Laserfiche WebLink
AFFORDABL <br /> SOLUTIONS FROMiR • SYSTEMS", INC. <br /> C A S E` ,S. T U Y <br /> ;x 5 it ,77 <br /> }� 1 <br /> FACn Aff¢`tste+uf r' oliectlonil +Eton for (V,}� irifities <br /> �(�J Gdi,A II ,'4�"ri.it hfk{' <br /> t. k„n7� ,uSl ee',1,III t s, r "'7' r ._ .. <br /> xa 'rS ,fin a1 T4� r�'r�rrlr �1 <br /> Low Life Cycle Costs Keep Rates Low _ <br /> 11 ini„IF'r-( Problem i,,i'' In the early 1990's the fast-growing town of Yelm,Washington YELM, WASHINGTON <br /> was served by outdated septic systems and lacked the wastewater <br /> infrastructure to support development.Yelm needed to build a sewer system ' <br /> without burdening residents with high rates or the cost of future growth. a <br /> Consequently,a phased system with low maintenance costs and low repair/ <br /> replacement costs was crucial. <br /> �F i ttfllhppll jl� <br /> The city of Yelm installed a modular,expandable Orenco <br /> Effluent Sewer System in 1994,With 67%growth throughout the 1990s,Yelm <br /> now has 1,700 connections.Yet maintenance costs(e.g,,tank pumping)and <br /> repair/replacement costs(e.g.,on-lot pumps)have remained low,resulting in Design Parameters <br /> low life-cycle costs and affordable sewer rates. 5,800 people <br /> • 1,700 STEP connections(residential <br /> and commercial) <br /> In the early 1990's,the small town of Yehn,Washington needed . 2,7 people/home(average) <br /> to replace outdated septic systems with a sewer system.The city's installation Date <br /> population was spread over a large area,and it anticipated its service • 1994 <br /> area would quickly double.I low could it build a wastewater collection Rate Structure <br /> system capable of accommodating growth?Sizing a conventional $43.161mnthtreddenee <br /> gravity sewer with 1001X,more capacity for future development would Coll ction1Syste and 1,500-gallon <br /> unfairly burden existing users by imposing unaffordable rates until new two compartment,precast concrete <br /> development occurred. interceptor tanks <br /> •Biombe'STEP packages with%-hp, <br /> To solve this problem,Yelm chose to install an mimeo Effluent Sewer, 115-V high-head effluent pumps <br /> saving the community hundreds of thousands of dollars in capital costs Smandlameter low-pressure sewer <br /> maliecompared with the cost of a gravity system and giving them the ability <br /> to defer a large portion of collection system costs until growth actually Seent <br /> condary <br /> yTequencingBatch ram Reactor(SBR) <br /> occurred. Discharge to surface waters under <br /> NPDES permit <br /> Because the low-pressure mains of an effluent sewer are small and Tank Pump-out <br /> shallowly buried(is water lines are),the city was easily able to oversize $0.24 per gallon,tipping fee included <br /> r them throughout the service area.Capital costs were a fraction of what _8_year pump-out frequency <br /> it would have cost to oversize conventional gravity sewer mains and lift •$3.38/mo/residence <br /> tl stations.In addition,since the majority of the costs for orenco Effluent pump Repair&Replacement <br /> § Sewers are for each property's on-lot equipment—the underground PS 00+replacpu s ae initial installations In <br /> t septic tank and its STEP(Septic Panic Effluent Pumping)system—the 1994 <br /> city was able to defer upwards of 75%of the future collection system <br /> costs until property development occurred. <br /> i <br /> NCS 7 <br /> ©2009 a-...Systems•Inc. He,1.0,©10/09 <br /> { Par,1 of 2 <br /> rr <br /> I <br />