Plant Startup - Following the correct start-up procedure is an important operational part of any reverse osmosis system. Prior to system start-up it is important to verify that all pretreatment systems are working according to their specifications. It may also be necessary to take water samples for analysis to confirm this.

Water quality

In the case of polyamide (thin film composite) membranes the free chlorine levels must be 0.0 ppm. The Silt Density Index (SDI) should be according to the plant system design guidelines, which are typically < 5.0.

If the water analysis (ions, temperature, pH) has changed significantly, it is strongly recommended that you run a new scale projection analysis. This scale projection can be carried out using our ROCsoft software calculator.

Start-up procedures

On start-up, the inlet valve should open prior to the initiation of the high-pressure pump, to completely fill the system with low pressure water (<100 psi [< 7 Bars]). This "soft start" is important as it will prevent hydraulic shock at start-up. Pre-treatment chemical addition should also begin at this time (making sure the chemicals are not over-injected). The high-pressure pump should then be started and the system slowly bought on-line, up to the recommended design permeate flow.

If starting-up the reverse osmosis system after a period of shutdown, you should flush the permeate to drain for at least 30 minutes to ensure the removal of any residual preservation chemicals. Produced water permeate can be used when it meets the quality requirement of downstream processes.

Technical support and advice

Reverse Osmosis Chemicals International work closely with a diverse range of global organisations, intelligently combining advanced treatment technologies with practical solutions to resolve complex issues. If you have a project you would like to discuss, or you require technical support and assistance; or if you simply have a question about our reverse osmosis technology solutions please contact one of our specialist advisors using our Technical Support page or call us on +44 (0) 330 223 31 31.