Any reverse osmosis operation must pay close attention to the pretreatment equipment's design to be successful.

The differential pressure, normalized permeate flow, percent rejection, and pressure drop coefficient are the five most crucial variables that need to be checked daily. They show the likelihood of fouling and the severity of fouling and/or scaling, which are the two main reasons for replacing membrane elements too soon.

What are the 5 key performance indicators of an industrial RO plant?

1. Silt Density Index (SDI)

The feedwater's suspended and colloidal particles are measured on-site using the SDI. It is employed to keep track of how well the pretreatment machinery is working. Pre- and post-multimedia filters, carbon filters, and post-cartridge filters should all be used when measuring SDI.

In order to give an SDI of less than 3.0 before employing the membranes, pretreatment should be efficiently regulated using the designed flow rates and differential pressure limitations for backwashing the equipment prior to the RO and replacement of the cartridge filters. Prior to multimedia filtration, SDI can be reduced with the help of filter aids, increasing filter effectiveness. Professionals should use caution while using cationic filter aids, though.

2. Reverse osmosis system pressure drop

Water is forced across the membrane surfaces of all the elements by the pressure differential between the concentrate stream pressure coming off the tail end elements and the intake to the initial membrane elements. The pressure drop or hydraulic differential pressure is used to describe this.

3. Normalized permeate flow

One of the most sensitive indicators of trouble in a RO system is normalized permeate flow. The permeate flow rate can be lowered by fouling. However, it is insufficient to measure the permeate flow rate alone because it depends on the feedwater temperature, feedwater conductivity, feed pressure, and permeate pressure (total dissolved solids, or TDS).

4. Percent rejection

Monitoring the permeate TDS is done using percent rejection. Since dissolved salts are removed by RO systems, monitoring salt (ion) rejection is a direct indicator of performance. The amount of TDS from the feedwater that has been eliminated in the permeate water is known as salt rejection.

The simplest technique to track salt rejection is to measure the conductivity of the feedwater and permeate water because many facilities don't monitor TDS. The percentage of TDS (conductivity) that the RO rejects is referred to as percent rejection. Percent rejection typically drops when the RO membranes are having problems, which means the permeate conductivity starts to rise.

5. Monitoring PDC

The majority of reverse osmosis plant operations track data from those processes. The performance of the unit can be trended using this data. The Pressure Drop Coefficient (PDC) versus P is one of the better methods for trending the data because, when PDC is normalized:

It is widely acknowledged as a best practice in the reverse osmosis sector for determining when to clean:

•       The normalized permeate flow decreases by 10%

•       A 5–10% increase in salt passage

•       A 10 to 15% increase in pressure drop

•       PDC rises by 10 to 15%

PDC is better suited to serve as the decisive factor in clean-on-place (CIP) operations since it is more sensitive to changes. Choose one of these requirements and adhere to it strictly. Waiting causes the foulant to be pushed further into the membrane, making it more difficult to clean.

How can we help?

Netsol customizes each system to match the needs of the customer, and each unit is produced to order.

Are you still unsure whether reverse osmosis is the best solution for your industry? The first step is to assess how much water you require and the quality of your raw water. We provide a free water analysis test to help you with this procedure. Please contact us as soon as possible to make arrangements.

Please contact us at +91-9650608473 or enquiry@netsolwater.com for further information or to make a purchase.