Wastewater Collection System and Maintenance
The City of Springfield’s sanitary sewer collection system has its documented beginnings in 1894 when the first sewers were constructed west of Grant between College and Walnut Street. The system is now an extensive and growing infrastructure that carries wastewater from area industries, businesses, and residences to the wastewater treatment plants.
The sanitary sewer collection system provides service to 70,666 residential connections and 6,734 commercial/industrial connections. The sanitary sewer watershed area can currently be divided into 15 drainage basins and 158 sub-basins. There are currently 19 lift stations. The system consists of over 1,188 miles of gravity pipe, 23.5 miles of pressure pipe, and 28,005 manholes, lamp holes, wet wells and flush tanks. The pipes vary in size from 4 inches to 72 inches at depths of 3 feet to 94 feet. New sewers are being built at a rate of 20-25 miles per year.
The initial sewers were built of brick and clay with lime and cement mortar. The pipe materials evolved to cast iron, concrete, reinforced and lined concrete, and polyvinyl chloride (PVC). The pipe joint materials evolved from the initial lime and cement mortar to jute, poured tar, polyurethane gaskets, and neoprene O-rings.
The collection system is divided into three areas for cleaning purposes. This division allows for quicker response and more crew responsibility. A 2-person crew works in each area using a high-pressure sewer jet/flusher or jet/vac with hydraulic saws. An easement machine aids in rear property access. The cleaning activities are performed on routine preventive and accelerated preventive schedules based on maintenance history. Each crew averages 2,800 feet of cleaning each 8-hour day. On average there is 1,211 service requests from the public and 97 stoppages occurring each year.
Two 2-person crews routinely perform sanitary sewer repair activities. Additional staff is utilized as necessary. The crews operate or have access to 3 extenda-hoe backhoes, 5 dump trucks, 1 bob cat, 1 Mini excavator, 2 sewer winch machines, a Coring machine, a 6 inch dry prime pump, 2 mobile air compressors and various other assorted equipment as needed. Each crewmember completes over 83 repairs and replaces or rebuilds 53 manholes per crew year. These same personnel also maintain the pressure lines and air relief valves on the current 32 miles of pressure pipe and perform snow removal duties on the streets of Springfield.
Infiltration and Inflow
A staff of 3 regular full-time and 5 temporary/contract employees performs infiltration and inflow reduction efforts. These personnel use several techniques to locate and minimize extraneous flow into the sewer collection system. This section of the Clean Water Services Division has a total of 25 regular full-time personnel and a seasonal complement of temporary personnel.