Authors: Robert Lacey (Delta Remediation) and Kurtis Trefry (Dominion Diamonds)
Delta Remediation has successfully completed bioremediation of long-chain (F1-F4G) hydrocarbons in Canada’s Arctic. Using its’ proprietary BioLogix technology to reclaim over 1,400 cubic meters of contaminated soils saving almost $200,000 after all expenses associated with the bioremediation treatment.
Located near Lac de Gras within the Northwest Territories, Canada approximately 300 km north of Yellowknife and roughly 200 km south of the Arctic Circle.The Ekati Diamond Mine is a surface and underground diamond mine providing quality employment and partnership with communities in the North. The Dominion Diamonds mine is only accessible by air, except for a brief period of annual winter road access. This remote nature of the mine provides many logistical challenges, specifically when it comes to limited timeframes to remove waste materials from the site and the high costs associated with trucking materials and offsite remediation.
Landfarming: Managing contaminated waste in a self-contained engineered treatment cell. With Dominion Diamonds mine being a Tier 1 mining operation with the highest level of environmental standards, all spills and contaminated media are removed from the site and stored within the Landfarm for remediation treatment.
These high costs associated with winter road utilization and off-site remediation to remove and remediate materials from the remote mine have led to the decision to look for innovative in-situ alternative solutions to soil remediation as a form of progressive reclamation and sound operational management. Bioremediation of hydrocarbon impacted soils through microbial augmentation has the potential to be a cost-effective in-situ remedial method to return materials back to within CCME Agricultural Guidelines that are required for the Dominion Diamond Mine.
Microbial metabolism of hydrocarbons has been proven on thousands of sites under various conditions, however typical environments have warmer temperatures that provide quicker metabolization of hydrocarbons. It is also understood that soils maintaining 10-20% moisture by weight encourages healthy microbial communities for bioremediation. With the Arctic being both cold and dry, this was a novel approach to a complex challenge (potentially the first of its’ kind in the Arctic).
The Landfarm Bioremediation Pilot Project aimed to evaluate whether bioaugmentation of microbial communities is an effective method of landfarm remediation while facing the cold climate and extreme photo-period fluctuations associated with the Canadian North. The Landfarm Bioremediation Project included a trial run in partnership with Delta Remediation. In June 2018, the initial trial has included 1400 m3 of hydrocarbon impacted materials being treated with a Biologix
technology to attempt to meet CCME Agricultural Guidelines.
Biologix is a proprietary blend of naturally-occurring microbes that were selected for their ability to degrade a wide range of organic chemicals, and specifically formulated for the remediation of petroleum and toxic organics. The overall benefit of bioaugmentation is the selective addition of beneficial microbes appropriate for the site conditions to reduce the risk and uncertainty that are associated with other stimulatory approaches to bioremediation. The strains were pre-evaluated in the product form for their ability to survive in the site’s soil (treated and non-treated) and how well they degraded total hydrocarbons. The soil itself was separately evaluated for nutrient content and it was found that the soil was most importantly limited in nitrogen and phosphates. A soil nutrient base containing ammonium nitrate was able to be sourced as a waste material on-site and was therefore included in the treatment.
Soil sampling was undertaken prior to and after the bioremediation process. By September 2019, the Biologix treatment had proved to reduce all petroleum hydrocarbon fractions. By September 2019 F1, F2, and F4 fractions were all able to meet CCME Agricultural Surface Soil Guidelines. F3 fractions were also proven to degrade with ranges of contamination ranging from 3120-8070 mg/kg before treatment and 1630-1880 mg/kg by September of 2019 In this timeframe, the microbes effectively degraded all fractions to the point that the entire trial windrow passes CCME Agricultural Subsoil Guidelines. This level of degradation meant that the entire trial windrow was able to be removed from the landfarm facility without the need to haul offsite.
Following the success of the Landfarm Bioremediation Pilot Project, 1000 m3 of previously hydrocarbon impacted soil has been able to be removed from the landfarm facility and was utilized as material to cap landfill waste below 1.5 m from the surface. This has proven that the bioremediation processes associated with the microbial degradation of hydrocarbons can be an effective method for treating hydrocarbon impacted soils within landfarm facilities within the Canadian Arctic.
The project will successfully reduce the remediation costs and greenhouse gas emissions associated with screening/bagging/hauling hydrocarbon impacted soils to Yellowknife for offsite remediation. When compared to the need to truck waste soils to an industrial landfarm in Yellowknife for remediation, the BioLogix process represents a net savings of ($194,000) or $194 per m3 treated.
Given that the material no longer requires to be transported offsite there are also significant reductions to the amount of carbon emissions released into the atmosphere. Considering that to transport 1000 m3 of hydrocarbon impacted soils offsite via the winter road would require 42 round trips from Yellowknife to Ekati approximately 672 running hours of diesel semi-trucks has been avoided. At a rate of 40 L of diesel per hour, 26,880 liters of diesel was not required. One liter of diesel creates 2.6 kg of greenhouse gas emissions when combusted. Therefore, with the successful completion of onsite bioremediation a total of 69,888 m3 of carbon emissions was saved from entering the atmosphere, just for a 1000 m3 trial.
The innovative nature of this investigation also provides alternative options for managing hydrocarbon impacted waste both at Ekati and other remote locations within challenging polar climates around the world.
For more information about Delta Remediation, please visit: deltaremediation.com