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Zhang X.,INRS Eau | Yan S.,INRS Eau | Tyagi R.D.,INRS Eau | Surampalli R.Y.,U.S. Environmental Protection Agency
Chemosphere | Year: 2011

Nanotechnology has attracted a great interest in recent years due to its expected impact on many areas such as energy, medicine, electronics, and space industries. This review provides the state-of-art knowledge on the synthesis of nanoparticles by microorganisms including bacteria, fungi, actinomycetes, and yeast, and their effect on microbiological processes. The available microbes and their predicted nanoparticle biosynthesis mechanism, the conditions to control the size/shape and monodispersity of particles, and microbiological reaction rate enhancement using nanoparticles as catalysts are presented. The current limitations and future scope for specific research are also discussed. © 2010 Elsevier Ltd.

Zhang X.L.,INRS Eau | Yan S.,INRS Eau | Tyagi R.D.,INRS Eau | Surampalli R.Y.,U.S. Environmental Protection Agency
Renewable and Sustainable Energy Reviews | Year: 2013

Vegetable oils and animal fats are the most often used feedstock in biodiesel production; however, they are also used in food production, which results in increasing the feedstock price due to the competition. Therefore, alternative feedstock is required in biodiesel production. Heterotrophic microalgae are found capable of accumulating high lipid (up to 57% w/w). They can use complex carbons such as sweet sorghum and Jerusalem artichoke as nutrients to produce equivalent quantity oil as that of using glucose, which provides a cheap biodiesel production strategy. It was found that nanomaterials could stimulate microorganism metabolism, which suggested that nanomaterial addition in the cultivation could enhance lipid production of microalgae. Furthermore, the use of nanomaterials could improve the efficiency of the lipid extraction and even accomplish it without harming the microalgae. Nanomaterials such as CaO and MgO nanoparticles have been used as biocatalyst carriers or as heterogeneous catalyst in oil transesterification to biodiesel. In this paper, the factors that could impact on lipid accumulation of heterotrophic microalgae are critically reviewed; the advances on application of nanotechnology in microalgae lipid accumulation, extraction, and transesterification are addressed. © 2013 Elsevier Ltd. All rights reserved.

Roy M.L.,University of Montréal | Roy A.G.,University of Montréal | Grant J.W.A.,Concordia University at Montréal | Bergeron N.E.,INRS Eau
Canadian Journal of Fisheries and Aquatic Sciences | Year: 2013

Stream-dwelling salmonid populations are generally thought to be composed of both relatively mobile and sedentary individuals, but this conclusion is primarily based on results obtained from recapture methods with low temporal resolution. In this study, the mobility of 50 juvenile Atlantic salmon (Salmo salar) was monitored using a large array of passive integrated transponder antennas buried in the bed of a natural stream. Fish locations were recorded at a high frequency for a period of 3 months in a 65mreach. Four types of daily behaviour were identified: stationary (detected primarily at one location), sedentary (limited movement between a few locations), floater (frequent movements in a restricted home range), and wanderer (movements across the reach). Most individuals exhibited low mobility on most days, but also showed occasional bouts of high mobility. Between-individual variability accounted for only 12%-17% of the variability in the mobility data. High mobility was more frequent at low flow, but no difference was observed between the summer (12-18 °C) and the autumn (4-12 °C). Individual variation on a daily basis suggested that movement behaviour is a response to changing environmental conditions rather than an individual behavioural trait.

Roy M.L.,University of Montréal | Roy A.G.,University of Montréal | Grant J.W.A.,Concordia University at Montréal | Bergeron N.E.,INRS Eau
Canadian Journal of Fisheries and Aquatic Sciences | Year: 2013

The magnitude of variation of diel activity patterns and habitat use of wild Atlantic salmon (Salmo salar) parr was examined during the summer and autumn through a gradient of declining temperature. Fish were marked with passive integrated transponders and tracked using a large network of flatbed antennas. High interindividual variability was observed, as some individuals were predominantly nocturnal whereas others frequently changed their daily activity pattern. Overall fish activity decreased with decreasing temperature and increasing flow stage, but most of these changes in daily activity were observed in crepuscular periods. Parr used habitats with lower velocity at night than in the day during the summer, but not in the autumn. Furthermore, there was no difference between day and night habitats for fish that were cathemeral (active both day and night during a given day), so differences between day and night habitats were the result of individuals adopting different activity patterns. These results suggest that habitat interacts with activity pattern, as individuals using suboptimal habitats seem to increase daytime foraging to secure sufficient energy. Temporal and among-fish variability of activity patterns illustrate the dynamic nature of foraging decisions that may partly result from trade-offs experienced at the microhabitat scale.

Mailhot A.,INRS Eau | Lachance-Cloutier S.,Center dExpertise Hydrique du Quebec | Talbot G.,INRS Eau | Favre A.-C.,Polytechnic School of Algiers
Journal of Hydrology | Year: 2013

The Peak-Over-Threshold (POT) approach is an interesting alternative to the one based on Annual Maxima (AM) series since it gives the opportunity to take into consideration extreme events that would not be considered otherwise. It has also been recognized that the regional approach improves statistical inference when compared to the local approach, assuming that the region is statistically homogeneous. A regional POT approach was developed and applied to the network stations located in southern Québec. POT series for 5-, 10-, 15-, 30-min and 1-, 2-, 6- and 12-h durations were constructed assuming a fixed exceedance rate. An analysis of local POT series showed that the intra-annual variability of the Generalized Pareto Distribution (GPD) parameters needs to be taken into consideration. Models of various complexities were defined combining local and regional representations as well as the intra-annual variability of GPD parameters. Regional likelihood was estimated and models were compared based on the Akaike Information Criterion (AIC). Models with regional shape and scale parameters and accounting for intra-annual variability were selected for all durations. Spatial covariates were also introduced through a simple model linking GPD parameters to latitude, longitude and altitude. The sensitivity of results to threshold values and selected models was also investigated. Interpolated maps of intense rainfall over the studied area are finally proposed. © 2012 Elsevier B.V.

Pilli S.,INRS Eau | Bhunia P.,Indian Institute of Technology Bhubaneswar | Yan S.,INRS Eau | LeBlanc R.J.,GMSC | And 2 more authors.
Ultrasonics Sonochemistry | Year: 2011

Ultrasonication is an emerging and very effective mechanical pretreatment method to enhance the biodegradability of the sludge, and it would be very useful to all wastewater treatment plants in treating and disposing sewage sludge. Ultrasonication enhances the sludge digestibility by disrupting the physical, chemical and biological properties of the sludge. The degree of disintegration depends on the sonication parameters and also on sludge characteristics, therefore the evaluation of the optimum parameters varies with the type of sonicater and sludge to be treated. The full-scale installations of ultrasonication have demonstrated that there is 50% increase in the biogas generation, and in addition evaluation of energy balance showed that the average ratio of the net energy gain to electric consumed by the ultrasound device is 2.5. This review article summarizes the benefits of ultrasonication of sludge, the effect of sonication parameters, impact of sludge characteristics on sludge disintegration, and thereby the increase in biogas production in anaerobic digester. Due to uncertainty in the unit representation by many researchers and nonavailability of the data, comparison of these results is complicated. Comparison of ultrasonication with other pretreatment options is necessary to evaluate the best economical and environmental pretreatment technology for sludge treatment and disposal. The optimum parameters for the ultrasonication vary with sludge characteristics. © 2010 Elsevier B.V.

This study compares, for the southern region of Quebec (Canada), different estimators of intensity- duration-frequency (IDF) curves based on the partial duration series (SDP) or series of annual maxima (SMA). Two models were considered for the SMA, the first one with one local parameter (SMA-1), and the second with two local parameters (SMA-2). For the SDP, the series were built defining, in one case, a regional threshold (SDP-1), and in the other case, the regional average number of threshold exceedences (SDP-2). The quantiles of these models and their 90% error bounds were estimated and compared. The SDP-1 model was finally selected because, according to the literature, it would suit a region like that under study which displays reasonable heterogeneity. Furthermore, the SDP-1 model fits the empirical quantiles and probabilities relatively well. At each site, quantiles estimated by this regional model are compared to those obtained using the local SDP model. © 2010 IAHS Press.

Zhang X.,INRS Eau | Yan S.,INRS Eau | Tyagi R.D.,INRS Eau | Surampalli R.Y.,U.S. Environmental Protection Agency
Renewable Energy | Year: 2013

It has been recognized that oils derived from microorganism and wastewater sludge are comparable replacements of traditional biodiesel production feedstock, which is energy intensive and costly. Energy balance and greenhouse gas (GHG) emissions are essential factors to assess the feasibility of the production. This study evaluated the energy balance and GHG emissions of biodiesel production from microbial and wastewater sludge oil. The results show that energy balance and GHG emissions of biodiesel produced from microbial oil are significantly impacted by the cultivation methods and carbon source. For phototrophic microorganism (microalgae), open pond system gives 3.6 GJ higher energy gain than photo bioreactor system in per tonne biodiesel produced. For heterotrophic microorganisms, the energy balance depends on the type of carbon source. Three carbon sources including starch, cellulose, and starch industry wastewater (SIW) used in this study showed that utilization of SIW as carbon source provided the most favorable energy balance. When oil extracted from municipal sludge is used for biodiesel production, the energy gain is up to 29.7 GJ per tonne biodiesel produced, which is higher than the energy gain per tonne of biodiesel produced from SIW cultivated microbes. GHG emissions study shows that biodiesel production from microbes or sludge oil is a net carbon dioxide capture process except when starch is used as raw material for microbial oil production, and the highest capture is around 40 tonnes carbon dioxide per tonne of biodiesel produced. © 2013 Elsevier Ltd.

Zhang X.,INRS Eau | Yan S.,INRS Eau | Tyagi R.D.,INRS Eau | Drogui P.,INRS Eau | Surampalli R.Y.,University of Nebraska - Lincoln
Bioresource Technology | Year: 2014

Various solvents, including water, hexane, methanol, and chloroform/methanol (1:1 v/v), were tested to identify the efficiency of lipid extraction from Trichosporon oleaginosus and an oleaginous fungal strain SKF-5 under ultrasonication (520. kHz 40. W and 50. Hz 2800. W) and compared with the conventional chloroform methanol (2:1 v/v) extraction method. The highest lipid recovery 10.2% and 9.3% with water, 43.2% and 33.2% with hexane, 75.7% and 65.1% with methanol, 100% and 100% w/w biomass with chloroform/methanol were obtained from T. oleaginosus and SKF-5 strain, respectively, at ultrasonication frequency 50. Hz and power input 2800. W. Ultrasonication chloroform/methanol extraction recovered total lipid in a short time (15. min) and low temperature (25. °C). Whereas the conventional chloroform methanol extraction to achieve total lipid recovery required 12. h at 60. °C. Ultrasonication chloroform/methanol extraction would be a promising method of lipid extraction from the microorganisms. © 2014 Elsevier Ltd.

Johnston P.,INRS Eau | Bergeron N. E.,INRS Eau
Ecology of Freshwater Fish | Year: 2010

Abstract - The objective of this study was to determine the proximate body composition of juvenile Atlantic salmon along the sequence of aquatic habitat types created by longitudinal changes in the riverbed substrate of two rivers (i.e., sedimentary links units). Interesting trends in the body composition were observed but our initial hypothesis, that fish of the upstream sections have higher energy content, was nevertheless not verified. No common longitudinal pattern was detected in the body composition (water, lipid, energy density) along the studied rivers. Trends in the body constituents were different between age-classes and rivers, whereas they were highly variable within- and among-samples. There was however a common trend in the pattern of variations, with the coefficient of variations increasing in the downstream direction for almost all constituents, age-classes and rivers. Potential abiotic and biotic factors that might have contributed to these observations are discussed. © 2010 John Wiley & Sons A/S.

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