Reuse, Recovery & Stormwater

    Zero Liquid Discharge (ZLD) Companies

    ZLD integrators combining membranes, evaporators, and crystallizers to eliminate liquid effluent and recover salts.

    16 providers

    This page is a good fit if you need:

    • Flat Sheet UF Membranes or Hollow Fiber RO capabilities
    • Suppliers with manufacturing sector experience
    • Providers operating in United Kingdom or Netherlands
    Providers
    16
    Verified
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    16 results from 16 matched providers

    Ecosystems International logo

    Ecosystems International

    Verified
    Indonesia51-200 employees
    Flat Sheet Microfiltration Units · Hollow Fiber MF Systems · Ceramic Microfiltration Modules +80 more
    apac · china · europe +3 more

    PT Ecosystems International (PT ESI) was established at Jakarta on 21st November 2006. We are an industrial effluent treatment systems integrator specializing in electrocoagulation (EC), a unique waste water treatment profile. PT ESI has capabilities in designing complete waste water treatment solutions by combining various effluent treatment systems such as the electro-coagulation, biological, chemical processes and membrane filtration, offering its customers a wide and comprehensive range of solutions, tailored to suit their various needs – ranging from basic effluent treatment for discharge to effluent recycling for water reuse. The Company is experienced in handling the design, engineering, procurement, construction and operation of new Effluent Treatment Plants (“ETP”) and possesses expertise in retrofitting existing ETP to increase the flow rate and treatment capability without any major infrastructure increase PT ESI is also a premier waste water treatment service company specializing in handling waste water generated from Exploration (Drilling) and Produced Water. Customers in Indonesia include major Oil & Gas companies such as Pertamina, Exxon, Chevron, Petro-China and Medco. Operations in Indonesia are provided by both mobile and fixed units. At drill sites where waste-water recycling is required, PT ESI supplement these treatment units with skid mounted mobile Reverse Osmosis systems. The technologies and solutions employed by PT ESI are developed in-house and examples of these are its proprietary Trident™ Electro Contaminant Removal (“ECR”) system, the Stage Contaminant Removal (“SCR”) process and Mobile On-Site Waste-Water Treatment (“OWT”) units

    Reverse Osmosis (RO) Systems
    Ultrafiltration (UF) Systems
    Multi-media Filtration (MMF) Systems
    +63 more
    agriculture
    manufacturing
    Brine Consulting logo

    Brine Consulting

    Verified
    Netherlands1-50 employees
    Mechanical Vapor Recompression (MVR) · Atmospheric Evaporator · Spray Evaporator +130 more
    apac · china · europe +3 more

    BRINE CONSULTING delivers senior-level strategy, technical design, and actionable insight across the full lifecycle of water-related challenges. We support clients with advisory and due diligence, advanced brine management and resource recovery, industrial and municipal water reuse, and MLD/ZLD systems. Our team also leads ESG and climate-resilience strategy, innovation scouting, and international development and PPP advisory. With deep specialization in desalination, brine valorization, circular economy models, and high-impact infrastructure, we help organizations turn water and waste streams into opportunities, providing clear thinking, rapid delivery, and solutions built for real-world results.

    Activated Carbon Filtration
    Reverse Osmosis (RO) Systems
    Ultrafiltration (UF) Systems
    +85 more
    manufacturing
    energy-production
    Hainan Litree Water Purification Technology Industry Co., Ltd. logo

    Hainan Litree Water Purification Technology Industry Co., Ltd.

    Verified
    China200+ employees
    Tubular Ultrafiltration Units · Hollow Fiber UF Modules · Flat Sheet UF Membranes +17 more
    apac · china · europe +3 more

    Litree: Pioneering Ultrafiltration for a Water-Secure World Founded in 1992, Litree has dedicated 30+ years to redefining water purification through ultrafiltration (UF) membrane technology—our core expertise and passion立升(Litree). As a global high-tech enterprise rooted in independent innovation, we’ve evolved from a membrane R&D startup to one of the world’s leading water problem solvers, with over 146 core patents and state-of-the-art manufacturing hubs in Haikou and Suzhou, China立升(Litree). Our signature hollow fiber UF membranes are engineered to deliver unmatched performance: 0.01μm precision removes 99.99% of bacteria, viruses, and contaminants while preserving essential minerals—striking the perfect balance between purity and health立升(Litree). This technology powers our diverse solutions, from residential whole-house systems to large-scale municipal projects and industrial wastewater treatment, all designed for sustainability and cost-efficiency. What truly sets us apart is our commitment to making safe water accessible. We’ve completed projects serving 50,000+ residents with centralized purification systems that cut construction costs and footprint by 50% compared to traditional setups—proof that advanced technology can also be affordable. Today, our solutions reach 60+ countries, supporting 3,000+ industrial clients and millions of households worldwide. At Litree, water isn’t just our business—it’s our mission. We believe every drop matters, and we’ll keep pushing boundaries to create a future where clean, safe water is a universal right, not a privilege

    Ultrafiltration (UF) Systems
    Membrane Filtration Technologies
    pH Adjustment and Neutralization
    +64 more
    agriculture
    manufacturing
    RCI Aquatech logo

    RCI Aquatech

    Verified
    India1-50 employees
    Mechanical Vapor Recompression (MVR) · Multiple Effect Evaporator (MEE) · Atmospheric Evaporator +76 more
    apac · europe · latam +1 more
    1 case studies

    Founded in 2009, formerly known as Red Circle Industries (RCI), RCI Aquatech creates custom wastewater solutions based on end users’ requirements, which allow for optimally chosen components resulting in a solution that meets or exceeds customer needs. RCI Aquatech’s wastewater treatment systems combine necessary process technologies to reach required state and federal discharge limits and comply with local regulations. Our systems focus on removal of pollutants such as heavy metals, greases, suspended solids, oils, high salt content, toxic compounds, phosphates and more. Using chemical-physical treatment (coagulation, flocculation, and sedimentation), biological treatment (aerobic and anaerobic) and wet chemical oxidation (persistent or toxic organics). Our expertise comprises the following technologies:  Filtration & softening systems  Physicochemical treatment (coagulation-flocculation)  Membrane filtration (UF & RO)  Ion exchange  Chemical oxidation  Biological treatment  Zero liquid discharge (ZLD) system

    Activated Carbon Filtration
    Microfiltration (MF) Systems
    Reverse Osmosis (RO) Systems
    +52 more
    manufacturing
    chemicals-pharmaceuticals
    EC Solutions logo

    EC Solutions

    Verified
    United Arab Emiratesfreelance
    Conventional EC
    apac · china · europe +3 more

    EC Solutions is a specialized consultancy focused on electrochemical technologies for water and wastewater treatment. We believe electrochemical processes, and electrocoagulation in particular, are among the most promising technologies in the water sector today. As a rule of thumb, anything that can be treated with conventional coagulation–flocculation can be pretreated with electrocoagulation, without adding chemicals. That means less chemical handling, lower sludge complexity, and more controllable treatment outcomes. We help industries evaluate, pilot, and implement electrocoagulation as a robust pretreatment or core process for color removal, heavy metals, TSS, emulsified oils, and complex industrial effluents. If you’re dealing with a difficult water challenge and want a cleaner, smarter alternative to chemical treatment, EC Solutions is built for that.

    Greywater Recycling Systems
    Industrial Process Water Reuse
    Industrial Wastewater Treatment Plants
    +2 more
    manufacturing
    food-beverage
    EE

    Eragon Enviro Tech. (Xiamen) Co., Ltd.

    Verified
    China51-200 employees
    Reverse Osmosis (RO) · Inclined Plate Settlers (Lamella Clarifiers)
    china · apac · europe

    Eragon Enviro Tech (Xiamen) Co., Ltd. is a specialized provider of industrial water and wastewater treatment solutions, supporting engineering teams, EPC contractors, and industrial clients in solving complex water challenges. We focus on process design, system integration, equipment manufacturing, and modular system supply for industrial wastewater treatment, water reuse, ultrapure water (UPW), and advanced ZLD/MLD applications. Our solutions are applied across semiconductor, electroplating, electronics, and new energy industries, as well as other industrial sectors dealing with complex wastewater streams. We help clients improve system reliability, optimize process stability, reduce operational risks, and meet stringent discharge and reuse standards in demanding industrial environments. With in-house engineering capability and manufacturing strength, we support global partners from design to execution for high-performance water treatment systems.

    mining-quarrying
    chemicals-pharmaceuticals
    Amazon Filters Ltd logo

    Amazon Filters Ltd

    United Kingdom

    Founded in 1985, UK-based Amazon Filters Ltd is one of Europe’s leading manufacturers and suppliers of bespoke filtration technology such as filter cartridges and housings. Our comprehensive range of products support critical liquid and gas applications in many industries. With over 40 years of continuous support to municipal water companies, we are ideally placed to solve water quality problems with our bespoke cartridge filtration technology. From small boundary boxes installations to large volume fully containerised system and rentable mobile skids, we can manufacture and supply it all. We offer solutions for: Turbidity Control Metals Removal (iron / manganese) Cryptosporidium removal Chlorine reduction Let us support your AMP 8 commitments: Securing Long Term Resilience Securing Cost Efficiency Securing Confidence and Assurance We operate a range of ISO-accredited Quality Management Systems to ensure excellence in customer service. We provide high quality, reliable products and services that exceed client expectations. We help you worry less about the filtration process so you can focus on what you do best.

    Accreditations
    ERG (Air Pollution Control) Ltd logo

    ERG (Air Pollution Control) Ltd

    United Kingdom

    ERG (Air Pollution Control) Limited is the leading supplier of wastewater odour control units (OCUs) for the UK Water Industry and increasingly supplies odour control systems around the world. In addition, ERG can provide specialist advice and solutions to assist in achieving IED compliance for relevant odour assets. In the past 10 years, we have provided over 200 OCUs and count all the UK water companies and major main contractors among our clients. So, whether you are looking for a large, multi-stage chemical scrubbing system, an environmentally friendly bio-trickling filter or bio-scrubber system, a simple but efficient activated carbon or dry media system, an Odorgard™ from ERG Hygrade, or even an RTO (Regenerative Thermal Oxidiser) system, ERG can develop a tailor-made solution to suit. All ERG Odour Control Systems are: Purpose-designed by our process engineers to eliminate the cocktail of inlet odours to the required standard. Optimised to give the best value capital and running costs. Built and tested to current BS EN and WIMES specifications. Guaranteed to achieve the required discharge odour concentration and supported by our skilled and experienced maintenance team. Minimising non-compliant emissions to atmosphere by regular, planned maintenance protects your reputation and saves you money. Our maintenance department can help keep your air pollution and odour control systems running effectively and at the lowest operating costs. Our specialist engineers are experts in maintaining most types of odour and air pollution control equipment and always work to the highest safety standards. We often save clients many thousands of pounds by repairing and enhancing dilapidated air pollution and odour control equipment. We are a framework supplier for odour control maintenance to Southern Water, Scottish Water and Thames Water, regularly maintaining more than 120 sites.

    Treatment Works Products/Services
    Gurney Environmental Ltd logo

    Gurney Environmental Ltd

    United Kingdom

    Gurney Environmental is a well established provider of systems and technologies used in the treatment of water and wastewater. From water supply to water re-use, we have designed and developed innovative, low cost and sustainable systems for the water and wastewater industries. Low CAPEX plus low OPEX equals low TOTEX. True sustainability is the benchmark for success with Gurney. We offer unique water and wastewater treatment systems, equipment and design including zero-to-low energy www and reservoir destratification systems. Our experience and knowledge of the water and wastewater treatment industries has successfully helped a wide variety of clients including major landowners (such as the Crown Estate) and many of the UK’s water utility companies. Our systems are today recognised internationally with a growing number of foreign municipals. Gurney has a total commitment to quality. Our systems and solutions represent the finest in long-term value, which is why we place such a strong emphasis on equipment with sturdy construction and fewer moving parts. Our commitment to a low total life cost is a key part of a commitment to quality.

    Treatment Process Technologies
    Mott MacDonald logo

    Mott MacDonald

    United Kingdom

    We are proud of being a world-class independent management, engineering and development consultancy. Being independent, wholly owned by our people, puts us in charge of our own journey and allows us to focus on what we believe is important for our clients, our colleagues and the communities we work and live in. We have more than 100 years’ experience in the water sector and are experts in every aspect of water development, with all the skills and commitment to deliver solutions that benefit every stakeholder.  We also established Mott MacDonald Bentley more than twenty years ago to deliver long-term programmes of work through a strategic focus, effective communication and flexibility in different models of working.  We are experts at building a trusted relationship with our clients. From investment planning to operational support, design to capacity building we work with private investors and listed companies, as well as national and local governments across the world in both developing and developed regions. As advisors, we think laterally and find the connections that others fail to make. We are pioneers with a thirst for innovation, who understand the challenges facing the water industry today, including biodiversity net gain, natural capital and ecosystem services, the practicalities of the journey to net zero, nature-based solutions and natural flood management and the need to consider everything from a fresh angle and turn obstacles into sustainable paths for both businesses and the lives they touch every day.

    Renewables & Energy Management
    Designers
    Spray Nozzle People logo

    Spray Nozzle People

    United Kingdom

    Suppliers of spray systems and solutions, including the StormBlaster™ stormwater attenuation tank cleaning system, the ScreenBlaster CSO screen cleaning head and specialised spray solutions for odour control, foam suppression and other water and wastewater applications. There are many applications for spray nozzles and systems within the water and wastewater treatment sector. SNP have worked on projects for most of the main water suppliers in the UK & Ireland as well as with many in Europe and beyond. We have listed some key applications for spray nozzles below. For a full list of applications and for further details on key applications, follow the menu to the right. Cleaning systems The United Kingdom’s water industry is poised for its most ambitious transformation yet under the AMP8 (Asset Management Period 8) investment cycle, which runs from 2025 to 2030. Backed by an unprecedented £108 billion investment, the largest in the sector’s history, AMP8 is focused not only on maintaining and upgrading ageing infrastructure but also on addressing growing environmental and regulatory challenges. A significant £11 billion of this total has been earmarked specifically for stormwater and sewage spill mitigation, reflecting mounting pressure from regulators, the public, and environmental groups to curb pollution in rivers, lakes, and coastal waters. At the heart of this environmental push lies the urgent need for more stormwater retention tanks and combined sewage overflow (CSO) systems. It is estimated that some 2,000 such systems will need to be updated, refurbished or built in the AMP round of funding. This stormwater management infrastructure is vital if the target of reducing spills and sewage discharges into waterways by 44% is to be met. Much of this new infrastructure will require specialised cleaning systems. Storm water attenuation tanks can cause serious smell pollution if left improperly cleaned after usage. The StormBlaster tank cleaning system is a more effective alternative to tipping buckets, swirl eductors and manual entry cleaning. Screen cleaning Combined Sewer Overflows (CSOs) are a key feature of combined sewer systems, where rainwater and wastewater share the same pipework. During heavy rainfall, these systems can become overwhelmed without proper control measures. CSO chambers manage excess flows by allowing water levels to rise and diverting surplus into overflow pipes. A crucial component of CSOs is the screening system, which traps solids and keeps them within the sewer network. This prevents solid waste from entering local waterways and protects the environment. Foam control The formation of a stable foam in the water treatment process is a common problem. Foam can occur in aeration tanks, anaerobic digesters or secondary clarifiers. Foam is undesirable because it can overflow vessels, create slippery and unsafe working conditions, interfere with processing, damage materials, and cause tanks to drain and dry slowly. Controlling foam can be accomplished by spraying liquid onto the pool, vessel, or reservoir’s surface and allowing the spray’s droplets to impact the foam bubbles, causing them to break. Spray nozzle arrays positioned above fluid level can be used to knock back the foam and keep it under control. Odour control The use of sprays to knock down and neutralise odour is a common application for our spray nozzles. Nozzles are either used to directly treat odour particles in the air or as part of scrubber systems.

    Treatment Process Technologies
    Accreditations

    Zero Liquid Discharge Systems: Evaporation, Crystallisation, and Brine Management Technologies

    Zero liquid discharge (ZLD) systems treat industrial wastewater and concentrate streams to the point where no liquid effluent is discharged to environment, producing only solid waste (salt cake, crystals, or sludge) for disposal or reuse. ZLD is driven by water scarcity regulations (India Ministry of Environment, Forest and Climate Change ZLD mandate for textile, leather, pharmaceutical, and power sectors since 2016), zero-discharge environmental permits for high-TDS industrial effluents, and water recovery maximisation in water-stressed regions. ZLD technology train: high-recovery RO or brine concentrators (BC) concentrate wastewater TDS from 5,000 to 200,000+ mg/L; evaporators (mechanical vapour recompression, MVR, or multiple-effect evaporation, MEE) further concentrate to 25 to 35 percent solids; crystallisers (forced circulation, evaporative crystalliser) produce dry salt or crystal slurry. Applications: power plant flue gas desulphurisation (FGD) wastewater (high sulphate, chloride); coal mine drainage; textile dye wastewater (India, Bangladesh); pharmaceutical and chemical plant effluent; semiconductor and electronics manufacturing; offshore oil and gas produced water.

    Brine concentrator technology: mechanical vapour recompression (MVR) evaporators are the most energy-efficient single-effect evaporation technology for ZLD applications. MVR principle: vapour generated from boiling brine is mechanically compressed (by centrifugal compressor or blower), raising its temperature and pressure, and then used as heating steam to evaporate more feed; closed loop reuses latent heat; SEC: 15 to 35 kWh per tonne of water evaporated (vs 500 to 700 kWh per tonne for single-effect steam evaporation). GEA, SUEZ, IDE Technologies, Aquatech International, Veolia WTS are leading MVR/MEE brine concentrator suppliers. Multiple effect evaporation (MEE): steam drives first effect, vapour from first effect drives second effect, etc.; for 3-effect MEE: steam consumption 0.33 to 0.35 kg steam per kg water evaporated (vs 1.0 for single-effect); useful where waste steam or heat is available. Brine concentrators typically operate at 90 to 98 percent recovery (produce 2 to 10 percent of feed volume as concentrated brine for crystalliser). Scaling control: antiscalant dosing (specialised formulations for high-TDS, high-temperature brine, e.g. Veolia Hydrex, King Lee Technologies); acid addition to prevent carbonate and hydroxide scaling; softening pretreatment to remove calcium before concentrating sulphate-rich brine (prevents gypsum scaling).

    Crystallisation for ZLD final stage: evaporative crystallisation in forced circulation crystallisers precipitates dissolved salts as solid crystals. Process: concentrated brine from BC/evaporator fed to crystalliser vessel; steam or vapour heating evaporates remaining water; salt crystals grow on seed particles; crystal slurry withdrawn and separated by centrifuge (producing salt cake at 95 to 99 percent TS); salt cake may be NaCl (sodium chloride), Na2SO4 (sodium sulphate, Glauber's salt), or mixed salt depending on feed chemistry. NaCl crystal quality: pharmaceutical grade (USP, BP) requires less than 10 ppm heavy metals; food grade NaCl greater than 99 percent purity; industrial grade for road salt; mixed salts (from complex industrial effluent) typically require landfill disposal as non-hazardous or hazardous waste. ZLD economics: CAPEX USD 2 to 10 million/1,000 m3/day treated; OPEX USD 5 to 20 per m3 treated (energy dominant - MVR electricity cost USD 3 to 12 per m3); justified where: discharge permit requires ZLD; fresh water cost exceeds USD 2 to 5 per m3 (high water scarcity); regulatory fines for non-compliance exceed ZLD operating cost. Life cycle analysis shows ZLD reduces freshwater consumption by 95 to 99 percent vs conventional once-through discharge.

    Frequently Asked Questions

    What is zero liquid discharge (ZLD) and when is it required?

    Zero liquid discharge (ZLD) is a wastewater management approach where all process liquid effluent is treated, recovered, and recirculated within the facility, with no liquid discharge to the environment. The only output is solid waste (salt, sludge) and recovered clean water for reuse. ZLD is required when: (1) Regulatory mandate: India's Central Pollution Control Board (CPCB) mandates ZLD for textile, tannery, pharmaceutical, and large paper mills since 2016; Rajasthan, Gujarat, and Tamil Nadu state governments enforce ZLD for industries in water-stressed areas; (2) Environmental permit conditions: some EU/UK environmental permits for high-TDS, toxic effluent (pharmaceutical, chemical) require ZLD or near-ZLD (less than 5 percent discharge); (3) Water scarcity: industries in arid regions (Middle East, western US, Australia) adopt ZLD to maximise water recovery; (4) Hazardous effluent: produced water from oil and gas wells may require ZLD where surface or groundwater disposal is prohibited; (5) Economics: where water is expensive (greater than USD 3 to 5 per m3) and wastewater can be fully recovered, ZLD may be cost-effective. ZLD is expensive (OPEX USD 5 to 20 per m3) and energy-intensive; it is a last resort where regulatory or water scarcity drivers justify the cost. Near-ZLD (greater than 95 percent recovery) is often more cost-effective.

    What is the cost of a zero liquid discharge system?

    ZLD system costs depend on feed volume, TDS, and salt chemistry: CAPEX: RO brine concentrator + MVR evaporator + crystalliser for 500 m3/day feed at 50,000 mg/L TDS: approximately USD 5 to 15 million (USD 10,000 to 30,000 per m3/day); smaller systems (100 m3/day): higher CAPEX per unit volume due to lack of scale economics (USD 20,000 to 50,000 per m3/day); larger systems (5,000 m3/day): lower unit CAPEX (USD 5,000 to 15,000 per m3/day). OPEX components: energy (dominant): MVR electricity 15 to 35 kWh/tonne water evaporated; at USD 0.10/kWh: USD 1.50 to 3.50 per m3 evaporated; for 90 percent recovery, processing 500 m3/day produces 450 m3 recovered water plus 50 m3 that goes to crystalliser; chemicals (antiscalants, acid): USD 0.50 to 2.00 per m3; labour and maintenance: USD 0.50 to 2.00 per m3; salt/solid waste disposal: USD 0.20 to 2.00 per tonne (road salt can be revenue-neutral; hazardous mixed salt disposal USD 50 to 200 per tonne); total OPEX: USD 5 to 20 per m3 treated. Financial justification: fresh water savings at USD 2 to 5 per m3 supply cost + ZLD water value = USD 2.00 to 5.00 per m3; OPEX exceeds savings for most applications; ZLD is justified by regulatory compliance, water scarcity severity, or brand/sustainability commitments.

    How does a brine concentrator work in ZLD?

    A brine concentrator (BC) in a ZLD system is typically a mechanical vapour recompression (MVR) or multiple-effect evaporation (MEE) unit that concentrates high-TDS wastewater (RO reject, blowdown) before final crystallisation. MVR brine concentrator operation: (1) Feed pretreatment: softening (lime/soda, IX) removes Ca2+ and Mg2+ to prevent CaCO3 and CaSO4 scaling on heat transfer surfaces; pH adjustment; deaeration to remove CO2; (2) Feed enters the evaporator vessel (forced circulation or falling film design); feed is heated in tube-and-shell heat exchanger by compressed vapour; (3) Feed partially flashes and evaporates in the vessel; vapour leaves overhead and is compressed by centrifugal compressor (GEA Wiegand, Sulzer, Pilling Turbines) at pressure ratio 1.1 to 1.3, raising condensing temperature by 5 to 15 degrees C; (4) Compressed vapour condenses inside heat exchanger tubes, releasing latent heat to evaporate more feed; condensate (clean water) recovered for reuse; (5) Concentrated brine (15 to 25 percent TDS) is withdrawn from circulation and sent to final crystalliser; (6) Crystal slurry from crystalliser is centrifuged to produce salt cake (95 to 99 percent TS); liquor returns to BC. Energy input: only compression work (10 to 25 kWh/tonne water evaporated); very efficient vs steam evaporation (500 to 700 kWh/tonne). Leading suppliers: IDE Technologies, GEA, SUEZ WTS, Veolia, Aquatech.

    Can ZLD systems recover usable salt?

    Yes, ZLD crystallisers can produce saleable salt if the feed wastewater chemistry produces a recoverable pure salt. Salt recovery scenarios: (1) NaCl (sodium chloride): from seawater desalination brine (37 to 50 g/L NaCl), coal mine drainage, or industrial sodium chloride-dominated effluent; crystalliser produces greater than 99 percent NaCl dry salt; potential markets: de-icing road salt (lower-grade, less than 97 percent), industrial process salt (chlor-alkali plants, less than 99 percent), water softener salt (less than 99.5 percent), food grade (less than 99.9 percent, USP specification); NaCl market price USD 30 to 80 per tonne; can partially offset ZLD OPEX; (2) Na2SO4 (sodium sulphate, Glauber's salt): from mining, textile, and chemical effluent high in sulphate; produces anhydrous Na2SO4 (less than 99 percent) used in glass manufacturing, detergent, and pulp; market price USD 50 to 150 per tonne; (3) Mixed salt (from complex industrial wastewater): mixture of NaCl, Na2SO4, NaNO3, and other salts; difficult to sell; typically requires landfill disposal as non-hazardous waste (if below RCRA/EU hazardous waste thresholds) or hazardous waste incineration. Salt revenue: at best partially offsets disposal costs; rarely generates significant positive revenue. For salt to be commercially viable: feed water must be predominantly one salt type; purity greater than 99 percent required for most markets; heavy metals and organic contamination must be below food-grade or industrial limits.

    Case Study·Specialty chemicals manufacturing, North West England
    Challenge

    A specialty chemicals plant near Warrington generated 180 m3/day of high-TDS effluent (TDS 42,000 mg/L, predominantly sodium sulphate and sodium chloride) from its reaction process. An Environmental Permit tightening required virtual zero discharge of this brine stream; the previous practice of discharging 140 m3/day to estuary under a Marine Licence was terminated by the EA following WFD quality objective concerns.

    Approach

    A ZLD train was designed: feed went through a high-recovery BWRO (85 percent recovery) reducing volume to 27 m3/day of concentrate at 280,000 mg/L TDS. The RO concentrate entered a single-effect MVR evaporator (GEA NIRO-type), producing a 25 percent solids slurry. A forced-circulation crystalliser then produced a mixed NaCl/Na2SO4 salt cake at 96 percent DS, dewatered by a Flottweg centrifuge. The 27 m3/day of MVR condensate (TDS less than 10 mg/L) was returned to the process, and the 6 to 7 tonne/day salt cake was disposed of as non-hazardous solid waste at GBP 48 per tonne.

    Outcome

    Zero liquid discharge to estuary achieved, resolving the EA enforcement notice. Water recovery 97.8 percent. Total OPEX GBP 42 per m3 treated (energy dominant at GBP 28 per m3 for MVR electricity at GBP 0.22 per kWh). The GBP 2.4 million capital cost was fully justified by the alternative of GBP 6 million in receptor monitoring, legal costs, and potential marine licence revocation fine of up to GBP 250,000 under EPR 2016.

    Questions to Ask Shortlisted Providers

    1. 1

      What is the specific energy consumption of the brine concentrator and crystalliser at our design TDS and flow, and how was this figure validated?

      MVR specific energy varies from 15 to 35 kWh per tonne water evaporated; at GBP 0.25 per kWh, a 10 kWh/tonne difference costs GBP 60,000 to 120,000 per year for a 200 m3/day system; independently verified energy data is essential.

    2. 2

      What scaling control strategy is used for the evaporator heat transfer surfaces, and what is the maximum expected antiscalant dosing rate?

      Calcium carbonate, calcium sulphate (gypsum), and silica are the principal scalants in brine concentrators; inadequate scale control leads to heat transfer fouling, reduced throughput, and expensive chemical cleaning shutdowns.

    3. 3

      Has the crystalliser been operated on feed water with similar chemical composition to ours, and can you provide reference sites?

      Mixed salt streams behave differently from single-salt systems; crystal habit, filterability, and centrifuge dewatering performance are all affected by minor feed constituents that only appear at full scale.

    4. 4

      What is the guaranteed water recovery rate, and what are the liquidated damages provisions if it is not achieved?

      ZLD contracts should specify minimum water recovery (e.g. 95 percent) with financial remedy for under-performance; ZLD economics are entirely dependent on maximising water recovered and minimising solid waste volume.

    5. 5

      How does the system handle feed variation (TDS spikes, pH excursions, organic contamination), and what pretreatment conditioning is required?

      Feed variation is the most common cause of ZLD operational failure; clarifying the pretreatment requirements and the system's operating envelope prevents costly field modifications after commissioning.

    What Drives Cost in This Category

    Feed volume and TDS concentration

    ZLD CAPEX scales approximately with feed volume to the power 0.7; a 100 m3/day system at 50,000 mg/L TDS costs approximately USD 4 to 8 million; doubling volume to 200 m3/day increases CAPEX by approximately 60 to 70 percent, not 100 percent.

    Energy cost and MVR electricity price

    MVR evaporation consumes 15 to 35 kWh per tonne water evaporated; at UK industrial electricity prices of GBP 0.15 to 0.28 per kWh, energy represents 50 to 70 percent of ZLD OPEX; on-site renewable generation or grid connection upgrades materially alter the business case.

    Salt disposal or revenue

    Pure NaCl salt cake (greater than 99 percent) can achieve GBP 30 to 60 per tonne as de-icing or water softener salt; mixed or contaminated salt costs GBP 40 to 200 per tonne to dispose at landfill or incineration; the difference is GBP 70 to 260 per tonne, which is material for systems producing 5 to 30 tonne/day.

    Pretreatment and feed conditioning

    High-strength feeds with calcium, silica, or organic fouling potential require softening, pH adjustment, and antiscalant dosing before the evaporator; these pretreatment systems add GBP 200,000 to 800,000 to CAPEX and GBP 2 to 8 per m3 to OPEX.

    Key Regulations & Standards

    Environmental Permitting Regulations 2016

    EPR 2016 (SI 2016/1154): industrial discharges to controlled waters or sewer require an Environmental Permit from the EA; tightening permit conditions or revocation of Marine Licence for brine discharge are the primary regulatory drivers for ZLD adoption in the UK.

    Marine Licensing Act 2009

    Marine and Coastal Access Act 2009, Part 4: discharging to tidal or coastal waters requires a Marine Licence from the Marine Management Organisation (MMO); brine discharge from industrial ZLD failure scenarios can trigger licence revocation and penalties up to GBP 500,000.

    Water Framework Directive (UK WFD)

    UK-retained Water Framework Directive requires that industrial discharges do not prevent water bodies from achieving or maintaining good chemical and ecological status; EA's river basin management plans impose discharge reduction obligations on high-TDS industrial dischargers near sensitive watercourses.

    EWC and Hazardous Waste Regulations

    Mixed salt crystalliser outputs are classified under EWC codes (typically 06 09 02 for non-hazardous process salt, or 06 09 99); if the salt contains listed hazardous substances above threshold concentrations, it is classified as hazardous waste under the Hazardous Waste (England and Wales) Regulations 2005, requiring licensed carrier and consignment note.