Under the streets of Dover Township, there is a vast network of sewer piping. There are approximately 150 miles of sewer lines throughout the township. The pipe sizes vary from 8" to 48" in diameter. The pipe is made up of a variety of materials, such as ductile iron, cast iron, PVC, clay, concrete, and transite. These pipes transport all that dirty water from your kitchen sink, laundry, and bathroom to the wastewater treatment facility. The sewers were placed in the ground deep enough to prevent freezing and at a downward slope to ensure gravity flow of wastewater to the treatment facility. At every change of direction or change of slope of the sewer line and at the junction of two or more sewer lines, there is a manhole. Dover Township has 1500+ manholes. It is the responsibility of Dover Township's sewer crew to maintain this complex system. The sewer utility crew objectives are:
• To maintain the system to insure continuous flow of sewage to the plant.
• To maintain the manholes and flow meters within the system.
• To prevent clean water (rain and groundwater) from entering the sewage collection system (inflow/infiltration).
Every ten feet, on average, there is a pipe joint, a lateral connection, or manhole. Each one of these is a site for potential for blockage, exfiltration, or infiltration. For 150 miles of sewer line, there are over 79,000 location where problems could occur. This does not even include all the lateral joints and cleanouts. Inspection of the system is done by a portable video camera. The sewer crew lowers a special camera attached to a long cable and visually inspects the sewer line for current or potential problems, and to check on the condition of past repairs.
Links to more information on sewers: