Collection System Improvements in Marshalltown, Iowa

Manhole and Pipe Lining Projects

The Marshalltown Infiltration/Inflow (I/I) program came about as a result of an Iowa Department of Natural Resources (DNR) Administrative Consent Order (ACO). This article will take a brief look at that and the manhole and pipelining projects that resulted from the ACO.

For details, we encourage you to contact the author, Mike Fields (515.233.0000) or attend his presentation on September 8, 2016 in Marshalltown at the Iowa Water Environment Association (IAWEA) Operators Conference. In his presentation, Mike will address in greater detail the City’s pipe rehabilitation using CIPP Lining and manhole repair using cementitious lining. He will include methods, quantities of Pipe and manholes lined or planned to be lined, and unit costs for the rehabilitation. Please contact Mike for more information.

The IDNR Consent Order was developed in 2008. Regional DNR Field Offices were instructed to Identify in their region 10 communities with the largest I/I problems; they were to give those cities, via a consent order, 3-year schedules to ELIMINATE wastewater bypasses.

Over the years, the Consent Order has evolved and changed as TV inspection of the sewer system identified the problems, the number of projects required, and scheduling the projects became more complicated.

Three main areas of construction were identified as necessary for achieving compliance with the Consent Order.

  • Increase flow capacity: add pumping capacity and additional flow equalization at the Wastewater Treatment Plant, and add overflow sewers to the city’s interceptor sewers to achieve the flows to the new equalization basin.
  • Rehabilitate the collection system through the use of no-dig Cured-in-Place-Pipe (CIPP) and spray lining of the manholes.
  • Rehabilitate the system by open-cut methods, including:
  1. Replacing lampholes, tee’s, bends, and transitions with new manholes
  2. Replacing manholes in bad condition with new manholes
  3. Making spot repairs of the sewer pipes that have failed
  4. Replacing pipe segments that were beyond lining capability or needing flow capacity modifications to reduce backups

Construction costs/estimates will be discussed as the City moves toward completion of the Consent Order.

Excess flow at the WWTP is handled with a 30 MGD Screw Pump Station, discharging into 34 MG of flow equalization basins

Excess flow at the WWTP is handled with a 30 MGD Screw Pump Station, discharging into 34 MG of flow equalization basins

2. CIPP cropped

Installation of 8″ Cured-in-Place pipe liner in middle of winter

The presenter, Mike Fields was employed by the City of Marshalltown as the Director of WPC and negotiated the City’s original Consent order/master plan for rehab.  Mike provided oversight of the Consent Order and projects thru 2011 before joined FOX Engineering in 2012.  The engineers at FOX have had the pleasure of working with Marshalltown staff since 1978.

 

FOX Engineering is an environmental engineering firm based in Ames, Iowa. We specialize in water and wastewater solutions for our diverse municipal and industrial clients. Our work varies in size and scope and can be found throughout the Midwest and beyond.