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XL-4040: Redefining Performance in 4" RO Membranes

Updated: Oct 3

ROTEK's XL-4040 is setting a new benchmark for performance and cost-effectiveness.

ROTEK present the highest output RO membrane XL4040
ROTEK presents the 5,000 GPD product water flow—the highest output currently available for a 4"x40" RO membrane.

Introduction

Reverse Osmosis (RO) membranes are the heart of every water purification system. While 8" elements have traditionally been the industry standard for high-flow applications, the demand for more compact yet powerful solutions has been growing. The XL-4040 membrane element represents a breakthrough in 4" RO technology by delivering an unprecedented 5,000 GPD product water flow—the highest output currently available for a 4"x40" RO membrane.


Innovative Design


The key to the XL-4040’s performance lies in its specially engineered feed spacer design. This unique construction allows more membrane flat sheets to be rolled into the same 4" standard diameter element without compromising efficiency or durability. By maximizing the active surface area, the XL-4040 achieves higher productivity than competing 4" membranes on the market.


Core Advantages

  • Largest Flow in Class – 5,000 GPD, surpassing typical 4"x40" membranes.

  • Optimized Feed Spacer – Special design enables greater membrane sheet packing density.

  • Compact Footprint – Achieves higher capacity within the same standard element size.

  • Versatile Application – Suitable for projects where system space and budget are critical.

ROTEK RO Membrane XL-4040 exceptional 5,000 GPD capacity

System Design Benefits


One of the greatest advantages of the XL-4040 is its ability to match the performance of an 8" membrane using only two 4" elements. For projects requiring more than 2 m³/hr of RO water, this can dramatically simplify system design. XL-4040 Datasheet


Cost-Saving Impact:

  • Reduced Capital Costs – Smaller pressure vessels, fewer pumps, and lower infrastructure requirements.

  • Flexible System Sizing – Ideal for projects that fall between small commercial and full-scale industrial capacities.

  • Operational Efficiency – High output with fewer elements reduces maintenance complexity.


Important Design Note


When designing systems with the XL-4040, it is critical to ensure sufficient feedwater supply. Always use a 3/4" feed port membrane housing to provide the necessary feed flow and maximize the element’s high-flow performance. Using a 1/2" feed connection may restrict flow and limit the membrane’s full potential.


Application Case


In a recent project requiring 2 m³/hr of RO product water, engineers were faced with the choice between adopting a full 8" membrane system or optimizing a 4" configuration. By selecting XL-4040 membranes, the system achieved the target flow at a significantly lower cost while maintaining a compact footprint. This design avoided the upfront investment in larger pressure vessels and pumping equipment, providing a faster return on investment for the client. About RXL Series

ROTEK RX-2T featuring the high-flow ROTEK XL4040 RO membrane.
ROTEK RXL-2T (2 m³/hr) featuring the high-flow ROTEK XL4040 RO membrane for cost-effective performance.
RXL RO System uses XL-4040 membrane instead of 8" membrane design
ROTEK RXL-6T (6 m³/hr)

Conclusion


The XL-4040 membrane sets a new benchmark for 4" RO technology. With its record-breaking 5,000 GPD capacity, enabled by advanced feed spacer design, it allows system designers to bridge the gap between commercial and industrial scale without the need to immediately transition to 8" membranes. For water treatment professionals seeking both performance and cost-efficiency, the XL-4040 is a compelling solution—provided system design incorporates proper feedwater connections to unleash its maximum potential.


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