SCS Engineers assisted the County with developing construction plans and specifications for a Yard Waste composting facility. The County 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 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 1 to 2 –acre area. Dewatered biosolids (50 tons per day) are accepted for co-composting with the yard waste.
The composting process involves:
Plans call for the use of ground yard waste mixed with biosolids at a 3 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 landfills 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 significant savings for the Division.
SCS 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.