& Biosolids
Biosolids
Sewer overflows and basement backups are occasional, but serious problems that can occur in the WLSSD sanitary sewer system.
The primary cause of sanitary sewer overflows in the WLSSD area is
inflow and infiltration. During heavy rainstorms or snowmelt,
the sanitary sewers can rapidly fill with clear water. This water mixes with untreated sewage
in the pipes and exceeds the capacity of the sewer system. Because the excess water and sewage
must go somewhere, it backs up into the basements of homes and businesses or overflows onto the
city streets. Eventually, much of the overflow ends up in the St. Louis River and Lake Superior.
A 12 year schedule to eliminate overflows is detailed in a joint WLSSD/City of Duluth Plan of Action, developed in response to an Administrative Order from the US Environmental Protection Agency. Strategies include building large storage basins to contain water during peak flows and encouraging municipalities to repair and line old pipes and to require residents to disconnect roof drains and footing drains that are connected to the sanitary sewer. Residents can be part of the solution by addressing water drainage issues at home.
I and I Solutions
Inflow and Infiltration: When clean water causes a problem!
During heavy rainstorms or snow melts in the WLSSD area, water soaks into the ground or runs along the
land to find its way to pipes and pathways designed for water drainage. Typically, this clear water
finds the right drainage system, the storm sewer. But sometimes the water finds
its way to the sanitary sewer system, where it can cause serious problems. This
problem of clear water entering the sanitary sewer system is called inflow and infiltration, or
I and I. It is the primary cause of sewer overflows in the
WLSSD area.
- Infiltration: Clear water seeping into cracked pipes or faulty pipe connections to enter the sanitary sewer system
- Inflow: Clear water flowing into the sanitary sewer system through foundation drains, improperly connected sump pumps or old roof drains in area homes and businesses.
When water enters the sewer system through I & I, it mixes with untreated sewage and the volume can exceed the capacity of the sanitary sewer pipe system. If there is too much water in the sanitary sewer, diluted sewage can back up into basements or overflow onto streets. This untreated sewage can end up in area streams, rivers and lakes.
Learn about how to check for and stop inflow in your own home. Many solutions can be quick and easy:
- Landscape your yard so that water flows away from your house and foundation drains
- Install gutters to direct rainwater away from your house
- Install a sump pump that drains into the well-sloped lawn, NOT into a sink
Homeowners can help stop sewer overflows. Be a part of the solution.
2 Sewer Systems
Across the country, most communities have 2 sewer systems: a sanitary sewer and the storm sewer. It is important that the water in each remain separate for each to work correctly.
- Sanitary Sewer System: carries wastewater from sinks, toilets, baths and other drains in homes and businesses to the wastewater treatment plant for cleaning.
- Storm Sewer System: carries water runoff from rain or snowmelts directly into creeks, rivers or lakes without treatment.
During heavy rainstorms or heavy snow melt events, the sanitary sewers can quickly fill with rain runoff that should be directed to the storm sewer. This extra clear water mixes with untreated sewage and overwhelms the sanitary sewer system, causing sewer overflows or basement backups of diluted sewage. Preventing this water from entering the sanitary sewer will prevent overflows.
Storm water is originally clean - just rain or melted snow. It should be harmless to local rivers and streams. However, as it runs over lawns and parking lots, it can pick up many contaminants that can harm water quality. Because this water drains directly to area rivers, streams and lakes, it is important that residents and businesses take steps to help keep it clean. Good steps:
- Use lawn and garden chemicals and fertilizers sparingly and carefully, or avoid using them at all.
- Clean up after your pets promptly. Bacteria from pet waste can contaminate waterways.
- Wash cars on lawns or at carwashes with water-handling systems. Lawns will absorb the dirty water.
- Never pour anything down a street storm drain.
WLSSD is a member of the Regional Stormwater Protection Team, a great resource for more information about keeping area creeks, rivers and Lake Superior clean.