Concrete Products

FEB 2019

Concrete Products covers the issues that attract producers of ready mixed and manufactured concrete focusing on equipment and material technology, market development and management topics.

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50 • February 2019 www.concreteproducts.com FEATURE PRECAST The California Water Resources Control Board recently certified the Jensen Deflective Sep- arator (JDS) as a Full Capture System Device for Trash Treatment Control. Certification of the technology from Sparks, Nev.-based Jensen Precast dovetails revised water qual- ity control plans—collectively known as the "Trash Amendments"—that the agency adopted in 2015 for drainage infrastructure serving public and private retrofit or new development projects. "Our stormwater customers in California will enjoy full compliance with all trash control stormwater regulations at both state and regional levels," says Jensen Precast Stormwater Systems Division Manager Walter Stein, P.E. "We are helping reduce and, in most cases, eliminate 100 percent of trash discharged from our stormwater drainage systems. We believe performance of the JDS System to capture trash is unmatched." Along with requirements to meet certifi- cation standards, Jensen Precast engineers provided additional JDS System research find- ings with their State Water Resources Control Board application, including results of: • Full scale and repeatable trash removal effi- ciency testing; • Full scale testing with materials smaller than the required 5-mm particles; and, • Scour testing verifying 100 percent retention of previously captured solids during flow bypass events. Stormwater treatment remains a key research and product development area for Jensen Precast, which continues to commit the necessary resources for system verifi- cation and performance tests. "No other technology being offered has verified the bypass retention efficiency," Stein affirms. "Once trash and debris go into a JDS System, they're not getting out until properly cleaned. Jensen Precast is an innovator in this area of stormwater treatment, providing a proven system superior to all others." ANSWERING EPA Full Capture System Device certification came on the heels of a successful JDS installation aimed at protecting southern California's 17,700-acre Los Cerritos Channel Freshwater Watershed. Through dry weather runoff and first flush stormwater flows, the urbanized, commercial, and industrial watershed was prone to eclipsing the U.S. Environmental Protection Agency total maximum daily load Trash Talk Jensen Precast system captures stormwater regulators' attention JDS Offline unit plus diversion structure with a high-flow bypass weir. (TMDL) limit for total suspended solids and several heavy metals. Seven cities in the watershed were bound by an EPA mandate to bring TSS and heavy metals below the TMDL levels. Bellflower, Cerritos, Downey, Lakewood, Long Beach, Paramount, and Signal Hill each needed a solution to manage and monitor water quality in their respective areas. Install- ing multiple stormwater treatment systems to eliminate the pollutants would be more costly and perhaps not as efficient as a single large diversion, treatment, and infiltration station on the Los Cerritos Channel—at the bottom of the entire watershed. The cities formed the Los Cerritos Chan- nel Watershed Group to streamline the infrastructure; instead of each addressing stormwater treatment individually, one large regional system would be built to collectively remove pollutants and curb costs. The Los Cerritos Channel Sub-Basin 4 Stormwater Capture Facility eliminates most polluted dry weather runoff while diverting, treating, and infiltrating first flush stormwater flows impacting the watershed. Jensen Precast engineers worked on the project with consulting firms Tetra Tech Inc., Long Beach, and GHD, San Diego, plus design-build contractor Mike Bubalo Construction Co., Baldwin Park, Calif. The producer designed, fabricated, and deliv- ered a flow splitting structure and dual JDS Hydrodynamic Separator units deployed inside two 16-ft. diameter precast concrete structures to capture suspended solids, trash and debris. The Los Cerritos Channel Sub-Ba- sin 4 Stormwater Capture Facility, notes Mike Bubalo Construction Vice President Dave Sorem, "Takes in 166 cubic feet per second through the transition structure, then into two hydrodynamic separators, then into an infiltration gallery. I don't know of any other system that could do that." "Our goal is to provide the best forward thinking solution for every customer every time," affirms Jensen Precast President Eric Jensen. "Certification of the JDS System is a great example. By streamlining state and regional compliance expectations, our engineering and contractor customers can complete their projects faster and more cost effectively."

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