Pilot-scale study on the treatment of basal aquifer water using ultrafiltration, reverse osmosis and evaporation/crystallization to achieve zero-liquid discharge

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.

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.

Decarbonized and circular brine management/valorization for water & valuable resource recovery via minimal/zero liquid discharge (MLD/ZLD) strategies

Brine (saline wastewater/water) from desalination, salt lakes, and industrial activities (e.g., pharmaceutical industries, oil & gas industries) has received a lot of attention around the world due to its adverse impact on the environment. Currently, several disposal methods have been applied; however, these methods are nowadays unsustainable. To tackle this problem, brine treatment and valorization is considered a promising strategy to eliminate brine discharge and recover valuable resources such as water, minerals, salts, metals, and energy. Brine valorization and resource recovery can be achieved via minimal and zero liquid discharge (MLD & ZLD) desalination systems. Commercially successful technologies such as reverse osmosis (RO) and distillation cannot be adopted as standalone technologies due to restrictions (e.g., osmotic pressure, high-energy/corrosion). Nonetheless, novel technologies such as forward osmosis (FO), membrane distillation (MD) can treat brine of high salinity and present high recovery rates. The extraction of several ions from brines is technically feasible. The minerals/salts composed of major ions (i.e., Na⁺, Cl^-, Mg²⁺, Ca²⁺) can be useful in a variety of sectors, and their sale prices are reasonable. On the other hand, the extraction of scarce metals such as lithium, rubidium, and cesium can be extremely profitable as their sale prices are extremely higher compared to the sale prices of common salts. Nonetheless, the extraction of such precious metals is currently restricted to a laboratory scale. The MLD/ZLD systems have high energy consumption and thus are associated with high GHGs emissions as fossil fuels are commonly burned to produce the required energy. To make the MLD/ZLD systems more eco-friendly and carbon-neutral, the authors suggest integrating renewable energy sources such as solar energy, wind energy, geothermal energy, etc. Besides water, minerals, salts, metals, and energy can be harvested from brine. In particular, salinity gradient power can be generated. Salinity gradient power technologies have shown great potential in several bench-scale and pilot-scale implementations. Nonetheless, several improvements are required to promote their large-scale feasibility and viability. To establish a CO₂-free and circular global economy, intensive research and development efforts should continue to be directed toward brine valorization and resource recovery using MLD/ZLD systems.

Zero Liquid Discharge System for the Tannery Industry—An Overview of Sustainable Approaches

The tannery industry is characterized by the consumption of a large quantity of water, around 30–40 m3 for processing 1000 kg of hide or skin. This amount becomes wastewater, containing about 300 kg of different chemicals, mainly refractory organic compounds, with high chemical oxygen demand (COD), total dissolved salts (TDS), chromium, and evolution of toxic gases, such as ammonia and sulfides, etc. The remaining tanning chemicals are released as effluent having high resistance against biological degradation, becoming a serious environmental issue. Usually, end-of-pipe treatment is not sufficient to meet the concerns of environmental issues. In terms of cleaner production options, the redesigning of the existing effluent treatment procedures with alternate or additional treatment techniques, which “supports resource recovery with no added chemicals”, is expected to give a sustainable solution for the management of toxic effluent. The Zero Liquid Discharge (ZLD) system serves to ensure zero water emission, as well as treatment facilities by recycling, recovery, and reuse of the treated wastewater using advanced cleanup technology. The international scenario shows the implementation of ZLD thanks to pressure from regulatory agencies. The ZLD system consists of a pre-treatment system with conventional physicochemical treatment, tertiary treatment, softening of the treated effluent, reverse osmosis (RO) treatment for desalination, and thermal evaporation of the saline reject from RO to separate the salts. By adopting this system, water consumption is reduced. Moreover, ZLD also becomes effective in disaster mitigation in areas where the tannery industry is a strong economic actor. With this review, we aim to give an outlook of the current framework.

Techno-economic assessment of zero liquid discharge (ZLD) systems for sustainable treatment, minimization and valorization of seawater brine

The challenge of brine disposal has sparked a lot of interest in advanced strategies for valorizing them through freshwater and salt recovery. This research article examines the technical and economic aspects of zero liquid discharge (ZLD) desalination systems using two different crystallization processes, namely brine crystallizer (BCr) in scenario 1 and wind-aided intensified evaporation (WAIV) in scenario 2 for sustainable treatment, minimization, and valorization of seawater brine. The results indicated that scenario 1 has a higher water recovery (99.14%) than scenario 2 (85.75%) as the crystallization process in scenario 2 (i.e., WAIV) does not recover freshwater; however, water is evaporated through WAIV technology and thus both systems have low brine volumes (<1 m³/day), achieving ZLD conditions. The total energy and cost demands of scenario 1 (22.15 kWh/m³ & US$100.5/day) are greater than those of scenario 2 (15.34 kWh/m³ & US$85.3/day). Both scenarios are viable, with profits ranging from US$180.49/day to US$225.85/day depending on whether only desalinated water or both desalinated water and solid salt are sold. The insight given in this techno-economic analysis will aid in the sustainable valorization and management of brine from several brine-generating industries.

Active Treatment of Contaminants of Emerging Concern in Cold Mine Water Using Advanced Oxidation and Membrane-Related Processes: A Review

Responsible use and effective treatment of mine water are prerequisites of sustainable mining. The behavior of contaminants in mine water evolves in relation to the metastable characteristics of some species, changes related to the mine life cycle, and mixing processes at various scales. In cold climates, water treatment requires adaptation to site-specific conditions, including high flow rates, salinity, low temperatures, remoteness, and sensitivity of receiving waterbodies. Contaminants of emerging concern (CECs) represent a newer issue in mine water treatment. This paper reviews recent research on the challenges and opportunities related to CECs in mine water treatment, with a focus on advanced oxidation and membrane-based processes on mine sites operating in cold climates. Finally, the paper identifies research needs in mine water treatment.

Zero-liquid discharge (ZLD) technology for resource recovery from wastewater: A review

Water resources are becoming scarce meaning that reuse options are receiving more and more attention. In this perspective, zero-liquid discharge (ZLD) is considered as an emerging technique to minimize waste, recover resources, treat toxic industrial waste streams, and mitigate potential water quality impacts in receiving water streams. Although ZLD systems are capable of minimizing contamination of water sources and amplifying water supply, its industrial scale applications are restricted due to their high cost and intensive energy consumption. In ZLD systems, membrane-based technologies are an attractive future strategy for industrial wastewater reclamation. Therefore, this review examines why a greater focus on environmental protection and water security is leading to more widespread adoption of ZLD technology in various industries. We highlight existing ZLD processing schemes, including thermal and membrane-based processes, and discuss their limitations and potential solutions. We also investigated global application of ZLD systems for resource recovery from wastewater. Finally, we discuss the potential environmental impacts of ZLD technologies and provide some focus on future research needs.

The Global Rise of Zero Liquid Discharge for Wastewater Management: Drivers, Technologies, and Future Directions

Zero liquid discharge (ZLD)-a wastewater management strategy that eliminates liquid waste and maximizes water usage efficiency - has attracted renewed interest worldwide in recent years. Although implementation of ZLD reduces water pollution and augments water supply, the technology is constrained by high cost and intensive energy consumption. In this critical review, we discuss the drivers, incentives, technologies, and environmental impacts of ZLD. Within this framework, the global applications of ZLD in the United States and emerging economies such as China and India are examined. We highlight the evolution of ZLD from thermal- to membrane-based processes, and analyze the advantages and limitations of existing and emerging ZLD technologies. The potential environmental impacts of ZLD, notably greenhouse gas emission and generation of solid waste, are discussed and the prospects of ZLD technologies and research needs are highlighted.