Remediation: Landfill to Business Park and Public Area

2021 American Council of Engineering Companies of Florida, ACEC-FL Engineering Excellence Award Winner

Countyline Corporate Park

Background
Countyline Corporate Park is a planned 8.5 million square foot, 500-acre premier logistics center built by one of Florida’s leading industrial developers. Most of the project site was a former Construction and Demolition (C&D) Debris Landfill.

Building on the former landfill adds significant capital and operational costs because of the required soil improvement, landfill gas management, groundwater remediation, stormwater management, and the ongoing inspection, monitoring, and reporting.

Challenge
Because most of the site is waste-filled, stormwater management options included relocating waste or using prized unfilled areas for stormwater ponds; however, both result in losing development land and the associated revenue. An alternative considered was purchasing stormwater rights in adjacent lakes. After further evaluation, the team recognized that these traditional options were cost-prohibitive. Additionally, costs for soil improvement and gas management were substantial. Further, groundwater remediation costs were estimated at $10 million.

Considering all the additional costs associated with construction on the landfill, creative, cost-saving solutions were vital to ensure the development would be feasible and remain cost-competitive in the future.

Outcome and Benefits
SCS Engineers, in collaboration with Flagler/Florida East Coast Industries (FECI), developed and evaluated alternatives addressing each of the environmental challenges. Each alternative considers the cost, technical feasibility, the likelihood of regulatory approval, and long-term performance for the site’s health and the community’s wellbeing.

The best cost-saving solution is an integrated stormwater-groundwater remediation system designed by SCS. The system effectively cuts off potential migration of ammonia-impacted groundwater offsite, thereby reducing future risks. More importantly, from an initial development-cost standpoint, it permits stormwater injection into the shallow aquifer, allowing the developer to maximize the development area. The solution doesn’t require the use of extremely costly offsite stormwater rights. This method of stormwater management is unique to the site.

The cost savings allowed for spending on other environmental facets of the project, such as deep dynamic compaction for soil improvement and passive gas management under habitable spaces, making the development feasible and environmentally responsible.

SCS’s remedial actions protect public health while opening the site for reuse. Phase I, consisting of 160 acres, is complete, with two million square feet of occupied businesses and a 30-acre community park. Development of the other three phases, which include another six million square feet, is underway.

The development will create hundreds of new jobs, deliver several hundred million dollars to the city and county tax base, and provide a 30-acre public park.

Highlights of the SCS Solution

  • Remedial Action Plan and Water Use Permitting
  • Design and safe permitting of Class I industrial deep injection well
  • Design and build 2-million gallons per day groundwater extraction system and pump station
  • Landfill gas survey and the design of gas management systems for warehouses
  • Assistance with the Environmental Quality Control Board