麻豆AV

Description

Anaerobic digestion of waste activated sludge (WAS) is one of the most common processes used for biosolids reduction because it can convert about 50% of organic matter present in sewage sludge into energy-rich methane biogas. It is increasingly recognized that a portion of the transformation process occurs by the direct transfer of energetic electrons between species through specializes electro-active biological structures. We and others have recently demonstrated that zero-valent iron (ZVI) as a conductive material can boost this transfer and improve the conversion of organic matter to methane. The objectives of this project are: (1) to elucidate the contribution of different methanogenic pathways involving ZVI, (2) to measure the electrical activities of microbial communities growing at the surface of ZVI particles and in the bulk organic matter, (3) to assess the response of the microbial community at the surface of ZVI particles to the addition of various substrates and inhibitors. Thus, the project, for the most part, will take place in the laboratory. Serum-bottle anaerobic digesters will be operated with the addition of ZVI particles kept as is or coated with silicon dioxide to isolate them electrically. ZVI with microbial biofilm will then be magnetically separated from the bulk organic matter. The separated ZVI-grown biofilm communities and the bulk communities will be fed several substrates that will stimulate different methanogenic microbial species. These experiment will allow the improvement of process models and the optimization of energy recovery.

Tasks per student

Perform the daily maintenance and sampling of the laboratory-scale reactors. Perform laboratory analyses to determine physico-chemical characteristics of samples. Contribute to computer data entry and trend analyses.

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Number of positions

1

Academic Level

Year 2

Description

The spread of antimicrobial resistance genes through human communities in due in part to the horizontal transfer of these genes between microbial species during the handling and treatment of municipal wastewater/biosolids and animal manures. After disposal of water and biosolids, the resistance genes rejected in the environment migrate back to humans via the consumption of foods and water. Therefore, improving the wastewater treatment processes is a key in reducing the environmental dissemination of antimicrobial resistance. Yet, engineering approach to mitigate this dissemination through waste handling and treatment are just starting to be developed. The goal of this project is to develop new technologies to reduce the prevalence of antimicrobials resistance genes in waste biosolids from activated sludge wastewater treatment plants. The project will investigate how useful are various pre-treatment technologies for the anaerobic digestion of biosolids for reducing antimicrobial resistance genes. The project, for the most part, will take place in the laboratory. Laboratory-scale anaerobic digesters will be continuously operated. During the internship time, several operation parameters will be tested including: the hydraulic and solids retention times, the temperature of operation, the pre-treatment intensity, and the source of solids to expose to the pre-treatment (influent WAS or partially digested solids). For this project, samples will be obtained from all phases of operation to analyse the prevalence of antimicrobial genes.

Tasks per student

Perform the daily maintenance and sampling of the laboratory-scale reactors. Perform laboratory analyses to determine physico-chemical characteristics of samples. Contribute to computer data entry and trend analyses. The analysis of antimicrobial resistance genes will be done by a suite of microbiology and molecular (DNA or RNA based techniques).

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Number of positions

2

Academic Level

Year 2

Description

The development of accurate mathematical model predicting both the microbial activities in wastewater systems (important for process optimization) and the fate of pathogens or antimicrobial resistance (important for publish health) require a good understanding of the transfer of microbial from sewers to the treatment reactors. We hypothesize that the main factor affecting the immigration process is the microbial substrate composition of the wastewater. The goal of this project is to operate in parallel several small-scale activated sludge reactors receiving wastewater of different compositions. Real wastewater will be samples weekly to obtain microorganisms from sewer systems. The operation data (COD concentrations, suspended solids concentrations, NH3-N, PO4-P) will be monitored. The composition of the microbial communities will be determined using molecular techniques.

Tasks per student

Field sampling of wastewater. Perform the daily maintenance and sampling of the laboratory-scale reactors. Perform laboratory analyses to determine physico-chemical characteristics of samples. Contribute to computer data entry and trend analyses. The analysis of antimicrobial resistance genes will be done by a suite of microbiology and molecular (DNA or RNA based techniques).

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Number of positions

2

Academic Level

Year 2

Description

An increasingly popular technique to produce drinking water is to pump water from the subsurface within 100 m from a river or a lake. The resulting drinking water is a mixture of surface and groundwater. The surface water is treated physico-chemically and biologically during the filtration process, making this technology efficient and inexpensive. A number of filtration wells are in activity around the Lake of Two Mountains. However, their usefulness in time is limited by the increase mobilisation of heavy metals. The goal of this project is to understand the microbial activities occurring the filtration process that influence the transport of metals. It is also to understand the migration of surface microbes that could cause diseases. In collaboration with a research team from Ecole Polytechnique, we will monitor several wells around the Lake of Two Mountains. The microbial communities will be isolated for analyses and a number of physico-chemical parameters will be determined.

Tasks per student

Field sampling of water wells. Perform laboratory analyses to determine physico-chemical characteristics of samples. Contribute to computer data entry and trend analyses. The analysis of antimicrobial resistance genes will be done by a suite of microbiology and molecular (DNA or RNA based techniques).

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Number of positions

1

Academic Level

Year 2

Description

Eighty percent of drinking water distribution systems within both institutional and residential buildings are copper pipes with fittings and solder that contains lead. These are cytotoxic to bacterial contamination but corrosion may result in increased levels in the drinking water. A field survey will be undertaken to determine the range of metal concentrations in drinking water at the point of consumption and correlate them with water quality parameters and infrastructure parameters.

Tasks per student

Students 1 and 2: Collaborate with a doctoral student in the design and implementation of the field survey and in the sample analysis.

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Number of positions

2

Academic Level

Year 3

Description

Low dissolved oxygen levels downstream of hydropower stations results in damage to the riverine ecosystem. An experimental rig has been designed to investigate retrofit options to increase DO levels downstream of the hydraulic turbines. The data acquisition system requires calibration and validation, so that a parametric study can be conducted.

Tasks per student

Assist post-doc in data acquisition system installation, calibration and validation.

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Number of positions

1

Academic Level

Year 2

Description

There are several thousand petroleum-contaminated sites in northern sub-Arctic Canada (Treasury Board of Canada Secretariat, 2014), and effective site management strategies are required to ensure that the risks to environmental and human health are minimized. Bioremediation is a cost-effective and clean technology for remediation of such sites. However, effective implementation of bioremediation in northern sites faces challenges such as low temperature and a limited window of site activity in the summer. Bioremediation strategies adapted to northern climates are needed enhance biodegradation rates and achieve cleanup goals efficiently. A thorough understanding of the soil microbial and physicochemical processes controlling the rates of biodegradation under cold temperatures is needed to develop efficient bioremediation strategies. We will develop an approach for identifying favorable conditions for biodegradation of different fractions of petroleum hydrocarbons during the course of bioremediation under cold temperatures. One such strategy is assessing if and how macronutrient (N, P) or trace nutrient requirements change under different cold temperature regimes and its impact on hydrocarbon degradation. The experiments will be conducted in the laboratory in soil microcosms and mesocosms incubated at temperature regimes relevant to the northern sites.

Tasks per student

Student 1: Research, design and fabricate a freeze-thaw chamber with temperature control features to conduct microcosm experiments Student 2: Conduct analysis of N, P and trace metals in soils from northern sites. Conduct microcosm experiments

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Number of positions

2

Academic Level

Year 2 or 3

Description

Deep groundwater aquifers may be a valuable resource, especially during severe droughts and in arid regions, in decades and centuries to come. It is now increasingly common to find groundwater wells drilled to several kilometer depths in California, Texas, the Middle East, and other arid regions. Therefore, we ask: which regions in the world could benefit most from analysis of their deep groundwater aquifers and what are the characteristics of these aquifers? The project involves developing and analyzing groundwater databases and for selected basins, applying numerical/analytical models. This project complements on-going research on characterizing and analyzing deep groundwater aquifers to manage and protect these resources.

Tasks per student

Database compilation and analysis, including using geospatial analysis tools (e.g., ArcGIS) and developing data processing tools (e.g., Matlab and Python scripts).

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Number of positions

1

Academic Level

No preference

Description

Methane is a potent greenhouse gas and reducing its emissions can substantially combat global warming in the short term. Recent measurements have shown that abandoned oil and gas wells are sources of methane to the atmosphere. The project involves preparing one or more field trip(s) to oil and gas-producing regions and analyzing the results in the laboratory. Various methods including flux chambers and mobile instruments will be used to measure methane flow rates and other geochemical parameters. The findings from this study will provide quantitative data for evaluating and designing mitigation solutions for the millions of abandoned oil and gas wells around the world.

Tasks per student

Prepare for one or more field sampling trip(s), conduct field sampling, and analyze results.

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Number of positions

1

Academic Level

No preference

Description

Highly fluorinated organics (PFASs) such as perfluorooctane sulfonic acid (PFOS) and perfluorooctane carboxylic acid (PFOA) are significant sources of persistent organic pollutants found worldwide. To understand how these pollutants behave in contaminated sites, it is necessary to develop models for the prediction of their microbial biotransformation pathways and half-lives, which are useful in a great number of applications. The project aims to develop in silico prediction capability of PFAS biotransformation in soil and aquatic environments. Representative PFAS found in the environment will be selected via chemoinformatics analysis and be subjected to biotransformation tests. The new knowledge of PFAS transformation pathways and kinetics will be used to improve an online prediction platform, and a newly curated database will be created and made available to those work on PFAS contaminated site assessment and for developing environmental forensics. The project requires the student to have programming skills (e.g., Java, Python), a good background in organic chemistry, experience in handling large data sets and performing statistical analysis.

Tasks per student

The student is expected to preliminarily establish a curated database. The tasks include data mining to collect relevant biotransformation information from publically available databases, chemical space analysis using cheminformatics programs, statistical analysis of half-life data, and missing rule analysis.

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Number of positions

1

Academic Level

Year 2