City of Franklin, TN
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Project Updates
The Water Reclamation Facility Upgrades & Expansion project began in November 2018 to upgrade the facility from its current capacity of 12 million gallons per day to a capacity of 16 million gallons per day. The project was awarded at $132,890,000 to Kiewit Infrastructure South Company. The project consisted of a new headworks facility to screen debris out of the wastewater stream for downstream equipment, new phosphorus removal capabilities, a new and more efficient ultraviolet light disinfection system, and a 10-million-gallon equalization basin to store additional wastewater flow during storm events. The Project also included new and more efficient ways of processing biosolids to promote the beneficial use of the end product. Through the innovative thermal hydrolysis process, bacteria and pathogens are reduced through the injection of steam at high temperatures in pressurized reactors. The cells lyse, or disintegrate, and harmful pathogens and bacteria are removed before being sent to the digesters. On their way to the digesters, the heated sludge is used to heat water that is used in the digesters, reducing the amount of energy needed to heat the digesters. In the digesters, the sludge is fermented and produces methane gas, which is harvested and used in our combined heat and power engine to produce electricity that will be put back into the facility grid. This production of electricity reduced the overall electrical consumption of the solids process, reducing the amount of fossil-fuel generated electricity and replacing with a sustainably derived source.
The end product, called biosolids, has received a Class A certification from the Tennessee Department of Environment and Conservation, indicating they are of the highest quality fertilizer that can be produced from wastewater. This certification will allow them to be used as a compost and soil amendment.
Historical updates