Anaerobic biodegradation enables zero liquid discharge of two-stage nanofiltration system for microelectronic wastewater treatment.

Nanofiltration (NF) is a promising technology in the treatment of microelectronic wastewater. However, the treatment of concentrate derived from NF system remains a substantial technical challenge, impeding the achievement of the zero liquid discharge (ZLD) goal in microelectronic wastewater industries. Herein, a ZLD system, coupling a two-stage NF technology with anaerobic biotechnology was proposed for the treatment of tetramethylammonium hydroxide (TMAH)-contained microelectronic wastewater. The two-stage NF system exhibited favorable efficacy in the removal of conductivity (96 %), total organic carbon (TOC, 90 %), and TMAH (96 %) from microelectronic wastewater. The membrane fouling of this system was dominated by organic fouling, with the second stage NF membrane experiencing a more serious fouling compared to the first stage membrane. The anaerobic biotechnology achieved a near-complete removal of TMAH and an 80 % reduction in TOC for the first stage NF concentrate. Methyloversatilis was the key genus involved in the anaerobic treatment of the microelectronic wastewater concentrate. Specific genes, including dmd-tmd, mtbA, mttB and mttC were identified as significant players in mediating the dehydrogenase and methyl transfer pathways during the process of TMAH biodegradation. This study highlights the potential of anaerobic biodegradation to achieve ZLD in the treatment of TMAH-contained microelectronic wastewater by NF system.

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.

Electrified Solar Zero Liquid Discharge: Exploring the Potential of PV-ZLD in the US.

Current brine management strategies are based on the disposal of brine in nearby aquifers, representing a loss in potential water and mineral resources. Zero liquid discharge (ZLD) is a possible strategy to reduce brine rejection while increasing the resource recovery from desalination plants. However, ZLD substantially increases the energy consumption and carbon footprint of a desalination plant. The predominant strategy to reduce the energy consumption and carbon footprint of ZLD is through the use of a hybrid desalination technology that integrates renewable energy. Here, we built a computational thermodynamic model of the most mature electrified hybrid technology for ZLD powered by photovoltaic (PV). We examine the potential size and cost of ZLD plants in the US. This work explores the variables (geospatial and design) that most influence the levelized cost of water and the second law efficiency. There is a negative correlation between minimizing the LCOW and maximizing the second-law. And maximizing the second-law, the states that more brine produces, Texas is the location where the studied system achieves the lowest LCOW and high second-law efficiency, while California is the state where the studied system is less favorable. A multiobjective optimization study assesses the impact of considering a carbon tax in the cost of produced water and determines the best potential size for the studied plant.

Gradient Graphene Spiral Sponges for Efficient Solar Evaporation and Zero Liquid Discharge Desalination with Directional Salt Crystallization.

Solar desalination is a promising strategy to utilize solar energy to purify saline water. However, the accumulation of salt on the solar evaporator surface severely reduces light absorption and evaporation performance. Herein, a simple and eco-friendly method to fabricate a 3D gradient graphene spiral sponge (GGS sponge) is presented that enables high-rate solar evaporation and zero liquid discharge (ZLD) desalination of high-salinity brine. The spiral structure of the GGS sponge enhances energy recovery, while the gradient network structures facilitate radial brine transport and directional salt crystallization, which cooperate to endow the sponge with superior solar evaporation (6.5 kg m-2 h-1 for 20 wt.% brine), efficient salt collection (1.5 kg m-2 h-1 for 20 wt.% brine), ZLD desalination, and long-term durability (continuous 144 h in 20 wt.% brine). Moreover, the GGS sponge shows an ultrahigh freshwater production rate of 3.1 kg m-2 h-1 during the outdoor desalination tests. A continuous desalination-irrigation system based on the GGS sponge for crop growth, which has the potential for self-sustainable agriculture in remote areas is demonstrated. This work introduces a novel evaporator design and also provides insight into the structural principles for designing next-generation solar desalination devices that are salt-tolerant and highly efficient.

High Breakthrough Pressure in Hydrogels Enabled Ultrastable Treatment of Hypersaline Wastewaters.

Surface effects of low-surface-tension contaminants accumulating at the evaporation surface easily induce wetting in membrane distillation, especially in hypersaline scenarios. Herein, we propose a novel strategy to eliminate the surface effect and redistribute contaminants at the evaporation interface simply by incorporating a layer of hydrogel. The as-fabricated composite membrane exhibits remarkable stability, even when exposed to solution with salt concentration of 5 M and surfactant concentration of 8 mM. Breakthrough pressure of the membrane reaches 20 bar in the presence of surfactants, surpassing commercial hydrophobic membranes by one to two magnitudes. Density functional theory and molecular dynamics simulations reveal the important role of the hydrogel-surfactant interaction in suppressing the surface effect. As a proof of concept, we demonstrate the membrane in stably processing synthetic wastewater containing 144 mg L-1 surfactants, 1 g L-1 mineral oils, and 192 g L-1 NaCl, showing its potential in addressing challenges of hypersaline water treatment.

Innovations in textile wastewater management: a review of zero liquid discharge technology.

Zero liquid discharge (ZLD) technology emerges as a transformative solution for sustainable wastewater management in the textile industry, emphasizing water recycling and discharge minimization. This review comprehensively explores ZLD's pivotal role in reshaping wastewater management practices within the textile sector. With a primary focus on water recycling and minimized discharge, the review thoroughly examines the economic and environmental dimensions of ZLD. Additionally, it includes a comparative cost analysis against conventional wastewater treatment methods and offers a comprehensive outlook on the global ZLD market. Presently valued at US $0.71 billion, the market is anticipated to reach US $1.76 billion by 2026, reflecting a robust annual growth rate of 12.6%. Despite ZLD's efficiency in wastewater recovery, environmental challenges, such as heightened greenhouse gas emissions, increased carbon footprint, elevated energy consumption, and chemical usage, are discussed. Methodologies employed in this review involve an extensive analysis of existing literature, empirical data, and case studies on ZLD implementation in the textile industry worldwide. While acknowledging existing adoption barriers, the review underscores ZLD's potential to guide the textile industry toward a more sustainable and environmentally responsible future.

Review on the escalating imperative of zero liquid discharge (ZLD) technology for sustainable water management and environmental resilience.

This comprehensive review delves into the forefront of wastewater treatment technology, with a specific focus on the revolutionary concept of Zero Liquid Discharge (ZLD). (ZLD), underpinned by a sustainable ethos, aspires to accomplish total water reclamation, constituting a pivotal response to pressing environmental issues. The paper furnishes a historical panorama of (ZLD), elucidating its motivating factors and inherent merits. It navigates a spectrum of (ZLD) technologies encompassing thermal methodologies, (ZLD) synergized with Reverse Osmosis (RO), High-Efficiency Reverse Osmosis (HERO), Membrane Distillation (MD), Forward Osmosis (FO), and Electrodialysis Reversal (EDR). Moreover, the study casts a global purview over the deployment status of (ZLD) systems in pursuit of resource recovery, accentuating nations such as the United States, China, India, assorted European Union members, Canada, and Egypt. Meticulous case studies take center stage, underscoring intricate scenarios involving heavily contaminated effluents from challenging sectors including tanneries, textile mills, petroleum refineries, and paper mills. The report culminates by distilling sagacious observations and recommendations, emanating from a collaborative brainstorming endeavor. This compendium embarks on an enlightening journey through the evolution of wastewater treatment, (ZLD)'s ascendancy, and its transformative potential in recalibrating water management paradigms while harmonizing industrial progress with environmental stewardship.

3D Cellular Solar Crystallizer for Stable and Ultra-Efficient High-Salinity Wastewater Treatment.

Recent developed interfacial solar brine crystallizers, which employ solar-driven water evaporation for salts crystallization from the near-saturation brine to achieve zero liquid discharge (ZLD) brine treatment, are promising due to their excellent energy efficiency and sustainability. However, most existing interfacial solar crystallizers are only tested using NaCl solution and failed to maintain high evaporation capability when treating real seawater due to the scaling problem caused by the crystallization of high-valent cations. Herein, an artificial tree solar crystallizer (ATSC) with a multi-branched and interconnected open-cell cellular structure that significantly increased evaporation surface is rationally designed, achieving an ultra-high evaporation rate (2.30 kg m-2  h-1 during 2 h exposure) and high energy efficiency (128%) in concentrated real seawater. The unit cell design of ATSC promoted salt crystallization on the outer frame rather than the inner voids, ensuring that salt crystallization does not affect the continuous transport of brine through the pores inside the unit cell, thus ATSC can maintain a stable evaporation rate of 1.94 kg m-2  h-1 on average in concentrated seawater for 80 h continuous exposure. The design concept of ATSC represents a major step forward toward ZLD treatment of high-salinity brine in many industrial processes is believed.

Design of a multistage hybrid desalination process for brine management and maximum water recovery.

Hypersaline brine production from desalination plants causes huge environmental stress due to the untenable conventional discharge strategies. Particularly, brine production is expected to drastically increase in the coming few decades due to the increasing desalination capacity in attempts of forestalling water scarcity. Thereby, zero liquid discharge (ZLD) is a worth-considering solution for strategic brine management. ZLD or minimal liquid discharge (MLD) systems provide maximum water recovery with least or zero liquid waste generation and valuable salt production. In this work, a theoretical design of ZLD/MLD system is proposed for reverse osmosis (RO) brine management. Different scenarios are investigated utilizing multistage freeze desalination (FD) and its hybridization with multistage direct contact membrane distillation (DCMD), and eutectic freeze crystallization (EFC) technologies. The design is based on the experimental assessment of the indirect FD process at different feed salinities, i.e., 2 g/L to 155 g/L. FD experiments showed that ice quality is reduced at greater crystallinity levels and initial concentration. Moreover, a computational fluid dynamics (CFD) model is utilized to assess the performance of DCMD. A single DCMD module could produce 53 kg/(m2.h) of pure water operating with 69% thermal efficiency. Eventually, water recovery, water quality, as well as specific energy consumption (SEC) are evaluated for the whole system. Based on different configurations of the hybrid ZLD system, the proposed design can achieve water recovery between 40 and 93% with SEC range of 28-114 kWh/m3. Results also showed that the produced water quality exceeds drinkable water standards ( ≪ 500 mg/L). This work has provided great evidence in the practicality of ZLD/MLD systems for sustainable brine management.

Mixed scaling patterns and mechanisms of high-pressure nanofiltration in hypersaline wastewater desalination.

Nanofiltration (NF) will play a crucial role in salt fractionation and recovery, but the complicated and severe mixed scaling is not yet fully understood. In this work, the mixed scaling patterns and mechanisms of high-pressure NF in zero-liquid discharge (ZLD) scenarios were investigated by disclosing the role of key foulants. The bulk crystallization of CaSO4 and Mg-Si complexes and the resultant pore blocking and cake formation under high pressure were the main scaling mechanisms in hypersaline desalination. The incipient scalants were Mg-Si hydrates, CaF2, CaCO3, and CaMg(CO3)2. Si deposited by adsorption and polymerization prior to and impeded Ca scaling when Mg was not added, thus pore blocking was the main mechanism. The amorphous Mg-Si hydrates contribute to dense cake formation under high hydraulic pressure and permeate drag force, causing rapid flux decline as Mg was added. Humic acid has a high affinity to Ca2+by complexation, which enhances incipient scaling by adsorption or lowers the energy barrier of nucleation but improves the interconnectivity of the foulants layer and inhibits bulk crystallization due to the chelation and directional adsorption. Bovine serum albumin promotes cake formation due to the low electrostatic repulsion and acts as a cement to particles by adsorption and bridging in bulk. This work fills the research gaps in mixed scaling of NF, which is believed to support the application of ZLD and shed light on scaling in hypersaline/ultra-hypersaline wastewater desalination applications.

Application of Machine Learning to Characterize the Permeate Quality in Pilot-Scale Vacuum-Assisted Air Gap Membrane Distillation Operation.

Membrane distillation (MD) is a thermal desalination technique proposed for the valorization of residual brines that other operations such as reverse osmosis cannot treat. Previous studies have shown that vacuum-assisted air gap (V-AGMD) operation in commercial multi-envelope modules improves the performance of MD noticeably. However, the permeate quality at pilot scale has not been thoroughly characterized so far. The aim of this study is, therefore, to assess and model the effect of the main operating conditions (feed flow rate, inlet temperatures, and feed salinity) on the permeate quality. Results from different steady-state experiments allowed to estimate descriptive metrics such as the salt rejection factor (SRF) and the membrane leak ratio (MLR). Given their non-linear behavior, these metrics were subsequently modeled using artificial neural networks (ANN) to estimate the permeate quality in the whole scope of operating conditions. Acceptable SRF results with MLR values lower than 0.2% confirmed the validity of MD as an operation for the treatment of concentrated brines, although the salinity of the resulting permeate does not comply in all cases with that permitted for human consumption.

Thermodynamic insights into selenium oxyanion removal from synthetic flue gas desulfurization wastewater with temperature-swing solvent extraction.

Temperature-swing solvent extraction (TSSE) is a cost-effective, simple, versatile, and industry-ready technology platform capable of desalinating hypersaline brines toward zero liquid discharge. In this work, we demonstrate the potential of TSSE in the effective removal of selenium oxyanions and traces of mercury with the coexistence of high contents of chloride and sulfate often encountered in flue gas desulfurization wastewater streams. We compare the rejection performance of the two common solvents broadly used for TSSE, decanoic acid (DA) and diisopropylamine (DPA), and correlate those with the solvent physicochemical properties (e.g., dielectric constant, polarity, molecular bulkiness, and hydrophobicity) and ionic properties (e.g., hydrated radii and H-bonding). The results show that TSSE can remove >99.5% of selenium oxyanions and 96%-99.6% of mercury traces coexisting with sulfate (at a sixfold Se concentration) and chloride (at a 400-fold Se concentration) in a synthetic wastewater stream. Compared to diisopropylamine, decanoic acid is more effective in rejecting ions for all cases, ranging from a simple binary system to more complex multicomponent systems with highly varied ionic concentrations. Furthermore, the H-bonding interaction with water and the hydrated radii of the oxyanions (i.e., selenate vs. selenite) along with the hindrance effects caused by the molecular bulkiness and hydrophobicity (or lipophilicity) of the solvents play important roles in the favorable rejection of TSSE. This study shows that TSSE might provide a technological solution with a high deionization potential for the industry in complying with the Environmental Protection Agency regulations for discharge streams from coal-fired power facilities.

Electrically conductive membrane distillation via an alternating current operation for zero liquid discharge.

Membrane distillation (MD) shows promise for achieving high salinity treatment and zero liquid discharge (ZLD) compared to conventional water treatment processes due to its unique characteristics, including low energy consumption and high resulting water quality. However, performance degradation due to fouling and scaling under high recovery conditions remains a challenge, particularly considering the need to control both cations and anions for maximum scaling mitigation. Accordingly, in this study, alternating current (AC) operation for electrically conductive membrane distillation (ECMD) is newly proposed, based on its potential for controlling both cations and anions, in contrast to conventional direct current (DC) operation. Systematic experiments and theoretical analysis show that water recovery in ECMD can be increased by 27% through AC operation. The proposed modification and effective AC operation of ECMD increase the practicality of using MD in desalination for a high recovery rate, perhaps even for ZLD.

Desalination, Water Re-use, and Halophyte Cultivation in Salinized Regions: A Highly Productive Groundwater Treatment System.

Groundwater salinization is a problem affecting access to water in many world regions. Though desalination by conventional reverse osmosis (RO) can upgrade groundwater quality for drinking, its disadvantages include unmanaged brine discharge and accelerated groundwater depletion. Here, we propose a new approach combining RO, forward osmosis (FO), and halophyte cultivation, in which FO optimally adjusts the concentration of the RO reject brine for irrigation of Salicornia or Sarcocornia. The FO also re-uses wastewater, thus, reducing groundwater extraction and the wastewater effluent volume. To suit different groundwater salinities in the range 1-8 g/L, three practical designs are proposed and analyzed. Results include specific groundwater consumption (SGC), specific energy consumption (SEC), wastewater volume reduction, peak RO pressure, permeate water quality, efficiency of water resource utilization, and halophyte yield. Compared to conventional brackish water RO, the results show superior performance in almost all aspects. For example, SGC is reduced from 1.25 to 0.9 m3 per m3 of drinking water output and SEC is reduced from 0.79 to 0.70 kW h/m3 by a FO-RO-FO system treating groundwater of salinity 8 g/L. This system can produce 1.1 m3 of high-quality drinking water and up to 4.9 kg of edible halophyte per m3 of groundwater withdrawn.

3D Printing of Solar Crystallizer with Polylactic Acid/Carbon Composites for Zero Liquid Discharge of High-Salinity Brine.

Zero liquid discharge (ZLD) is a technique for treating high-salinity brine to obtain freshwater and/or salt using a solar interface evaporator. However, salt accumulation on the surface of the evaporator is a big challenge to maintaining stable water evaporation. In this study, a simple and easy-to-manufacture evaporator, also called a crystallizer, was designed and fabricated by 3D printing. The photothermal layer printed with polylactic acid/carbon composites had acceptable light absorption (93%) within the wavelength zone of 250 nm-2500 nm. The micron-sized voids formed during 3D printing provided abundant water transportation channels inside the crystallizer. After surface hydrophilic modification, the crystallizer had an ultra-hydrophilic channel structure and gravity-assisted salt recovery function. The results revealed that the angles between the photothermal layers affected the efficacy of solar evaporation and the yield of solid salt. The crystallizer with the angle of 90° between two photothermal layers could collect more solid salt than the three other designs with angles of 30°, 60°, and 120°, respectively. The crystallizer has high evaporation and salt crystallization efficiency in a high-salinity brine environment, which is expected to have application potentials in the zero liquid discharge of wastewater and valuable salt recovery.

Electro-oxidation of tannery wastewater to achieve zero discharge - a step towards sustainability.

Pilot-scale electro-oxidation equipment with a functional capacity of 0.2 m3/hr, with titanium electrodes coated with TiO2/RuO2/IrO2 as both anodes and cathodes, was designed. It was installed on the premises of a commercial tannery. The waste streams from all the unit processes were combined. The composite wastewater, after conventional pre-treatment was subjected to electro-oxidation. The treated wastewater was reused four times with intermittent electro-oxidation treatment, after each reuse. EO could bring about a significant reduction in pollution load. Reduction in BOD, COD, TKN and TSS was 92%, 87.5%, 96.2% and 94.6% respectively. Generation of oOCl radicals, during electro-oxidation, were ascertained with DMPO-spin trapping techniques using Electron Spin Resonance (ESR) spectroscopy. The characteristics of the treated wastewater indicated that the wastewater was fit for reuse. No significant change in the quality of the water after each reuse was observed. The physical properties of the leathers obtained following the reuse processes were akin to those of the control leathers, which was indicative that the reuse did not cause adverse quality deviations. This technique could provide the plausibility for minizine the discharge of wastewater to near-zero level.

Denitrification of nitrate in regeneration waste brine using hybrid cation exchanger supported nanoscale zero-valent iron with/without palladium nanoparticles.

The Sustainable Development Goals require that reducing waste is a priority. This work described the application of an innovative zero-waste hybrid ion exchange nanotechnology that concurrently removed nitrate and induced denitrification to ammonia, with the ability to generate fertilizer for the agriculture sector from the recycled by-products. Herein, hybrid cation exchanger-supported zero-valent iron (Fe0), and bimetallic Fe0/Pd nanoparticles (HCIX-Fe0 and HCIX-Fe0/Pd) were synthesized and successfully validated for denitrification of nitrate in spent waste brine that contained nitrate. The kinetics of nitrate catalysis by both HCIX-Fe0 and HCIX-Fe0/Pd were compared and presented by six kinetic models, namely, zero-order, pseudo first- and second-order reaction, pseudo first- and second-order adsorption, and Elovich. HCIX-Fe0/Pd displayed a higher kinetic value than HCIX-Fe0, with k1 of 0.0019 and 0.0026 min-1, respectively. Nitrate was predominantly catalysed to NH4+ at a ratio of ammonia to other nitrogen compounds of around 80:20. Although HCIX-Fe0/Pd showed slightly better (14%) kinetic results, it was determined as unfavourable for real-life application due to low selectivity toward N2 gas and the need to use H2 gas. Based on practicability, the HCIX-Fe0 was further validated. The effect of salt (using NaCl) and the role of initial pH conditions were optimized and discussed. The recovery of nitrate removal was also calculated, and a recovery range of 91.42-99.14% was obtained for three consecutive runs. The sustainable, novel, zero waste hybrid ion exchange nanotechnology using the combination of two fixed-bed columns containing nitrate-selective resin for nitrate removal and novel HCIX-Fe0 for nitrate reduction to NH4+ may be a promising sustainable solution toward the goal of discharging zero nitrate waste to the environment.

Treatment of textile industry wastewater based on coagulation-flocculation aided sedimentation followed by adsorption: Process studies in an industrial ecology concept.

This study examines the feasibility of treatment of textile industry wastewater using a two-step process that includes coagulation-flocculation aided sedimentation and adsorption. It also aims at finding reuse potential of the generated sludge while making the treated water recyclable for the same industry in an industrial ecology concept. The wastewater was collected from a small-scale textile plant with a discharge of 400 L/week, where more than 70 similar textile plants are located in and around the area. FeCl3 was selected as the coagulant for the initial step in the treatment process, and a bimetallic oxide Graphene Oxide (GO) hybrid was selected as the adsorbent for the latter step of the treatment process. The experimental conditions for the coagulation process included the optimization of dose, stirring speed, stirring time, and settling time. For the adsorption process it included the optimization of stirring time, dose, and rate. The parameters like Chemical Oxygen Demand (COD) and color were checked during the treatment process and near complete removal of COD and color were achieved using the suggested materials and process. The treated water was found fit for recycling - towards making zero liquid discharge plant. Later, the sludge generated from both the steps in the processes was sundried and mixed with cement and tested for 7 days and 28 days of compressive strength. A total of 26 kg of cement was replaced, by using sludge generated from treating 100 L of textile wastewater, in the sludge-cement mix. In addition to solving the sludge problem, the process can help in reducing the requirement of cement in concrete. Finally, a detailed economic assessment for the entire study was also performed and is reported.

Ionic resource recovery for carbon neutral papermaking wastewater reclamation by a chemical self-sufficiency zero liquid discharge system.

Papermaking industry discharges large quantities of wastewater and waste gas, whose treatment is limited by extra chemicals requirements, insufficient resource recovery and high energy consumption. Herein, a chemical self-sufficiency zero liquid discharge (ZLD) system, which integrates nanofiltration, bipolar membrane electrodialysis and membrane contactor (NF-BMED-MC), is designed for the resource recovery from wastewater and waste gas. The key features of this system include: 1) recovery of NaCl from pretreated papermaking wastewater by NF, 2) HCl/NaOH generation and fresh water recovery by BMED, and 3) CO2 capture and NaOH/Na2CO3 generation by MC. This integrated system shows great synergy. By precipitating hardness ions in papermaking wastewater and NF concentrate with NaOH/Na2CO3, the inorganic scaling on NF membrane is mitigated. Moreover, the NF-BMED-MC system with high stability can simultaneously achieve efficient CO2 removal and sustainable recovery of fresh water and high-purity resources (NaCl, Na2SO4, NaOH and HCl) from wastewater and waste gas without introducing any extra chemicals. The environmental evaluation indicates the carbon-neutral papermaking wastewater reclamation can be achieved through the application of NF-BMED-MC system. This study establishes the promising of NF-BMED-MC as a sustainable alternative to current membrane methods for ZLD of papermaking industry discharges treatment.

Mapping the research on desulfurization wastewater: Insights from a bibliometric review (1991-2021).

Desulfurization wastewater in coal-fired power plants (CFPPs) is a great environmental challenge. This study aimed at the current status and future research trends of desulfurization wastewater by bibliometric analysis. The desulfurization wastewater featured with high sulfate (8000 mg/L), chlorite (8505 mg/L), magnesium (2882 mg/L) and calcium (969 mg/L) but low sodium (801.82 mg/L), and the concentrations of the main contaminants were critically summarized. There was an increasing trend in the annual publications of desulfurization wastewater in the period from 1991 to 2021, with an average growth rate of 15%. Water Science and Technology, Desalination and Water Treatment, Energy & Fuels, Chemosphere, and Journal of Hazardous Materials are the top 5 journals in this field. China was the most productive country (58.3% of global output) and the core country in the international cooperation network. Wordcloud analysis and keyword topic trend demonstrated that removal/treatment of pollutants dominated the global research in the field of desulfurization wastewater. The primary technologies for desulfurization wastewater treatment were systematically evaluated. The physicochemical treatment technologies occupied half of the total treatment methods, while membrane-based integrated processes showed potential applications for beneficial reuse. The challenges and outlook on desulfurization wastewater treatment for achieving zero liquid discharge are summarized.