Frequently Asked Questions

What is the Reverse Osmosis Process?

Osmosis is the natural diffusion of two mixable solutions through a semipermeable membrane resulting in the equalization of concentration between the two solutions. The solution with a lower concentration diffuses through the semipermeable membrane and into the solution with a higher concentration.

osmosis process

Figure 1: Naturally Occurring Osmosis

For the purposes of desalinating water, the sea water is a high concentration solution and the potable water is low concentration. Therefore, the sea water cannot naturally diffuse through a semipermeable membrane to create potable water.

To overcome this dilemma, the BWD system utilizes high pressure to cause reverse osmosis.

High pressure forces the high concentration solution (sea water) through the semipermeable membrane (RO Membrane) resulting in increased low concentration solution (potable water).

Reverse Osmosis Process

Figure 2: Reverse Osmosis Process

What size watermaker do I need?

There are several factors that will help determine the proper size system for your vessel.  These include your daily fresh water requirements, the size of your fresh water holding tank, the number of hours per day that you wish to run your system and the size of your generator.

Blue Water Desalination systems are available in capacities ranging from 200 gallons per day (GPD) to 1,850 GPD.  More importantly, this equates to between 8 gallons per hour (GPH) and 77 GPH since the systems are rated based on 24 hours per day of operation.  If your average daily requirement is 200 gallons per day and you wish to run your system for 5 hours each day, then you should target a system that produces approximately 40 GPH, which would equate to a system rated at 950 GPD.  If your requirements are 200 gallons per day and you want to run your system for 8 hours per day, you could utilize a system that produces 25 GPH or 600 GPD.

Be sure to check the system start amperage to ensure that your vessel’s generator can handle the electrical load.  Feel free to contact Blue Water Desalination or your local BWD dealer to discuss the proper system for your vessel.


What is a Fresh Water Flush?

The Fresh Water Flush (FWF) feature runs de-chlorinated fresh water through the system.  The sea water in the system is displaced with fresh water so that the internal parts of the watermaker are not left in contact with sea water for long periods of time which helps reduce biological growth in the membranes and prevent corrosion of the internal metallic components.

The FWF process begins automatically when the system is shut down.  It will continue to flush the system at regular intervals which can be programmed through the system controller.  The FWF uses fresh water from the vessel’s tank which is run through an activated carbon filter to remove any chlorine before being pumped through the watermaker.   All Blue Water Desalination systems come standard with a FWF system.