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Session 3A: "Biodiesel, Biogas, and Pre-treatment"
1:20pm - 2:40pm
Session Chair: David Bernard Levin
1:20pm - 1:40pm
Consistent monitoring and analysis of reactor operation and microbial community composition over five years delivers insight into the stability and resilience of an anaerobic dairy manure digester
Elsie Maria Jordaan1, Nazim Cicek1, Hooman Derakhshani2, Ehsan Khafipour2
1Department of Biosystems Engineering, University of Manitoba, Winnipeg, MB, R3T 5V6; 2Department of Animal Science, University of Manitoba, Winnipeg, MB, R3T 2N2
The use of high-throughput sequencing methods to characterize microbial communities in anaerobic digestion systems is becoming more frequent, yet little is known about the long-term stability and evolution of such communities. Over the course of more than 1650 days the operational parameters of a bench-scale mesophilic dairy manure digester were continually monitored with periodic samples taken for microbial analysis. The batch-fed digester went through four distinct disturbances, preceded and followed by five periods of steady state operation, each lasting between 150 and 330 days. The disturbances were the result of using manure feed batches that had been modified due to normal dairy operation, either through changing the feeding regimen to include dried distillers grains and solubles (DDGS) or by a recent application of copper sulfate footbath solution. While the addition of DDGS increased biogas production, the presence of copper sulfate inhibited biogas production and led to a significant increase in VFAs. Steady state conditions were re-established by using regular manure as feedstock. Initial analysis of sequenced 16S rRNA genes revealed a diverse bacterial community that maintained a fairly stable steady state composition with distinct changes occurring mainly during periods of disturbance. Methanosarcina dominated the archaeal community during steady state periods, while compositional changes during disturbances were largely attributed to inhibition of methanogens. Upcoming analysis aims to determine whether the dairy manure digester maintained a core group of bacteria and archaea during all steady state periods despite the various disturbances disrupting community composition.
1:40pm - 2:00pm
INVESTIGATING THE EFFECTS OF WASTE VEGETABLE OIL ORIGIN ON BIODIESEL PROPERTIES
Sabbas Nwabueze Asoegwu3, Collins Osita Chukwuezie1, Nnaemeka Reginald Nwakuba2, Kevin N Nwaigwe4
1Federal University of Technology, Owerri, Nigeria; 2Imo State Polytechnic Umuagwu, Ohaji; 3Michael Okpara University of Agriculture, Umudike, Abia State; 4Department of Mechanical and Industrial engineering, University of South Africa Pretoria, SouthAfrica
Waste vegetable oils (WVOs) were collected from three restaurants; Levi, Renny’s and Sunic’s all situated at Owerri, capital of Imo State, Nigeria. The WVOs were grouped into three based on feedstock origin and WVOs compositions. WVOs from Levi restaurant formed group one namely: 100% waste ground nut oil (WGO), 100% waste cotton seed oil (WCO) and 100% waste palm oil (WPO) and group two namely: 50%WGO+50%WCO, 50%WGO+50%WPO, 50%WCO+50%WPO, and 33%WPO+33%WCO+33%WGO) were produced. Waste vegetable oil of these groups were characterized and subsequently converted to biodiesel according to ASTM standards. The work compared effects of the waste oil characteristics of these three groups on the biodiesel properties produced from them. The results showed variations in the characteristics of waste vegetable oil are based on feedstock origin, and on waste vegetable oil composition. They affected the properties of biodiesel that were produced. The uncontrolled mixture under group three produced the highest free fatty acid (FFA) of 1.602, while the lowest FFA was 0.9331 from controlled mixture (50%WGO+50%WCO) under group two. The highest in water content was also from uncontrolled mixture with value 0.42% while the lowest was 0.21 of 50%WGO+50%WCO mixture. The highest in calorific value was WPO (group one) with value of 41.40JM/kg, while the lowest was 33%WPO+33%WCO+33%WGO (group two) with value 35.09JM/kg. The results also showed that the properties of biodiesel produced from the three groups met ASTM standards.
2:00pm - 2:20pm
Microwave-assisted alkali pretreatment and enzymatic saccharification of selected agricultural residues
Obiora Samuel Agu1, Lope G. Tabil1, Tim Dumonceaux2, Venkatesh Meda1
1University of Saskatchewan, Canada; 2Agriculture and Agri-Food Canada, Saskatoon Research Centre
Microwave-assisted alkali pretreatment was investigated to enhance enzymatic saccharification of canola straw and oat hull for the production of bioethanol. Pretreatment is a necessary step for efficient and effective conversion of lignocellulosic biomass to biofuel. The study compared the effectiveness of microwave-assisted alkali pretreatment, microwave alone and alkali treatment for enzymatic digestibility on canola straw and oat hull. Microwave pretreatments were employed by immersing the biomass in dilute alkali solutions (NaOH and KOH) at various concentrations of 0, 0.75and 1.5% (w/v) for microwave-assisted times of 6, 12, and 18 min. Alkali treatments were carried out using the same procedure but by soaking and without microwave heating. The highest glucose yields after enzymatic saccharification for both canola straw and oat hull were obtained when these biomass were ground using 1.6 mm hammer mill screen size and subjected to microwave-assisted alkali pretreatment using 1.5% and 0.75% NaOH for 18 min respectively. SEM analysis indicated a more significant modification in the structure of biomass samples subjected to microwave-assisted alkali pretreatment compared to untreated and alkali treated biomass samples. Results indicated that microwave-assisted alkali pretreatment at short residence time enhanced glucose yield.
2:20pm - 2:40pm
Turning winter into summer: Operating a truck with B100 biodiesel all year round in cold regions
Obiajulu Nnaemeka1, Eric Bibeau2
1University of Manitoba, Canada; 2University of Manitoba, Canada
A fundamental problem to use B100 biodiesels in engines in the cold regions is due to the relatively higher cloud point compared to petroleum diesel. Several methods have been implemented in the past to lower the biodiesel cloud point such as use of additives and winterization, but none of these have proven successful due to the unique molecular stacking present in biodiesel. Therefore, the fuel is often blended to a maximum of 5% for use in diesel engines made by North American manufacturers. We hereby propose a novel passive tank design which can be implemented in existing diesel trucks to enable these to operate using B100 biodiesels in winter by having the biodiesels stay above a set point temperature for extended periods. The tank implements a latent energy storage system to capture waste heat from the diesel engine and maintain the temperature in the biodiesel tank above the cloud point for up to 5 days. Our analysis presents a numerical validation of the concept used in the actual scaled tank using the software Ansys Fluent. The result for the sample cases simulated indicated that using a latent energy storage system in the tank could increase the period when the biodiesel remains above cloud point.