Wastewater Collection Systems

Wastewater collections systems are comprised of gravity pipes, manholes, pump stations, control structures, and force mains that gather used water from residential and nonresidential customers and convey the flow to the wastewater treatment plant. It takes thousands of miles of pipeline to collect this wastewater so it can be treated and returned to the environment. Please see the sewer construction presentation in Features Column for a detailed description of the wastewater collection system infrastructure and how it is constructed.

The wastewater collection system carries wastewater from homes and businesses to the UCSD’s Northeast and Southwest Wastewater Treatment Plants for treatment. UCSD is responsible for the maintenance and operation of 95 miles of interceptor sewers, 36 miles of collector sewers, 28 pump stations, 18 miles of force main, and 2,806 manholes. The great majority of sanitary sewers in the District operate solely by gravity drainage flow, but there are wastewater pump stations located in lower elevation areas of the District which pump wastewater through special sanitary sewers called force mains. The City of Champaign, City of Urbana, and Village of Savoy operate and maintain the collector sanitary sewers within their municipal boundaries.

Maintenance Programs

There are several maintenance programs which are managed by UCSD to ensure that the wastewater collection system continues to operate effectively and efficiently, and to rehabilitate the aging infrastructure. These programs include weekly and monthly inspections, cleaning program, root control, televised inspection, cured-in-place pipe lining (CIPP), and point repairs.

Weekly & Monthly Checks: District staff performs weekly manhole checks looking for backups and flow constrictions in areas that have experienced problems in the past due to grease, roots, debris, or other issues. In response to those checks and reported backups, collector sewers and interceptors receive additional cleaning and televising. UCSD staff also does a bi-monthly check of all bolt down manhole lids.

Cleaning Program: All sanitary sewers are flushed with a powerful water jet nozzle and solid materials/debris are removed from the sewers and disposed of at a landfill at least once every 5 years for collector sewers and once every 20 years for interceptor sewers as part of the cleaning program.

Root Control: Some sewer mains are susceptible to invasion of roots from vegetation, which can diminish the structural integrity and inhibit the flow capacity of the pipe. These sewers are placed on the root control program which annually routs the pipes with a mechanical saw and then flushes the pipes. This action does not harm the trees.

TV Inspection: The District owns a televising inspection truck which includes a remote control carriage mounted video camera which can be inserted into a sewer manhole and dispatched up a sanitary. The video camera is linked to the televising truck via a cable which transmits video to the truck and relays commands to the camera. The camera carriage can traverse sewers as small as 8-inch and the video camera itself can rotate and tilt to investigate any lateral, joint, or imperfection which is identified. The televising truck generates a digital media recording which can be analyzed at a later date to identify cracks, dislodged pipe joints, locations of house lateral connections, flow conditions, and any other sewer characteristics.

CIPP: Cured-in-Place Pipe Lining is capital improvement performed by outside contractors and managed by the District. Many compromised or failing sanitary sewers can be 100% rehabilitated by a trenchless technology known as CIPP. The process involves inserting a resin-impregnated felt liner similar to a sock into an existing sanitary sewer pipe through the manhole. Once the liner is in place, hot water or steam is injected into the sock, and the heated water or stream activates the resin material which is impregnated in the liner. As the resin is activated, it cures and forms into a solid plastic material which transforms the flexible liner into a rigid pipe which exhibits structural strength equivalent to a new sewer. Additionally, the new cured pipe provides a smooth and efficient flow channel which thoroughly renews the sewer without excavating the pipe. Once the pipe liner has cured, a robotic tool is inserted into the new pipe and is remotely directed through the pipe to cut out the lateral service connections, and the new pipe is placed back into service. The entire process typically requires 6-12 hours.

Point Repairs: The Miscellaneous Sewer Repair Contract is a capital improvement program performed by outside contractors and managed by the District. The term "point repair" refers to construction required to correct a severe problem (pipe collapse or inadequate slope) at a specified location in a sewer pipe which cannot be corrected by cured-in-place lining. Point repairs require excavation to the sewer pipe, removal of the existing sewer pipe, installation of a new pipe, backfilling the excavation, and restoration of the surface whether it is pavement or lawn. Point repair locations are identified during internal sewer televised inspections.

Cured in Place