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Dr. Delatolla lecture Aug 31, on wastewater treatment

Federal Wastewater Regulations - Biofilm Technologies for Cost-Effective Ammonia Removal

R. Delatolla, Ph.D.

Department of Civil Engineering

University of Ottawa, Ontario

The first federal Wastewater Systems Effluent Regulations (published in Canada Gazette Part II, Vol. 146, No. 15) were published on July 18, 2012 and will be implemented across the country between January 1, 2013 and January 1, 2015. These new regulations require a minimum of secondary level wastewater treatment or equivalent and specify an effluent concentration limit for unionized ammonia (NH₃). Ammonia is one of the constituents responsible for the highest occurrence of acute and chronic toxicities in lakes and rivers in Canada. Biological treatment is currently the most common and economical means of ammonia removal in wastewater. However, at cold temperatures nitrification rates (biologically mediated oxidization of ammonia to nitrate) have been shown to decline substantially or become completely impeded. The over 1000 aerated lagoon facilities and 250 stabilization pond facilities that are currently in operation in Canada drop to cold temperatures throughout the winter months. Particularly, these systems drop to temperatures of 4°C and 1°C at various stages of the treatment process due to their long retention time and large surface areas and hence they require upgrading to achieve ammonia removal throughout the entire year and many require upgrading to meet the newly published federal wastewater regulations.

This seminar will summarize the findings of laboratory and pilot scale studies investigating the ability of biofilm technologies to achieve long-term biologically mediated ammonia removal at cold temperatures as replacement or upgrade solutions for lagoon or northern treatment systems. Particularly, the talk will present the kinetics of biological aerated filter (BAF) and moving bed bioreactor (MBBR) nitrification during long exposures to 4°C and 1°C. Furthermore, results of advanced microscopic methods such as environmental scanning electron microscopy and confocal laser scanning microscopy in combination with fluorescent in situ hybridization and viability staining used to characterize the effects of exposure to cold temperatures on the biofilm and embedded nitrifying biomass will be presented and discussed. The talk will conclude on the promise of biofilm technologies as economical, low carbon footprint solutions for ammonia removal at cold climates.