Utilizing Earth’s Saltwater through Reverse Osmosis


Most of the earth is covered in water.  Although it is mostly undrinkable, being lodged in seas and oceans, this water can be unlocked through reverse osmosis.

Saline or seawater can be converted into something that can be potable or even for agricultural or industrial use.  In this article, we feature another safe water solution: Reverse Osmosis systems or RO.

This solution is part of GiftingLife’s strategic and sustainable investment into solutions and technologies that actually help realize the UN Sustainable Development Goals, one of which is to achieve universal and equitable access to safe and affordable drinking water for all by 2030.

Purifying seawater

Water is definitely vital to life, for drinking and sanitation, as well as industrial purposes such as agriculture and manufacturing.  This is why technologies that harness seawater, the most abundant form of liquid water on earth, are much helpful to augment the world’s needs.  Based on estimates, seawater make up 97% of all the water on earth.  This is a lot, which before cannot be put to good use because of its high salt content.  Reverse osmosis technology has done a lot to purify and desalinate this water, the mechanism of which will be discussed in this blog.

Reverse Osmosis Technology

Reverse Osmosis, simply called as RO, is a water purification method that removes ions, molecules and other larger particles from water using a semipermeable membrane.  Desalination or removing salt from seawater is done by using reverse osmosis.

A solvent is forced into a region of low soluble concentration from a high solute concentration by applying pressure.  This solution passes through a semipermeable membrane and while it does, unwanted particles and molecules are removed.

Usually, a single-pass seawater RO system has the following:

  1. Intake –  A pump at the source of water to be purified.
  2. Pre-treatment – This stage involves removal of solids, sediments, carbonic acid from water, and dosing of oxidising biocodes to kill bacteria.
  3. High-pressure pump – This allows the water to pass through the membrane.  The pressure needed for seawater ranges from 800 to 1180 psi, and for brackish water, 225 to 376 psi.
  4. Membrane – There is a pressure vessel with a membrane, allowing feed water to be pressed against the membrane. RO system membranes are made in a range of configurations and the two most common are spiral-wound and hollow-fiber.
  5. Energy recovery – This is used to reduce energy consumption. 
  6. Remineralisation and pH adjustment – desalinated water needs to be stabilized to protect downstream pipelines and storage by adding lime or caustic soda which prevents corrosion.
  7. Disinfection – This secures secondary protection against downstream and membrane problems.

Hitachi Aqua-Tech Standardised RO Desalination Systems

One example of such technology is the Hitachi Aqua-tech Standardised RO Desalination Systems.  These systems are built into. brand new 20- and 40-foot containers that meet international quality standards, and can pump out at least 2,000 liters of water per hour.

In Sea Water RO systems, pressure is applied to the seawater, forcing fresh water through a semi-permeable membrane while most salts, bacteria, colloids and other impurities are rejected by the membrane.

How this technology can be used

RO systems are most efficient where ground or fresh water is not readily available but a supply of seawater is present.  Also, due to the amount of water and energy needed, it is also suitable where the demand of water is high. 

Do you know of any communities that can benefit from this innovation? Let us know!  We are excited to work with you in bringing sustainable development solutions.  To help achieve clean and safe drinking water for all, send us an email at [email protected].