The network of pipes, manholes, and associated equipment that transport wastewater from homes and businesses to the treatment plant is referred to as the collection system. Because KUB's collection system keeps the flow of sewage separate from rainwater, it may also be referred to as a sanitary sewer system.
- KUB's system serves more than 68,000 customers, covers 248 square miles, and has 1,320 miles of service mains (or pipes).
- KUB’s system is primarily a gravity system. Wastewater flows from homes and businesses by gravity into the collection system, where it is conveyed to a treatment plant.
- In some cases, due to terrain or other factors, wastewater may flow to pump stations, where it can be pumped through mains to the plant.
KUB has little control over what most customers discharge to the sewer lines attached to their homes and businesses. As a result, grease, rags, and other materials can enter the collection system. Those materials can restrict the flow of wastewater in the pipe or cause partial or full blockages and result in sanitary sewer overflows (SSOs). Click here to see a log of any recent overflows.
Other sources of problems can occur on the customer's property. Broken or leaking private laterals [the pipes that connect customers' property to KUB's sewer system], for example, can allow tree roots or debris into the pipe, which may cause blockages, building backups, or overflows into the environment. As part of a Federal Consent Decree, KUB must inspect laterals, notify customers with lateral problems, and ensure the property owner makes repairs.
Defective laterals and prohibited connections also let stormwater into KUB sewers. That extra water costs more to treat, and it may overload the system, causing overflows. Prohibited connections include roof downspouts, groundwater sump pumps, foundation drains, and drains from window wells, driveways, etc.
Direct stormwater to storm sewers or drainage ditches, or let it soak into the ground.
KUB tracks SSOs and categorizes them according to these primary causes:
- Combined Sewers: KUB is one of a few large systems in the country with no combined sanitary/storm sewers. Combined sewers were completely eliminated in 1998, thus eliminating a major source of overflows.
- Grease: Grease discharges from restaurants and residential areas can clog lines. KUB works to educate businesses and residential customers about good grease disposal measures that can help prevent grease-related blockages.
- Debris: Debris can enter sewers through discharges from home systems or other entry points and can cause blockages.
- Roots: Small tree roots can enter pipes through cracks or leaky joints. Once inside, they can grow and cause obstructions in the pipes that lead to SSOs.
- Inflow and Infiltration (I&I): During periods of heavy rain, water can flow into the system through manholes, broken customer laterals, or cracks or leaks within the system itself.
- Undersized lines: Sewer lines that are undersized for the amount of flow they receive can also cause overflow problems. This is not a common problem in KUB’s system as lines are adequately sized for most dry weather flow conditions.