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Home My Public Portal AboutExhibit MSD 83B- MSD's Supplemental Response to the Rate Commission's Sixth Discovery RequestExhibit MSD 83B BEFORE THE RATE COMMISSION OF THE METROPOLITAN ST. LOUIS SEWER DISTRICT MSD’S SUPPLEMENTAL RESPONSE TO THE SIXTH DISCOVERY REQUEST OF THE RATE COMMISSION ISSUE:2023 STORMWATER & WASTEWATER RATE CHANGE PROCEEDING WITNESS:METROPOLITAN ST. LOUIS SEWER DISTRICT SPONSORING PARTY:RATE COMMISSION DATE PREPARED:JULY 5, 2023 1 Exhibit MSD 83B BEFORE THE RATE COMMISSION OF THE METROPOLITAN ST. LOUIS SEWER DISTRICT For Consideration of a Stormwater & Wastewater Rate Change Proposal by the Rate Commission of the Metropolitan St. Louis Sewer District ) ) ) ) MSD’S SUPPLEMENTAL RESPONSE TO THE SIXTH DISCOVERY REQUEST OF THE RATE COMMISSION Pursuant to §§ 7.280 and 7.290 of the Charter Plan of the Metropolitan St. Louis Sewer District (the “Charter Plan”), Restated Operational Rule § 3(7) and Procedural Schedule §§ 16 and 17 of the Rate Commission of the Metropolitan St. Louis Sewer District (the “Rate Commission”), The Metropolitan St. Louis Sewer District (the “District”) hereby responds to the June 15, 2023 Sixth Discovery Request of the Rate Commission for additional information and answers regarding the Rate Change Proposal dated March 24, 2023 (the “Rate Change Proposal”). 2 Exhibit MSD 83B BEFORE THE RATE COMMISSION OF THE METROPOLITAN ST. LOUIS SEWER DISTRICT For Consideration of a Stormwater & ) Wastewater Rate Change Proposal ) by the Rate Commission of the ) Metropolitan St. Louis Sewer District ) MSB’S SUPPLEMENTAL RESPONSE TO THE SIXTH DISCOVERY REQUEST OF THE RATE COMMISSION Pursuant to §§ 7.280 and 7.290 of the Charter Plan of the Metropolitan St. Louis Sewer District (the “Charter Plan”), Restated Operational Rule § 3(7) and Procedural Schedule §§16 and 17 of the Rate Commission of the Metropolitan St. Louis Sewer District (the “Rate Commission”), the Rate Commission requests additional information and answers from the Metropolitan St. Louis Sewer District (the “District”) regarding the Rate Change Proposal dated March 24, 2023 (the “Rate Change Proposal”). The District is requested to amend or supplement the responses to this Discovery Request, if the District obtains information upon the basis of which (a) the District knows that a response was incorrect when made, or (b) the District knows that the response, though correct when made, is no longer correct. The following Discovery Requests are deemed continuing so as to require the District to serve timely supplemental answers if the District obtains further information pertinent thereto between the time the answers are served and the time of the Prehearing Conference. 3 Exhibit MSD 83B DISCOVERY REQUEST 8. In Ex. MSD 731, the cost of the Fluidized Bed Incinerator (“FBI”) project was estimated to be $477,300,000 in 2018. In Ex. MSD 73K, the estimated cost is listed as $951,200,000. Please explain the factors contributing to the increase in total project cost. How certain is the District that the current cost estimate will not increase further? RESPONSE: The hvo main factors that affected the increase in total project cost are (1) scope modifications to address production capacity and operational needs, and (2) inflationary impacts MSD staff has developed a comprehensive packet of information which supplements our prior response to this question (see Exhibit MSD 83B1 - MSB’s Supplemental Information Packet) MSD does not anticipate further cost increases in the project, barring unforeseen conditions or changes that are out of the control of MSD. 10. Please provide a layman’s summary of all sludge management options evaluated in Ex. MSD 73G (Tech Memo 3), along with a summary of why each solution was or was not selected. RESPONSE: Exhibit MSD 73G is a 530-page document with several technical memorandums addressing several areas At a high level, there are essentially three (3) approaches to treatment and disposal of biosolids: Anerobic digestion (to make fertilizer) with subsequent land application or landfilling, landfilling of raw solids, and incineration. MSD looked at various options for all of these and evaluated them across a triple bottom line matrix based on social, environmental, and economic factors MSD considered several versions of anaerobic digestion technologies to treat biosolids Anaerobic digestion is a biological process that works best with consistent feeds rates and fuel content For all of these, the variability in biosolids quantity and chemical makeup of the biosolids currently produced at the Bissell and Lemay plants would make treatment operations with digesters difficult. The chemical makeup of the biosohds that MSD must process at these two plants is significantly affected by the flow of the Mississippi River and grit and soil received in the combined sewer system. When the river is high, inflow from the river comes to the wastewater treatment plants impacting the variability in the biosolids This variability causes biosolids quantities to go up, and the amount of organic material (or fuel content) in the biosolids to go down. This impacts the key biological components of the digestion process. This was a major factor, among others, in MSD’s decision not to pursue this option Additionally, a more significant consideration, one that is not considered in Exhibit MSD 73G, is future regulation on disposal of biosolids containing Per- and Polyfluoroalkyl Substances (PFAS) The anaerobic digestion technology/ will not remove PFAS from biosohds, adding uncertainty to future disposal options. For example, regulatory requirements for using biosolids as a fertilizer and land application will soon be much more stringent due to changes that EP A is making to address PFAS 4 Exhibit MSD 83B MSD staff also considered biosolids landfilling but concluded that was not a good alternative MSD doesn’t own the land where an appropriately sized landfill could be located Assuming the land could be acquired, MSD would need to haul 40-60 trucks per day of raw solids MSD would be storing undigested and odorous solids for extended periods at the Bissell Point and Lemay plants Trucking raw solids also represents an odor and nuisance hazard Also, there is significant concerns about the long-term viability of landfilling raw solids due to future PFAS regulation The solution that the team selected was replacing the existing biosolids incineration equipment at Bissell Point and Lemay with fluidized bed incineration (FBI) facilities. These new facilities are designed to handle the variability in biosohds quantity and chemical makeup, without other facility changes Fluidized bed incineration is also a promising PFAS destruction technology Additionally, included emission control processes, like granular activated carbon, should remove PFAS fi-om the exhaust. Finally, MSD will be able to continue to dispose of ash in its existing landfill The FBI approach also scored highest in the TBL assessment. MSD staff has developed a comprehensive packet of information which supplements our prior response to this question (see Exhibit MSD 83B1 - MSD’s Supplemental Information Packet) 11. Kansas City’s sludge management solution is Thermal Hydrolysis. Did the District consider this technology? If so, what factors led the District to not select it? If not, why did the District not consider it? RESPONSE: Yes, the District considered the Thermal Hydrolysis Process, or THP THP is not a standalone treatment process, but rather a component of an anerobic digestion process. Several factors led MSD to not select anaerobic digestion, see 10 above Additionally, THP relies on high pressure steam reactors to help the anaerobic digestion process Not only is this operationally more complex, but inorganic grit and soil, major components of the low-volatile solids produced at Bissell Point and Lemay, can create hazardous safety issues in the THP’s high-pressure steam reactors The same hmitingfactors regarding PFAS and potential land application would apply to this process as well Different situations and problems require different solutions. We want to point out that other cities and sewer districts use fluidized bed incineration. For example, the only other comparatively sized wastewater treatment facility in the Mississippi River basin is m Minneapolis-St. Paul, MN, and that facility uses fluidized bed incineration And in the Kansas City area, both Little Blue Valley Sewer District and the City of Independence use fluidized bed incineration. MSD staff has developed a comprehensive packet of information which supplements our prior response to this question (see Exhibit MSD 83B1 - MSD’s Supplemental Information Packet) 12. Since the District selected the FBI technology for sludge handling, there have been developments such as federal incentives for energy recovery, potential regulation of PFAS, etc., that would have impacts on a sludge management program. Has the District conducted any recent 5 Exhibit MSD 83B Respectfully submitted, review of the selected technology and plan to confirm that the FBI solution remains the best alternative for the District, given the many technical, financial, and environmental considerations? MSD staff has developed a comprehensive packet of information which supplements our prior response to this question (see Exhibit MSD 83B1 - MSD’s Supplemental Information Packet). RESPONSE: Yes. The District has evaluated these additional developments and confirmed the FBI solution to be the best solution. Susan M. Myers ' Brian Stone THE METROPOLITAN ST. LOUIS SEWER DISTRICT 2350 Market Street St. Louis, Missouri 63103 Tel: (314) 768-6366 smyers@stlmsd.com bstone@stlmsd.com 6 Exhibit MSD 83B CERTIFICATE OF SERVICE The undersigned certifies that a copy of the foregoing was sent by electronic transmission to Lisa O. Stump and Brian J. Malone, Lashly & Baer, on this 5th day of July, 2023. Lisa O. Stump Lashly & Baer, P.C. 714 Locust Street St. Louis, Missouri 63101 lostump@lashlybaer.com Brian J. Malone Lashly & Baer, P.C. 714 Locust Street St. Louis, Missouri 63101 bmalone@lashlybaer.com Susan M.rsSusan M. Myers ' Brian Stone THE METROPOLITAN ST. LOUIS SEWER DISTRICT 2350 Market Street St. Louis, Missouri 63103 Tel: (314)768-6366 smyers@stlmsd.com bstone@stlmsd.com 7