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Avalos Ramirez A.,Universite de Sherbrooke | Avalos Ramirez A.,Institute Of Recherche Et Of Developpement En Agroenvironnement Irda | Garcia-Aguilar B.P.,Universite de Sherbrooke | Garcia-Aguilar B.P.,Technological University of Mexico | And 2 more authors.
Process Biochemistry | Year: 2012

The effect of non-ionic surfactants on the biofiltration of methane (CH 4) was analyzed. Two biofilters (BF) treating CH 4 were operated for one year at fixed CH 4 concentration of 4.8 g m -3 and air flow rate of 0.25 m -3 h -1. Three polyoxyethylenes (Brijs), and 3 mono polyoxyethylenesorbitans (Tweens) were added to the nutrient solution at a concentration of 0.5% (w/w). Without surfactant, CH 4 conversion had an average level of 35%, with Brijs the CH 4 conversion varied between 38% and 46%, and with Tweens between 43% and 48%. The non-ionic surfactants decreased the biomass accumulation in the packed bed due to their detergent character. Biofilters were operated in a range of nitrogen concentration in the nutrient solution from 0.5 to 2 gN L -1 using Tween 20 at a concentration of 0.5% (w/w). The EC max observed in this study, 45 g m -3 h -1, occurred when the nitrogen concentration was 1 gN L -1. © 2011 Elsevier Ltd. All rights reserved.

Raby K.,Universite de Sherbrooke | Avalos Ramirez A.,Universite de Sherbrooke | Avalos Ramirez A.,Institute Of Recherche Et Of Developpement En Agroenvironnement Irda | Heitz M.,Universite de Sherbrooke
Environmental Technology (United Kingdom) | Year: 2013

Experiments were performed to remove nitrogen as ammonium in biotrickling filters (BTFs) treating synthetic swine manure. Two BTFs packed with polypropylene spheres and ceramic beads were used. BTFs were continuously fed, and leachate obtained was recirculated at different flow rates in the range from 0 to 1.5 L min-1. When increasing the recirculation flow rate, the carbon dioxide (CO2) production rate increased from 16.5 to 25.6 g CO2 m-3 h-1 and nitrogen elimination decreased from 99% to 86% for the polypropylene spheres, whereas for the ceramic beads the CO2 production rate decreased from 20.3 to 15.0 g CO2 m-3 h-1 and nitrogen removal from 99% to 90%. The increase of recirculation flow rates also promoted the production of nitrite () in the leachate. For both packing types, when increasing nitrogen loads from 60 to 240 g N m-3 day-1 without recirculation of leachate, the BTFs achieved nitrogen removals of more than 99%. For the same nitrogen loads, nitrogen removal increased from 90% to 99% for the BTF packed with ceramic beads at a recirculation flow rate of 0.6 L min-1. Operating the BTFs with continuous purge was optimal for biomass production with a maximum level of 71.3 g m-3 day-1. © 2013 Taylor and Francis Group, LLC.

Avalos Ramirez A.,Universite de Sherbrooke | Avalos Ramirez A.,Institute Of Recherche Et Of Developpement En Agroenvironnement Irda | Jones J.P.,Universite de Sherbrooke | Heitz M.,Universite de Sherbrooke
Journal of Chemical Technology and Biotechnology | Year: 2012

BACKGROUND: The treatment of methane in bioreactors with an aqueous phase such as biofilters is limited by low methane water solubility. In the case of biotrickling filters (BTF), the continuous trickling water is a barrier to methane transfer. In a previous study, the use of non-ionic surfactants improved the performance of biofilters treating methane. RESULTS: Three BTFs treating methane were operated for 1 year under fixed operating conditions of methane concentration of 4.8 g m -3 and air flow rate of 0.25 m -3 h -1. Three kinds of packing material were tested and a non-ionic surfactant (Brij 35) was periodically added to the nutrient solution at a concentration of 0.5% w/w. Methane conversion was a function of the type of packing materials and the presence of Brij 35 in the nutrient solution. When Brij 35 was added, the methane conversion doubled with respect to the BTFs without surfactant. CONCLUSION: The addition of Brij 35 to the nutrient solution increased the performance of the BTF for the three packing materials tested. The non-ionic surfactant also affected the carbon dioxide production. The BTFs were stable when the packed bed was washed to remove the excess of biomass. © 2012 Society of Chemical Industry.

Gagnon B.,Agriculture and Agri Food Canada | Ziadi N.,Agriculture and Agri Food Canada | Cote C.,Institute Of Recherche Et Of Developpement En Agroenvironnement Irda | Foisy M.,University of Guelph
Canadian Journal of Soil Science | Year: 2010

Gagnon, B., Ziadi, N., Côté , C. and Foisy, M. 2010. Environmental impact of repeated applications of combined paper mill biosolids in silage corn production. Can. J. Soil Sci. 90: 215-227. Paper mill biosolids (PB) may provide benefits for crop yields and soil nutrients. However, few data are available on metal accumulation and pathogenic populations resulting from applications in silage corn production. A study was initiated to determine the effect of annual spring application of combined PB during 3 consecutive years, with or without calcitic lime, on yield and on the environmental risk posed by N, P, heavy metals (Cu, Zn, Cd, Mo) and Escherichia coli to a silage corn cropped in a loamy sand in eastern Ontario, Canada. Treatments consisted of complete mineral NPK fertilization (PB0), 30 Mg wet weight ha-1 with supplemental N and K, and 60 and 120 Mg wet ha-1 supplemented with K, either with or without 2.5 Mg ha-1 calcitic lime. The PB at 30 Mg wet ha-1 with reduced mineral N and PB at 60 Mg wet ha-1 provided comparable yields to the mineral N fertilization in all years, whereas application of PB at 120 Mg wet ha-1 increased corn yield by 6.0 Mg ha-1 in the third year. After 3 yr, contents of soil NO3-N and the Psaturation index (P/Al) were increased, indicating a possible risk of nitrate and Pleaching. Lime increased soil pH by 0.8 unit, which in turn caused a large increase in the tissue Mo concentration and Mo uptake by silage corn. The PB, particularly at 120 Mg wet ha-1, produced significant accumulations of Cd and Zn in soil, plant tissue and uptake. The PB showed small counts of E. coli, and consequently very little contamination was observed in the soil and on the harvested crop. Based on these results, the PB used are a good source of nutrients that benefits silage corn yields and represent as well a low risk for human and animal health and for the environment when the application does not exceed 60 Mg wet ha-1 yr-1.

Grigg-Mcguffin K.,University of Guelph | Scott I.M.,Agriculture and Agri Food Canada | Bellerose S.,Institute Of Recherche Et Of Developpement En Agroenvironnement Irda | Chouinard G.,Institute Of Recherche Et Of Developpement En Agroenvironnement Irda | And 2 more authors.
Pest Management Science | Year: 2015

Background: Codling moth is a major pest of pome fruit worldwide. Insecticide resistance has become a widespread pest management issue. However, the current status of insecticide resistance in Ontario and Quebec codling moth populations is unknown. Results: Codling moth populations were collected from 27 orchards in Ontario and Quebec from 2008 to 2010. A series of laboratory bioassays were performed to establish baseline susceptibility of adults and larvae to azinphos-methyl, thiacloprid, chlorantraniliprole and methoxyfenozide. Adult codling moth percentage mortality ranged from 22 to 97% and from 21 to 85% when exposed to topical bioassays using azinphos-methyl and thiacloprid respectively. Azinphos-methyl LC50 values from three selected orchards were ca fivefold greater than those from an insecticide-susceptible population. Neonate larva percentage mortality ranged from 5 to 50%, from 15 to 65%, from 90 to 100% and from 10 to 40% when exposed to diet bioassays using azinphos-methyl, thiacloprid, chlorantraniliprole and methoxyfenozide respectively. Conclusion: Based on the response of the field-collected populations, resistance development to some registered insecticides was evident in some Ontario and Quebec populations. With the present status of insecticide resistance documented in these regions, modifications to codling moth management strategies should be initiated before changes in field efficacy occur. © 2014 Society of Chemical Industry © 2014 Society of Chemical Industry.

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