Seawater Desalination

Stage 01 · Source basis

Seawater Intake

Set intake hydraulics and the feedwater basis.

Purpose

Establish the flow, salinity, temperature, solids, and biological basis that drives pretreatment and RO design.

Next decision

Choose the solids and biological protection strategy for the RO feed.

Engineering questions

What intake condition and seasonal envelope must the plant handle?
What solids and biological loads arrive at the plant?
What intake or outfall constraints affect recovery?

Key inputs

Intake flowm³/h
Seawater temperature°C
Seawater TDSmg/L
Intake turbidityNTU

Key outputs

Declared RO-feed design flowm³/h
Declared salinity envelopemg/L

Design Considerations

Seawater quality is not a single fixed number.
Intake, pretreatment, RO, and concentrate decisions are coupled at the process level.

Engineering guidance

Engineering guidanceSeawater IntakeNo current ATLAS tool evaluates intake hydraulics, seasonal seawater variability, source solids and biology, or intake and outfall constraints.

Supporting research

No stage-specific research mapping is published for this boundary.

Stage 02 · Pretreatment

Screening & Pretreatment

Protect chemical and membrane barriers.

Purpose

Reduce solids, colloids, and biological loading before the feed reaches dosing and RO.

Next decision

Set the chemical duties that protect the RO membrane and downstream product quality.

Engineering questions

What pretreatment quality is required at the RO feed?
Which fouling mechanism is dominant?
Is conventional or membrane pretreatment supported by the project basis?

Key inputs

Pretreatment flowm³/h
Pretreatment turbidityNTU
SDI or solids basissite basis

Key outputs

RO-feed solids qualityNTU

Design Considerations

UF/MF is an available screening tool; conventional pretreatment remains a project-specific design choice.
Pretreatment must be evaluated against the actual seawater envelope.

Alternative paths at this stage

Conventional clarification and filtration Use when raw-water testing and the RO-feed basis support conventional pretreatment; no dedicated ATLAS clarifier calculator is attached.
UF/MF membrane pretreatment Use the live UF/MF designer for a membrane pretreatment screen.

Tools for this stage

Available UF/MF System Designer Screen membrane area, flux, train count, and recovery for the UF/MF pretreatment option. Open tool Available Activated Carbon Sizing Conditional: screen carbon vessel requirements only for a defined dissolved-organic adsorption duty. Open tool

Engineering guidance Screening & Pretreatment Screen carbon vessel requirements only for a defined dissolved-organic adsorption duty. Activated Carbon Sizing is not a general suspended-solids pretreatment, a replacement for conventional clarification, or a universal seawater pretreatment step. Conventional screening and clarification have no dedicated ATLAS calculator.

Supporting research

RO vs. MED vs. MSF: Why the Thermodynamically Better Desalination Process Isn't the One Winning the MarketReverse osmosis now holds roughly two-thirds of global desalination capacity, but multi-effect distillation is the more thermodynamically efficient process by second-law accounting. The gap between 'wins the market' and 'wins on efficiency' comes down to feedwater chemistry, energy quality, and what a site already has lying around.Chemical Treatment Programs for Reverse Osmosis Membrane Systems: Antiscalants, Dechlorination, Biocides, and Cleaning FormulationsA functional breakdown of the six chemical treatment categories governing RO membrane performance — antiscalants, dechlorination, biocides, coagulants, pH adjustment, and CIP — with dosing benchmarks, compatibility limits, and advanced fouling-monitoring parameters.

Stage 03 · Chemical conditioning

Chemical Dosing

Control scale, oxidant, and feed chemistry.

Purpose

Make the RO feed chemically compatible with the membrane array and the target recovery.

Next decision

Carry the declared feed chemistry into the RO performance screen.

Engineering questions

Which antiscalant, dechlorination, pH, or cleaning duty is in scope?
What dose and chemical-strength basis is being used?
What residual must be proven before the membrane?

Key inputs

Chemical-feed flow basism³/h
RO-feed salinitymg/L
RO-feed pHpH
Candidate chemical dosemg/L

Key outputs

Screened chemical dosemg/L
Conditioned pH basispH

Design Considerations

Chemical selection must remain compatible with membrane materials and the downstream operating envelope.
The calculator screens dose; it does not select a proprietary chemical program.

Tools for this stage

Available Chemical Dosing Basis Calculator Calculate active and commercial-product feed for a declared dose and RO-feed flow; it does not select the chemical program. Open tool

Engineering guidance Chemical Dosing The dose calculator does not select antiscalants, model seawater scaling, set dechlorination targets, or verify oxidant residual ahead of the membrane.

Supporting research

Chemical Treatment Programs for Reverse Osmosis Membrane Systems: Antiscalants, Dechlorination, Biocides, and Cleaning FormulationsA functional breakdown of the six chemical treatment categories governing RO membrane performance — antiscalants, dechlorination, biocides, coagulants, pH adjustment, and CIP — with dosing benchmarks, compatibility limits, and advanced fouling-monitoring parameters.

Stage 04 · Membrane treatment

UF/MF Option

Screen membrane pretreatment when needed.

Purpose

Check a membrane pretreatment option before RO without assuming that every desalination plant requires one.

Next decision

Use the selected pretreatment flow and chemistry as the basis for RO.

Engineering questions

What flux and recovery basis is supportable?
How many trains and elements are needed for the duty?
What fouling and backwash boundary must operations manage?

Key inputs

UF/MF feed flowm³/h
UF/MF feed turbidityNTU
Feed temperature°C

Key outputs

Screened filtrate flowm³/h
Screened membrane recovery%

Design Considerations

The UF/MF result is a preliminary system screen.
Membrane compatibility and pretreatment cleaning need representative data.

Tools for this stage

Available UF/MF System Designer Screen membrane area, train arrangement, flux, and recovery for a selected UF/MF option. Open tool

Engineering guidance UF/MF Option Confirm seawater feed suitability, pretreatment performance, cleaning, and backwash assumptions with representative feed data and selected module information.

Supporting research

Stage 05 · Membrane treatment

Reverse Osmosis

Screen recovery, flow, and concentrate limits.

Purpose

Turn the pretreatment basis into a multi-stage RO screening result with explicit recovery and concentrate behavior.

Next decision

Confirm product-water conditioning and the final disinfection boundary.

Engineering questions

What recovery and permeate-flow target is defensible?
Where do osmotic pressure, fouling, or pressure limits govern?
What is the concentrate path?

Key inputs

RO feed flowm³/h
RO feed TDSmg/L
RO feed pressurebar
RO feed temperature°C

Key outputs

Membrane permeate flowm³/h
RO recovery ratio%
Concentrate TDSmg/L

Design Considerations

The RO designer is a screening and design-basis tool, not a vendor projection.
Concentrate disposal or reuse must remain visible in the train.

Tools for this stage

Available RO System Designer Screen seawater RO permeate, recovery, salt passage, and concentrate TDS across a multi-stage array. Open tool Available Unit Converter Normalize pressure, flow, and concentration units for the RO calculation. Open tool

Engineering guidance Reverse Osmosis Use vendor projections and project-specific energy-recovery and concentrate-management review before selecting an array or operating recovery.

Supporting research

Stage 06 · Polishing

Product Conditioning

Set product-water chemistry for use and delivery.

Purpose

Set the product-water chemistry and stability basis before final disinfection or delivery.

Next decision

Close the product-water microbiological barrier and monitoring plan.

Engineering questions

What alkalinity, pH, or stability target is required?
What chemical dose or blending duty is needed?
Does the product-water claim include a distribution corrosion or taste requirement?

Key inputs

Permeate flowm³/h
Permeate pHpH
Product-water alkalinitymg/L as CaCO₃

Key outputs

Conditioned product-water pHpH
Conditioned alkalinity basismg/L as CaCO₃

Design Considerations

The chemistry target is site- and use-specific.
No generic remineralization recipe is implied.

Tools for this stage

Available Chemical Dosing Basis Calculator Calculate active and commercial-product feed for a declared conditioning dose; product-water stability still needs chemistry review. Open tool

Engineering guidance Product Conditioning The dose calculator can size feed for a declared dose; no current ATLAS tool establishes remineralization chemistry, calcite stability, blending, or corrosion-control targets.

Supporting research

Stage 07 · Disinfection

Disinfection

Apply the final microbiological barrier.

Purpose

Define the contact-time and monitoring boundary that protects the product-water claim.

Next decision

Release product water only against the stated quality and monitoring basis.

Engineering questions

Which disinfection technology and validation basis are in scope?
What contact time and water-quality conditions govern?
Where is residual or CT verified?

Key inputs

Product-water flowm³/h
Product-water temperature°C
Contact-time basismin

Key outputs

Disinfection CT basismg·min/L

Design Considerations

A CT screen is not a complete validation or regulatory approval.
Final barriers must be tied to actual product-water operations.

Tools for this stage

Available Ozone Dosing & CT Screening Screen ozone generator demand and a preliminary CT basis when ozone is selected. Open tool Available Chemical Dosing Basis Calculator Calculate chemical product feed for a declared disinfectant dose; it does not model CT. Open tool

Engineering guidance Disinfection The ozone screen applies only when ozone is selected and uses generic baffling; chlorine, UV, contact-basin hydraulics, and regulatory validation remain outside the current tool set.

Supporting research

No stage-specific research mapping is published for this boundary.

Stage 08 · Reuse / discharge

Product & Concentrate Boundary

Carry product and residuals into review.

Purpose

Make the product-water objective and concentrate/residuals destination explicit in the desalination review.

Next decision

Carry the product and concentrate records into detailed design, outfall, reuse, or ZLD review.

Engineering questions

What quality and quantity are delivered as product water?
Where does concentrate go and what limits it?
What operating data is required to keep recovery defensible?

Key inputs

Product-water flowm³/h
Product-water TDSmg/L
Overall recovery%

Key outputs

Declared plant recovery%
Declared product/concentrate qualitymg/L

Design Considerations

The concentrate boundary is part of the process design, not a footnote.
Any final discharge or ZLD step needs its own defensible design basis.

Tools for this stage

Available RO System Designer Quantify RO array permeate, recovery, and concentrate flow and TDS before outfall or reuse review. Open tool Available Unit Converter Normalize product and concentrate reporting units before handoff. Open tool

Engineering guidance Product & Concentrate Boundary The RO array mass balance does not determine outfall permitting, diffuser performance, mixing-zone effects, or whole-plant residuals and ZLD feasibility.

Supporting research

Search ATLAS engineering resources

Seawater Desalination

Desalination Treatment Train

Engineering guidance — Stage 01 — Seawater Intake

Tools for Stage 02 — Screening & Pretreatment

Tools for Stage 03 — Chemical Dosing

Tools for Stage 04 — UF/MF Option

Tools for Stage 05 — Reverse Osmosis

Tools for Stage 06 — Product Conditioning

Tools for Stage 07 — Disinfection

Tools for Stage 08 — Product & Concentrate Boundary

Seawater Intake

Engineering guidance

Supporting research

Screening & Pretreatment

Alternative paths at this stage

Tools for this stage

Supporting research

Chemical Dosing

Tools for this stage

Supporting research

UF/MF Option

Tools for this stage

Supporting research

Reverse Osmosis

Tools for this stage

Supporting research

Product Conditioning

Tools for this stage

Supporting research

Disinfection

Tools for this stage

Supporting research

Product & Concentrate Boundary

Tools for this stage

Supporting research

Research and Intelligence Context