ENV · Desalination
Seawater and brackish water desalination
Reverse osmosis desalination where the pretreatment is designed against the actual intake, not a nominal seawater analysis — because that is what decides membrane life.
The starting point
What problem does it solve?
- “There is no fresh water source left to develop”
- “Our wells are getting saltier every year”
- “The desalination plant we have keeps fouling”
- “Energy cost per cubic metre is unsustainable”
- “We need drinking water quality and a reliable supply”
Your solution can be desalination — designed against your intake.
Coastal and water-scarce regions need to produce fresh water from saline sources, and reverse osmosis is the route that dominates because it scales and because energy recovery has made it affordable. Seawater desalination plants for drinking water are one of Glorinda's four core areas of water activity.
The difference between a desalination plant that runs and one that fights its membranes is almost always the pretreatment. An intake with seasonal algal blooms, suspended silt, high organic load or oil contamination will destroy a membrane array that was sized on a textbook seawater analysis. We design the pretreatment against the real intake, seasonally, before anything else is fixed.
Brackish water is a different problem again: lower salinity but often higher silica, hardness and specific ion challenges, which pushes the design towards different membranes and different recovery strategies.
Why it pays
Benefits
Pretreatment sized on real data
Media filtration, dissolved air flotation, ultrafiltration, and ceramic or silicon carbide membranes where the intake is difficult — selected against seasonal analysis rather than a nominal one.
The right membrane for the salinity
Seawater RO for full-strength intake; brackish water RO where salinity is lower and silica or hardness dominate; and high-efficiency RO where fouling is the practical limit.
Energy where it can be recovered
Energy recovery on the high-pressure reject is what makes seawater RO viable. We design it in rather than treating it as an option.
Post-treatment for the actual duty
Remineralisation for potable supply; ion exchange, mixed bed or EDI where the water feeds a boiler or a process. Desalinated water is not automatically fit for either without conditioning.
Concentrate is part of the design
Brine disposal, dilution or — where a valuable salt is present — recovery. A plant designed without a concentrate strategy is not a finished design.
Operable by the people you have
Automation, instrumentation and operator training scaled to the site. A remote municipal plant and a refinery utility block need very different control philosophies.
Process
How it works
A desalination plant is an intake, a pretreatment train, a high-pressure membrane array with energy recovery, a post-treatment stage and a concentrate route. The membranes get the attention; the intake and the concentrate cause the problems.
Process diagram
Intake → pretreatment → SWRO/BWRO with energy recovery → post-treatment → distribution
Reserved for a static diagram showing intake and screening, pretreatment options, high-pressure pumping with energy recovery device, membrane array, post-treatment and remineralisation, and the concentrate outfall.
Static process diagram — final artwork to be supplied.
Intake and screening
Open intake or beach well, screening, and the seasonal characterisation that determines everything downstream: turbidity, silt density index, algal load, organics and any industrial contamination in the vicinity.
Pretreatment
Dissolved air flotation for algal blooms and oil, media filtration for bulk solids, and ultrafiltration or ceramic and SiC membranes where the intake is genuinely difficult. This stage sets membrane cleaning frequency and membrane life.
Reverse osmosis with energy recovery
High-pressure pumping through the membrane array, with energy recovery on the reject stream. Seawater and brackish water arrays differ in pressure, staging and recovery, and brackish water systems often need a second pass or a different antiscalant strategy for silica.
Post-treatment
Remineralisation and pH adjustment for potable supply. For industrial duty, ion exchange, mixed bed or EDI polishing where the water feeds boilers or process, and disinfection where the distribution system requires a residual.
Concentrate management
Outfall design and dilution where discharge is permitted; further concentration where it is not. Where the brine contains recoverable salts, crystallisation turns a disposal problem into a product.
Applications
Where it is used
Municipal supply and industrial sites in water-scarce or coastal regions, plus inland sites facing rising groundwater salinity.
Industries
- Municipal water authorities and utilities
- Power generation — make-up water in coastal plants
- Oil, gas and petrochemical — coastal refinery and terminal supply
- Mining — remote sites with only saline water available
- Food and beverage — process water in water-scarce regions
- Agriculture — brackish water treatment for irrigation supply
- Industrial parks and new-build developments
- Hospitality and remote infrastructure
Typical applications
- Seawater desalination for drinking water supply
- Brackish water desalination for inland municipal supply
- Industrial make-up water where fresh sources are exhausted
- Irrigation supply from brackish groundwater
- Debottlenecking an existing desalination plant limited by fouling
- Replacing tankered water on remote sites
- Emergency and temporary supply
Equipment
Related products
Ion exchange resins
Over 200 types — cation, anion, mixed bed, chelating, adsorbent and chromatography media, with resin screening and process design support.
Read moreAnalyzer & metering systems
TOC, oil-in-water, pH, conductivity, dissolved oxygen and CEMS packages with sampling systems and shelters.
Read moreLiquid ring vacuum pumps
Vacuum and compression duties across wastewater, chemical, paper and power applications, including explosion-protected models.
Read moreSteam turbines
50 kW to 180 MW plus energy recovery sets that convert surplus steam pressure into power.
Read moreEngineering services
Engineering support for this technology
Selecting a process is an engineering decision, not a purchasing one. We run feasibility and pre-feasibility studies, characterise the stream, compare the routes on capital and operating cost, and act as owner's engineer while somebody else builds it if that suits you better.
Evidence
Projects
Sample layout. Reference projects are being cleared for publication with the clients concerned. The structure below is final; the content is placeholder.
SampleWater reuse retrofit — sample card
Card layout for a completed water reuse project: stream data before and after, recovery achieved, scope Glorinda held, and the client's own words.
SampleZLD package — sample card
Card layout for a zero liquid discharge package: feed characterisation, evaporator type selected, solid output route, and commissioning duration.
SampleOwner's engineer mandate — sample card
Card layout for an advisory mandate: the client's decision, the options assessed, and what changed in the tender as a result.
FAQ
Questions engineers ask
Taken from the questions procurement teams, plant managers and consultants actually send us.
Seawater or brackish water — does it change the design much?
Substantially. Seawater RO runs at much higher pressure, needs energy recovery to be economic, and lives or dies on intake pretreatment. Brackish water RO runs at lower pressure but often faces higher silica and hardness, which changes the antiscalant strategy, the recovery target and sometimes the membrane choice.
What data do you need to design a plant?
A seasonal intake analysis — not a single sample. Turbidity, silt density index, TDS and full ionic composition, organics, algal load, temperature range and any nearby industrial discharge. Plus the product water spec, the required output and the concentrate route available to you.
Can you fix a plant that keeps fouling?
Usually, and usually by changing the pretreatment rather than the membranes. We would start with a membrane autopsy and a proper intake characterisation to find out what is actually fouling, then decide.
Is the water fit for boiler feed straight out of the plant?
No. Desalinated water needs conditioning for whatever duty it serves. For potable supply that means remineralisation and pH adjustment; for boiler feed it means ion exchange, mixed bed or EDI polishing.
What happens to the brine?
It depends on the permit. Outfall with proper dilution where discharge is allowed; further concentration and crystallisation where it is not, or where the salts are worth recovering. We settle the concentrate route before finalising the recovery target, not after.
Conversion
Take this further
Send us the stream data, the discharge limit or the equipment list you are working from. An engineer reads every enquiry and replies with the questions that actually decide the solution — not a brochure.