4/26/2011 SEWER COMMISSION Minutes

Home Browse Search

Page 37 their problems. In 1986, the first STEP system was introduced within the Lacey UGA. Today, the City of Lacey has a 33 square mile wastewater service area that includes approximately 100 miles of gravity sewer mains and 46 miles of STEP mains. The existing wastewater customer base includes approximately 7800 gravity sewer cona&cfions-and280(LSTEP�onnections_tha#-dischaTe_directly into-the-grav-itysewer-in#astr-uctum. From a- - - - -— performance standpoint, the on-site interceptor tanks perform 45-55% of sewage treatment. Elkton, OR In the late eighties, individual onsite septic systems in Elkton, Oregon—along the beautiful Umpqua River were failing, threatening the river's water quality. In addition the septic systems were limited in capacity, and merchants realized they couldn't expand their businesses without making improvements. In 1989, a watertight effluent sewer system that conveys effluent from about 100 onsite septic systems, of which 1/3 are gravity and 2/3 are STEP, to a 60x120 Recirculating Sand Filter(RSF) designed to treat 30,000 gal/day. Final disposal of the treated effluent is to a drainfield consisting of 11,000 lineal feet, divided into twelve (12)zones.With a total system cost of$897,800, the average installation was less than $7,000 per connection, a fraction of the cost of a conventional/traditional approach/solution. Long term operational costs are reduced because septage pumping is typically no more frequent than once every 10-15+years depending upon occupancy loading. Diamond Lake, WA In the early 1970s, residents of Diamond Lake, Washington knew that something had to be done about their wastewater.According to Bob McGowan, long-time member of the Diamond Lake Water& Sewer Commission, "Our lake was being destroyed by leaking septic tanks and failing drainfields." The community needed federal funding assistance. Even so, "A gravity system was way out of reason," recalled Larry Garwood,former system operator, now retired. After nearly 15 years of research and planning, the Commission decided on an effluent sewer. Several years after startup, pumps remain dependable,typically last 20 years, and thus life-cycle cost are minimized. Pumps are lightweight, typically 25-30 Ibs, '/2 Hp, 115V, and are relatively inexpensive to replace (-$400). References and Performance Data References of system owners,engineers, and operators are available from Orenco. In addition, project tours are often available through the local regulatory jurisdiction or an Orenco equipment distributor. Call Orenco for more information about references or tours.