Tarpon Springs, Florida Wastewater Treatment Plant
The Tarpon Springs wastewater treatment plant in Tarpon Springs, Florida, produces aerobically digested biosolids. For years, the biosolids were dewatered with two small belt presses. The presses were undersized, requiring almost continuous operation to keep up with the process. Due to the constant running time and age of the presses, frequent maintenance was required. Performance was also a problem; cake solids in the dewatered cake were low and filtrate quality was poor. Since disposal costs and plant flows were rising, the City began were looking for a new dewatering device that could provide better performance with reduced manpower and lower maintenance costs.
A better way to load the dewatered biosolids onto the haulage trucks was also needed. For many years, the solids from the belt presses were distributed onto the floor of a warehouse building, and then subsequently loaded onto the trucks with a small bucket loader. This process resulted in an odor problem and was maintenance intensive.
The City requested proposals for a dewatering and sludge conveyance system. The request was primarily written for a belt press, but a centrifuge was allowed as an alternate. USFilter reviewed the installation and determined that a decanter centrifuge would be an excellent choice and submitted a proposal for a complete system that included feed pumps, polymer system, and dewatered solids conveyors.
After careful review, the City decided that the USFilter decanter centrifuge would be the best solution for them. The system was compact, highly automated, provided the highest cake solids and was enclosed, minimizing odors and mist.
The selected decanter centrifuge was an 18″ diameter bowl machine with a hydraulic scroll drive to produce the highest cake solids. In addition to the decanter centrifuge, USFilter provided the polymer system, system control panel and dewatered solids conveyors. The conveyors were designed and built in the Holland, Michigan facility. All components of the system are controlled from the system control panel located in a nearby control room.
The trucks used to haul the dewatered solids are quite large with a long bed. The specifications required that the solids be distributed evenly in the truck bed with minimal operator attention. Two shaftless screw conveyors were provided to elevate and transport the solids. The horizontal distribution conveyor uses multiple slide gates to meet this requirement. The gates operate automatically to minimize operator attention and effort.
Since the building was not designed to support the conveyors, floor supports were needed. These were also provided by USFilter.
This project demonstrated the benefits to be gained by a single source of responsibility for equipment design and supply. The project was accomplished with a minimum of problems, was completed on time and within budget.
Langley Separation and Process can now offer service and support as well as supply complete systems like the one originally provided by USFilter for Tarpon Springs.