Desalination (Seawater RO)
When the only source is salt — and tankering is not an option.
The technology explained.
Seawater desalination is reverse osmosis sized for very high feed-water salinity. Pre-treated seawater (typically ~35 000 mg/L TDS) is pumped at 55–80 bar across high-rejection thin-film composite membranes; permeate passes through, the concentrate is depressurised through an energy-recovery device (ERD) that returns most of its pressure energy back into the feed pump.
- Rejects 99.4–99.8% of dissolved salts from seawater feeds.
- Delivers potable-grade permeate (TDS typically <500 mg/L) ready for re-mineralisation and distribution.
- Energy-recovery devices recover up to 60% of the feed-pump energy from the concentrate stream.
- Designed for continuous duty in marine bio-fouling and high-chloride conditions.
- Coastal lodges and resorts with no usable freshwater source.
- Island and offshore installations dependent on the sea for supply.
- Coastal industrial sites where rainwater alone cannot cover demand peaks.
- Marine vessels and offshore platforms.
- ×Wrong tool for low-TDS brackish water — over-pressurised and over-spent.
- ×Energy cost is substantial — 2.5–4.0 kWh/m³ even with modern ERDs; project economics require honest modelling.
- ×Concentrate disposal back to the marine environment needs an environmental authorisation and diffuser design.
- ×Marine bio-fouling demands rigorous pre-treatment — UF and dosing chemistry that cost more than brackish systems.
Where Desalination is used.
- Coastal town and lodge supply
- Island resort water security
- Marine vessel and offshore platforms
- Industrial coastal sites
How HidroVerse deploys Desalination.
Desalination is the answer when the only available source is salt. We deploy it on coastal lodges, island resorts and remote marine sites where tankering is the alternative. Pre-treatment (UF, dosing), the high-pressure stage, the ERD selection and the marine concentrate diffuser are designed as one integrated package, not bought from separate suppliers.
A typical Desalination treatment chain.
Seawater desalination is a high-engineered package — intake, pre-treatment, RO core, ERD, post-treatment and concentrate disposal are designed as one system.
Pre-treatment
Coastal intake (beach well, open sea or HDD), chlorination, coagulation, multi-media or UF to bring SDI₁₅ below 5 on the membrane feed.
Core stage
High-pressure (55–80 bar) seawater RO with high-rejection thin-film membranes; energy-recovery devices on the concentrate side; chlorine removal upstream of the membrane.
Post-treatment
Re-mineralisation (calcite or dolomite contactor) to lift hardness and stabilise pH; UV disinfection; chlorine residual for distribution.
Waste handling
Concentrate diffuser discharge under marine environmental authorisation, designed to dilute brine in the receiving water within a defined zone of impact.
Buyer's guide.
The questions every commercial buyer should put on the table before signing for a water system. Can't see yours? Send us a brief — a HidroVerse specialist replies within one business day.
Yes — we keep a current reference list organised by application and scale. After a short qualifying call we release names, contacts and (with the host's permission) site-visit options. The conversation between two operations managers is the most honest reference we can offer; we do not gate-keep it.
We start with a SANAS-accredited feed-water panel, profile your demand against verified occupancy or production data (not brochure numbers), and specify against the worst-credible feed and peak demand — with disclosed margins. If a simpler technology will hit the brief, we'll specify the simpler technology and tell you why. We do not earn more by over-spending you; we earn more by you renewing service contracts year after year.
PFD, P&IDs, sizing calculations against verified influent data, equipment schedules with serial numbers, control philosophy, pre-treatment justification, waste-handling and regulatory compliance trail. Audit-ready by an external ECSA-registered engineer is the standard we design to — not a brochure pack with marketing fluff.
Pre-treatment is technology-specific (sediment, hardness, chlorine, biological load) and non-optional. Skipping it is the single largest cause of premature failure on every membrane, media bed and disinfection stage. Watch for suppliers quoting only the core stage — they are selling you a 12-month problem.
Every consumable and major component has a quantified replacement trigger (differential pressure, flow drop, UV intensity drop, salt-passage drift). Replacement schedules and trigger limits are written into the HidroVerse Care contract — visible, auditable and triggered on monitoring data, not guesswork.
Critical components are specified with duty/standby and automatic fail-over so a single failure does not stop supply. Our SLA on critical lines is 4 hours on site; the median lived response over the last 14 months is 2 hours 40 minutes. Telemetry triggers tickets before the operator notices — most failures are flagged, not phoned in.
Continuous telemetry on flow, pressure, conductivity, turbidity and on-skid water quality. Monthly SANAS-accredited compliance sampling is included on HidroVerse Care — not invoiced piecemeal. The audit pack builds itself monthly so when DWS or your insurer arrives, the file is ready in 30 minutes.
Potable applications: SANS 241:2015 (mandatory under the Water Services Act 108 of 1997), the National Water Act 36 of 1998 for abstraction and discharge, NSF/ANSI component certification, WHO Guidelines for design margin. Wastewater: the relevant DWS discharge authorisation under General Authorisation 665 or a site-specific Water Use Licence. We sign off against the legal floor and design to a margin above it.
Survey 1–2 weeks, design 2–4 weeks, install 4–10 weeks, commissioning and proof of compliance 1–2 weeks — typically 8–14 weeks for a lodge or estate, longer for mining and municipal. Delays come from civil works, third-party council approvals and architectural changes; the engineered scope rarely slips.
Survey, lab analysis, design pack, equipment, install, commissioning, operator training, the first year of monthly compliance sampling and the agreed scope of HidroVerse Care. Civils, electrical reticulation, third-party council fees and any architectural integration work are quoted separately and scheduled into the contract. If your quote has 'allowances' and 'provisional sums' across the page, you are buying a future invoice.