Demineralized Water Treatment Companies
Demin plant suppliers, two-bed, mixed-bed, and membrane-based demineralization for boiler feed and industrial process water.
15 specialist providers · 8 countries
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Specialists in demineralized water treatment
Providers whose services or self-declared specialties match this category.
EnviroFALK
Germany
EnviroFALK is a German manufacturer of process water and ultrapure water treatment systems with over 30 years of expertise. It designs, builds and services plants for manufacturing, laboratories, hospitals, medical technology and green hydrogen, combining reverse osmosis, electrodeionization, membrane filtration and ion exchange with regeneration and holistic water management services.
Buyer's guide
The buyer's guide to demineralized water treatment
Demineralized Water Treatment for Boilers, Power, and High-Purity Process
Demineralized (DM) water treatment removes all dissolved ions to deliver conductivity <0.1 μS/cm and silica <10 μg/L for high-pressure boiler feed (>60 bar), power-plant condensate polishing, semiconductor process, and pharmaceutical Water for Injection (WFI) precursors. Technology stack: pre-treatment (multimedia filter, activated carbon for chlorine removal, ultrafiltration to SDI<3), two-pass reverse osmosis (95–98% TDS rejection per pass, combined 99.5–99.9%), electrodeionization (EDI) replacing mixed-bed ion exchange to deliver <0.1 μS/cm continuously, with terminal polishers (mixed-bed IX cartridge or ultrafiltration 0.05 μm) at point of use.
Boiler feed-water specifications follow ABMA, ASME PTC 39.1, VGB R 450L, EPRI Cycle Chemistry Guidelines: subcritical drum boilers 30–100 bar require conductivity <5 μS/cm, silica <100 μg/L, iron <20 μg/L; supercritical >221 bar require <0.2 μS/cm, silica <10 μg/L, iron <2 μg/L. Semiconductor ASTM E1245-04 Type I water: resistivity 18.18 MΩ·cm at 25°C (theoretical max), TOC <10 μg/L, particles >0.05 μm <100/L, bacteria <1 CFU/L. Pharmaceutical WFI per USP <1231> / EP requires conductivity ≤1.3 μS/cm at 25°C, TOC ≤500 μg/L, bacterial endotoxins <0.25 EU/mL, distilled or RO-EDI sourced.
Standards and lifecycle: NSF/ANSI 61 for potable contact (where applicable), ASME BPVC for pressure equipment, IEC 61439 for electrical, ASTM D1193 for laboratory water grades. Membrane replacement 5–10 years, IX resin 5–15 years (mixed-bed regenerated externally), EDI modules 7–15 years. Operating cost dominated by electricity ($0.15–0.45/m³ at 0.8–2.5 kWh/m³ at €0.10/kWh) and chemical regeneration ($0.10–0.40/m³). Aguato lists DM water providers across power (CCGT, supercritical coal), petrochem, semiconductor fab, pharmaceutical (WFI), and high-pressure boiler service.
Frequently asked questions
What's the difference between RO + IX and RO + EDI?
RO + mixed-bed ion exchange (MBIX): polishes RO permeate to <0.1 μS/cm batch-wise; requires off-site regeneration with acid/caustic every 30–180 days, generating chemical waste 1–5 kg per kg ionic load removed. RO + EDI: continuous polishing using electric current to drive ions through ion-exchange membranes; no chemical regeneration, no waste stream beyond reject (5–10% of feed). EDI capex 1.5–2.5× MBIX but opex 40–70% lower at 0.5–2 kWh/m³ vs. chemical cost. EDI is the default specification for new DM plants since ~2010; MBIX retained only for specialty applications requiring <50 μg/L sodium.
What boiler feed-water specification do I need at my operating pressure?
Industrial 10–30 bar drum boilers: conductivity <50 μS/cm, silica <500 μg/L: economic with single-pass RO + softener. 30–60 bar drum: conductivity <10 μS/cm, silica <100 μg/L: two-pass RO + EDI. 60–150 bar drum (utility): conductivity <1 μS/cm, silica <20 μg/L: two-pass RO + EDI + condensate polishing. Supercritical >221 bar: conductivity <0.2 μS/cm, silica <10 μg/L, iron <2 μg/L: two-pass RO + EDI + mixed-bed polisher. Always specify per EPRI Cycle Chemistry Guidelines and align with boiler-manufacturer warranty terms.
How is silica controlled in DM water?
Silica is the hardest contaminant to remove and the limiting factor for high-pressure boilers (volatile silica carryover to turbine blades causes deposition). Two-pass RO removes ~99.5% silica; first pass at pH 9–10 (caustic-elevated) improves silica rejection from 99.0% to 99.7%. EDI further polishes to <10 μg/L. Reactive silica (SiO₂ monomeric form) is the regulated species; colloidal silica requires UF or coagulant pretreatment. For superheater protection, silica <10 μg/L feedwater + boiler-water silica curve compliance per EPRI prevents deposition above 350°C operating temperature.
What is the energy consumption of a complete DM water plant?
Two-pass RO plus EDI delivering 0.1 microsiemens/cm: 1.2 to 2.5 kWh/m3 permeate, dominated by RO high-pressure pumps. Three-stage RO plus EDI plus mixed-bed polishing for semiconductor: 1.8 to 3.5 kWh/m3. WFI plants with vapour-compression distillation post-EDI consume 5 to 15 kWh/m3 (thermal energy dominant). Heat-recovery and energy-recovery devices on RO reject can reduce energy 8 to 15%, usually only justified above 500 m3/day capacity. At GBP 0.10 to GBP 0.18/kWh, DM water energy cost runs GBP 0.12 to GBP 0.45/m3, a meaningful but rarely limiting operating cost driver.
Illustrative scenario · Gas-fired combined cycle power station, 780 MW, North East England, steam boiler feed water
A composite drawn from typical projects in this category, not a single client engagement. Figures are indicative.
- Challenge
- A CCGT power station with a supercritical steam cycle operating at 280 bar required boiler feed water at conductivity below 0.1 microsiemens/cm and silica below 5 micrograms/L. The existing single-pass RO plus mixed-bed ion exchange plant was achieving conductivity averaging 0.6 microsiemens/cm and requiring monthly off-site regeneration of IX resin, creating 14-day supply interruptions at a reagent and transport cost of GBP 42,000/year.
- Approach
- A two-pass RO plant with caustic dosing at 9.5 mg/L NaOH between first and second pass was retrofitted, followed by an EDI module train replacing the mixed-bed IX. First-pass RO achieved 99.2% TDS rejection; second-pass at elevated pH achieved 99.95% silica rejection. EDI continuous polishing delivered conductivity consistently below 0.05 microsiemens/cm.
- Outcome
- Boiler feed water quality improved to conductivity 0.04 to 0.08 microsiemens/cm and silica 1.8 to 3.2 micrograms/L, well within supercritical cycle requirements. IX resin regeneration eliminated, saving GBP 42,000/year plus GBP 18,000/year in chemical waste disposal. EDI power consumption of 1.8 kWh/m3 added GBP 8,500/year in electricity. Net annual saving was GBP 51,500.
Questions to ask shortlisted providers
5
- 01
What boiler pressure and cycle chemistry guideline are you designing to (EPRI, VGB, ABMA) and what are the silica and conductivity targets for our operating pressure?
Silica and conductivity specifications vary significantly by operating pressure. A system designed for 60 bar drum boiler specification (silica below 100 micrograms/L) will not meet supercritical requirements (silica below 10 micrograms/L) without a second RO pass and EDI. Misspecification leads to turbine blade silica deposition and forced outages.
- 02
Do you propose caustic elevation of pH between RO passes for silica rejection, and have you validated this against our feed-water silica concentration?
Second-pass RO at pH 9.0 to 10.0 improves silica rejection from 98% to 99.5 to 99.9%. Without caustic elevation, high-silica feeds (above 10 mg/L silica in supply water) cannot achieve superheater protection targets. Vendors who propose two-pass RO without pH elevation for high-silica feeds are underdesigning.
- 03
What is the guaranteed EDI module performance (conductivity output, silica leakage) and what is the module replacement interval?
EDI module performance degrades over 7 to 15 years. Conductivity creep or silica breakthrough triggers module replacement at GBP 15,000 to GBP 60,000 per module depending on flow rate. Vendors should specify guaranteed output conductivity and silica at both new and end-of-life conditions.
- 04
How does the system handle RO membrane fouling by TOC and iron, which are common in power-station cooling-water and raw-water sources?
Iron above 0.05 mg/L in RO feed causes rapid membrane fouling and iron fouling is notoriously difficult to CIP. TOC above 3 mg/L on polyamide RO membranes requires activated carbon pre-treatment for chlorine removal and biocide management. Power-station DM plants on poor raw-water sources require more extensive pre-treatment than vendors typically propose for industrial-park water supplies.
- 05
What is the reject water recovery rate and where does the RO reject and EDI dilute-stream go?
Two-pass RO with 75 to 80% recovery generates a concentrate at 3 to 4 times feed TDS. For a 500 m3/day DM plant, this is 100 to 125 m3/day of concentrate that must be managed as Trade Effluent if discharged to sewer, or recycled to cooling tower blowdown where conductivity permits.
What drives cost in this category
4
- Number of RO passes required by the target water quality specification
- Single-pass RO plus EDI costs GBP 250K to GBP 600K for a 500 m3/day DM plant. Two-pass RO plus EDI costs GBP 400K to GBP 900K. The additional RO pass adds 30 to 50% to capital cost but reduces silica leakage by a factor of 10 to 20, required for supercritical and above 150 bar drum boilers.
- Pre-treatment scope driven by raw-water quality (iron, TOC, turbidity, silica)
- A simple city-water feed requires multimedia filtration and activated carbon at GBP 40K to GBP 100K for 500 m3/day. High-iron groundwater (above 0.3 mg/L Fe) requires oxidation plus greensand or iron-removal media, adding GBP 30K to GBP 80K. High-TOC surface water may require UF pre-treatment at GBP 80K to GBP 200K before RO to achieve SDI below 3.
- EDI module versus mixed-bed IX capital and operating cost comparison
- EDI modules cost GBP 20K to GBP 80K per module for 500 m3/day capacity, with no chemical regeneration opex but electricity consumption of 1.5 to 2.5 kWh/m3. Mixed-bed IX external regeneration runs GBP 25K to GBP 50K/year in reagent and transport costs for a 500 m3/day plant. EDI payback over MBIX is typically 3 to 6 years on operating cost savings.
- Condensate polishing system if plant also handles returned steam condensate
- Power stations with condensate return require a separate condensate polishing plant (CEDI or regenerable MB IX) to remove iron corrosion products and trace dissolved solids. This adds GBP 200K to GBP 600K and is frequently scoped out of the initial DM plant quotation, creating a budget surprise during detailed design.
Key regulations and standards
4
- Pressure Systems Safety Regulations 2000 (PSSR)
- RO pressure vessels and high-pressure pump systems operating above 0.5 bar in DM water plants are subject to PSSR 2000. A Written Scheme of Examination must be prepared by a competent person (Appointed Engineer), with inspection frequency and maximum working pressure defined. Non-compliance is a criminal offence under HSE enforcement.
- EPRI Cycle Chemistry Guidelines for Power Plants
- The Electric Power Research Institute (EPRI) Cycle Chemistry Guidelines for Fossil Plants and Combined Cycle/Heat Recovery Steam Generators define feedwater quality targets by boiler pressure and chemistry programme (AVT, OT). These are used as the design basis for DM water plants in power-station applications globally.
- Water Supply (Water Quality) Regulations 2016 (if potable connection)
- If the DM plant draws on mains water supply, the connection must comply with WS(WQ)R 2016 backflow prevention requirements (EN 1717). A fluid category 4 risk (chemical contamination from RO reject or chemical dosing) requires a verifiable backflow prevention device approved to Water Regulations Advisory Scheme (WRAS) standards.
- Environmental Permitting Regulations 2016 (RO Concentrate Discharge)
- DM plant RO concentrate discharged to sewer requires Trade Effluent Consent from the local sewerage undertaker under the Water Industry Act 1991. Discharge to surface water requires an Environmental Permit from the EA. Concentrate conductivity, TDS, and chemical oxygen demand from any chemical dosing must be within consent limits.