Design-Build of Wastewater Treatment Plant Sludge Thickening and Dewatering Buildings

In 2013, the Board of Miami-Dade County Commissioners approved a Consent Decree (CD) that had been negotiated with the United States Environmental Protection Agency (EPA), the United States Department of Justice (DOJ) and the State of Florida Department of Environmental Protection (FDEP). Consent Decree activities to be undertaken are intended to reduce exceedances of treated effluent permit limitations. One key project under the CD is the design of the sludge thickening and dewatering buildings at the Central District WWTP (CDWWTP) and at the South District WWTP (SDWWTP).  The CDWWTP is rated for 143 mgd AADF and the CDWWTP Thickening and Dewatering Building must be designed to handle 502,516 lbs/day during maximum weekly average condition.  The SDWWTP is rated for 112.5 mgd and the SDWWTP Thickening and Dewatering Building must be designed to handle 175,267 lbs/day during maximum weekly average condition.

Carollo is the lead design engineer for this ongoing $185 million design-build project that will deliver a total of 256 dry tons per day of biosolids thickening and dewatering capacity for the Central District Wastewater Treatment Plant (CDWWTP) and South District Wastewater Treatment Plant (SDWWTP). Both sites include combined sludge thickening and dewatering buildings to house sludge thickening systems, and digested sludge dewatering systems. Support systems for each site include thickening and dewatering dry polymer feed and storage, polymer delivery systems, dewatered cake pumping and storage, cake conveyance, thickened waste activated sludge pumping, thickening and dewatering centrate pumping, monorails, bridge crane, and truck loadout facilities for dewatered cake. The resilient designs address stormwater management, sea level rise, and storm surge. The electrical systems incorporate new transformers, switchgears and motor control centers, all in climate-controlled spaces.