06-28-1999 Council Packet - Laserfiche WebLink

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FROM KCZS-. • • • ^ I • V - / , • • • » A • • • • X • • « * '*- *. .. ..*••• **v;.^ ^• • • Alternative Sewage Treatment System Installation, Operation, and Maintenance Costs J.L. Anderson, D. Gustafson, and K. Olson University of Minnesota Extension Service Excessively high construction costs and lack of federal subsidies for building regional wastewater treatment plants has refocused many public officials and leaders on the question of how to provide affordable wastewater treatment alternatives to rural residents. Individual or on-site sewage treatment systems may be part of tlie answer. There are a variety of technologies, that are being used or evaluated to provide on-sitc treatment. These can be matched to fit each unique set of circumstances encountered by communities, technologies, or individuals. All onsite sewage treatment system for an individual residence typically consists of the house jewer, the sewage tank (septic or aerobic), the outlet sewer and distribution lines, a senes of drain field trenches, a seepage bed or a sewage treatment mound. As local government units evaluate their wastewater treatment needs, they need to assess not only the use of these standard or t3^ical systems, but also the suitability of technologies where wastewater (sewage tank effluent or raw wastewater) is collected from a group or cluster of residences and delivered to a single location for final treatment and dispersal. In most cases this leads to the use of some of alternative technologies in combination with more typical treatment units. Alternatives include, aerobic tanks or package plants, constructed wetlands, sand or peat filters and alternative means of soil dispersal such as drip irrigation. A typical sequence for the individual residence then becomes, bouse sewer, sewage tank (usually septic tank), outlet to collector sewer, common soil treatment (dispersal) area. ... Construction (or installation) costs of these different types of on-site technologies is one major question that local governments need sound objective answers. In addition, they need to know the long term management costs of the alternatives and combinations to decide if they are an affordable option. Individuals also need information on what it costs to install and maintain these systems. Installation costs can vary from less than S2,000 to well over $10,000 per residence depending on site conditions and the land of system needed. Having cost informarion available allows individuals to choose the most cost effective system within the limitations imposed by the site conditions and required by ordinance^ In this section we attempt to document both the construction (installation) and operation and maintenance costs. This information is compiled and summarized from several sources including tire current Legislative Commission on Minnesota Resources Alternative Sewage Ttealmcnt System Project, the Metropolitan Councils, Alternative Sewage Treatiuent Demonstration Project, a 1993 National Small Flows Clearinghouse survey, and a report from North Carolina presented at the 1996 National On-site Wastewater Recycling Association (NOWRA) Conference. In Table 1, typical ranges in costs are provided for sewage treatment options that assumes the use of a septic tank and then cither direct dispersal through sewage Ucatmc.r. -cnchcs or mound or into an alternative soil dispersal option. Annual operation and maintenance costs were determined with a base cost of cleaning a 1500 gallon septic tank every two years. Increases from this base cost were on the estimated needs for each additional component. These costs are representative for estimated flows between 450-1000 gallons per day. The total cost over a 20 year estimated system life is calculated using the mid-point of the ranges provided in the first two columns a- ’ multiplying the annual cost by 20 years.