Organics Management – Yard-Waste Biosolids Co-Composting Facility, Charlotte County, Florida

SCS Engineers Yard Waste Co-CompostingSCS Engineers assisted Charlotte County, Florida, with developing construction plans and specifications for a yard-waste composting facility. The County’s Wastewater Division was spending a significant sum on long hauling biosolids for disposal at a private landfill (200-mile round trip) and was looking for a less expensive solution.  At the same time, the County’s Solid Waste Division was looking to use yard trash as a temporary daily cover at the landfill.

The facility takes in yard waste and temporarily stockpiles it in a one- to two-acre area. Dewatered biosolids (50 tons per day) are accepted for co-composting with the yard waste.

The composting process involves:

  • Removal of plastic bagging of yard waste
  • Grinding of the yard waste
  • Mixing of the yard waste and biosolids
  • Formation of multiple static windrows on a concrete pad
  • Final curing pile and final grinding

Plans call for the use of ground yard waste mixed with biosolids at a 3:1 or 4:1 ratio. The mixture will be placed in static pile windrows for approximately 45 days of curing, then transferred to a final curing pile for another 21 days to stabilize. The facility includes leachate collection and pumping facilities to the landfill’s existing leachate treatment plant.

The project included the economic feasibility of the yard-waste facility, taking the biosolids for co-composting and potentially saving the Wastewater Division significant dollars. Co-composting demonstrated a substantial savings for the Division.

SCS Engineers also evaluated the regulatory and health risk aspects associated with potentially allowing the use of the compost by the general public. SCS prepared construction plans and bid operations specifications as the County opted to contract out the facility operation.