Saving Costs on Reverse Osmosis Systems



Waco Filters partnered with a large chemical manufacturer to address issues with their reverse osmosis system. The manufacturer extracts inorganic chemicals from various sources, relying on deionized water for extraction. Waco Filters identified a problem with prefiltration in the water system, causing frequent fouling and clogging of expensive reverse osmosis membranes. To resolve this issue, Waco Filters proposed an alternative solution that protected the membranes and improved operational efficiency, resulting in cost savings for the chemical manufacturer.

The Challenge

The chemical manufacturer faced ongoing fouling and clogging of their reverse osmosis membranes without understanding the cause, leading to significant costs in terms of shutdowns or bringing in mobile DI water systems. Seeking assistance, the plant contacted Waco Filters, who conducted a thorough process audit. The audit revealed that inconsistent incoming water and suboptimal prefiltration were the issues. To ensure efficient reverse osmosis membrane performance, it was essential to maintain a silt density index (SDI) of less than 3. Fluctuations in water pressure and dirtiness caused system pulsation, resulting in the contraction and expansion of string-wound prefilters. This allowed bypass and significantly exceeded the SDI limit, leading to reverse osmosis issues.

The Solution

Waco Filters identified a superior prefiltration solution to address the challenges. They recommended using Global Filter’s PP-Series pleated polypropylene filter as a replacement for the string-wound filter. The PP-Series cartridge featured pleated filter media, offering higher capture efficiency and increased surface area compared to the string-wound alternative. The trial’s primary goal was to assess whether the new filter could prevent bypass during system pulsation and maintain an SDI of 3 or less. By achieving this, the membranes would be protected from fouling and clogging, resulting in significant cost savings for the chemical plant.

The Result

The trial yielded excellent results, prompting the chemical manufacturer to adopt Global Filter’s pleated polypropylene filter cartridge (PP-Series). The new filter effectively prevented bypass and maintained an SDI of less than 3, safeguarding the reverse osmosis system from membrane fouling and frequent clogging. The increased surface area and higher capture efficiency of the PP-Series also extended the service life of the prefiltration step, reducing the frequency of changeouts for both the RO membranes and prefilters. Waco Filters proactively stocked the PP-Series filters due to the potential for immediate changeouts in the event of water-related issues. Overall, the change resulted in reduced downtime, minimized maintenance, and eliminated the need to incur expenses for mobile DI water systems. The documented cost savings from this change amounted to approximately $65,000 in the first year and continued savings year over year.