Ph.D Candidate (Hydrological and Ecological Engineering)
BSc (Geosciences) University of Lausanne, Switzerland
MSc (Environmental Sciences) University of Lausanne, Switz
Phone: +64 3 364 2987 (internal: 7322)
Fax: +64 3 364 2758
Postal Address: Dept. of Civil and Natural Resources Engineering, University of Canterbury, Private Bag 4800, Christchurch, New Zealand
Reading, hiking, music, footbag, friends
Quantifying rate-limiting processes in sulfate-reducing bioreactors treating mine-influenced waters
Mining-influenced waters (MIW), commonly acidic in nature, pose a serious environmental challenge in New Zealand and worldwide due to a legacy of mining activities (O'Halloran et al., 2008). The impact of MIW on neighbouring aquatic systems including subsurface environments can be severely detrimental, even compromising potential fresh water resources for domestic and industrial uses. Conventional MIW treatment technologies such as lime dosing plants are chemical and energy cost-intensive. Consequently, alternative cost-effective and environmentally safe remediation strategies have developed over the past two decades. These include a range of engineered wetlands and similar bioreactors relying on biogeochemical processes to immobilize contaminants from MIW. Although the designs of such systems and their short-term efficiencies are relatively well quantified, their long-term effectiveness is still poorly understood due to inherently complex biogeochemical processes.
Previous research in the Hydrological and Ecological Engineering group at UC have found excellent contaminant removal efficiencies treating MIW from coal mines in New Zealand by employing waste substrates in biogeochemical reactors. This included using mussel shells, a large volumetric waste produced nationally, which yielded acidity mitigation potential greater than mined lime (McCauley et al., 2009). Furthermore, the research found that systems designed with a variety of carbonaceous waste products provided enhanced treatment efficiencies.
This proposed research will estimate the long-term efficiencies of engineered treatment systems as a function of waste substrate complement. It will achieve this by quantifying the rate-limiting steps of alkalinity generation, sulfate reduction and various forms of carbon degradation - all of which are key biogeochemical reactions responsible for MIW treatment. Data from laboratory experiments will be employed along with empirical data in modeling efforts that aim to assess long-term treatment potential.
Alessi, D. S., Uster, B., Veeramani, H., Stubbs, J. E., Lezama-Pacheco, J. S., Bargar, J. R. and Bernier-Latmani, R. (2012) Quantitative separation of monomeric U(IV) from UO2 in products of U(VI) reduction. Environmental Science & Technology, 46 (11): 6150-6157.
Alessi, D. S., Uster, B., Borca C, Grolimund D. and Bernier-Latmani, R. (2013) Beam-induced oxidation of monomeric U(IV) species. Journal of Synchrotron Radiation, 20 (1): 197-199.
CRL Energy Postgraduate scholarship (2012-2014)