Sustainable Land Development Today - January 2009 - (Page 34)

By Steve Gaze Industry Spotlight AIRVAC is a pioneer in vacuum sewer technology. Vacuum sewers don’t rely on gravity, so installation trenches are typically only 3-5 feet deep compared with gravity sewer trenches that can be 10-20 feet deep. That means less excavation, and little or no shoring or dewatering, so the installation is much faster and less disruptive. Vacuum sewers also require fewer pumping stations than do gravity sewers. A single AIRVAC vacuum station typically can replace three to eight lift stations. And AIRVAC stations are equipped with backup generators, so there is never a loss of service due to an electrical power outage. The net result is a 30-40% cost savings when using vacuum sewers compared to conventional gravity sewers. And, vacuum technology has progressed to the point where annual operation and maintenance costs are now on par with, or even lower than, conventional gravity systems. From an environmental standpoint, vacuum sewers provide crucial advantages over gravity systems. First, vacuum sewers are sealed systems. Untreated sewage cannot escape, nor can groundwater or surface water enter the system – a cost-saving measure at the treatment plant. Also, workmen rarely, if ever, come in contact with raw sewage. Vacuum technology is remarkably simple and efficient. Wastewater flows from each house by a gravity line to a nearby vacuum valve pit. Each pit is equipped with an interface valve that activates when wastewater in the sump reaches a predetermined level, usually about 10 gallons. Operation of the valve is completely pneumatic, so electrical power is not required. When the valve activates, wastewater enters the collection line followed by a volume of air. Differential air pressure moves the sewage through the line so rapidly that buildups or blockages are rare. For over three decades, vacuum sewer technology has proven an excellent, and often preferable, option to gravity sewers in all types of terrain and conditions. Places like Albuquerque (NM); Sarasota County (FL); York County (VA), and hundreds of other communities enjoy the efficiency and convenience of AIRVAC sewer systems. SLDT Developers Benefit From Vacuum Sewers Gravity sewer systems have long been the standard for most municipalities and developers. But gravity systems, despite their simplicity, are not always the most cost-effective, environmentally sound solution. The limitations of gravity sewers are especially evident in difficult or unique geographic situations. Land developers know the complexities and costs associated with installing gravity sewers in difficult areas. Many residential and commercial developments are in low-lying areas or near oceans or other bodies of water. Typically, these areas share some similar geographic features: high groundwater, flat terrain, and sandy soil. Many times, the end result is high construction costs. On top of this, developers often face sensitive environmental concerns when developing these sites. Increasingly, developers and engineers are turning to vacuum sewer technology as an effective solution for difficult or unique sewer installations. Vacuum sewers offer many significant advantages over traditional gravity systems, and they can be installed for significantly less money in many instances. 1 2 3 4 34 January 2009 Sustainable Land Development Today

Table of Contents Feed for the Digital Edition of Sustainable Land Development Today - January 2009

Sustainable Land Development Today - January 2009 Contents Our Voice Your Voice The BottomLine SLDI in Focus Calendar Industry Rebound Will Require Balanced Approach What Happened to Fannie and Freddie? Added Value in Entitlements Industry Spotlights Technology Wastewater Innovation Classifieds Advertiser Index Editorial Board SLDT Resources Last Word

Sustainable Land Development Today - January 2009

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