Plastic Wheeler Bottom Inserts (PWI) provide the ability to construct or rehabilitate precast and Monolithic Wheeler Bottoms with ease, efficiency and cost effectiveness. 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. PWIs were installed in Plainfield, Michigan because of the need to treat the emerging contaminant in drinking water, PFAS. To achieve this goal, activated carbon was engaged, while traditionally, Wheeler Bottom underdrains require support gravel to operate, the height of the support gravel limited the amount of activated carbon the City could use in their treatment process. The media retaining PWI HDPE deck completely replaces the support gravel layer, allowing the City to add activated carbon to the PFAS treatment process in the existing footprint. The Roberts PWI allowed the City to utilize it's existing infrastructure to treat and remove PFAS without adding additional treatment units.
“We have used Roberts Filter Bottom Inserts over the last two years to facilitate a change of filter media from traditional sand and gravel filters to activated carbon. This was done to eliminate PFAS substances from our drinking water. So far we have changed 6 filter beds to the Roberts inserts. We will be doing the same for two more filters in the spring of 2021, supplying us with a total of 8 MGD of carbon filtration….The Roberts Inserts enabled us to provide a thicker bed of activated carbon to meet the contact time requirements to remove PFAS compounds. The inserts were applied to the old Wheeler filter bottoms. Roberts conducted the project seamlessly and on time. They removed and disposed of the old sand, gravel and anthracite, and Calgon supplied the Activated Carbon. This project garnered much notoriety in the State of Michigan and indeed across the United States, as this was not a typical application of carbon (the governor of Michigan even visited to see the project). Activated Carbon is usually placed in pressurized tanks in a tank farm. The project was much more economical than the tank farm solution, and it could not have been accomplished without the Roberts Inserts to support the activated carbon vs. the Wheeler bottoms, which would pass the carbon through.” - Donald Petrovich, Plainfield Water Treatment Superintendent
To learn more about where Plainfield water comes from and how it’s treated, take a virtual tour of the Plainfield, Michigan water department: https://www.youtube.com/watch?v=ZaXHYpbUbFk