Miami-Dade Selects Severn Trent Technology

The Miami-Dade Water and Sewer Department's South District Wastewater Treatment Plant has selected Severn Trent Services' TETRA® DeepBed™ filtration technology as part of a high-level disinfection project that expands the plant's capacity by 60 million gallons per day (mgd) up to 142 mgd and is the precursor to future wastewater reclamation.

As Miami-Dade County's population continues to increase, using reclaimed water enables the department to provide a sustainable water resource for its environment and its future.

The high-level disinfection project includes the construction of one of the largest deep bed sand filter systems in the United States. As the general contractor, Poole and Kent, a subsidiary of EMCOR Group, Inc., will oversee the construction of 30 TETRA DeepBed filter cells. The filters will employ a jacketed, concrete filter underdrain, which is designed to provide resistance to uplift during air and water backwash as well as superior resistance to live load.

The filters will have space for expansion up to 48 cells in the future and include the capability of denitrifying. Once in operation, these filters will provide effluent meeting Florida Department of Environmental Protection regulations of less than 5 parts per million total suspended solids. In the short term, the effluent from these filters will be pumped down a deep well. Long-term plans include using this quality effluent for irrigation and possible industrial reuse.

In 2006, an eight-month pilot study was conducted by design engineer Hazen & Sawyer in Hollywood, Fla., to evaluate several types of commercially available filter technologies. The firm concluded that TETRA DeepBed filter offered more reliability and flexibility. Severn Trent Services was represented by Moss-Kelley , Inc. on this project.

Once started, construction is expected to be completed in about five years.