Plastic Wheeler Bottom Underdrain 

PWI™ 
Plastic Wheeler Bottom Underdrain

PWI™ is the ideal choice for new underdrain installations and wheeler bottom underdrain rehabilitations. PWI™ inserts eliminate the need for porcelain spheres and support gravel; increasing freeboard. PWI™ improves hydraulic distribution by emulating the porcelain spheres through an integrally molded distribution control plate. As an alternative to the graveless arrangement, Roberts' offers PWI™ with gravel support. PWI™ improves upon the Wheeler Bottom's longstanding reputation for strength and distribution.

Structurally Stable

Wheeler Bottom underdrains are the most reliable underdrains ever installed. Many of Roberts' existing installations have been in operation for over 60 years. Wheeler Bottoms are structurally stable and hydraulically balanced to assure many years of trouble-free operation. 

Eliminate Need for Porcelain Spheres and Support Gravel

The Roberts' plastic wheeler bottom underdrain has successfully improved upon the Wheeler bottom system by removing porcelain balls and gravel while further achieving greater free board with porous plate technology.  

Construct And Rehabilitate

With over 75 years of experience in the construction and rehabilitation of Monolithic and Precast Wheeler Bottoms, Roberts' construction crews install and rehab thousands of square feet of underdrains each year.

Cost Effective

The most cost effective means of gaining freeboard - Convert your existing Wheeler bottoms into a gravel-less configuration without costly filter demolition, substantial filter down time, and without compromising the structural and hydraulic characteristics of your treatment plant. 

Retroliner inserts eliminates the typical wear and tear caused by the rotation of porcelain distribution spheres; while still maintaining the integrity and performance of the Wheeler Bottom Underdrain. To learn more, click here. 

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