Daly Middle East · Water Treatment · SWRO45
The Daly RO45 Watermaker is a skid-mounted seawater reverse osmosis system engineered for offshore rigs and marine environments — pre-filtration, chemical dosing, a three-stage LG membrane train and PLC-supervised production of remineralised potable water, from Arabian Gulf seawater up to 42,000 ppm.
The process
This page follows the water itself — from raw Gulf seawater at the intake to remineralised drinking water at the outlet. Five stages, exactly as they run on the skid.
Seawater first passes through filter tanks FT-1 and FT-2, operating in parallel through layered media beds. Healthy pre-filtration is what keeps the membranes downstream alive — and a differential pressure above 1 bar between the SW feed and SWRO gauges is the trigger to backwash.
Before the membranes, a 10 micron cartridge filter polishes the feed while two dosing pumps guard the chemistry: SMBS neutralises chlorine during flushing, and antiscalant runs during production to hold scaling at bay.
The HP pump drives the feed against osmotic pressure while the operator throttles the brine control valve — slowly, to avoid water hammer — until the system stabilises at around 57.9 bar. A 63 bar safety relief valve stands guard above it.
Feed water works through three pressure vessels in series — LG SW 400 SR, LG SW 400 R and LG SW 400 ES membranes — splitting into low-salinity permeate and concentrated brine reject at every stage.
Pure RO permeate is aggressive and flat-tasting, so it passes through a remineralisation tank of calcite and gravel media before delivery — restoring hardness and taste to true drinking-water quality. Permeate flows out at roughly 1.88 m³/h, with brine rejected at about 3 m³/h.
Pre-filtration, up close
Both tanks filter in parallel while the backwash pump stays off. Watch the two gauges: the pressure drop across the beds tells you when the media needs cleaning.
Backwash must be carried out when the differential pressure between the SW Feed and SWRO pressure gauges exceeds 1 bar.
On the skid
Real photography and drawings from the training manual — the same views your operators will use.
Eighteen numbered components on the process side alone — HP pump, inlet sensors and gauges, conductivity sensor, permeate and brine flow meters, dump valve, brine control valve and the pressure vessel train, all piped on a single frame.
Operator sequence
Click through the sequence — the gauge shows where the system pressure should be at each step.
Energise the panel and verify the electrical supply before anything moves.
Supervision & protection
Factory-configured setpoints protect the membranes and the permeate quality around the clock.
Below this, the system protects itself against dry running and cavitation.
Hard ceiling above the 57.9 bar operating point, backed by a 63 bar relief valve.
Early alert that permeate quality is drifting before it becomes a problem.
Automatic trip stops off-spec water from ever reaching the product line.
Consumables
Chlorine neutraliser dosed during flushing to shield the membranes from oxidation.
Dosed during production to keep scale from forming inside the membrane elements.
Dissolves gently into the permeate to restore minerals, hardness and taste.
Support bed beneath the calcite for even flow distribution through the tank.
Why SWRO45
The Arabian Gulf is among the most saline bodies of water on earth — reverse osmosis here has to be engineered, not improvised.
The full process — pre-treatment to remineralisation — ships and installs as one compact unit, ready for coastal sites, islands and remote camps.
Initialisation delay, timed 5-minute flush, valve sequencing and dosing all run automatically — the operator starts it, the logic protects it.
SMBS flush dosing, 10 µm cartridge filtration, antiscalant injection and a conductivity trip all exist for one reason: long membrane life.
Calcite remineralisation after the membranes returns balanced, palatable potable water — the step many small RO units skip.
480 V three-phase supply with 24 V and 230 V AC control circuits — standard industrial power, clearly indicated on the panel.
63 bar main relief, 3 bar permeate relief, motorised inlet valve, emergency stop and a deliberately slow pressurisation procedure.
Where it's deployed
The Daly Watermaker range is designed specifically for offshore and marine service, with variants for onshore, remote and containerised installations.
Fed from the platform's seawater ring main. The core design case — compact footprint, marine-grade build.
Ships and floating units needing reliable potable water in an offshore/marine environment.
Coastal sites and camps beyond the grid, engineered for local salinity and temperature.
The full skid packaged for transport and rapid deployment where a plant room isn't available.
Standard units
The Daly RO45 shown throughout this page is the compact standard unit. When demand runs higher, the RO82 delivers nearly double the output on the same proven platform. Both can be custom-built for site-specific salinity and temperature.
| Specification | Daly RO45THIS PAGE · SWRO45 | Daly RO82HIGHER OUTPUT |
|---|---|---|
| Permeate output | 45 m³/day · 283 bbl/day | 82 m³/day · 515 bbl/day |
| Seawater supply | 115 m³/day @ 1.2–5.2 bar | 210 m³/day @ 1.2–5.2 bar |
| Feed water | Arabian Gulf seawater, salinity up to 42,000 ppm | |
| Recovery | ≈40% feed water recovered as freshwater; ≈60% rejected as brine | |
| Operating pressure | HP pump ≈55–60 bar (SWRO45 operating point ±57.9 bar) | |
| Membranes | 3-stage train — LG SW 400 SR / R / ES, selected to suit salinity | |
| Unit size (W×L×H) | 1350 × 2000 × 1812 mm, skid mounted | |
| Frame | Carbon steel, epoxy coated, one-piece skid | |
| Electrical panel | Schneider type · 1000 (h) × 800 (w) × 400 (d) mm | |
| Piping & fittings | LP: PVC throughout · HP piping & brine control valves: 316 SS | |
| Power supply | 480 VAC, 3 phase, 60 Hz | |
| Pre-filter skid | Dual cartridge assemblies, duty + standby · optional feed booster pump | |
| Remineralisation | Calcite + gravel column restores pH, hardness and taste | |
FAQ
At the design operating point of ±57.9 bar, permeate flow is approximately 1.88 m³/h — around 45,000 litres per day of remineralised drinking water — with a brine reject stream of roughly 3 m³/h.
Raw seawater, conditioned through the twin media pre-filter tanks (FT-1/FT-2) at an inlet pressure of 3–5 bar, then polished through the on-skid 10 micron cartridge filter. The inlet pressure sensor protects the system below 1.2 bar.
The 5-minute flushing cycle rinses the membrane train with low-pressure water while the SMBS pump doses chlorine neutraliser. Chlorine is one of the fastest killers of RO membranes, so flushing keeps the elements protected whenever the system starts or stops.
Whenever the differential pressure between the SW Feed and SWRO gauges exceeds 1 bar. Backwashing is done one tank at a time — FT-2 keeps filtering while FT-1 is cleaned, and vice versa — using the backwash pump selected from the control panel.
A conductivity sensor monitors the permeate continuously. The HMI raises a warning at 850 µS and trips the system at 900 µS, so off-spec water never reaches the product line. A sampling point lets operators verify quality manually at any time.
Two dosing chemicals and two media: SMBS chlorine neutraliser (mixed 5 g per 100 L of permeate), antiscalant (1:9 — 10 L chemical to 90 L permeate), plus calcite and gravel in the remineralisation tank (2 bags of each).
480 VAC three-phase, 60 Hz incoming supply, verified across each phase at start-up, with 24 V AC and 230 V AC control circuits indicated by lamps on the panel.
In broad terms, about 40% of the feed seawater is recovered as freshwater and the remaining 60% is rejected as concentrated brine. The RO45 draws roughly 115 m³/day of seawater to produce its 45 m³/day of permeate.
They share the same engineering platform and materials; the RO82 is simply sized for higher demand — 82 m³/day (515 bbl/day) versus the RO45's 45 m³/day (283 bbl/day), drawing about 210 m³/day of seawater. Both are optimally sized for an offshore rig, and both can be custom-built for a specific location's salinity and temperature.
Yes. Our commissioning engineers are fully T-BOISET trained and carry out final set-up and commissioning on the rig — in dock or operational. We hold critical spares in our Dubai warehouse and can attend at short notice, and we recommend keeping user-serviceable spares on the rig.
No — the start-up is a five-step sequence: isolator on, 20-second initialisation, automatic 5-minute flush, production start, then slow pressurisation via the brine control valve to ±57.9 bar. The PLC handles valve sequencing and dosing automatically. Daly Middle East provides operator training with every system.
Tell us your feed water source, daily demand and site conditions. Our water treatment team in Dubai will configure the right SWRO package — with commissioning, training and GCC-wide after-sales support included.
