landfill redevelopment

ACEC Engineering Excellence for Landfill Transformation into Business Space and Park

January 12, 2021

Countyline Corporate Park in Southeast Florida. Image courtesy of Florida East Coast Industries.

SCS Engineers and Florida East Coast Industries (FECI) are to be honored at the annual conference in Florida planned for August 2021. The firms will receive a 2021 Engineering Excellence Award by the American Council of Engineering Companies of Florida. The honor acknowledges SCS for the environmental engineering firm’s innovative design that integrates groundwater remediation with the stormwater management system on a 500-acre former landfill site. The design enabled the developer to remediate the former landfill into the Countyline Corporate Park in Southeast Florida.

Industrial real estate is in high demand, but former landfills and brownfields present environmental challenges that can become cost-prohibitive to redevelop without sound environmental expertise.  FECI retained the professional services of SCS Engineers to provide consulting and design services addressing the environmental concerns preventing the transformation of a former landfill into a state of the art business park.

Environmental guidelines require 28% (or about 140 acres) of the site to be set aside for stormwater retention. The set aside would require the relocation of several thousand cubic yards of waste and prevent the 140 acres’ redevelopment. The estimated loss of $300 million in potential real estate sales, coupled with the groundwater remediation expense, made the site redevelopment cost-prohibitive. Unless resolved, the problem also impeded FECI’s corporate sustainability goals.

SCS’s experts in landfill design, closure, and remediation, developed a solution tying together the groundwater remediation and stormwater management systems. The integrated system allows for shallow aquifer recharge with stormwater and captures impacted groundwater at the site’s boundary. “We were able to provide an alternative design acceptable to all the permitting agencies, eliminating the need to set aside large areas for stormwater retention,” said Mr. Som Kundral, P.E., SCS’s senior project manager.

SCS’s remedial actions protect public health while opening the site for reuse. The project will be completed in phases. 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. “The engineering solution protects the environment while meeting FECI’s strategic, social, economic, and sustainability goals,” said Mr. Eduardo Smith, P.E., SCS’s senior vice president of client success.

Learn more about these related topics, events, and case studies at SCS Engineers:

 

 

 

 

 

Posted by Diane Samuels at 6:00 am

Dynamic Compaction – An Effective and Viable Option for Land Redevelopment

July 27, 2020

Brownfields redevelopment - SCS Engineers

The value of land in large metro areas has climbed so high that developers investigate developing sites previously filled with trash, garbage, debris, or used by industry or the military. Redevelopment or rehabilitation of these properties is performed in accordance with approved urban renewal plans, and under site-specific environmental agencies. Some of these sites have regulatory agency files but filed when regulations were not as strict as they are today. Other sites are so old that they have not been on regulatory agency radar.

Due Diligence

Developers usually pay a lower price for such lands compared to a virgin land, which is rare to find in prime commercial or industrial areas, or land that has a dilapidated building on it, only suitable for demolition. Developers know that they are responsible for handling any environmental issues as soon as they open a file with a regulatory agency for the redevelopment of the property. Environmental due diligence helps determine the costs of addressing environmental issues before purchase.

Another essential part of due diligence is examining the foundation – whatever is below the ground surface, to determine its load-bearing properties for future development. There are several options available to improve load-bearing capability depending on the type, depth, and age of the below-surface material and the load-bearing properties required of the proposed development. Developers hire geotechnical engineers, to factor this, and many more parameters into an evaluation of the site, and to develop options for improving foundation strength.

Dynamic Compaction

One option for improving foundation strength is through dynamic compaction, which involves dropping a heavy load from a significant height for a certain number of times on locations identified by a grid pattern. The kinetic energy of the weight at the time of impact on the substandard foundation compresses the material, reduces voids in-between material particles, and increases internal friction or shear strength of the material. The practice has been around for decades, and developers are familiar with the methodology. The design of a dynamic compaction program is best carried out by a geotechnical engineer familiar with site conditions and parameters. Dynamic compaction is a reasonable and cost-effective option for specific vertical development to improve load-bearing foundations.

Installing Piles

Another option is installing piles in a grid pattern into the ground, extending into the virgin ground. The piles carry the building load via pile skin friction or point resistance at the tip of the piles. Driving piles is more expensive than the dynamic compaction option discussed above. Piles are characteristically useful for high design loadings. Dynamic compaction is useful to minimize ground settlement around the piles, preventing voids from forming below the building as the ground settles over time. While the building remains at its constructed elevation above piles, dynamic compaction helps avoid problems with utilities below the building slab, including water lines, sewer lines, and electrical lines. Limiting the amount of settlement prevents future vertical shifts in ingress and egress structures, driveways connected to the building, docking ports for trailers, and outside staircases if not located on piles.

The gas vapor barrier system under the building prevents unwanted gas from moving upward from materials in the ground into the building. Minimizing settlement by performing dynamic compaction prevents the barrier from vertically shifting and opening passages for unwanted gas moving into the building. The integrity of the barrier layer is essential in maintaining the building’s protection. These problems are tremendously expensive to fix, and agency officials could deem the structure unsafe for occupation.

Excavation

A third option is the excavation of unsuitable material then backfilling with suitable soil. Depending on the contamination, it is possible to clean the soil then return it clean as backfill. For the building foundation to have sufficient bearing capacity, a geotechnical engineer oversees the operation. Filling the excavation in dry conditions is less complicated than wet conditions. In sites where excavation is deep and groundwater is high, dynamic compaction of the backfill, placed in the ground in wet conditions, may be necessary to achieve sufficient shear strength to support the proposed development.

Developers and city planners want viable solutions that are financially reasonable. While dynamic compaction may sound like a crude methodology, it plays a vital role in improving substandard foundations. If you are considering redevelopment of a landfill, Brownfield or other property where the foundation is currently unsuitable consider establishing a business relationship now with a reliable dynamic compaction contractor since they are highly in demand and their availability can affect the project schedule.

 


 

About the Author:  Ali Khatami, Ph.D., PE, LEP, CGC, is a Project Director and a Vice President of SCS Engineers. He is also our National Expert for Elevated Temperature Landfills, plus Landfill Design and Construction Quality Assurance. He has nearly 40 years of research and professional experience in mechanical, structural, and civil engineering.

Dr. Khatami has many followers of his blog series “SCS Advice from the Field” on SCS’s website and social media channels. Send him a question or topic you’d like him to address.

 

 

 

 

 

 

 

 

 

Posted by Diane Samuels at 6:00 am

Innovative Projects on Landfill Sites

March 15, 2018

Landfill Sites are Finding Second Lives as Real Estate Properties

Innovative projects have sprung up over the years that house retail, apartments, golf courses, conference centers and hotels. Engineers in the solid waste space are applying several structural design techniques that other industries have leveraged for years like building on piles, which has historically been done on marshlands and other unstable ground. They’re also designing floating foundations that allow for movement and making adjustments when differential settlements happen.

Over the years, SCS has designed landfill-related systems for dozens of projects, mainly apartments, business complexes, entertainment complexes, hotels, parks and golf courses. In the past three years,SCS has fielded calls from developers looking into options, resulting in projects moving into the development stages. From small to the largest landfill redevelopment project in the nation , this article gets you started and leads to more information.

 

Posted by Diane Samuels at 6:00 am