How to Save $30 Million and Maximize Operations Efficiency for Wastewater Utilities: Consolidation Evaluation for the City of St. Petersburg

The City of St. Petersburg, Florida, owns and operates four water reclamation facilities. The existing Albert Whitted Water Reclamation Facility (AWWRF) is the smallest and oldest of the city’s four water reclamation facilities and was permitted to dispose of effluent in excess of reuse demands via their on-site Class V injection wells. Due to regulatory changes by the Environmental Protection Agency and Florida Department of Environmental Protection, the existing Class V injection wells were reclassified to Class I injection wells. Class I injection wells do not allow for the disposal of reject water via the wells and therefore, as a result of the reclassification of the injection wells, the city would be required to construct dedicated reject storage facilities.As an alternative to the additional costs that would be incurred to construct the new 26.5-million-liter (7.0-million-gallon) reject water storage tank, which would need to be located at a remote location, the city decided to investigate the feasibility for reducing their current water reclamation facilities from four to three. The city contracted with CDM Smith to evaluate alternatives to the continued operations and maintenance of the aging facility. The objective of the evaluation was to provide a present-worth analysis based on marginal cost for keeping AWWRF in service, versus two alternatives for flow diversion and treatment if the plant were taken out of service. The flow diversion alternatives included installing a master pump station in proximity to AWWRF and new force main(s) that would discharge to the other treatment facilities.This paper will provide an overview of the present worth analysis procedure, including the impact of variations on inflation rates and discount rates, results of the present worth analysis which lead to the final recommendation. Although a previous study to evaluate the feasibility for removing the AWWRF from service had been performed in 2002, this study showed a different outcome. Based on the outcome of this present worth analysis, which showed an opportunity to save $30 million, the city proceeded with a flow diversion and pipeline routing study and preliminary pump station design. Once the flow diversion and pipeline route were selected the project moved into full design and is now in construction with completion anticipated in the fall of 2014. In order to expedite the project and increase efficiency, the city took a unique approach in splitting the final design of the pump station and pipeline into five separate bid packages which were designed in parallel. Although this paper will focus on the present worth analysis, which was the driver for implementation of the project, it will also present some details of the project progress to date.