Equipment offers low profile, easy installation
Severn Trent Services was awarded a contract to supply its TETRA LP Block filter underdrain system  for the City of Kansas City, Mo., Water Services Department’s primary water treatment plant—a 240 million gal per day plant located along the Missouri River. The project’s engineer, Black & Veatch, specified the equipment. The contract called for the installation of 24 14-ft-by-50-ft filter cells covering a surface area of 16,800 square feet. In addition, Severn Trent provided new stainless steel backwash air headers for the filter in order to simultaneously backwash with air and water. The 10-in.-diameter air headers were uniquely designed to fit under the floor of the filters with J-Risers to bring air through holes in the concrete floors to the underdrain.
Joe Bonazza, filtration director for Severn Trent Services, said, “The TETRA LP Block is an excellent product within the water industry due to its low profile, low head loss, lightweight construction and easy installation. The TETRA LP Block is easy to assemble, has exceptional installation strength and a maintenance-free life.”
The TETRA LP Block is a dual parallel lateral underdrain system constructed from HDPE molded plastic blocks that provide effective distribution of both air and water for either concurrent or sequential backwashing. The system’s lightweight construction and easy assembly and installation make it ideal for both new and retrofit filter underdrain applications. Its nozzleless design ensures there are no blockages that could potentially affect filter performance.
TETRA underdrain filters feature the patented Grout Grip design, which increases resistance to uplift from the filter floor and offers twice the pullout strength of a conventional underdrain filter block. The wide, low-profile design requires fewer blocks to be installed to cover a filter floor, so fewer joints and less grout are needed.