Southwesterly Composting Facility – Odor Control Improvements

This project will reduce emissions to the atmosphere, replace equipment that has reached the end of its useful life, and increase flexibility within DOSD’s biosolids beneficial use program. The compost facility receives biosolids from Columbus’ two wastewater treatment plants (Jackson Pike and Southerly) for processing. Material is processed in accordance with CFR Part 503 regulations using the negative aerated static pile technique to produce a Class A compost called Com-Til. Com-Til is used for agriculture, landscaping and top soil blending.

The existing equipment was installed in 2001 and has reached the end of its useful life. This project will replace the existing equipment with new as well as upgrade the technology and techniques used for composting. These improvements will result in better control of odors emitted to the surrounding area. In general the project consists of:

  • 3 Compost Pads including blowers and aeration legs. Larger blowers and more efficient aeration headers will be constructed to capture more emissions from the compost pads and convey foul air to biofilters for treatment
  • 12 Biofilters including blowers, headers and new foul air distribution piping. New manifolds will collect foul air from all compost pads and allow it to be distributed evenly to the biofilters for treatment. This common manifold system will replace the existing dedicated biofilters resulting in more even loading of foul air and therefore improved control of odors.
  • New instrumentation, monitoring and control system. Additional instrumentation will allow for more frequent monitoring and improved control of the process. These improvements will also allow adjustments in air flow when necessart resulting in improved control of odors.
  • Improved leachate management. Expansion of the existing lagoon, new collection piping, new hard piped drains and a new will improve capture of leachate.
  • Site Layout. The new composting pads and biofilters will be moved farther away from residents that are downwind of the prevailing winds
  • New electrical distribution equipment. This equipment will include redundant feeds to prevent down time due to maintenance and inspection.

Replacement of the equipment will; increase reliability, reduce odors, reduce maintenance costs, and increase systems life to beyond 20 years. Construction is scheduled to begin in mid-2023 and is anticipated to last 2.5 years. Construction is sequenced to maintain two composting pads in service to maximize treatment capacity during the project. Financing for this contract is being provided by a below-market rate loan obtained through the OEPA’s Water Pollution Control Loan Fund (WPCLF) and the debt is being serviced through City of Columbus sewer customer revenue.

The Ohio EPA has completed a Limited Environmental Review (LER) for this project. View the LER and the letter(PDF, 323KB) of "Notice of Issuance of a Limited Environmental Review and Finding of No Significant Impact” 

If you have any questions concerning this construction contract, please contact City Project Manager Holly Boyer, PE, in the Treatment Engineering Section of the Division of Sewerage and Drainage, at 614-645-2988 or