Protecting our natural resources by reducing Combined Sewer Overflows

The City of West Lafayette is committed to protecting our natural resources. The City has recently updated its 20-year CSO Long-Term Control Plan, which will help keep the Wabash River cleaner.

What is a combined sewer overflow?

According to the U.S. Environmental Protection Agency, CSOs are remnants of the country's early infrastructure. In the past, communities built sewer systems to collect both stormwater runoff and sanitary sewage in the same pipe. During dry weather, these "combined sewer systems" transport wastewater directly to the sewage treatment plant. In periods of rainfall or snowmelt, however, the wastewater volume in a combined sewer system can exceed the capacity of the sewer system or treatment plant. For this reason, combined sewer systems are designed to overflow occasionally and discharge excess wastewater directly to nearby streams, rivers, lakes, or estuaries.

CSOs contain not only stormwater but also untreated human and industrial waste, toxic materials, and debris. This is a major water pollution concern for cities with combined sewer systems. CSOs are among the major sources responsible for beach closings, shellfishing restrictions, and other water body impairments.

While not subject to secondary treatment requirements, CSOs must nevertheless meet water quality-based and technology-based standards under National Pollution Discharge Elimination System (NPDES) permits to comply with the Clean Water Act. Based upon U.S. EPA's 1989 CSO strategy and 1994 National CSO Policy, CSO communities are required to implement nine minimum control technologies and develop a long-term CSO control plan to meet water quality standards. The nine minimum controls are generally met through management of the existing Combined Sewer Systems (CSS), while the long-term controls will involve capital improvements such as retention and treatment, or sewer separation.

More than 100 Hoosier cities and towns have CSOs. There are over 700 cities with combined sewers nationwide. In West Lafayette, there are 3 CSO locations.

What is West Lafayette Doing to Reduce CSOs?

In 1993, the city began an aggressive 20-year plan to significantly reduce CSOs and comply with federal regulations related to the Clean Water Act. Major improvements were made, including:
Weather Treatment Facility Expansion (2024-2025) $31 Million

• A $18 million upgrade to the wastewater treatment plant that included ammonia removal and dechlorination before discharge to the Wabash River. (1993-1997)
  
  

• Completion of the $2.2 million foundation drain disconnect program in the Barbarry Heights neighborhood (1999) 
  
  
• Construction of the $2.3 million North River Road lift station (1998)
  
  
• Upgrade to the River Road Interceptor. (1999-2001) $1.8 million
  
  
• The $1.9 million rehabilitation of the Happy Hollow interceptor (2001)
   
• Construction of the $5.9 million wet weather treatment facility to significantly reduce CSO impacts on the Wabash River (2003)
  
  
• Western Sanitary Sewer Interceptor Phase I (2007), Phase II (2008), Phase III (2009), Phase IV (2011), and Phase V (2012) $15 Million including removal of 3 Lift Stations
  
  
• Aeration Tank Addition and Minor Wet Weather Treatment Facility Improvements. (2012) $2.1 Million
  
  
• CSO Relief Interceptor (2016) $19 Million
  
  
• River Road CSO Tunnel (2022-2023) $8 Million

• Wet Weather Treatment Facility Expansion (2024-2025) $31 Million

 Provided for reference, please view the CSO Long Term Control Plan.

Sign up for the City's CSO Public Notices

The Wastewater Treatment Utility is committed to reducing CSO impacts to the Wabash River. If you would like to receive CSO notifications via email.  Please click here.

Resources

• Indiana Department of Environmental Management CSO page

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