Tampa Electric applied Feb. 2 with the Florida Public Service Commission for approval of the company’s proposed Big Bend plant effluent limitations guidelines compliance study for cost recovery through the commission-administered Environmental Cost Recovery Clause.
On Nov. 3, 2015, the U.S. Environmental Protection Agency published the final Steam Electric Power Generating Effluent Limitations Guidelines (ELG) in the Federal Register. The effective date of the rule is Jan. 4, 2016. The ELG establish limits for wastewater discharges from flue gas desulfurization (FGD) processes, fly ash and bottom ash transport water, leachate from ponds and landfills containing coal combustion residuals (CCR), gasification processes, and flue gas mercury controls. The final rule requires compliance as soon as possible after Nov. 1, 2018, and no later than Dec. 31, 2023.
Since these limitations will be incorporated in National Pollutant Discharge Elimination System (NPDES) water permits, the exact compliance date will be determined through discussions with the Florida Department of Environmental Protection (FDEP), whom EPA has delegated to administer these permits, Tampa Electric noted.
Tampa Electric facilities located at the company’s Big Bend Station are affected by the ELG. Big Bend Station operates four coal-fired units equipped with electrostatic precipitators, Selective Catalytic Reduction (SCR) and Limestone Forced Oxidized (LSFO) Flue Gas Desulfurization (FGD) systems.
The FGD system is designed to operate at a chloride concentration of no more than 30,000 ppm chlorides. Chloride control is obtained by blowing down the FGD system at approximately 200 gpm. This blow-down stream is sent to a physical chemical treatment system to remove solids, some metals, ammonia and adjust pH prior to discharge to Tampa Bay via the once-through condenser cooling system water. This treatment system will need to be modified or replaced in order to achieve compliance with the new EPA regulations.
Other ELG waste stream categories present at Big Bend Station are bottom and fly ash transport water, which will be used for FGD scrubber make-up water, as allowed by the ELG. There are no other facilities at Big Bend Station affected by the ELG. The company is proposing the Big Bend ELG study program to determine the most appropriate ELG compliance measures for that station.
Tampa Electric facilities located at the company’s Polk Station may be affected by the ELG. There is a coal/petcoke gasification unit at this mostly natural gas-fired plant. Tampa Electric is evaluating the ability of the station’s existing treatment systems to meet the ELG’s new limits for gasification wastewater and CCR leachate. Depending on the results of this evaluation, Tampa Electric may need to hire an engineering consultant to complete a Polk Station ELG study at a later time. The company will file a separate petition requesting approval for a Polk Station ELG study and associated cost recovery through the environmental cost recovery clause (ECRC), if it is needed.
The company said it will hire an experienced engineering consulting firm to perform a Big Bend ELG study, to be conducted during 2016 and 2017, concluding with a determination of the most appropriate ELG compliance measures. This petition seeks approval of the company’s proposed Big Bend ELG study program and associated cost recovery through the ECRC. The measures selected in order to achieve ELG compliance at Big Bend Station will be the subject of a follow-up petition after completion of the Big Bend study and selection of the various compliance measures.
Tampa Electric intends to contract for a two-phase study. Phase I of the study will concentrate on effluent data analysis, identification of all potential options and screening of said options. Phase II will encompass Front End Engineering and Design (FEED) of the preferred option. The treatment technologies to be considered will include at a minimum, on-site deep well injection, evaporation processes, biological treatment processes and hybrid Zero Valance Iron (ZVI) processes.