover, biochar bacterial agent significantly increased the abundances of genes involved in NR. The total copy numbers of bacterial 16S rRNA, nirS, nirK, drsA and drsB genes in the TFCW3 were 1.1- to 3.76-fold higher than those in the TFCW1; Especially at low C/N ratio, the copy number of drsA and drsB in the upper layer of TFCW3 were 85.5 and 455 times that of TFCW1, respectively. Thus, BIB provide a more feasible and effective amendment for constructed wetlands to improve the N removal of the saline wastewater by enhancing the microbial NR capacity mainly via aerobic and sulfur autotrophic denitrification., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Saline chemical wastewater containing ammonia and toxic organic pollutants has been a challenge for conventional wastewater treatment technology. Advanced treatment is thus required. In this study, the removal of ammonia and phenol in saline chemical wastewater by radiation was investigated in detail. The results showed that chloridion in saline chemical wastewater could be transferred to •Cl and •ClO by radiation, which promoted ammonia oxidation, but inhibited phenol degradation. Solution pH affected the types of reactive species, which further affected the removal of ammonia and phenol. When ammonia and phenol co-existed in saline chemical wastewater, the removal efficiency of ammonia was depressed compared to that in the absence of phenol. Similarly, the phenol removal efficiency was also depressed in the presence of ammonia when the solution pH was lower than 7.0. Interestingly, the phenol removal efficiency was improved with increase of either chloridion concentration (2-8 g/L) or dose (2-5 kGy), which was attributed to the formation of intermediate nitrogen-centered radicals that can react with phenol. In addition, the intermediate products of phenol degradation under different conditions were identified. The acute toxicity of saline chemical wastewater after radiation treatment was evaluated. The results of this study could provide an insight into the removal of ammonia and phenol from saline chemical wastewater by radiation technology., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Saline wastewater poses a challenge during bio-treatment process due to salinity affecting the physiological activity of microorganisms and inhibiting their growth and metabolism. Thus, screening and engineering the salt-tolerant strains with stronger performances are urgent. Shewanella aquimarina XMS-1, a salt-tolerant dissimilated metal reducing bacteria (DMRB), was isolated from seawater environment. Its ability for reducing pollutants and generating electricity was enhanced by overexpression of riboflavin synthesis pathway encoding genes from S. oneidensis MR-1 under salt stress. Furthermore, upon contact with graphene oxide (GO), the engineered strain XMS-1/pYYDT-rib with enhanced flavins synthesis could reduce GO and self-assemble to form a three-dimensional (3D) biohybrid system named XMS-1/flavins/rGO. This 3D biohybrid system significantly enhanced the EET efficiency of S. aquimarina XMS-1. Our findings provide a feasible strategy for treatment of salt-containing industrial wastewater contaminated by metal and organic pollutants., Competing Interests: Declaration of competing interest We declare that we have no financial and personal relationships with other people or organizations that can inappropriately influence our work, there is no professional or other personal interest of any nature or kind in any product, service and/or company that could be construed as influencing the position presented in, or the review of, the manuscript entitled., (Copyright © 2021 Elsevier B.V. All rights reserved.)

In the current study, MFCs treating saline wastewater with the different conductivities of 5.0 ± 0.2, 7.7 ± 0.6, 10.5 ± 0.9, 13.0 ± 1.0, 15.3 ± 1.0, and 16.0 ± 0.1 mS/cm were investigated. Increasing salinity drives a considerable shift of microbial communities, and it also affects metabolic pathways in MFCs. Overwhelming acetate oxidizing electron transfer with moderate conductivities between 7.7 and 13.0 mS/cm led to high energy outputs. Power generation at the low conductivities of less than 7.7 mS/cm was restricted by the competition between fermentative bacteria (e.g., Lactobacillus) and exoelectrogens (e.g., Pseudomonas and Shewanella) for substrate utilization. Increasing salinity beyond 13 mS/cm suppressed the fermentation of glucose to butyrate. It also induced sulfidogenesis; sulfide oxidizing bacteria Desulfovibrio (5.2%), Desulfuromonas (3.7%) and exoelectrogen Pseudomonas (1.1%) formed a sulfur-driven current production, thereby resulting in low energy outputs. The present study revealed the effects of ionic conductivity on electrical energy production and provided insights into the dynamics of the MFCs substrate utilization., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier B.V. All rights reserved.)

This study compared the membrane fouling mitigation in two novel types of biofilm membrane bioreactor coupled with a pre-anoxic tank (BF-AO-MBR)-namely a fixed biofilm membrane bioreactor (FB-MBR) with fiber bundle bio-carriers and a moving-bed biofilm membrane bioreactor (MB-MBR) with suspended bio-carriers-relative to an anoxic/oxic MBR (AO-MBR), at salinities ranging from zero to 60 g/L. The results showed that the FB-MBR mitigated membrane fouling to a greater degree than the MB-MBR and AO-MBR. During operation, the FB-MBR exhibited the lowest fouling development, with three membrane filtration cycles, while the AO-MBR and MB-MBR had 22 and nine cycles, respectively. The key fouling factor in all reactors was cake layer resistance (R C ), which contributed to 89.61, 62.20, and 83.17% of the total fouling resistance (R T ) in AO-MBR, FB-MBR and MB-MBR, respectively. Additionally, in the FB-MBR, the pore blocking resistance (30.07%) was also an important cause of fouling. Fiber bundle bio-carriers and suspended bio-carriers reduced the R T by 37.68% and 21.24% (mainly the R C ) compared to that of AO-MBR. Furthermore, FB-MBR and MB-MBR caused a decrease of suspended biomass (80.14 and 15.90%, respectively), and the latter exhibited a higher sludge particle size than AO-MBR, possibly resulting in the cake layer decline. The studied BF-AO-MBRs further alleviated the fouling propensity by reducing the amount of soluble microbial product (SMP) and extracellular polymeric substances (EPS) under all salinity levels, especially the FB-MBR. Among the protein components, the amounts of tryptophan protein-like substance and aromatic protein-like substance were significantly lower in the FB-MBR compared to the AO-MBR and MB-MBR. Additionally, at 60 g/L salinity, the structure of the microbial community in the FB-MBR had a lower abundance of Bacteroidetes and more biomacromolecule degraders, which may have contributed to the moderation of membrane fouling., Competing Interests: Declaration of competing interest We declare that we have no financial and personal relationships with other people or organizations that can inappropriately influence our work, there is no professional or other personal interest of any nature or kind in any product, service and/or company that could be construed as influencing the position presented in, or the review of, the manuscript entitled “Membrane fouling mitigation in different biofilm membrane bioreactors with pre-anoxic tanks for treating mariculture wastewater”., (Copyright © 2020 Elsevier B.V. All rights reserved.)

High salinity and low temperature are generally considered to have negative effects on the formation, stability and performance of aerobic granular sludge (AGS). This study investigated whether and how salinity acclimation strategies can enhance aerobic granulation at low temperature (12 °C) in three sequencing batch reactors (SBRs). Stepwise increased concentrations of NaCl (2-10 and 4-20 g/L) were added to the influent of R1 and R2 with steps of 1 and 2 g/L per week respectively, while R0 was set as a control (salt-free). The granulation processes in R1 and R2 were rapidly started up within 9 days, and were completed within 21 and 18 days, respectively. By contrast, R0 took 25 days and 49 days to start and complete granulation. The salinity acclimation strategies improved sludge hydrophobicity, reduced repulsion barrier between cells, and stimulated EPS production during granulation processes, which simultaneously promoted the formation of AGS. When the influent salinity reached 14 g/L on day 35, granule hydrophobicity, density and size in R2 sharply decreased and granules began to disintegrate afterwards. When operated under salt-free condition, sludge bulking occurred in R0 since day 60. The treatment performance was thus impaired in these two reactors, especially in R2 with significant biomass loss. Conversely, the AGS developed in R1 maintained stable structure with high biomass concentration (8.0 gSS/L) and excellent treatment performance for COD (90%), ammonium (95%) and total nitrogen (70%). Genera Thauera, Azoarcus, and Nitrosomonas were more enriched, while Flavobacterium and Meganema were more suppressed in R1, which would have contributed to granule stability and treatment performance. In conclusion, great care has to be taken for cultivating and operating AGS at low temperature for treating saline wastewater. Increasing salinity with a lower salt gradient provides a possibility for rapid granulation of AGS with excellent treatment performance under such conditions., Competing Interests: Declaration of competing interest The authors declare no competing financial interest., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Biochar supported copper oxide composite (BC-CuO) was synthesized and attempted to activate peroxymonosulfate (PMS) for treating highly saline (100-400 mM) wastewater. In the BC-CuO/PMS system, rapid removals of Methylene Blue (MB), Acid Orange 7, Rhodamine B, Atrazine and Ciprofloxacin from the highly saline system were observed within 30 min, attaining a high efficiency of 99.68%, 100%, 100%, 100% and 78.27%, respectively. Meanwhile, the BC-CuO/PMS can remove >88.61% of MB in other salt systems containing one or more salt components and 68.43% of COD from landfill leachate. Experimental results confirmed that sulfate radical (SO 4 ▪- ), hydroxyl radical ( ▪ OH) and singlet oxygen ( 1 O 2 ) all contributed to the pollutants degradation, but 1 O 2 was dominated in highly saline systems. On the basis of the characterization and analysis data, possible activation mechanisms of the oxygenated functional groups of biochar and hydroxylation of CuO surface accelerating the generation of 1 were proposed. BC-CuO activating PMS is a promising technique for the removal of organic pollutants from highly saline wastewater or complex background.2 were proposed. BC-CuO activating PMS is a promising technique for the removal of organic pollutants from highly saline wastewater or complex background., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Saline wastewater originates from many industries, containing a large amount of salt (NaCl) and other toxic and harmful organic matter, which have a great impact on the soil and groundwater. However, the treatment of saline wastewater is a serious problem because organic contents are hard to degrade with the high salinity by the common water treatment technologies. Herein, an electrochemical process coupled with ultraviolet (UV) irradiation was proposed for the saline wastewater treatment. High efficiency of p-nitrophenol (p-NP) and ammonia degradation were contributed from the in situ electrochemical produced active chlorine and photo-induced chlorine radicals. Under the optimal conditions (0.10 A, 0.05 M NaCl, and pH 6.00), approximately 98.91% p-NP was removed after 60 min with the rate constant of 7.521 × 10 - 2  min - 1 in the electrochemical process, and 28.99% mineralization rate was obtained, while with the synergistic effect of UV and electrochemistry, approximately 100% of p-NP removal (k = 9.331 × 10 - 2  min - 1 ) was achieved by 30 min treatment and about 83.70% of p-NP can be mineralized to CO 2 after 60 min. The study on the synergistic mechanism of enhanced degradation performance illustrated that Cl with high oxidation capacity played an important role in the p-NP oxidation. Besides, based on the chlorine radical reactions, this method was also effectively applied to remove ammonia nitrogen (92.00% removal of total nitrogen in 100 min) for nitrogen-containing wastewater. Thus, this study offers a promising approach for the treatment of saline industry wastewater., Competing Interests: Declaration of competing interest We declare that we have no financial and personal relationships with other people or organizations that can inappropriately influence our work, there is no professional or other personal interest of any nature or kind in any product, service and/or company that could be construed as influencing the position presented in, or the review of the manuscript. All authors have read and approve this version of the article, and due care has been taken to ensure the integrity of the work., (Copyright © 2020 Elsevier B.V. All rights reserved.)

As a solution of the sludge loss in the treatment of saline wastewater, the granulation of halophilic sludge was explored in this study. The inoculated estuarine sediment was granulated to an average diameter of 1155 ± 102 μm under the selective settling pressure in the airlift sequencing batch reactor (SBR) when the influent organic loading rate (OLR) was doubled to 0.36 g COD/L·day. The results indicated that the OLR doubled the amount of total extracellular polymeric substance (EPS) and that protein was predominant in the EPS (72.8 ± 2.0%). The correlation between aggregate size and protein content was better than that between aggregate size and polysaccharide content. The amount of alginate-like exopolysaccharides (ALE) increased linearly at the mature granular stage, co-occurring with the compact and elastic structure of the granules. According to the results of 16S rRNA high -throughput sequencing, the Shannon-Weaver index of mature granule decreased by >50% compared to the inoculated sediment. Bacteria of Propionibacteriaceae family constituted 34% of the population in granules and were in symbiotic relationship with halophiles of family Rhodocyclaceae, Vibrionaceae, Flavobacteriaceae, and Cryomorphaceae. The aerobic halophilic granular sludge showed COD removal efficiency of 90.9 ± 0.8% and ammonia removal efficiency of 72.6 ± 4.0% for 30 g/L saline wastewater. An average nitrite accumulation ratio of 94.5 ± 2.9% was observed during nitrification. Granulation of halophilic sludge provides an effective solution to the saline sludge loss problem, which is a step forward to realize the biological treatment of saline wastewater by halophiles., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Wastewaters generated in regions with water scarcity usually have high alkalinity, hardness, and elevated osmotic pressure (OP). Those characteristics should be considered when using biological systems for wastewater treatment along with the salinity heterogeneity. The interaction of different salts in mixed electrolyte solutions may cause inhibition, antagonism, synergism, and stimulation effects on microbial communities. Little is known about those effects on microbial activity and community structure of nitrifying and denitrifying bacteria. In this work, factorial design was used to evaluate the effects of NaCl, MgCl 2 and CaCl 2 on nitrifying and denitrifying communities. Antagonistic relationships between all salts were observed and they had greater magnitude on the nitrifying community. Stimulus and synernism were more evident on the nitrifying and denitrifying experiments, respectively. For this reason, the highest nitrification and denitrification specific rates were 1.1 × 10 -1 mgN-NH 4 + gSSV -1  min -1 for condition 01 and 6.5 × 10 -2 mgN-NO 3 - gSSV -1  min -1 for control condition, respectively. The toxicity of the salts followed the order of NaCl > MgCl 2  > CaCl 2 and the antagonism between MgCl 2 and NaCl was the most significant. PCR/DGGE analyses showed that Mg 2+ may be the element that expresses the least influence in the differentiation of microbial structure even though it significantly affects the activity of the autotrophic microorganisms. The same behavior was observed for Ca 2+ on denitrifying microorganism. In addition, microbial diversity and richness was not negatively affected by different salinities. Genetic sequencing suggested that the genus Aeromonas, Alishewanella, Azospirillum, Pseudoalteromonas, and Thioalkalivibrio were outstanding on ammonium and nitrate removal under saline conditions. The specific toxicity of each salt and the interactions among them are the major effects on microbial activity in biological wastewater treatments rather than the osmotic pressure caused by the final salinity., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Effective biological treatment of high salt content wastewater requires consideration of both salt and organic toxicity. This study treated a synthetic saline wastewater containing NaCl (100gL -1 ) and 2,4-dimethylphenol (1.2gL -1 ) with a hybrid system consisting of a biological reactor containing spiral-coiled polymeric tubing through which the mixed feed was pumped. The tubing wall was permeable to the organic contaminant, but not to the salt, which allowed transfer of the organic into the cell-containing bioreactor contents for degradation, while not exposing the cells to high salt concentrations. Different grades of DuPont Hytrel polymer were examined on the basis of organic affinity predictions and experimental partition and mass transfer tests. Hytrel G3548 tubing showed the highest permeability for 2,4-dimethylphenol while exerting an effective salt barrier, and was used to verify the feasibility of the proposed system. Very high organic removal (99% after just 5h of treatment) and effective biodegradation of the organic fraction of the wastewater (>90% at the end of the test) were observed. Complete salt separation from the microbial culture was also achieved., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Anaerobic digestion was an important way to remove phenols from saline wastewater; however the anaerobic microorganisms were adversely affected by high concentration of salts. In order to clarify the performance robustness and microbial community structure for anaerobic digestion of saline phenolic wastewater, the UASB reactors were compared to treat phenolic wastewater under saline and non-saline conditions. The saline reactors were operated stably with phenols concentration increasing from 100 to 500mgL -1 at 10g Na + L -1 . The robustness of the saline reactors was weakened at 1000mg phenols L -1 and 10g Na + L -1 . However, the substrate utilization rates (SURs) for phenol, catechol, resorcinol, hydroquinone, and the specific methanogenic activity (SMA) of sludge were decreased by 95%, 85%, 97%, 78%, and 68%, respectively with phenols concentration enhancing from 1000 to 2000mgL -1 . Moreover, the SURs for phenol, catechol, resorcinol, hydroquinone, and the SMA of sludge were reduced by 32%, 65%, 74%, 45%, and 59%, respectively with Na + concentration increasing from 10 to 20gL -1 , in comparison with the values obtained at 10g Na + L -1 and 1000mg phenols L -1 . Finally, the analysis of microbial community structure demonstrated that phenols degraders were less tolerant to high concentrations of Na + and phenols than methanogens., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Constructed Wetlands (CWs) can be a valuable technology to treat high salinity wastewaters but it is not known their potential for removal of both nutrients and salt, and the type of plants to use. This study evaluated the effect of three plants on salt reduction and simultaneous nutrient removal in CWs microcosms with expanded clay and in hydroponic conditions. Initial values of the synthetic wastewater tested were EC=15dSm -1 , SAR=151; NH 4 + -N=24mgL -1 ; PO 4 3- -P=30mgL -1 and NO 3 - -N=34mgL -1 . With expanded clay CW removal efficiency for NH 4 + -N was 21, 88 and 85%, while for NO 3 - -P. However, salt removal was apparent in the hydroponic system only after 23days of HRT, despite clear salt excretion visible in both Spartina maritima and Juncus maritimus. This study demonstrates the potential of two halophytic plants for saline wastewater treatment. However, salt removal in such a scenario could not be well documented and might prove to be impractical in future work.4 3- -P was adsorbed completely in the expanded clay. However, in hydroponic system, removal efficiencies for NH 4 + -N were 53 and 50%, while PO 4 3- -P removal was 89 and -14% for Spartina maritima and Juncus maritimus, respectively. Nutrient removal in planted microcosms was statistically higher than unplanted controls for NH 4 + -N and PO 4 3- -P. However, salt removal was apparent in the hydroponic system only after 23days of HRT, despite clear salt excretion visible in both Spartina maritima and Juncus maritimus. This study demonstrates the potential of two halophytic plants for saline wastewater treatment. However, salt removal in such a scenario could not be well documented and might prove to be impractical in future work., (Copyright © 2016 Elsevier B.V. All rights reserved.)

A technique is proposed to treat saline hazardous wastewater by using marine activated sludge, cultivated with sea mud as seed. Since the developed marine activated sludge had phenol-tolerant microorganisms (MAS-1, MAS-2 and MAS-3) which originated from the ocean, it was envisaged that these bacteria could survive and breakdown phenol in saline environments. In this work, typical phenol-tolerant microorganisms were isolated from the marine activated sludge and identified. After a hierarchical acclimation process, the marine activated sludge was used to treat the industrial phenolic wastewater with high salinity. The marine activated sludge was able to break down phenol and other organic components effectively and efficiently in treating the wastewater with salinity of 5.7% w/v. The results showed a high removal of phenol (99%), COD (80%) and NH 3 -N (68%)., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Two different saline sediments were used to inoculate potentiostatically controlled reactors (a type of microbial bioelectrochemical system, BES) operated in saline conditions (35 gNaCl l(-1)). Reactors were fed with acetate or a mixture of acetate and butyrate at two pH values: 7.0 or 5.5. Electroactive biofilm formation lag-phase, maximum current density production and coulombic efficiency were used to evaluate the overall performance of reactors. High current densities up to 8.5 A m(-2) were obtained using well-defined planar graphite electrodes. Additionally, biofilm microbial communities were characterized by CE-SSCP and 454 pyrosequencing. As a result of this procedure, two anode-respiring bacteria (ARB) always dominated the anodic biofilms: Geoalkalibacter subterraneus and/or Desulfuromonas acetoxidans. This suggests that a strong electrochemically driven selection process imposed by the applied potential occurs in the BES system. Moreover, the emergence of Glk. subterraneus in anodic biofilms significantly contributes to broaden the spectrum of high current producing microorganisms electrochemically isolated from environmental samples., (Copyright © 2015 Elsevier B.V. All rights reserved.)

Currently, the treatment of aquaculture-origin effluents is mainly performed through land-based recirculating aquaculture systems (RAS). In this study, we evaluate and introduce a novel immobilized/packed bed bioreactor which uses a synthetic textile as the support medium. A marine microbial consortium was developed on the textile by its inoculation with the microalgae Picochlorum sp. The bioreactor was tested with variable loadings of C and N and showed outstanding performance approaching removal rates up to 95% within a few hours (4-5h) of operation. Pyrosequencing analysis revealed a novel microbial consortium consisting mainly of chitrinomycetes, Pseudomonas sp. and the absence of β-proteobacteria, which is the Class encompassing autotrophic nitrifiers. Quantitative polymerase chain reaction further confirmed these findings suggesting heterotrophic nitrification and aerobic denitrification as the principal mechanisms of N-removal from the bioreactor. Overall our findings reveal the potential of the AdvanTex System for the treatment of marine aquaculture effluents-COD reduction and N-removal, in a single stage., (Copyright © 2015 Elsevier B.V. All rights reserved.)

The agricultural reuse of pretreated industrial wastewater resulting from cheese manufacture is shown as a suitable option for its disposal and management. This alternative presents attractive advantages from the economic and pollution control viewpoints. Pretreated cheese whey wastewater (CWW) has high contents of biodegradable organic matter, salinity and nutrients, which are essential development factors for plants with moderate to elevated salinity tolerance. Five different pretreated CWW treatments (1.75 to 10.02 dS m(-1)) have been applied in the tomato plant growth. Fresh water was used as a control run (average salinity level=1.44 dS m(-1)). Chemical characterization and indicator ratios of the leaves, stems and roots were monitored. The sodium and potassium leaf concentrations increased linearly with the salinity level in both cultivars, Roma and Rio Grande. Similar results were found in the stem sodium content. However, the toxic sodium accumulations in the cv. Roma exceeded the values obtained in the cv. Rio Grande. In this last situation, K and Ca uptake, absorption, transport and accumulation capacities were presented as tolerance mechanisms for the osmotic potential regulation of the tissues and for the ion neutralization. Consequently, Na/Ca and Na/K ratios presented lower values in the cv. Rio Grande. Na/Ca ratio increased linearly with the salinity level in leaves and stems, regardless of the cultivar. Regarding the Na/K ratio, the values demonstrated competition phenomena between the ions for the cv. Rio Grande. Despite the high chloride content of the CWW, no significant differences were observed for this nutrient in the leaves and stems. Thus, no nitrogen deficiency was demonstrated by the interaction NO3(-)/Cl(-). Nitrogen also contributes to maintain the water potential difference between the tissues and the soil. Na, P, Cl and N radicular concentrations were maximized for high salinity levels (≥2.22 dS m(-1)) of the pretreated CWW., (© 2013 Elsevier B.V. All rights reserved.)