The Environment

Professor Grant Allen

The majority of our research in the environmental area is conducted through research consortia. This past year, we completed a four-year consortium titled “Minimizing the Impact of Pulp and Paper Mill Operations” and began a new consortium titled “Towards Ecological Balance in Pulp and Paper Operations: Application of Molecular and Engineering Sciences for the Development of Strategies for Improved Environmental Management”.

The research in the previous consortium centred on four areas: Endocrine Disruptors/Bioactive Compounds; Biological Wastewater Treatment; Biosolids; and Biofiltration for Air Pollution Control. The consortium was supported by ten industrial partners who committed a total of $834,000 over four years. The University team, led by Professors Grant Allen and Doug Reeve, consisted of nineteen researchers and twelve supervising faculty. We were successful in further leveraging the funding provided by our consortium partners through grant and scholarship funds, much of which comes from the federal granting agency (NSERC). We successfully applied for an NSERC strategic grant on “Utilizing DNA Microarrays for Monitoring and Managing Wastewater Treatment Systems” that provides a total of $430,000 over four years and a Collaborative Research and Development (CRD) grant on “Biofiltration for the Control of VOC and Reduced Sulphur Emissions”, which will provide a total of $166,000. The areas in which we conduct research continue to attract excellent people, many of whom bring in the majority of their own funding through externally funded scholarships and fellowships. A few highlights from the past year are discussed below, as well as our future direction.

The biofilter reactors

We have made significant advances in the application of biological gas cleaning, or biofiltration as it is commonly known, as a potential cost and energy efficient method for controlling the release of reduced suphur compounds and volatile organic compounds. In particular, we have demonstrated that thermophilic biological processes can be used to achieve treatment of hydrogen sulphide at reactor loadings up to 35 g/m3 reactor/h and temperatures up to 70oC. This discovery has the potential to expand the operating temperature of these systems well beyond the traditional 40oC so that they can be used for a range of air emissions in a kraft mill. We have applied for a patent and are seeking to commercialize this invention in the coming year.

Colour formation during secondary treatment using ASB treatment systems

We have also continued with important advances in both the fundamental understanding and the improvement of biological wastewater treatment by tackling problems using chemistry, engineering, microbiological, and mathematical approaches. We have shown that biological treatment can significantly increase effluent colour of whole mill effluent and specific effluent streams when treated anaerobically and that this problem can be minimized through controlling the redox conditions of the effluent. Further research on the mechanisms underlying colour formation is underway with the expectation that the findings can be applied to reduce final effluent colour discharges. We have also shown how disturbance conditions (temperature, dissolved oxygen) lead to changes in microbial floc properties and microbial communities and to subsequent deflocculation and suspended solids carry-over. We are further investigating the underlying microbial response to such stresses and methods for operating treatment systems that can alter floc properties to improve treatment system robustness with respect to disturbances. We have also begun to pursue an innovative approach to understanding microbial communities in treatment by using interacting species models, which are known to be capable of producing chaotic effects when there are more than two species. Our ultimate goal is to use this tool to assess the limits to the predictability of treatment and to develop possible operating strategies for dealing with outbreaks of undesirable microbial species.

cDNA microarray manufacture

cDNA microarray detection of multi-gene expression

We have made significant advances in developing DNA microarray technology to rapidly assess endocrine modifying activity in effluents. We have established the gene expression pattern in response to known endocrine disrupting compounds and established a method for extracting effluent samples and applying these effluents to cultured cells. This makes it possible to take the work to the next stage and test a range of effluents and in-mill streams to detect those effluents with the greatest potential bioactivity and identify operating and treatment methods that mitigate these effects.

The newest consortium, led by Professor Grant Allen, focusses on three main themes: Biosolids Management, Bioactive Compounds, and Air Emissions. The research continues to build on our existing strengths but includes additional faculty and facilities to allow us to branch out into new areas of relevance to industry. In particular, we are expanding investigations in the air emissions area with projects that involve minimizing odour emissions from mills and their treatment and utilizing an advanced mobile system to fingerprint particulate emissions from a mill. Minimizing and managing biosolids emissions by minimizing their generation and discharge and maximizing their utility is also an important new thrust in the consortium. We are actively looking for additional partners in this exciting venture.


Contact:

Professor D. Grant Allen at:

Phone: (416) 978-8517
Fax: (416) 978-8605
Email: allendg @ chem-eng.utoronto.ca

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