Agenda - 02-04-2025; 5-a - Applications for Zoning Atlas Amendment, Comprehensive Plan Amendments, & UDO Text Amendments to Realize “Fiddlehead Corner”, a Master Plan Development – Conditional District

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119 Is7mallCommunity Collection Systems: Construction Costs Background Small rural community water and wastewater systems currently account for approximately 90%of environmental regulation violations,according to the Electric Power Research Institute(EPRI).1 In addition,according the EPA,.....small communities tend to be economically disadvantaged,under-served and resource-poor."Consequently, "they face significant barriers to building and maintaining effective wastewater treatment services"including ... • Economic/financial limitations • Inability to sustain community-wide systems(lack of economies of scale) • Inability to attract and maintain system operators • Lack of managerial competency and consistency • Extreme topography and climate • Geographic isolation/re mote ness2 Gravity sewer costs can overtax small communities. Manholes, lift-stations,and other appurtenances essential for gravity sewers are expensive when applied to areas lacking critical density,a commonality of small communities.Slope requirements for gravity sewers often result in excessive burial depths in hilly or flat terrain, increasing the cost per foot installed. In the late 1960's,the cost of conventional gravity collection systems in rural communities was found to dwarf the cost of treatment and dispersal.3 In the late 197O's,conventional gravity sewer estimates for the small community of Glide,Oregon, represented between 85 to 90%of the total system (collection and treatment)costs. Lacking operational knowledge, resources,and adequate budgets,small communities rarely develop or enforce ordinances aimed at regulating sanitary sewer connections,often leading to excessive infiltration and inflow(1/1)over time.Unabated, extraneous flows from sanitary sewers increase the need for(1) larger sanitary sewer pipe,(2) lift station capacity and operation and maintenance(0&M) requirements,and (3)treat- ment plant capacity and 0&M requirements, including energy consumption. Electrical costs associated with the processing of 1/1 can be expen- sive and costs are on the rise.Energy use consumes 30%to 40%of the 0&M budgets at small WWTPs.4 In many sanitary sewers,extraneous flow consisting of 1/1 is a major cause of hydraulic overloading of both the collection systems and the treatment plant(Santry, 1964; "Municipal Requirements for Sewer Infiltration," 1965; Brown and Caldwell, 1957).1/1 in a sanitary sewer system in one Midwestern suburban community was found to be as high as 0.02 cfs/acre or in excess of 1,300 gpd/capita(5 m3/d/capita).Average dry weather flows,on the other hand,were less than 70 gpd/capita(0.3 m3/d/capita).5 Alternative wastewater collection systems(also known as"pressure sewers")were conceived to circumvent the challenges of gravity sewers when they are applied to small communities.These include effluent sewers and grinder sewers.Alternative sewers are particularly cost effective in ... (1)sparsely populated or suburban areas (2) hilly or flat terrain (3)poor soil conditions:areas with rock (4) high groundwater (5)small communities that require lift station(s)or include creek or river crossings (6)small communities with minimal 0&M capability The cost savings of alternative sewers can be significant. For example,a 1998 report from the Illinois Community Action Association,titled Alternative Wastewater Systems in Illinois, included the results of comparative bidding for both effluent sewers and gravity sewers for the City of New Minden, IL.The cost to install an effluent sewer was$1,090,000 (1998 US Dollars),while the cost to install a comparable gravity sewer was $2,090,000,equating to a savings of$1,000,000.6 Orenco has collected and analyzed constructed costs from more than forty publicly funded and bid collection systems serving small communities. On average,Orenco effluent sewers cost 41%less than gravity sewers.The monthly debt retirement savings—per connection—equates to$28.44/month/connection (30 years, 3%),well above estimated 0&M costs for Orenco effluent sewers.As reported in "Operational Costs of Two Pressure Sewer Technologies: Effluent(STEP)Sewers and Grinder Sewers,"the uniform equivalent monthly(0&M)costs for effluent sewers manufactured by Orenco are$7.05/month/EDU includes solids management),while the uniform equivalent monthly(O&M)costs for grinder ©2014 Orenco Systems®Inc. NFS-EFS-CC-1 Rev.1.6,©08/14 Page 1 of 13