TECHNOLOGIES

The highly trained experienced staff at Nature Works provides expertise in all phases of remediation with a special focus on those techniques that use natural biological processes. The field of bioremediation is new and exciting. Researchers around the globe frequently announce new and exciting innovative technologies that have been demonstrated at bench or lab scale sizes. At Nature Works we have concentrated our research efforts at problems that are associated with large-scale industrial operations in the areas of mining, smelting, pulp and paper and hydrocarbon extraction and processing.

Removing and sequestering heavy metals whether in soil or in ground or surface water has been a primary focus. We have designed and perfected a system that removes and sequesters high concentrations of heavy metals such as zinc, copper, lead, cadmium and others. The metals are converted to sulphides by biological processes and these insoluble salts are subsequently filtered from the effluent stream and remain within the bioreactor. Of special note is the strong removal efficiencies attained in treating water that contains high concentrations of arsenic. Our treatment system consistently reduces arsenic concentrations from mean levels of up to 200 parts per million (ppm) to less than 0. 4 ppm while at the same time reducing mean concentrations of zinc from 300 ppm to less than 0.5 ppm and cadmium from mean concentrations of 5 ppm to less than 0.01 ppm.

This high removal efficiency for arsenic is the subject of a current recent project that the company has undertaken in collaboration with researchers at the CANMET labs in Ottawa, The Light Source at the University of Saskatoon, The Environmental Sciences Group at The Royal Military College in Kingston and the Environmental Studies lab at the Institute of Petroleum Sciences and Geology in Calgary. The research is directed to elucidating the biological processes underlying the observed high concentration arsenic removal with a view to isolating and culturing the organisms responsible. It is supported, in part, by funding from the Industrial Research Assistance Program (IRAP) of the National Research Council.

One of the most important technologies used at Nature Works is Phytoremediation – a form of bioremediation where the degradation and/or removal of pollutants from a contaminated medium is caused, mediated, and/or assisted by plants. This in situ technology can be employed where degradation, removal or stabilization of contaminants in soil, sludge, sediment, wastewater or groundwater is required.

Passive treatment system designs using phytoremediation are generally very economic and can be used for remediation, wastewater treatment or waste management. The Nature Works system consists of a series of site specific engineered wetlands. The treatment option can be used for either organic or inorganic contaminants including:

Phytoremediation is most applicable where moderate–to–low levels of contaminants are present and where clean ups over relatively long time scales are acceptable. Thte practice can employ a variety of bioengineering techniques and is often used in situations to enhance already occurring natural attenuation processes that are taking place. .

Some of the most common mechanisms used are as follows:

Phytostimulation – Using plants to stimulate bacteria and fungi to mineralize pollutant using exudates and root sloughing. Some plants can release as much as 10-20% of their photosynthates in the forms of root sloughing and exudates. This can result in a 100-fold increase in microbial counts (Burken, 1996).

Phytoextraction – Uptake and accumulation of the pollutant into harvestable tissue either in the cell walls as lignin or in the vacuoles, generally on land.

Rhizofiltration – Pollutant is removed from water by plant roots in hydroponic solution.

Phytodegradation – Plants degrade the pollutant with or without uptake. It can be hard to define whether the plants or the microbes in the soil do the work.

Phytovolatization – Pollutant is converted to volatile form and released into the air.

RELATED TERMS

Landfarming – Placing contaminated soil in the uncontaminated A-horizon soil in a large open area to dilute the pollutant concentration sufficiently to allow both chemical and aerobic microbial degradation (Felsot et al., 1997)

Phreatophytes – fast growing plants that use large amounts of water in transpiration (Conger et al., 1997)