British Columbia Mine Reclamation Symposium

Biofuel crop production on biosolid-amended mine tailings at Highland Valley Copper Crawford, S.; Gardner, W.G.; Karakatsoulis, J. 2012

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 BIOFUEL CROP PRODUCTION ON BIOSOLID-AMENDED MINE TAILINGS AT HIGHLAND VALLEY COPPER   S. Crawford, BNRSc., W.G. Gardner, Ph.D. and J. Karakatsoulis, Ph.D.   Thompson Rivers University 900 McGill Road Kamloops, BC, V2C 5N3  ABSTRACT   Due to an increasing demand on arable land, researchers are now turning to decommissioned mine areas to grow biofuel crops. In the summer of 2010 a growth study was conducted on one of the decommissioned tailings ponds at Highland Valley Copper, a copper-molybdenum mine located in the interior of British Columbia. The objectives of the study were to determine whether three commonly used biodiesel- producing plant species - canola (Brassica napus L.), Indian mustard (Brassica juncea L.) and crambe (Crambe abyssinica Hochst ex Fries) - could achieve sufficient enough growth on biosolid-amended mine tailings to produce biofuels. After seeding, growth was monitored and the crops harvested at the end of one growing season. All aboveground plant biomass was measured and gross energy content and chemical composition of the plants was determined. Canola and Indian mustard achieved nearly equivalent growth in terms of dry biomass production but canola produced significantly more seed pod mass than Indian mustard. Crambe produced the least amount of biomass and seed pod mass. All yields were below standards for biodiesel production, which indicates seed production on this site is insufficient to sustain biodiesel production. However, further studies with an earlier seeding date are needed, as a late seeding date of mid-June may have placed restraints on the growth of the crop. Energy analysis indicates the gross energy content of both canola and Indian mustard are comparable to currently used cellulosic ethanol feedstocks, whereas crambe was significantly lower.  Key Words: canola, Indian mustard, crambe, energy content, biodiesel, bioethanol    INTRODUCTION  It is widely agreed upon that global supplies of fossil fuels are past their peak and many estimate most major crude oil reserves will be depleted by the year 2050 (Shafiee and Topal 2009). As a result, interest in biofuels as a renewable alternative to non-renewable fossil fuels has been increasing. A biofuel can be broadly defined as energy in the form of a solid, liquid, or gas that is produced by living organisms – usually plants – and converted into combustible fuel (McKendry 2002). Though the methods and feedstocks that produce these are numerous, generally they fall within two broad categories: oil-based fuels (biodiesel) and carbohydrate-based fuels (bioethanol). Biodiesel is produced from either animal or vegetable fats. These natural fats are converted to methyl ester fuel by a process known as transesterification (Mekhilef et al. 2011). Commonly, plant species with a high content of oil in the seed (oilseeds) such as soy, palm, and canola are used as biodiesel feedstocks, though recently a wider variety of oilseed species are being examined for potential as biodiesel producers. Conversely, bioethanol is produced from the breakdown and subsequent fermentation of simple carbohydrates – such as sugars or  cellulose – to form ethanol (McKendry 2002). A wide variety of plants are used to produce bioethanol, such as corn, sugarcane, switchgrasses, and wood fibers (McKendry 2002).  With escalating global food demand, production of fuel crops on agricultural land is increasingly controversial as arable land becomes scarce and in many cases degraded (Pimental et al. 2009). Additionally, in many cases land that is cleared of its traditional vegetation can result in an overall increase in release of greenhouse gases (GHGs), which are widely believed to be responsible for global climate change (Fargione et al. 2008). Therefore, many biofuels that require arable croplands today produce more GHGs than traditional fossil fuels (Pimental et al. 2009, Searchinger et al. 2008). As a result, many researchers are now looking for methods to produce biofuels without occupying valuable arable land. One that holds strong potential is using reclaimed mine spaces for the production of biofuel crops, as mines all over the world need realistic reclamation strategies for the unproductive areas left behind by mining activities. In Canada alone, approximately 400,000ha of land has been disturbed by mining activity to date, with mine openings, expansions and decommissions occurring on a regular basis. Recently Natural Resources Canada (NRCan) has been examining ways to return reclaimed mine areas to economically productive capacity by initiating research that studies the potential for producing biofuels on these “waste” areas. The Green Mines Green Energy (GMGE) initiative of NRCan has also incorporated the use of municipal and industrial organic residuals – such as pulp effluent or biosolids – into biofuel production (Natural Resources Canada 2009). In addition to providing a renewable source of energy, if these studies prove successful it would allow for the productive resolution of two former problems: the long term storage and use of organic residuals, and use of waste tailings that might otherwise not be economically productive.  Members of the Brassicaceae family are often used for the production of biodiesel, as many are classified as oilseeds, meaning the seed has oil content usually greater than 40% (Thomas 2003). Of particular interest in Canada are canola, crambe, and Indian mustard. Canola is a general term used to describe one of two cultivars of rapeseed: Brassica napus L. and Brassica campestris L.; this project examined B. napus, which is grown worldwide for the production of edible oil (Thomas 2003). Indian mustard (Brassica juncea L.) is another edible oilseed species grown worldwide, but to a lesser extent than B. napus (Gan et al. 2008). It is often used in mine reclamation and considered more drought tolerant than canola (Gan et al. 2008). Crambe (Crambe abyssinica Hochst ex. Fries) is a relatively unknown oilseed species, the oil of which is non-edible and used for industrial lubricants (UNFAO 2007a).  Highland Valley Copper (HVC) is an open pit copper-molybdenum mine located in the southern interior of British Columbia, Canada, near the town of Logan Lake. Biosolids from the greater Vancouver area have been in use at HVC for the purpose of reclamation for over a decade (Teck-Highland Valley Copper 2010). Biosolids are organic materials left over after the sewage treatment process. They are generally rich in organic matter, thus are extremely valuable to provide a suitable growing medium when incorporated into nutrient-poor waste rock and tailing material from mine sites. In 2009 HVC and Metro Vancouver joined NRCan’s GMGE initiative and launched a study to determine whether biofuel crop growth on biosolid-amended mine tailings would be feasible at HVC. Over the summers of 2009 and 2010 two small-scale pilot studies were conducted on a decommissioned tailings pond at HVC to determine the potential for biofuel crop growth on the Valley tailings pond after it is decommissioned. In 2009 the  studies were limited to determining which species would grow on the site, which allowed three species to be selected for further trial in 2010. The 2010 study attempted to further quantify biofuel production potential by measuring biomass, seed production, and energy content.  Though many studies have looked at the potential for biofuel production from oilseed crops (Jham et al. 2009, Peterson and Hustulid 1998), few have examined the potential for growth of these crop species on mine tailings. Even fewer have looked at the use of biosolids as a carbon and nutrient source for the production of these fuels. The specific climatic conditions of the HVC site create many unknowns regarding whether crop production would be feasible. Also little is known about whether the readily available minerals from the mine tailings or biosolids will have an effect on the growth and seed yield of the fuel crops, or whether these minerals will affect whether the crop residue can be used in cellulosic ethanol production. Studies such as this one seek to provide further insight into the rapidly expanding and highly important fields of energy production, residuals management, and mine reclamation.  The objectives of the 2010 study were to (1) determine whether canola, crambe, and Indian mustard could achieve significant growth on biosolid-amended tailings at HVC, (2) determine whether enough seed could be produced by the crops for each to be considered a viable biodiesel feedstock, and (3) determine what amount of energy from biomass could be produced from growth on the site.  MATERIALS AND METHODS  Study Area The GMGE study site was located on the Bethlehem tailings pond at 50°30’58”N, 120°58’43”W and an elevation of approximately 1450m. The growing season of this area typically spans from April to September. Details of long-term climatic normals, as well as 2010 climatic data, for the growing season are outlined in Table 1. The Bethlehem tailings pond was chosen in 2009 because the texture of the mine tailings there is silty-loam (Gardner et al. 2010), which is comparable to those present in the active Highland tailings pond, thus providing a representative pilot study for the field trials. Vegetation from previous reclamation efforts was removed from the site and bare tailings exposed. An area of approximately 1ha near the north end of the tailings pond was fenced off for the study to prevent browsing by ungulates.  Table 1: Long term climatic normals and 2010 climate data for the Highland Valley (Lornex) weather station, located 5km from the Bethlehem tailings pond. Year(s) April May June July August September 1971-2000 Temperature Normals (°C) 3.6 7.9 11.5 14.5 14.4 10.4 2010 Temperatures (°C) 3.9 6.3 10.4 15.7 15.1 9.9 1971-2000 Precipitation Normals (mm) 21.9 37.8 44.1 39.4 38.1 28.7 2010 Precipitation  Levels (mm) 24.3 62.0 16.0 11.0 61.2 48.1  Previous 2009 Trial In early spring of 2009 HVC staff established eighteen 5m x 5m (25m2) plots on the Bethlehem tailings and had Annacis WWTP (Wastewater Treatment Plant) biosolids from Metro Vancouver applied at a rate  of 200 dry tonnes ha-1 (dt ha-1), the standard for mine reclamation in British Columbia (Gardner 2010). Wildlife fencing was installed around the site to prevent browse on the crops. The scope of the 2009 trial was limited to selection of species; that is, determining which of several potential biofuel feedstocks would achieve growth on the site. The plots were seeded/planted with nine different species in duplicate in late May and growth occurred during the subsequent summer. Species trialed included: canola (Brassica napus), centennial Canada wild rye (Elymus canadensis), corn (Zea mays), crambe (Crambe abyssinica), dacotah switchgrass (Panicum virgatum), grouse green needlegrass (Nasella viridula), hybrid poplar (Populus x spp.), Indian mustard (Brassica juncea), and tomahawk Indian grass (Sorgastrum nutans). A survey by HVC staff in mid-summer showed poor germination of the plants (i.e. <5% growth), but photos taken in the fall showed significant growth and flowering over some of the plots had occurred after the mid-summer inspection. However, it was not noted at the time exactly which species had grown most successfully, nor was any biomass quantified. The data from the 2009 trial was used in the experimental design of this 2010 study.  2010 Study In early June of 2010 after an initial inspection of standing dead material from the 2009 studies by representatives from HVC, Metro Vancouver, and Thompson Rivers University, three of the species were selected for further trial: canola, crambe, and Indian mustard. Four plots remaining from the 2009 season were re-used in 2010 and had no new biosolids applied. The four plots that were re-used were selected based on least chance of contamination of the seed bank from the previous species: two that were previously corn – as corn had shown zero germination – and two that were previously hybrid poplar, as the seedlings were easy to transplant elsewhere. The biosolids remaining from the 2009 season were reincorporated into the tailings to a depth of approximately 30cm using a motorized rotary tiller to ensure sufficient mixing throughout the rooting depth of the crop species. However, it should be noted that though the plots had been roto-tilled, given the nature of the two materials being mixed there was still a fair amount of heterogeneity within the soil matrix.  Each of the four 5m x 5m plots were divided into four plots measuring 2.25m x 2.25m (5.06m2), leaving a 50cm buffer strip between all plots. A total of 16 plots were prepared.  In each plot 5 soil samples were taken to a depth of 10cm with a soil corer systematically across the plot to form a composite soil sample for the plot. These samples were sent to ALS Laboratory Group (Burnaby, BC) and analyzed for pH, electrical conductivity, and available nutrients, including: nitrate, phosphate, potassium, and sulfate. The three species were randomly assigned to the plots, with each species having 5 replicates. One plot remained unseeded to be used as a “control” to obtain an estimation of biomass production without seeding. The plots were seeded on June 15th, 2010 with the rates outlined in Table 2. Due to a miscalculation the canola plots were seeded at a higher rate (17.6 kg ha-1) than recommended by most industry standards of 5-6 kg ha-1 (Thomas 2003, Government of Saskatchewan 2008). After seeding, the plots were lightly raked to increase soil coverage of seed. Growth was monitored periodically throughout the summer and at the time of each survey weedy species encroaching from the surrounding area were removed.  On September 27th, 2010 all aboveground material was harvested from the plots by hand. At the time of harvest it was noted that seed pods were present and appeared to have started producing seed; however  upon opening of the seed pods it was determined that the seeds were underdeveloped and could not be quantified. Because it was so late in the growing season at that time, the decision was made to harvest the crops regardless, as there was little likelihood of further significant growth and seed development on the site. It was deemed that an estimation of seed production could be obtained from a weight measurement of seed pod production. Normally a yield would be reported in terms of actual seed mass (without the pod material); since seeds were not developed the seed pods serve as a proxy for seed production. Harvesting all of the seed pods from each plant could not have been done in a reasonable time frame, so at the time of harvest a representative plant (i.e. one of average height and vigour) from each plot was selected to obtain a measure of seed pod production by species. All plant material was subsequently dried in an industrial drying oven for three days at 60°C until a constant weight was achieved. Seed pods from each representative plant were removed and weighed. The amount of seed produced by each representative plant was divided by the weight of that representative plant in order to establish a ratio of seed production to biomass production. This ratio was then used to extrapolate seed pod production on a kg ha-1 basis based on biomass production.  Near-infrared spectroscopic (NIRS) analysis (Foss InfraXact™, Foss North America, Eden Prairie, Mn) was employed to determine several chemical parameters of cellulosic material from each of the sample plants. Prior to analysis a branch (including stem and leaf material) from each of the fifteen dried samples – one from each plot – was randomly selected and ground to a particle size <1mm. Each sample was then analyzed for copper content (μg g-1), iron content (μg g-1), percent lignin, percent soluble carbohydrates, and percent simple sugars, which were deemed most relevant to the study questions. Due to limitations in the NIRS database and specific chemical parameters of the plant, copper and simple sugar data from crambe could not be used. Using these same samples energy content of the three species was determined using a Parr Model 1341 Oxygen Bomb calorimeter (Parr Instrument Company, Moline, Il.). All results were examined for variance using Minitab statistical software (Version using one-way ANOVA analysis procedures. Where assumptions of the ANOVA were not met and attempts to transform the data were unsuccessful, a nonparametric equivalent test (the Kruskal-Wallis) was used on ordinal data.  RESULTS  Tailings There was no significant difference in tailings parameters across the plots at the p<0.05 level. The pH of the samples ranged from 6.49 to 7.45. Though metal contents of the tailings were not determined in this study, Gardner et al. (2010) provide extensive details on the Bethlehem tailings. Total copper and molybdenum on unamended tailings were 675 and 34 mg kg-1 respectively in 2002, which is far greater than typical agricultural soils (McKenzie 1992).  Biomass and Seed Pod Production Canola and Indian mustard produced significantly more biomass (p=0.009) than crambe (Table 2). The control plot produced 1406.1kg ha-1 of biomass, consisting mostly of yarrow (Achillea millefolium), hawkweed (Hieracium spp.), fescue (Festuca spp.), Poa spp, and timothy (Phleum spp.). Per plot, canola produced significantly more seed mass (p=0.007), followed by Indian mustard, while crambe produced the least amount of seed pod mass per plot (Table 2). Using the ratio of seed pod production to biomass  production to calculate an overall estimation of potential seed pod production, canola production was significantly higher than both Indian mustard and crambe (p=0.011). Estimated seed pod production followed the same trend with canola producing the most, followed by Indian mustard and crambe (Table 2).  Table 2: Summary of mean growth data for canola, Indian mustard, crambe. The projected seed pod production is based on the ratio of seed pod mass produced per gram of plant material produced, multiplied by the average biomass produced for each of the species. SEM given in italics. A * denotes a significantly lower production. Species Seeding rate (kg ha-1) Biomass (kg ha -1) Seed pod production (g plot-1) Estimated seed pod production(kg ha-1) Canola 17.8 4024.9 ± 953.4 4.8 ± 0.84 140.5 ± 50.5 Crambe 104.0 569.3 ± 197.3* 0.3 ± 0.13* 2.45 ± 1.1* Indian Mustard 22.0 4033.6 ± 176.6 1.6 ± 0.62* 49.4 ± 19.3*  Plant Nutrient Composition and Energy Production Levels of copper, lignin and simple sugars were not significantly different between the species (Table 3). Content of soluble carbohydrates in crambe was significantly higher than both canola and Indian mustard (F=16.43, p<0.001). There was a significant difference in the amount of energy produced between the species (F=36.71, p<0.000) with crambe producing a significantly lower amount of energy than the other two species (Table 3).  Table 3: Chemical parameters and energy of the cellulose material of the crop species. Due to limitations in the NIRS database, copper and simple sugar content could not be determined for crambe. Parameters with a * are significantly different at the p=0.05 level.  Canola Crambe Indian Mustard Copper ± S.E.M. (µg g-1) 5.06 ± 0.55 -- 5.89 ± 0.83 Iron ± S.E.M. (µg g-1) 115.4 ± 1.84 -- 102.6 ± 12.3 Lignin ± S.E.M. (%) 6.79 ± 0.46 7.79 ± 0.12 7.67 ± 0.62 Simple Sugars ± S.E.M. (%) 4.68 ± 0.62 -- 3.24 ± 1.18 Soluble Carbohydrates ± S.E.M. (%)* 7.21 ± 0.48 12.28 ± 0.66 6.80 ± 1.01 Energy ± S.E.M. (J g-1)* 16557± 152 14743± 124 16617 ± 232  DISCUSSION  Based on the above growth, seed pod production, and energy results, crambe is not suitable for use as a biofuel feedstock when grown on this site. Cover of this species was less than 25% on each plot, which may allow for increased eolian dispersal of tailings and biosolid material (Mendez and Maier 2008). Seeding rate (104kg ha-1) was far greater than projected seed pod production (2kg ha-1), resulting in a net loss of seed. Additionally, energy content was significantly lower than canola and Indian mustard, as well as many other commonly used cellulosic ethanol feedstocks (McKendry 2002). Henceforth this paper will examine the two remaining species in terms of their suitability for (1) biodiesel production and (2) cellulosic ethanol (bioethanol) production, and offer suggestions for improvements in experimental design for future studies.   Biodiesel Production Based solely on the projected seed pod production, initially the crops examined in this study would seem unsuitable for the production of biodiesel, as the yields are far below standard yields (Thomas 2003). However, as mentioned above, the crops were harvested before the seed had a chance to fully mature; though seed pods were present, seeds were underdeveloped, thus no actual seed yield was obtained. This is likely because the crops were seeded late (June 15th), whereas most crop manuals recommend a seeding date of late April to mid May for spring-sown canola (Thomas 2003, Gunasekera et al. 2005).  Thus, in terms of using seed pod production as a proxy for suitability of these crop species for biodiesel production on this site, this study is inconclusive. However, by examining the data and conducting a search of pertinent literature, estimations of potential growth restrictions and each crop’s suitability for the site can be achieved. This information is presented within various categories, including nutrients, timing of seeding, and metals in the soil.  Nutrient availability of the site can have drastic effects on seed quality and yield (Thomas 2003, Gunasekera et al. 2005). As we see in Table 2, the estimated seed pod yields of canola are significantly higher than those of Indian mustard. This difference is likely not due to the climate; as mentioned previously, Indian mustard is generally considered more tolerant of climatic stressors than canola and has been shown to have higher yields than canola on stressful sites (Gan et al. 2008). Nitrogen, and nitrate in particular, is considered important in plant growth and in many cases a limiting nutrient in oilseed crop production (Jackson 2000). Indian mustard is regarded as an efficient user of nitrogen (Gan et al. 2008). However, the recommended level of nitrate for Brassica crops in the soil is approximately 30mg/kg (Howell 2006), so it is unlikely that nitrate levels in the soil were limiting for growth even in Indian mustard plots. Potentially, other factors may be interfering with the production of seed pod mass in Indian mustard. Factors such as pH, cation exchange capacity, and electrical conductivity all play a role in bioavailability of nutrients and may have impacted nutrient uptake. However, the pH of the sub plots ranged from 6.49 – 7.45, which is considered neutral for soils and within the normal growth range for both canola and Indian mustard (Thomas 2003, Gunasekera 2008) and EC was below the critical threshold of 4 dS m-1, beyond which plant growth is negatively affected.  Depending on growth conditions, the average maturation time for Brassica napus is 95-125 days (Thomas 2003), Brassica juncea is 75-100 days (UNFAO 2007b), and Crambe abyssinica is 83-106 days after seeding (Endres and Schatz 1993). In this study the time between seeding and harvesting of the plots was 104 days, which indicates that under normal conditions the plants likely should have had adequate maturation time. However, at the time of harvest many flowers were present on most of the plants, which indicates that the crops had not yet reached the seed development stage for those flowers (Thomas 2003).  Timing of seeding is one of the most important aspects of oilseed crop production (Government of Saskatchewan 2008, Thomas 2003). The specific climatic conditions of the site – higher elevation and cooler temperatures during the growing season – may mean the crops require a longer growth period (Thomas 2003, Gunasekera et al. 2000). The crops may have delayed flowering during the hottest part of the growing season by entering into a semi-dormant state to avoid seed pod abortion (Government of Saskatchewan 2008, Thomas 2003), which would have left inadequate time for seed development in the fall. Additionally, the timing of precipitation and peak temperatures in the 2010 season were different than  the 30-year normals (Table 1). June and July were drier and hotter than normal, whereas May and September were cooler and wetter than the normal. Both April and August were warmer and received more precipitation than the long-term average. Since the crops were seeded in mid-June, there may have been insufficient moisture within the first critical germination phase; very little precipitation occurred in the two weeks after seeding, which may have delayed germination and subsequent growth. Irrigation of the crops during this time may have increased growth potential.  Since the crops were grown on mine tailings, both copper and molybdenum are present in higher concentrations than typical growing mediums for oilseed crops. Many Brassica species are classified as hyperaccumulators; that is, they readily uptake minerals and remove them from the growing medium (Mendez and Maier 1998). While copper is an essential nutrient at moderate levels, it can be toxic at high levels and has been shown to cause oxidative stress through the generation of free radicals in the plant tissue and can result in poor growth and decreased seed yield in both canola and Indian mustard (Khurana et al. 2006).  Gardner et al. (2010) reported total copper levels in Bethlehem tailings to be 675 mg/kg, which is far above the soil sufficiency level of 1mg/kg (McKenzie 1992). However, despite high copper levels in the growing medium, the copper levels of the plants in this study were near deficiency levels as the threshold of copper deficiency has been reported as anything below 2.6μg/g (Thomas 2003).  Since seeds were underdeveloped at the time of harvest, mineral content of the seed material cannot be quantified. Higher metal content in the seeds, and subsequently in the oil, can degrade the quality of biodiesel derived (Sarin et al. 2009). Hyperaccumulators have differential ability to uptake and transport metals; some species sequester metals in the roots whereas others accumulate metals in the shoot, seeds and leaf material (Mendez and Maier 2008). Those species that accumulate metals within the seed material are likely less suitable for biodiesel production. Both Indian mustard (Singh and Sinha 2005) and canola (Ivanova et al. 2010) have been shown to accumulate metals in greater concentration in root material, which may indicate metal levels in seed are lowest. However, metal accumulations within the various plant organs have been shown to vary as the plant grows (Ivanova et al. 2010), so timing of harvest may affect concentration of metals within seeds.  Cellulosic Ethanol Production Use of plant residues (the stem and leaf material left behind after seed is removed) for the production of cellulosic ethanol has been controversial in the past. Removal of residue material from the growing medium has been said to increase wind erosion, decrease soil organic carbon content, and result in an increase in GHG emissions (Lal 2005). This study removed all biomass material from the plots and determined overall production, energy contents of the material, as well as chemical composition in order to provide insight into whether removal of these residuals from the site would be feasible for production of cellulosic ethanol.  In the literature a variety of biomass types are currently being examined for use as feedstocks for cellulosic energy production. A crop must produce considerable biomass to be considered as a feedstock on the site. Canola and Indian mustard produced 4025 and 4034kg/ha of biomass respectively. This is low  when compared to biomass yields for switchgrass (8920kg ha-1, McKendry 2002), but comparable to others including winter wheat (3900kg ha-1) and barley (5200kg ha-1) (George et al. 2003). Though the climatic parameters may have been limiting, likely the largest factor in the lower biomass yield is the late seeding date.  The scope of this study was limited to examining energy content of materials produced on the site, but inferences can be made from the NIRS data obtained as well. The most important compounds for the production of bioethanol are cellulose and hemicelluloses, as these are the broad categories for the wide variety of sugars than are fermented to produce ethanol (Hamelinck et al. 2005).  According to McKendry (2002), suitability of a biomass as a bioethanol feedstock is dependent on moisture content, energy value, carbon and volatile content, ash content, alkali metal content, and the cellulose to lignin ratio. The energy content of canola and Indian mustard (both 16.6MJ kg-1) determined by this study are comparable to energy values of currently used cellulosic feedstocks, such as barley straw (16.1MJ kg-1), wheat straw (17.3MJ kg-1), and to a lesser extent switchgrass (18.3MJ kg-1) (McKendry 2002). Thus, based on energy content the residues of both canola and Indian mustard may be considered acceptable feedstocks for the production of cellulosic ethanol. However, both the simple sugar and the soluble carbohydrate contents of the crops were low, which suggests that easily available sugar sources were low. This is similar to the results of George et al. (2010), who found that canola residue was likely a poor feedstock for the production of cellulosic ethanol due to low cellulose content, but suggested further studies given the high production of residue by canola. As well, crops on this site showed lignin levels far below standard compositional values, which may be considered valuable as lignin impedes the production of cellulosic ethanol because it is not easily broken down and exists as a residue after ethanol production (Hamelinck et al. 2005).  High metal concentrations in plant material can lower its quality as a biofuel feedstock (Hamelinck et al. 2005) due to increased likelihood of ash content (McKendry 2002). As hyperaccumulators of metals, Brassica species may prove to be poor feedstocks due to high metal accumulation potential when grown on high metal content mediums such as this site. The NIRS data provided us with metal contents of the plant residue material. Though copper levels in both canola and Indian mustard were low, iron levels were well above the standard (Thomas 2003).  CONCLUSIONS  The broad objective of the GMGE project at HVC is to determine whether biofuel crop production is feasible on biosolid-amended mine tailings at HVC. As mentioned previously the objectives of this pilot study were to (1) determine whether canola, crambe, and Indian mustard could achieve significant growth on biosolid-amended tailings at HVC, (2) determine whether enough seed could be produced by the crops for each to be considered a viable biodiesel feedstock, and (3) determine what amount of energy from biomass could be produced from growth on the site.  The first objective was achieved in that the growth of all three of the tested species was quantified. Based on field observations, canola and Indian mustard appear to be capable of growing well on this site, while crambe appears to be poorly suited for the site. Though biomass yields were lower than commonly used  crop feedstocks, an earlier seeding date may allow for greater biomass yields at the end of the growing season. Additionally, seeding all crops at appropriate rates will likely increase overall biomass production on the site.  The second objective of this study could not be achieved with this study as the seed pods were not at maturity at the time of harvest, likely due to the late seeding date. High elevation sites such as this one are prone to late frosts, but given the long term average daily temperatures for HVC of 3.6°C in April and 7.9°C in May (Environment Canada 2011), a seeding date of approximately mid May would allow for seeds to germinate with less risk of lethal low temperatures, at the same time allowing the crops to flower prior to the hottest part of the growing season in July/August and leave adequate time for pod development afterwards (Thomas 2003).  The third objective of this study, determining energy contents of the crops, was achieved via bomb calorimetry and NIRS analysis. The energy contents of canola and Indian mustard are comparable to currently used cellulosic ethanol feedstocks, but heightened levels of metals present in the plant tissues may degrade the quality of these plants as feedstocks. Future studies should incorporate a more in-depth analysis of plant composition, including metal concentrations present within the tailings and plant tissue. Additionally, actual production of cellulosic ethanol from the crops grown on this site would be extremely valuable for answering the central question. Using gross energy content to determine value of a crop as a biofuel feedstock can provide a rough estimation of overall energy content, but further analysis is needed to determine easily obtainable energy.  The concepts behind the GMGE initiative are highly valuable in moving towards a more energetically sustainable future. On a broad scale, by moving away from non-renewable fossil fuels and concurrently finding a suitable use for non-economically productive mine lands and organic residuals, there is great potential for environmental, scientific, and social advancement.  FUTURE RECOMMENDATIONS  Determining whether biofuel crop growth is possible at this site is only one aspect of feasibility. Energetically, an oilseed crop plantation may require extensive inputs in the form of irrigation and pesticides. The nutrient demand may be met by the addition of biosolids. Conducting a life cycle analysis of the energetics associated with all the stages of biofuel production is important. This would provide an opportunity to determine whether energetics associated with the production of biofuels on the site – such as biosolid transportation and application, seeding and cultivation of the crops, harvesting, and production of fuels – would outweigh the amount of energy produced from the biofuels on the site.  Another important aspect to consider is determining whether the production of biofuels on this site is economically feasible. Future studies need to include a cost benefit analysis of crop production, including examination of energy yields from different crops or biomass sources. In future years as global fossil fuels diminish and costs of these fuels rises, renewable energy will likely become more economically feasible. Additionally, since technology surrounding biofuel is continually advancing, costs associated with production will likely decline.  REFERENCES  Endres, G. and Schatz, B. 1993. “Crambe Production”. Available: Accessed: 29 April 2011. Environment Canada. 2011. Climate data. “Highland Valley Lornex” weather station. Available: Accessed 18 March 2011. Fargione, J., Hill, J., Tilman, D., Polasky, S., and Hawthorne, P. 2008. Land Clearing and the Biofuel Carbon Debt. Science. 319. Pp 1235-1237. Gan, Y., Mahli, S., Brandt, S., Katepa-Mupondwa, F., and Kutcher, H. 2008. Optimizing the production of Brassica juncea canola, in comparison with other Brassica species, in different soil-climatic zones. Report, prepared for Saskatchewan Canola Development Commission. Available online: [Accessed 18 Feb 2011]. Gardner, W., Broersma, K., Naeth, A., Chanasyk, D., and Jobson, A. 2010. Influence of biosolids and fertilizer amendments on physical, chemical, and microbiological properties of copper mine tailings. Canadian Journal of Soil Science. 90. Pp 571-583. George, N., Yang, Y., Wang, Z., Sharma-Shivappa, R., and Tungate, K. 2010. Suitability of Canola Residue for Cellulosic Ethanol Production. Energy Fuels. 24. Pp 4454-4458. Government of Saskatchewan. 2008. “Canola Production”. Available: Accessed 18 March 2011. Gunasekera, C., Martin, L., Siddique, K., and Walton, G. 2005. Genotype by environment interactions of Indian mustard (Brassica juncea L.) and canola (B. napus L.) in Mediterranean-type environments 1. Crop growth and yield. European Journal of Agronomy. 25. 1-12. Hamelinck, C., Hooijdonk, G., Faaij, A. 2004. Ethanol from lignocellulosic biomass: techno-economic performance in short-, middle-, and long-term. Biomass and Bioenergy. 28. 384-410. Howell, J. 2006. “Nutrient Management for Brassica Crops” Available: [Accessed 11 April 2011]. Ivanova, E., Kholodova, V., Kuznetsov, V. 2010. Biological Effects of Copper and Zinc Concentrations and Their Interaction in Rapeseed Plants. Russian Journal of Plant Physiology. 57. 864-873. Jackson, G. 2000. Effects of Nitrogen and Sulfur on Canola Yield and Uptake. Agronomy Journal. 92. Pp 642-649. Jham, G., Moser, B., Shah, S., Holser, R., Dhingra, O., Vaughn, S., Berhow, M., Winkler-Moser, J., Isbell, T., Holloway, R., Walter, E., Natalino, R., Anderson, J., and Stelly, D. 2009. Wild Brazilian Mustard (Brassica juncea L.) Seed Oil Methyl Esters as Biodiesel Fuel. Journal of the American Oil Chemists’ Society. 86. Pp 917-926. Khurana, N., Singh, M. and Chatterjee, C. 2006. Copper Stress Alters Physiology and Deteriorates Seed Quality of Rapeseed. Journal of Plant Nutrition. 29. Pp 93-101.  Lal, R. 2005. World crop residues production and implications for its use as a biofuel. Environment International. 31. 575-584. McKendry, P. 2002. Energy production from biomass (part 1): overview of biomass. Bioresource Technology. 83. Pp 37-46. McKenzie, R. 1992. Micronutrient Requirement of Crops. Agri-Facts (Agdex 531-1). Available:$department/deptdocs.nsf/all/agdex713/$file/531- 1.pdf?OpenElement. Accessed: 3 April 2011. Mekhilef, S., Siga, S., and Saidur, R. 2011. A review on palm oil biodiesel as a source of renewable fuel. Renewable and Sustainable Energy Reviews. 15. Pp 1937-1947. Mendez, M. and Maier, R. 2008. Phytostabilization of Mine Tailings in Arid and Semiarid Environments – An Emerging Remediation Technology. Environmental Health Perspectives. 116. Pp 278-283. Natural Resources Canada. 2009. ‘What is the Green Mining Initiative?” [Website]. Available from: Accessed 30 September 2010. Peterson, C. and Hustrulid, T.  1998. Carbon cycle for rapeseed oil biodiesel fuels. Biomass and Bioenergy. 14. Pp 91-101. Pimentel, D., Marklein, A., Toth, M., Karpoff, M., Paul, G., McCormack, R., Kyriazis, J. Krueger, T. 2009. Food Versus Biofuels: Environmental and Economic Costs. Human Ecology. 37. 12pp. Sarin, A., Arora, R., Singh, N., Sharma, M., Malhotra, R. 2009. Influence of metal contaminants on oxidative stability of Jatropha biodiesel. Energy. 34. 1271-1275. Searchinger, T., Heimlich, R., Houghton, R., Dong, F., Elobeid, A., Fabiosa, J., Tokgoz, S., Hayes, D. and Yu, T. 2008. Use of U.S. Croplands for Biofuels Increases Greenhouse Gases Through Emissions from Land-Use Change. 319. Pp 1238-1240. Shafiee, S. and Topal, E. 2009. When will global fossil fuel reserves be diminished? Energy Policy. 37. Pp 181-189. Singh, S. and Sinha, S. 2005. Accumulation of metals and its effects in Brassica juncea (L.) Czern. (cv. Rohini) grown on various amendments of tannery waste. Ecotoxicology and Environmental Safety. 62. Pp 118-127. Teck-Highland Valley Copper. 2010. Assessment of Operationally Reclaimed Sites. Annual Reclamation Report. Thomas, P. 2003. Canola Growers Manual. Canola Council of Canada. Available: Accessed 30 September 2010. United Nations Food and Agricultural Organization (UNFAO). 2007a. Data Sheet: Crambe abyssinica. Available: 24 March 2011. United Nations Food and Agricultural Organization (UNFAO). 2007b. Data Sheet: Brassica juncea. Available: Accessed 24 March 2011.


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