Environmental Protection Agency - CSO Award

In 2002 the Lincoln Sanitary District received a 1st place award from the Environmental Protection Agency for Combined Sewer Overflow Management. Over the past 20 years the district has demonstrated an aggressive and proactive plan for removing all roof drains, implementing a sewer use ordinance that prohibits discharge of roof and cellar drains, eliminating more than 75% of the sump pumps and cellar drains connected to the collection system, and annually cleaning 30% of the collection system. The District had also upgraded its main pumping station and its wastewater treatment plant to deal with the remaining wet weather flows. An average of 95% of collection system flow is now captured for treatment, all of which receives a minimum of primary treatment and disinfection as required.

When the plant was constructed in 1981, most but not all of the combined sewer system was separated. Spring flows due to inflow and infiltration routinely cause activation of a single CSO. Since 1981 the LSD has removed additional storm drains, all roof drains, and has began a basement sump pump inspection program to remove active floor drains and sump pumps from the sanitary sewer system. A sump pump / active floor drain fee was implemented to encourage disconnection of these sources of ground water from the sanitary sewer system. An inflow and infiltration study was conducted in 1994 including continuous CSO flow monitoring, followed by a television inspection and sewer line rehabilitation in cost effective areas as part of the CSO Abatement Plan. In 1997, it became clear that additional sewer rehabilitation was not cost effective and the decision was made to upgrade the main pump station and treatment plant to handle the highest flows on record. The system upgrades were constructed in 1999 at a total cost of $2,250,223.31.