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Mr. Michael Grochala April 8, 2020 Page 2 K:\015144-000\Admin\Docs\AUAR - Update 2020\Water Wastewater\MEMO - 040820 - Wastewater.docx Existing Conditions Within the City of Lino Lakes, there are approximately 5,200 connections to the municipal sanitary sewer system. Of the 5,200 connections to the public sanitary sewer system, most are single family residential with some multi-family residential, commercial/ industrial, and institutional connections. The City has approximately 1,705 properties that are served by on-site septic systems. Based on Metropolitan Council Environmental Services (MCES) meter data from 2014 - 2018, the City’s existing average daily wastewater flow is 1.04 million gallons per day (MGD). Since the wastewater generated within the City of Lino Lakes is primarily from residential units, the wastewater characteristics are assumed to be of typical domestic strength. Table 1 is a summary of the estimated existing wastewater characteristics for Lino Lakes. Table 1. Estimated Existing Wastewater Characteristics and Total Average Loading Parameter Concentration (mg/L) Average Load (lbs/day) Biochemical Oxygen Demand 220 1,909 Total Suspended Solids 220 1,909 Ammonia – Nitrogen 25 217 Total Phosphorous 8 69 Wastewater generated within the City is collected by a series of laterals, trunk sewer mains, and lift stations and is then directed to one of three interceptor sewers that are owned, operated, and maintained by MCES (Interceptors 9106, 8361, and 9708). Wastewater is then conveyed through the MCES regional collection system to the Metropolitan WWTP. The Metropolitan WWTP has a design capacity of 314 MGD and currently receives an average daily flow of 191 MGD. Proposed Conditions Three possible development scenarios were considered. The 2040 Comprehensive Plan corresponds to revised Scenario 1. Scenario 2 has also been revised. The third scenario considered is the 2030 Comprehensive Plan Scenario. The projected wastewater flow for each scenario is based on the planned land uses as described below. The municipal collection system currently extends to Main Street on either side of I-35E. The municipal trunk sewers will continue to be extended as development progresses. As detailed in the 2040 Comprehensive Sanitary Sewer Plan, development within Sanitary Sewer District 3 and 5 will require at least one large regional lift station and several smaller lift stations. The majority of the wastewater generated within the study area will discharge to MCES Interceptor 802325 which is currently stubbed at the City boundary at the intersection of Main Street and Elmcrest Avenue. The remainder will discharge to MCES Interceptor 7651 which currently serves the existing Sanitary Sewer District 3. All of the flow generated within the study area will be conveyed through the MCES regional collection system to the Metropolita n WWTP. 2020 Scenario 1 The proposed development within the study area for revised Scenario 1, the assumed wastewater flow for each land use type, and the projected wastewater flow for that development are summarized in Table 2. There are a number of properties within the southern portion of the study area that are already sewered, so these areas have been removed from the areas listed in Table 2.