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careful review of history reveals that The city's leadership began to realize a need for a mu- <br /> Provincetown,Mass.,not Plymouth Rock, nicipal sewer system as early as the 1950s,Tourism was <br /> was the initial stopping place for the growing,and the number of summer visitors began to tax <br /> Pilgrims in November 1620. This small the existing point source system. However, no meaning- <br /> town at the tip of Cape Cod was home ful headway in the discussion was made until the 1990s. <br /> to America's first European settlers for approximately It was during this time that a sewer infrastructure study <br /> 5 weeks before they sailed across Cape Cod Bay to the revealed that 17% of Provincetown's properties were <br /> mainland and stepped ashore, not in compliance with the Massachusetts Department <br /> Located on the narrowest sliver of land on Cape Cod, of Environmental Protection's Title 5 regulations. Title 5 <br /> Provincetown is today a popular resort area.Its population established minimum requirements for the subsurface <br /> of 3200 can swell to 50,000 in summer as visitors arrive to disposal of sanitary wastewater. <br /> enjoy the beaches and mild weather. Like many oceanside communities,Provincetown has <br /> The explosion of people each summer creates sig- a high water table. In order to meet Title 5 guidelines, <br /> nificant infrastructure issues. One of the most pressing many property owners installed septic systems.However, <br /> is sewer capacity.Since it was first a fishing village in the according to the guidelines,the septic systems had to be <br /> late 1600s, the town had relied on point source waste- elevated to allow 1.5 m (5 ft) of separation between the <br /> water treatment, primarily cesspools. That changed in bottom of the soil absorption system and the maximum <br /> 2003,when Provincetown completed work on Phase 1 of groundwater elevation. As property owners upgraded <br /> a hybrid wastewater collection network that includes a their onsite systems to meet Title 5,more and more raised <br /> backbone vacuum system complemented by sections of leach fields began to appear across town.In 1994,the city <br /> low-pressure and gravity systems. The new system pro- responded with the passing of Article 17,which directed <br /> vides service to more than 500 homes and,businesses. the town to develop a municipal sewer plan. <br /> The experience has been exceptional.There have been <br /> zero complaints,and the town gets frequent requests from Learning the System <br /> homeowners to join the collection network as residents The town's board of selectmen decided early that they <br /> hear from their neighbors about the benefits of the cen- did not want to be in the business of designing,installing, <br /> tralized system. Getting the city's first municipal sewer and maintaining a municipal sewer system.Instead,they <br /> system took about 300 years, but by all accounts, it was opted for a design-build—operate (DBO) procurement <br /> worth the wait, process.An important part of the successful DBO group's <br /> proposal was the use of vacuum sewers,something new <br /> Seaside Geology to this region. <br /> Provincetown, with its crowded narrow streets and Vacuum sewer technology solved several significant <br /> collection of historic sites, is built on a sandbar. To the design and installation issues.The high groundwater table <br /> .north is the Atlantic Ocean;to the south is Cape Cod Bay. beneath Cape Cod made excavation a troublesome problem. <br /> For approximately two centuries nearly everyone here Gravity lines would require deep trenches along the narrow, <br /> utilized a cesspool system,which worked well because of densely populated streets of Provincetown.Digging up the <br /> the excellent leaching characteristics of sand. streets would have been a logistical nightmare that would <br /> How A traditional gravity When Ill gal of wastewater Wasl eater travel,of 15 to 18 fps Wastewater etnon the collection Vacuum pumps cycle on and <br /> line carries wastetvaler milccts in the sump,the in the vacuum main,which 1, tank.IVhvn the tank tills to a off as needed to maintain a <br /> Vacuum fmm the customer valve-pens and differential loid in a sawtooth fashion to predetermined Ievcl,pumps constant level of vanmm on <br /> Systems m a Valve pit package pressure propels the content, insure adequate vacuum levels transfer the contents to Au ilu entim collection systvm, <br /> y into the Vacuum main. ul the end of each]file. Irealment plant via a force main. <br /> Woric 1 2 3 4 <br /> __ <br /> - Vdcuum Stnlion Cotleetton Tank' <br /> `f,Airintake Valve Pit <br /> i� Package <br /> Wtwm <br /> r�. <br /> u <br /> © WE&T WWW.WEF.0RGJMAGAZiNE O2007 Water Environment&Technology All rights reserved <br />