Miami — Poole & Kent Company of Florida has been recognized for Design-Build Excellence by the DBIA Florida Region for improvements to the existing cogeneration facility at the South District Wastewater Treatment Plant (SDWTP) in Miami. The project was named the Best Overall in the Water/Wastewater category as part of the organization’s 2015 Design-Build Awards program.

“The South District Wastewater Treatment Plant project offered opportunities for Poole & Kent to increase value to the owner, given the existing cogeneration system hadn’t been upgraded since being built in 1991,” stated Patrick Carr, President & CEO, Poole & Kent Company of Florida.  “Significant technological advances have been made over the last 20 years in equipment used in cogeneration systems that improve efficiency and reliability. The improvements provided an opportunity for plant staff to be re-trained on the state-of-the-art technology that is safer and provides nearly three times more electrical generation capacity than the previous system.”

The project involved a comprehensive overhaul of the plant’s cogeneration system; Poole & Kent was responsible for design, permitting, and construction of four new 2,000 kw cogeneration units with infrastructure for a future, fifth unit. The project also entailed replacement of the digester and landfill gas conditioning systems, hot oil heat recovery system, integrating hot water system with an existing system, a new electrical room and ventilation system, a 100-ton non-electric absorption chiller, digester scrubbing system and siloxane removal system.  Poole & Kent provided programming for all the system controls and performed onsite training for staff at the plant.

The project was Miami-Dade Water and Sewer Department’s first design-build effort inside an operating wastewater treatment plant, demonstrating the value of employing design-build delivery. In addition to the aggressive implementation schedule, the project required the complete upgrade of an existing operational cogeneration system to increase its rated capacity by a factor of three without taking it out of service and without impacting the daily activities of plant staff.  

The plant is now one of the first cogeneration systems of its size to be capable of using three different types of fuel feedstocks (digester, landfill and natural). From a sustainability standpoint, the new plant includes two heat recovery systems that use the heat generated by the cogeneration engines to offset the use of electrical power. The captured heat is used for the digester water hot water loop and for an absorption chiller that produces sufficient chilled water to provide all of the required cooling for the cogeneration building and switchgear room. The expansion requires less electrical energy usage than the existing system while generating three times the amount of electricity.