As part of a major upgrade, we were approached to design a fresh water generation system capable of producing 35 m³/d (1.46 m³/h) to replace the existing RO plants on-board. The criteria was to design and manufacture a pair of duty/standby RO plants with a 40% higher output and incorporating seawater carbon filtration (as the seawater intake is treated with chlorine from an electrochlorinator).The equipment had to fit into the same space envelope as the outgoing equipment.
In order to increase the plant capacity, we did not include a CIP system (as this accounts for 20% of the plants piping, valves and instrumentation). This removed the possibility of an RO permeate shutdown rinse, however, we included an automatic 24 hour flush using fresh water, dechlorinated via the carbon filter. It has been historically proven that this methodology has increased RO membrane life as well as simplifying operational routines.
In order to simplify things when it came to maintenance, some parts of the plant were also made to be removable.
The design was developed and a prototype manufactured to demonstrate to the customer that the plant will perform as required. The testing of the prototype was successful and we were awarded a contract to supply 16 identical RO plants.