Agenda - Council - 04/13/2021 - Laserfiche WebLink

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Riverstone South EAW January 2021 b. Describe effects from project activities on water resources and measures to minimize or mitigate the effects in Item b. i. through Item b. iv. below. i. Wastewater - For each of the following, describe the sources, quantities and composition of all sanitary, municipal/domestic and industrial wastewater produced or treated at the site. 1) If the wastewater discharge is to a publicly owned treatment facility, identi any pretreatment measures and the ability of the facility to handle the added water and waste loadings, including any effects on, or required expansion of municipal wastewater infrastructure. The project is expected to produce normal domestic wastewater that is typical of residential developments. The project will not include industrial wastewater production or onsite wastewater treatment. Sanitary wastewater production for the project was estimated using methods described in the Sewer Availability Charge (SAC) Procedure Manual (Metropolitan Council 2017). Metropolitan Council has established 274 gallons per day (GPD) as the average daily wastewater production from a typical residential unit. Based on this residential equivalent, the project is expected to generate an average flow of 66,582 gallons of wastewater per day. Sanitary sewer will be extended from Riverdale Drive to serve the development area. The project will be served by a sanitary sewer lift station that will be installed along Pearson Boulevard in the southeastern part of the site. This lift station will also serve future residential development east of the site and future commercial development north of the site. In addition, the City is looking at scenarios that may use the lift station to serve existing single- family homes located south and west of the project at some point in the future. Domestic wastewater from the project will be routed through the City of Ramsey sanitary sewer system and ultimately to the Metropolitan Wastewater Treatment Plant (MWWTP) located on the Mississippi River near Pig's Eye Lake in St. Paul. With the capacity to treat 251 million gallons of wastewater per day (MGD), this is the largest wastewater treatment facility in Minnesota. The MWWTP is owned and operated by Metropolitan Council. The Metropolitan Council's 2040 Water Resources Policy Plan includes a specific plan to serve the region's projected growth through 2040 and a general plan to serve the region's growth far beyond 2040. The City of Ramsey and Metropolitan Council have planned for increased capacity to convey and treat sanitary wastewater. The proposed project is not expected to require expansion of wastewater treatment infrastructure or raise wastewater treatment capacity concerns. 2) If the wastewater discharge is to a subsurface sewage treatment systems (SSTS), describe the system used, the design flow, and suitability of site conditions for such a system. Wastewater will not be discharged to subsurface sewage treatment systems. 3) If the wastewater discharge is to surface water, identify the wastewater treatment methods and identify discharge points and proposed effluent limitations to mitigate impacts. Discuss any effects to surface or groundwater from wastewater discharges. Wastewater will be treated in the MWWTP described above and then discharged to the Mississippi River. The MWWTP is an advanced secondary wastewater treatment plant located on the east bank of the Mississippi River, approximately three miles south of downtown St. Paul. Treatment 13