Anaerobic Digestion Facility at Little Miami Plant




MSD is designing and building an anaerobic digestion facility at the Little Miami treatment plant to process waste solids from the Little Miami, Polk Run, and Sycamore Creek treatment plants on the east side of Hamilton County. Waste solids, also known as treatment residuals, are removed from wastewater during the treatment process.




Anaerobic digestion is a biological treatment process for treatment residuals. Bacteria break down the residuals - in the absence of oxygen - into biogas and biosolids. The process destroys pathogens and reduces the volume of the residuals. With this project, treatment residuals will be thickened, anaerobically digested, dewatered, and hauled off site for beneficial reuse.




  • Diverts Waste from Landfill for Beneficial Reuse: MSD is evaluating the most economical and environmentally friendly ways to reuse the biosolids (e.g., soil amendments and fertilizers)
  • Reuses Biogas as Energy Source: Biogas, which is primarily methane, is produced by anaerobic digestion. It will be reused onsite as a renewable energy source to run other plant operations. This will reduce our carbon footprint and reliance on the grid and improve energy efficiency
  • Improves Plant Operations: New solids handling and processing facilities at Little Miami will help optimize operations and maintenance and provide flexibility for the future.
  • Reduces Truck Traffic: Fewer trucks are needed to haul away biosolids, due to 30-45% reduction in solids volume
  • Reduces Odors: New odor controls will be installed on solids handling processes to minimize/eliminate odors
  • Save Money: Since the project involves renewable energy generation (biogas), MSD is potentially eligible for IRS reimbursement of up to $50 million in project cost.




Here's the current project status:


  • In December 2022, MSD awarded a progressive design-build project to Jacobs Project Management Company to design and construct an anaerobic digestion facility at the Little Miami Wastewater Treatment Plant in the East End/Columbia-Tusculum neighborhoods.
  • Design kicked off in January 2023; 30% design expected to be complete by end of 2023.
  • Tree clearing on City-owned property will occur sometime between November 2023 and March 2024. MSD is working with our contractor to leave the maximum buffer of trees possible between the construction site and the Ohio River Trail.
  • Construction is anticipated to start in 2024 and run through 2028.



  • MSD will expand the footprint of the plant to the north/northwest by about 7 acres (City property) and will leave the maximum buffer zone possible when removing trees.
  • Levee around the plant will be expanded to protect the extension
  • The existing entrance drive off Kellogg Avenue may need to be relocated

Photo showing expanded footprint at the Little Miami plant




  • A portion of the Ohio River Trail runs east of the plant
  • The new facilities will not obstruct the trail; the plant grounds and trail will be separated by 25 feet at a minimum
  • MSD is working closely with the City’s Department of Transportation & Engineering (DOTE), who maintains the trail
  • MSD is committed to minimizing impacts to trail users