Providing sustainable, effective remedial solutions for complex soil and groundwater contamination since 1993

Nature-based solutions in even the most challenging conditions.

Project Spotlights

Fractured Bedrock

New Stanton, PA

Target contaminants: trichloroethene and its degradation products

Depth: Up to 45 ft bgs

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Project Objective:
A Phyto-Integrated® combined-remedies approach that utilized targeted soil excavations, enhanced in-situ bioremediation, and TreeMediation® technologies to reduce concentrations of VOCs in on-site groundwater and mitigate the migration of VOC-impacted groundwater off-site and to downgradient off-site surface water.
Implementation:
A pilot TreeMediation study was installed in September 2014 consisting of 52 TreeWell® units planted with a mix of willow and hybrid poplar trees. The TreeWell units were planted to target migration pathways in shallow surface soils (up to 10 ft bgs) and shallow fractured shale bedrock (up to 45 ft bgs). Based on the success of the pilot study, a full-scale implementation consisting of 166 additional TreeWell units was installed in October 2016 in three plots downgradient from the pilot area. The full-scale installation included 62 shallow units installed to approximately 17 ft bgs, and 112 units installed to depths ranging from approximately 25 to 45 ft bgs. The full-scale installation was planted with alternations of willows, London plane trees, black locusts, and hybrid poplars. Additionally, due to shallow groundwater encountered in a portion of the planting area, 16 of the shallow units were installed as modified TreeWell units; installed to depths of 4.5-7 ft bgs, and planted with red twig dogwoods. Root camera tubes were installed in three of the units to monitor the root systems of each species of tree. Six piezometers and two nested piezometers were installed within individual TreeWell units to equip transducers, with the purpose of monitoring water levels.
Results to Date:
The growing seasons to date for the pilot study include 2014-2021, and the growing seasons for the three downgradient plots include 2017-2021. Tree growth and viability were observed to be “very good” for the entire TreeWell unit plantation. The tree health assessments do not show any indicators of plant stress. The height and canopy of most of the trees in the TreeWell units have continued to increase. Trees are displaying vigorous growth and, based on hydrogeologic monitoring data, are providing hydraulic capture. Preliminary hydrogeologic data suggest they are on track to perform as designed.

Deep Groundwater & Phytotoxicity

Carlyss, LA

Target contaminants: benzene, chlorobenzene, toluene, diphenyl ether, phenol; 1,1,2-TCA; 1,2-DCA; PCE; TCE; Chloroform; cis-1,2-DCE; trans-1,2-DCE; 1,1-DCE; vinyl chloride; 1,1-DCA; and lower concentrations of several other VOC constituents in shallow soils and groundwater

Depth: Approximately 25 – 115 ft bgs

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Project Objective:
Evaluate the efficacy of a TreeMediation® system for providing hydraulic control and remediation of groundwater impacted with high concentrations of VOCs including Dense Non-Aqueous Liquid (DNAPL) impacts. Target treatment depths ranged from 25 to 115 ft bgs.
Implementation:
The TreeMediation implementation consisted of 90 TreeWell® units installed in three different parts of the site over three separate installations. The first installation was performed in December 2015 and consisted of 18 TreeWell units installed on a 20 by 20 foot spacing to approximately 25 ft bgs. A set of hackberry, Russian olive, live oak, and black locust trees were planted in each of the 18 TreeWell units during the first phase of TreeMediation installation. During the 2015 installation the 18 TreeWell units were divided into three subsets with one subset filled with engineered soil with organic matter amendments, a second subset filled with a mixture of soil and zero-valent iron (ZVI), and a third subset filled with a mixture of soil, ZVI, and Daramend® (a proprietary electron donor). In 2017 phase II of the installation commenced with the installation of 18 close-bottomed straw TreeWell units in a second portion of the site. The straw TreeWell units were divided into zones with targeted depths ranging from 44-115 ft bgs. One set of shallow Phase II units were filled with a mixture of soil and ZVI, and the second set of shallow Phase II units and set of deep units were filled with engineered soil with organic matter amendments. Phase III of the installation commenced in 2019 with the addition of 51 straw TreeWell units in a third part of the site. The 2019 units were planted with 35 willow and 25 black locust trees in March 2020. Throughout the installations, a monitoring network consisting of piezometers and camera tubes was constructed to monitor the effectiveness of the TreeWell system at enhancing biodegradation of the COCs in shallow soils and groundwater and exert hydraulic influence on shallow groundwater.
Results to Date:
For the post installation (2016-2021) growing seasons, tree growth and viability were observed to be “very good” for the entire TreeWell unit plantation with no notable indications of plant stress observed. The height and canopy of most of the trees in the TreeWell units continues to increase. To date, no signs of VOC phytotoxicity have been observed.
VOC Concentrations:
Results of vertical profiling of total VOC and chloride concentrations in groundwater within TreeWell units indicate total VOC concentrations decrease as water flows upwards within all TreeWell units installed at the site. Although units with ZVI or ZVI and Daramend® in the backfill exhibited slightly more attenuation than units with only loam soil in the backfill, complete degradation of VOCs was still observed in units without ZVI or Daramend®. Additionally, the groundwater data indicate the straw TreeWell units are functioning as designed by transmitting groundwater from as deep as 115 ft bgs into the TreeWell units, facilitating remediation of VOCs within the TreeWell units.

Regulatory Closure

Sarasota, FL

Target contaminants: 1,4-Dioxane and a consequential plume migrating offsite via an aquifer.

Depth: ~ 15 ft bgs

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Implementation:
This 154 TreeWell®-unit project in Sarasota, FL was installed in the spring of 2013. The design targeted fractured bedrock contaminated with 1,4-Dioxane and a consequential plume migrating offsite via an aquifer. Slash pine, willow, sycamore, cypress, and laurel oak trees were used for the remediation of this site.
Results to Date:
After just three years, “No Further Action” was granted in 2016, and site closure (a Site Rehabilitation Completion Order) was issued by the Florida Department of Environmental Protection in March 2019. Prior to the installation of the TreeWell system, the client had been working toward their remedial goals for over 20 years. Additionally, with the success of Applied Natural Sciences’ intervention, an ineffective pump and treat system with UV/Peroxide that cost over $300k per year was dismantled.

**Traditional phyto has its limits.**

Conventional or non-engineered approaches treat shallow, impacted soil and groundwater and are appropriate for low-contaminant concentrations or low-level phytotoxicity. Problems with restricted root development and annual rainfall hinder broad implementation of such traditional systems.

**We have solutions.**

Our innovative systems expand the applicability and efficacy of phytoremediation. By engineering the growth of roots and managing the water that gets to them, we are able to utilize trees to reliably reach groundwater at depths exceeding 100 feet and direct root growth and water consumption to a target horizon in the aquifer of interest, while excluding water from other sources.
We are experts in the use of plants to remediate contaminants in groundwater and soil as well as the hydraulic control of plume geometry and contaminant migration.

Contaminants successfully treated by TreeWell® Systems

• Volatile Organic Compounds (VOCs) • Semi-Volatile Organic Compounds (SVOCs) including 1,4-dioxane • Pesticides • Agricultural inorganics such as nitrate & ammonium • Tritium • Solubilized metals: lead, arsenic, boron, zinc, cadmium

*Applied Natural Sciences is currently working on multiple pilot-scale TreeWell projects for the remediation of PFAS-impacted groundwater.

**Benefits of Our Patented TreeWell Remediation Systems**

On average, the lifetime cost of our remediation system is substantially lower than conventional remedies such as groundwater pump-and-treat systems.
Our systems have been successfully used to provide contaminant degradation in soil and groundwater under a variety of lithologic conditions. Additionally, our systems can be used to provide hydraulic control of groundwater, thereby mitigating plume migration.
Treatable contaminants include soluble compounds in soil and groundwater, including most VOCs, agricultural inorganics, solubilized metals, PFOA/PFAS, and semi-volatile organics.
While significant remediation is taking place in the soil and groundwater in the subsurface, the foliage of beautiful willows, hackberries, live oaks, palms, poplars, or spruce trees is growing above the surface.
As the trees mature, their groundwater uptake rates increase, providing improved hydraulic control and contaminant mass removal. Also, the root system typically hosts robust microbial populations that are capable of degrading many contaminants.
Our pioneering work in phytoremediation began in 1988. In 1993, Applied Natural Sciences was founded to implement our unique TreeMediation system. We have successfully completed dozens of projects in North America, South America, and Europe, including projects with a wide range of climatic and physiographic conditions.

Additional Resources

**Past PHYTO_INTEGRATED™ Remediation Project Overview**

**Conventional Phytoremediation vs. TreeWell-based System**

Our Services

Site evaluation, remedial design, phytoremediation implementation, monitoring and maintenance, and coordination of combined remediation strategies that incorporate our TreeWell-based engineered phytoremediation systems with other non-phyto remedial technologies

Nature-based solutions in even the most challenging conditions.

Project Spotlights

Fractured Bedrock

Deep Groundwater & Phytotoxicity

Regulatory Closure

Traditional phyto has its limits.

We have solutions.

Contaminants successfully treated by TreeWell® Systems

• Volatile Organic Compounds (VOCs) • Semi-Volatile Organic Compounds (SVOCs) including 1,4-dioxane • Pesticides • Agricultural inorganics such as nitrate & ammonium • Tritium • Solubilized metals: lead, arsenic, boron, zinc, cadmium

Benefits of Our Patented TreeWell Remediation Systems

Lower cost

Adaptable to a range of settings and contaminants

Aesthetically pleasing

Long-term effectiveness

Experience