Wastewater systems is the sixth topic in our U.S. infrastructure series. The American Society of Civil Engineers (ASCE) assigned the United States’ WASTEWATER infrastructure a grade of “D-” on their 2009 Report Card for America’s Infrastructure. Here we explore the funding issues that effect the aging treatment plants and waterways that make up our nation's wastewater infrastructure.
33 30 00 Sanitary Sewerage Utilities
Buffalo Township’s wastewater treatment plant is located along Buffalo Creek in Pennsylvania, beneath the State Route 28 bridge. This type of wastewater treatment plant is perfect to serve smaller communities. It supports 6,000 people with 3,100 sewer connections to homes and businesses throughout Sarver, Pennsylvania, and the vicinity. It’s an excellent example of an efficient wastewater infrastructure that uses extended aeration to treat raw sewage, without any initial sedimentation.
Sanitary sewer utility piping carries waste water and sewerage from residences, institutions and industries to treatment plants for processing. Sanitary sewer piping should not be confused with storm sewer piping, which is completely different in terms of water source and quality, flow characteristics, and design parameters. Even though closed and buried pipes are used in their construction, sanitary sewers are considered open channel, gravity flow systems. The slope of sanitary sewer piping is designed to provide flows that will prevent any stagnation and settling, but not be so fast as to scour the pipe interiors. This is typically a flow rate of less than 10 feet per second in most applications. Sanitary sewer systems are designed for what is expected to be a theoretical peak flow condition, assuming most system users would apply waste water into the utility at the same time.