Waste Commission of Scott County, Iowa

The Scott County landfill generates significant quantities of leachate.This leachate was previously treated by hauling the leachate to the Davenport Wastewater Treatment Plant. Foth was retained to design a low-cost leachate recirculation system for leachate treatment. This project required engineering, operations and permitting skills in order to design, operate and permit a leachate recirculation system to meet the needs of the regulators and the WCSC.

Challenges:

• Obtaining approval from regulators. While leachate recirculation is permittable in Iowa, regulatory staff members need considerable information on design, operations and contingencies in order to permit leachate recirculation systems
• Designing low-cost subsurface leachate recirculation systems that are easy to operate,  are expandable and are large enough to accommodate the leachate generated.
• Spraying the leachate onto the working face was not an option that was acceptable to the WCSC.
• Designing a leachate recirculation system that is expandable for the expected 20-year life of the landfill and would not interfere with future landfill
  gas development at the site

Benefits:

• Leachate recirculation using low-cost designs has saved the WCSC thousands of dollars annually in leachate hauling and treatment costs
• The system designed by Foth can be operated easily and can be expanded using onsite equipment and personnel. This allows the WCSC to expand the recirculation system as needed to provide additional leachate treatment capacity
• The implementation of leachate recirculation has
  also provided additional airspace through settlement and waste decomposition. This increased airspace has provided the WCSC with additional capacity at very low cost.