By Challenge / Contaminant

    Heavy Metals Removal Companies

    Heavy metals treatment, precipitation, IX, sorbents, and membranes for lead, mercury, cadmium, chromium, arsenic.

    19 providers

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    • Cartridge Filters or Flat Sheet UF Membranes capabilities
    • Suppliers with manufacturing sector experience
    • Providers operating in United Kingdom or Netherlands
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    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
    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
    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
    Liquid X logo

    Liquid X

    Verified
    United Arab Emirates1-50 employees
    Granular Activated Carbon (GAC) Filters · GO–Polymer Composites · Cartridge Filters
    mea

    Liquid X is a water technology consultancy and commercialization platform focused on accelerating the deployment of next-generation filtration solutions, with a core emphasis on graphene-based water treatment. Founded to address the gap between breakthrough innovation and real-world implementation, Liquid X operates at the intersection of advanced material science, water infrastructure, and market deployment. While significant advances in water technologies exist globally, many remain confined to laboratories or early-stage ventures. Liquid X bridges this gap by identifying, validating, and commercializing high-impact solutions—particularly graphene-based filtration systems—within the GCC and wider MENA region. Our consultancy model is built around a full lifecycle approach: from technology scouting and technical evaluation to pilot design, validation, and scaled deployment. We work with asset owners, governments, and enterprises to translate emerging technologies into practical, site-ready solutions. This includes designing pilot programs with measurable performance metrics, enabling data-driven decision-making, and ensuring that innovations are proven under real operating conditions before scale-up. A key focus of Liquid X is the commercialization of graphene-based water filters. Graphene, a two-dimensional material with exceptional strength, permeability, and adsorption capacity, has the potential to fundamentally transform water treatment. Its nano-scale structure allows precise separation of contaminants while enabling faster water flow and lower energy consumption compared to conventional systems. Through strategic partnerships with innovators, researchers, and manufacturers, Liquid X is actively working to bring graphene filtration technologies from concept to market. These systems are being developed to address some of the most critical water challenges, including the removal of PFAS and emerging contaminants, heavy metals, dissolved solids, and industrial pollutants—while significantly reducing waste and energy intensity associated with traditional technologies such as reverse osmosis. Our role extends beyond technology development. Liquid X supports the full commercialization journey, including: Technical due diligence and performance validation Pilot implementation and third-party verification Integration with existing infrastructure Development of scalable deployment models Coordination with EPC contractors, facility managers, and regulators Ongoing monitoring, compliance, and optimization By operating as a vendor-agnostic platform, we ensure that solutions are selected based on performance, suitability, and long-term value—not vendor bias. The MENA region faces some of the world’s most acute water challenges, including scarcity, high desalination dependence, and rising energy costs. Liquid X is positioned to introduce more efficient, decentralized, and sustainable alternatives through advanced filtration technologies. Graphene-based systems, in particular, offer the potential for lightweight, modular, and energy-efficient treatment solutions that can be deployed at scale across residential, commercial, and industrial applications. At its core, Liquid X is not just a consultancy—it is an enabler of the next generation of water infrastructure. By combining deep regional expertise with global innovation networks, we are helping transform how water is treated, distributed, and consumed. Our mission is to accelerate the transition from legacy, resource-intensive systems to smarter, more sustainable water solutions—unlocking the full potential of graphene and other advanced materials to build a more water-secure future.

    Activated Carbon Filtration
    Nanofiltration (NF) Systems
    Point-of-Use (POU) Filtration Systems
    +11 more
    food-beverages
    hospitality-tourism
    PNR ITALIA Srl logo

    PNR ITALIA Srl

    Verified
    Italy51-200 employees
    Spray Evaporator · Self-cleaning Screen Filters
    apac · europe · latam +2 more
    19 case studies

    We produce a comprehensive range of spraying solutions, encompassing everything from small-scale nozzles to large industrial spraying systems. Our diverse product line includes various types of nozzles tailored to meet the specific requirements of every application and customer need. The company was established in Milan in November 1968, focusing on distributing parts and components for fire protection systems. Over time, we expanded our offerings to include a diverse range of industrial sprayers tailored to various applications. In addition to our distribution and manufacturing of fire protection system components and industrial sprayers, we specialize in designing and producing pneumatic spray nozzles for industrial use and tank washing nozzles. Our product line also encompasses a variety of complementary accessories essential for industrial washing, including filters, spray guns, and hoses. Furthermore, we offer ejectors, blower nozzles, swivel joints, and hose clamps to provide comprehensive solutions for our customers' needs. PNR Italia is part of the Tecomec Group and oversees four other affiliated companies to form PNR Company, a consolidated reality with a significant presence on the market.

    Microfiltration (MF) Systems
    Disinfection Technologies
    Disinfection Chemicals
    +7 more
    agriculture
    manufacturing
    Evergreen Water Solutions logo

    Evergreen Water Solutions

    United Kingdom

    A leading supplier of progressive wastewater treatment systems Evergreen Water Solutions works closely with a number of international engineering companies whose expertise are in scalable wastewater treatment systems and containerised wastewater treatment systems for municipal and industrial application. Evergreen Water Solutions offers a comprehensive engineering service. Our company incorporates initial design and planning, to implementation of projects that are delivered on time and on budget. Our expertise in wastewater treatment covers infrastructure development, package sewage treatment systems and advanced treatment technology for wastewater recycling with the strictest treatment requirements. The goal of Evergreen Water Solutions is to exceed the expectations of our clients, foster long-term relationships, and make a positive impact on the environment and industry standards. Evergreen Water Solutions use innovative products and suppliers to source, design and implement leading environmental water and wastewater treatment products and solutions. All new equipment and suppliers are required to undergo pre-qualification program and a series of acceptances and trials are applied prior to the approval of the vendor. Evergreen Water Solutions’ pre-qualification program guarantees you our clients that the products we source are of the highest standard within the industry, these products along with the expertise within Evergreen Water Solutions ensures that the solution we provide will meet and exceed any expectation you might have.

    Treatment Works Products/Services
    Contractors
    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
    Cadman Cranes Ltd logo

    Cadman Cranes Ltd

    United Kingdom

    Cadman Cranes is a leading provider of lifting solutions in the UK with over 50 years’ experience and a reputation for quality, reliability and safety. At the very forefront of sustainability within the industry, Cadman Cranes offer responsible and collaborative turn-key solutions across all industries. From depots in Colchester and Brentwood, Cadman is ideally positioned to cover the East of England and beyond, living and breathing its mission to provide safe lifting solutions to industry and communities in a collaborate, considerate and sustainable way. Cadman has always placed great importance on delivering so much more than just crane hire. Its values are focussed on the success of its clients, its people and its community, and it takes great pride in going the extra mile on every job, no matter how big or small. Cadman Cranes add value to your hard work and offer a full-service lifting solution that goes far beyond just crane hire. It doesn’t just look for customers, it looks for partnerships based on trust, quality and safety. Services include: Contract lift services: Our complete package service is ideal for those who require a fully managed lifting solution, removing your risk and liability, and ensuring that we deal with all of the ‘heavy lifting’. Crane hire services: Cadman Cranes is the leading crane rental company in the East of England, providing crane hire across London, Essex, East Anglia, and all over the UK. With cranes available 24/7, 365 days a year, we are well positioned to keep your operations moving. Tank clearance, dredging, and grab solutions: Cadman Cranes offers innovative tank clearance solutions with our custom-designed grab attachment. The remote-controlled grab, mounted to the hooks of our mobile cranes, can reach up to 60 meters and handle a variety of materials, including sewage waste, sludge, grit, mud, and sand. This service is ideal for wastewater treatment plants, sewage facilities, digester tanks, aeration tanks, ports, and any industrial sites that require regular tank cleaning, maintenance, or dredging. Specialist lifting equipment for utility installation projects: Utilising our range of specialist lifting equipment, we have assisted on some of the most complex utility installation projects throughout the East of England, solving problems currently unimaginable by other mobile crane hire companies. Our innovative Compact Crawler Cranes, in combination with our remote-controlled telescopic hydraulic grab, have proved invaluable in providing the highest level of service and crane hire to the utilities sector. If you would like to work with Cadman Cranes or are looking to add a safe and considerate crane hire solution to your list of approved suppliers, Cadman would love to hear from you.

    Asset Maintenance & Rehabilitation
    EMS Industries Ltd logo

    EMS Industries Ltd

    United Kingdom

    EMS are a UK based manufacturer of positive displacement ram pumps and grit removal solutions used traditionally in the wastewater industries but also in the food waste (AD) sector. EMS Industries was established in 1995 and has since grown into a world-renowned name for providing robust, reliable products which have provided our substantial client list with many years of trouble free service. All EMS products are designed, manufactured and tested in our Stoke on Trent operational facilities where we can also offer additional services including spare parts, service and repairs, installation, commissioning, operator training packages and full CAD and 3D modelling services. As a framework provider to some of the major UK utility companies, we ensure that our products meet with all current legislation and continually strive to provide innovative products to the market place.

    Treatment Process Technologies
    Greenbank Group logo

    Greenbank Group

    United Kingdom

    A specialist engineering company with a global customer base. Greenbank provides a wide range of products and services to companies operating across a number of industries and is now establishing itself in the clean and wastewater sector. For many years the company has utilised the unique properties of volcanic basalt for lining products used in heavy industries such as power generation and minerals extraction. In partnership with Czech firm Eutit, the company has also been pioneering the use of basalt in the renovation and restoration of sewer systems in central European following a series of successful projects in Prague. As a result of devastating floods, the city’s sewer system was extensively rebuilt and upgraded with basalt being used in a number of key locations to provide a new level of security to the system. More than a decade on, the new system continues to perform well and has set a standard that’s now been followed in other European cities. Well suited for the most demanding of applications, thanks to the partnership between Greenbank and Eutit, a wide range of basalt solutions are now available in the UK market. These include products and systems that bring a wide range of benefits to the industry, including: Basalt tiles that can also be used to line existing brickwork, a more cost-effective solution than full replacement, and their reduced drag co-efficient means improved flow – in effect a smaller-diameter pipe or tunnel lined with basalt can carry a higher volume of water than a larger one with traditional brick surfaces. The effective life expectancy of basalt-lined sewer systems is between 100 and 200 years, thanks to their excellent resistance to abrasion and chemical damage – as well as the rigours of high-pressure water jetting that’s often used to clear unwanted blockages. For larger round or ovoid systems, basalt can be used in the lower sections to deal with the wear and tear with concrete upper sections to provide optimum life performance. Alternatively, steel pipes lined with basalt can be produced up to 3000mm diameter producing a lighter therefore lower cost installation option to thick wall concrete. Ease of installation and reduced maintenance costs make basalt ideal for bottom gutters, branch pipes and tubes and slip-resistant elements for walkways, and Greenbank can also supply bespoke-shaped tiles to meet the unique requirements of individual clients. With manufacturing facilities in Derbyshire and Nottinghamshire, supported by the additional capacity and expertise provided by the latest addition to the group, Franklyn Yates Engineering, Greenbank is well placed to react quickly and efficiently to the needs of new and existing clients.

    Hydro International logo

    Hydro International

    United Kingdom

    Hydro International, a CRH company,  provides advanced products, services and expertise to help municipal, industrial and construction customers to improve their water management processes, increase operational performance and reduce environmental impact. Hydro International can help water companies meet their AMP and environmental obligations, including the reduction of sewer overflows and the Water Industry National Environment Programme (WINEP). Hydro International provides total solutions for Inlet Works, Combined Sewer Overflows (CSOs), Stormwater Management, Flood Warning and Prevention, and Water Resource management, from design to supply and installation through to ongoing preventative maintenance, servicing and emergency repair.  These solutions include: Hydrometric data collection, monitoring analysis and reporting for river level, reservoir, network and weather. Continuous water quality monitoring for compliance with Section 82 of the Environment Act. Water resource analysis and consultancy. Stormwater management solutions, including options for Sustainable Drainage Systems. (SuDS) and Smart Maintenance. CSO event duration monitoring. CSO and storm tank treatment and screening. Passive flow controls for flood prevention schemes, SuDS, CSOs and WwTWs. Inlet works screening and grit removal solutions. Sludge screening. Dropping sewage or water safely from height. Hire, repair and maintenance of inlet works screens and screenings handling equipment

    Networks - Sewerage
    Asset Maintenance & Rehabilitation

    Heavy Metals Removal Technologies: Precipitation, Ion Exchange, and Membrane Processes

    Heavy metals in industrial wastewater (lead, cadmium, chromium, mercury, arsenic, nickel, zinc, copper) are removed by chemical precipitation, ion exchange, adsorption, or membrane processes. Chemical precipitation raises pH to 8.5 to 11 (lime, NaOH, or Na2S dosing) to form insoluble metal hydroxides, sulphides, or carbonates with residual concentrations of 0.05 to 0.5 mg per L for most metals. Chromium (VI) requires reduction to Cr (III) at pH 2 to 3 using sodium bisulphite or ferrous sulphate before precipitation. US EPA Best Available Technology (BAT) for electroplating wastewater specifies effluent limits: Cd 0.69 mg per L, Cr 0.38 mg per L, Pb 0.69 mg per L, Hg 0.032 mg per L (40 CFR Part 413).

    Ion exchange resins provide polishing to below 0.01 mg per L for most heavy metals. Chelating resins (iminodiacetic acid type) offer high selectivity for heavy metals over calcium and sodium, enabling treatment of high-TDS effluents where strong-acid cation exchange would be saturated by competing ions. Activated carbon is not effective for most dissolved metals but removes organic-metal complexes (e.g. EDTA-metal, amino-metal). Adsorbent media including iron oxide-coated sand, GFH (granular ferric hydroxide), and activated alumina achieve arsenic residuals below 10 micrograms per L (WHO and US EPA MCL). Fixed-bed adsorbers are designed at EBCT of 3 to 6 minutes for arsenic removal, with media regenerated by NaOH at pH 12 to 14.

    Nanofiltration and reverse osmosis achieve removal of 95 to 99 percent of dissolved heavy metals by size exclusion and charge repulsion. NF is selective for divalent ions (90 to 98 percent rejection of Pb2+, Cd2+, Cu2+) while passing monovalent ions (Na+, Cl-); this enables concentration of metals for recovery while producing low-TDS permeate for reuse. Electrocoagulation (EC) applies sacrificial iron or aluminium electrodes to generate coagulant in-situ, achieving metals removal to below discharge limits without chemical dosing; capital cost $50,000 to $500,000 for 10 to 1,000 m3 per day capacity. Zero-valent iron (ZVI) reactive barriers treat groundwater metals and chlorinated solvent plumes at contaminated sites at low operating cost.

    Frequently Asked Questions

    What is the most effective method for removing heavy metals from water?

    For industrial wastewater with metals above 10 mg per L, chemical precipitation (lime or NaOH to pH 9 to 11) is the most cost-effective first step, reducing concentrations to 0.5 to 2 mg per L. For polishing to below 0.1 mg per L (discharge or reuse standards), follow with: ion exchange (chelating resin, achieves below 0.01 mg per L), adsorption media (GFH or iron-oxide media for arsenic below 10 micrograms per L), or nanofiltration (95 to 99 percent rejection). For low-concentration influents (0.1 to 10 mg per L), direct ion exchange or adsorption may be more economic than two-stage precipitation plus polishing. Emerging electrochemical methods (electrocoagulation, electrodialysis) are gaining adoption for selective metals recovery and zero liquid discharge applications.

    What are the discharge limits for heavy metals in industrial wastewater?

    US EPA effluent limits (40 CFR Part 413, Electroplating) in mg per L: cadmium 0.69, chromium total 0.38 (Cr6+ 0.05), copper 1.2, lead 0.69, mercury 0.032, nickel 1.9, silver 0.43, zinc 2.6 (30-day average limits for POTW discharge). EU Industrial Emissions Directive (2010/75/EU) and associated BAT Conclusions set sector-specific limits; non-ferrous metals sector BAT-AEL: nickel 0.5 mg per L, zinc 1.0 mg per L, lead 0.3 mg per L. UK Environment Agency regulated limits are set in discharge consents and typically align with EU BAT-AEL values. WHO Drinking Water Guidelines (2017) are relevant for treated water: arsenic 10 micrograms per L, lead 10 micrograms per L, mercury 6 micrograms per L, cadmium 3 micrograms per L.

    How is chromium removed from wastewater?

    Chromium exists in two forms requiring different treatment. Cr(VI) (hexavalent, chromate and dichromate, highly toxic) must first be chemically reduced to Cr(III) (trivalent, far less toxic) at pH 2 to 3 using sodium metabisulphite, ferrous sulphate, or SO2 gas. The reduction reaction (Cr6+ + 3 Fe2+ yields Cr3+ + 3 Fe3+ in alkaline rearrangement) is complete within 5 to 15 minutes at pH 2 to 3. Then pH is raised to 8.5 to 9 with lime to precipitate Cr(III) as Cr(OH)3 (s); residual Cr after precipitation is typically 0.05 to 0.2 mg per L. Sludge from chromium precipitation contains Cr(OH)3 and is classified as hazardous waste in most jurisdictions. Ion exchange with strong-acid cation resin further polishes Cr(III) to below 0.01 mg per L.

    Can heavy metals be recovered and recycled from wastewater?

    Yes, for sufficiently concentrated waste streams. Selective ion exchange using chelating resins allows metal-rich eluates to be recovered and sold as metal salt solutions or processed by electroplating suppliers. Nickel recovery from electroplating rinse water by evaporator concentration and crystallisation produces nickel sulphate (minimum 98 percent purity) for direct reuse. Copper recovery by cementation (scrap iron addition to acidic Cu2+ solution, Cu deposits as metal) is used in printed circuit board manufacturing; copper purity 85 to 90 percent is achievable. Lead-acid battery wastewater lead recovery by electrowinning achieves 99.99 percent purity lead. Economic recovery thresholds: copper above 100 mg per L, nickel above 500 mg per L, gold above 0.5 mg per L are typically worth concentration and recovery versus chemical precipitation and landfill disposal.

    Case Study·Surface finishing
    Challenge

    A metal finishing company in the West Midlands operating nickel electroplating and chromium plating lines generated 150 m3/day of mixed rinse water containing Cr(VI) at 15 to 80 mg/L, Ni at 20 to 60 mg/L, and Zn at 5 to 25 mg/L. The company held a Trade Effluent Consent to sewer with limits of Cr total 1 mg/L, Ni 2 mg/L, and Zn 3 mg/L, which it was regularly breaching. The EA had issued an enforcement notice requiring compliance within 6 months.

    Approach

    Installed a three-stage treatment system: (1) Cr(VI) reduction at pH 2.5 using sodium metabisulphite (residence time 20 minutes, ORP control to below -250 mV); (2) pH adjustment to 9.5 with lime for co-precipitation of Cr(III), Ni, and Zn hydroxides in a lamella settler; (3) polishing by chelating ion exchange resin (iminodiacetic acid type) to achieve Ni below 0.1 mg/L. Sludge dewatered by filter press to 35 percent solids, classified as hazardous waste, and disposed to licensed landfill.

    Outcome

    Trade Effluent Consent compliance achieved: Cr total 0.12 mg/L (limit 1 mg/L), Ni 0.08 mg/L (limit 2 mg/L), Zn 0.4 mg/L (limit 3 mg/L) at the 95th percentile. EA enforcement notice closed. Annual chemical cost for the treatment system (NaHSO3, lime, acid for IX regeneration) was 28,000 GBP. Sludge disposal 18 tonnes per year at 450 GBP per tonne. Capital cost 320,000 GBP, payback 4.2 years versus the Trade Effluent Consent penalty tariff.

    Questions to Ask Shortlisted Providers

    1. 1

      What characterisation data do you need from us (flow, heavy metal concentrations, pH range, organic load, and complexing agents), and how will your design handle the variability in our batch discharge pattern?

      Heavy metals treatment performance depends critically on the speciation and complexing agents in the wastewater. EDTA-complexed metals (common in circuit board and PCB processes) do not precipitate at standard pH because the metal-EDTA complex is more stable than the metal hydroxide. Understanding whether complexing agents are present and designing pretreatment accordingly is essential; a designer who does not ask about complexing agents has not done adequate characterisation.

    2. 2

      What Cr(VI) reduction method do you propose, and how will you control ORP (oxidation-reduction potential) and pH during the reduction stage?

      Cr(VI) reduction is the most failure-prone stage of chromium treatment. Incomplete reduction (ORP not reached, insufficient residence time, pH too high) results in Cr(VI) passing to the precipitation stage where it does not precipitate and breaches the consent limit. ORP online monitoring with automatic sodium metabisulphite dosing, and pH control at 2 to 3, are the minimum controls. Manual batch dosing without online ORP control is inadequate for regulatory compliance.

    3. 3

      What sludge production rate (kg dry solids per m3 of wastewater), cake solids content (percent), and disposal route have you assumed in the cost model?

      Heavy metals sludge disposal is a hazardous waste cost that can equal the annual chemical treatment cost. Design assumptions for sludge production rate (varies with metal concentration, pH, and lime dose) and cake solids (12 to 25 percent for belt press, 25 to 35 percent for filter press) directly affect the disposal cost. A design that underestimates sludge production by 50 percent creates a disposal budget overrun within the first year of operation.

    4. 4

      What ion exchange resin do you propose for polishing, and have you tested it against our wastewater matrix to confirm selectivity for Ni and Cr over the competing cations (Ca, Mg, Na) present in our water?

      Chelating resins for heavy metal polishing are highly selective when properly matched to the wastewater matrix. Strong-acid cation resins in hard water will be saturated by Ca and Mg before removing sufficient Ni, requiring very frequent regeneration and adding chemical cost. A bench-scale or pilot test of the specific resin on your actual wastewater (after precipitation, simulating the actual IX feed) is required before committing to the design.

    5. 5

      How will the hazardous waste sludge be characterised, classified, and disposed of, and do you have an agreement with a licensed hazardous waste carrier and disposal facility for the anticipated sludge volume?

      Heavy metal hydroxide sludge from electroplating wastewater is classified as hazardous waste under the UK Hazardous Waste Regulations 2005. A pre-disposal waste characterisation test (WC test) is required to confirm the European Waste Catalogue code and leachate toxicity. Disposal must be with a licensed hazardous waste carrier and at a permitted facility. Failure to correctly classify and manifest hazardous waste is a criminal offence with unlimited fines.

    What Drives Cost in This Category

    Heavy metal concentration and flow rate

    Chemical precipitation costs scale directly with metal load (kg/day of heavy metals requiring treatment). A plant treating 150 m3/day at 50 mg/L Ni requires 7.5 kg/day Ni in sludge. At 2.5 kg NaOH per kg Ni precipitated, this requires 18.75 kg/day NaOH (approximately 10 GBP/day chemical cost). For the same flow at 5 mg/L Ni, chemical cost falls 90 percent. Accurate metal concentration data from representative sampling is the most important input to cost modelling.

    Cr(VI) specific pre-treatment step

    Chromium treatment requires an additional reduction step (sodium metabisulphite, ferrous sulphate, or SO2) before precipitation, adding 20 to 40 GBP per kg Cr(VI) removed in chemical cost. This makes chromate wastewater significantly more expensive to treat per m3 than nickel or zinc-only streams. An online ORP control system for the reduction step costs 8,000 to 20,000 GBP but prevents under-reduction events that cause consent breaches.

    Polishing stage for stringent discharge limits

    Chemical precipitation achieves Ni at 0.5 to 2 mg/L, which may satisfy some Trade Effluent Consents but not direct river discharge standards (typically 0.1 to 0.3 mg/L). Adding chelating ion exchange polishing to achieve below 0.1 mg/L adds 40,000 to 120,000 GBP in CAPEX and 15,000 to 40,000 GBP per year in regenerant chemicals and resin replacement. This cost must be weighed against the consent limit and enforcement risk.

    Sludge dewatering and disposal

    Filter press (25 to 35 percent cake solids) costs 30,000 to 80,000 GBP CAPEX for a small industrial plant; belt press (18 to 22 percent cake solids, lower operating cost) costs 50,000 to 120,000 GBP. Disposal cost is 300 to 600 GBP per tonne for hazardous waste landfill. For 18 tonnes per year of filter cake, disposal is 5,400 to 10,800 GBP per year. Investing in higher cake solids (filter press over belt press) reduces disposal cost by 30 to 50 percent: typically 2 to 4 year payback.

    Key Regulations & Standards

    Water Industry Act 1991 -- Trade Effluent Consent Limits for Heavy Metals

    Trade Effluent Consent under the Water Industry Act 1991 Section 119 specifies discharge limits for heavy metals to public sewer. UK sewer consent limits for electroplating and surface finishing typically include: Cr total 1 to 5 mg/L, Cr(VI) 0.1 mg/L, Ni 2 to 5 mg/L, Zn 3 to 10 mg/L, Pb 1 to 2 mg/L, Cd 0.1 to 0.5 mg/L. Consents must be obtained before discharge; breach is a criminal offence. Consent conditions are reviewed and may be tightened when the sewerage undertaker conducts periodic consent reviews.

    Environmental Permitting Regulations 2016 -- IED Permit for Surface Treatment Facilities

    Surface treatment facilities (electroplating, anodising, phosphating) above thresholds in Schedule 1 of the Environmental Permitting Regulations 2016 require an Environmental Permit from the Environment Agency, applying IED BAT conclusions from the Surface Treatment with Solvents (STS) BREF and related sectors. BAT-AELs set discharge standards for heavy metals to water. EA environmental permits include wastewater monitoring and reporting requirements.

    UK Hazardous Waste Regulations 2005 -- Heavy Metal Sludge Classification

    Heavy metal hydroxide sludge from electroplating and surface finishing wastewater treatment is classified as hazardous waste under the UK Hazardous Waste Regulations 2005 (EWC code 19 08 13* for metal-bearing sludge). A pre-disposal waste characterisation test (WC3 for landfill acceptance) is required. Sludge must be transported by a licensed hazardous waste carrier with consignment notes per the Hazardous Waste (England and Wales) Regulations 2005. Disposal at a permitted hazardous waste facility only.

    REACH (UK REACH) -- Hexavalent Chromium as SVHC

    Hexavalent chromium (Cr(VI)) compounds (chromates, dichromates) are Substances of Very High Concern (SVHC) under UK REACH (retained EU REACH Regulation 1907/2006). Articles containing Cr(VI) above 0.1 percent by weight cannot be supplied to UK consumers without notification. Industrial uses of Cr(VI) in chrome plating require authorisation under REACH Annex XIV. The water treatment system must ensure Cr(VI) does not pass to the receiving environment and that Cr(VI) in process residues is correctly classified and managed.