Trilateral® HDPE Underdrain
Reliable, Economical, and Proven Backwash Performance
The Trilateral® HDPE underdrain from Roberts Filter Group combines innovative hydraulic design with durable materials to deliver reliable backwash distribution at an affordable cost. Engineered with a triangular internal chamber, the Trilateral® HDPE ensures balanced flow of air and water during backwash cycles — improving cleaning efficiency and filter performance over the long term.
Why Choose the Trilateral® HDPE?
Balanced Backwash Distribution
The unique triangular chamber design optimizes air scour and water flow, preventing maldistribution that can lead to uneven cleaning and reduced filter effectiveness.
Proven Reliability
Reinforced porous plate construction and long-lasting HDPE materials provide consistent performance, even under variable flow rates and seasonal water conditions.
Economical Solution
With decades of design refinement, the Trilateral® HDPE is one of the industry’s most reliable and cost-effective underdrains, offering excellent performance without unnecessary complexity.
Field-Tested Confidence
Roberts simulates system hydraulics at our in-house testing facility, giving customers confidence in underdrain performance before installation.
Ideal Applications
- Municipal gravity filters
- Surface water treatment
- Pretreatment filter for membrane systems
- Industrial process water filtration
- Filter retrofits and replacements where cost-effectiveness is critical
- Tertiary Treatment Filters
Benefits at a Glance
- Balanced backwash air and water distribution
- Improved cleaning efficiency and media longevity
- Affordable, long-lasting construction
- Backed by Roberts’ 135+ years of filtration expertise
Lifecycle Support
As with all Roberts underdrain systems, the Trilateral® HDPE is supported by our full lifecycle services — including inspections, retrofits, media changeouts, and turnkey installation.
Looking for a reliable, economical underdrain solution?
The Trilateral® HDPE delivers proven performance, efficient backwash, and the confidence of Roberts Filter Group’s engineering expertise.
