WCW16 Annual Conference & Exhibition October 4-7 2016 Calgary AB wcw16.wcwwa.ca CHARTING A NEW DIRECTION FOR WASTEWATER TREATMENT IN NUNAVUT Kenneth Johnson, Stantec Consulting Ltd., Edmonton
ABSTRACT The so-called “leaky lagoon” was a generally accepted design concept for many years in the Nunavut Territory, formerly the Northwest Territories. However, because of the application of more stringent effluent quality standards, and the requirement of a controlled effluent discharge, this design concept is now unacceptable. The current design concept applied for lagoon systems in the far north is a retention lagoon with a seasonal discharge. In addition, the use of wetlands has emerged as a supplementary process for lagoon systems. The construction of retention lagoons applies modern geomembranes in many cases because of the absence of fine soil materials for the construction of structures with low permeability. New issues are emerging with the construction of these relatively complex earth structures because of the extreme cold climate, permafrost earth regime, and construction techniques. The anticipated costs of remedial work to address these issues are in the order of ½ of the original capital costs of the original multi million dollar structures, which are beyond the available capital funding. A much needed new direction is being charted based upon research to develop the northern science for wastewater treatment. This science is being communicated to the audience of regulators, as well as the communities to incorporate the “social science”, and “applied science” or engineering is also being incorporated. With this activity it is anticipated that a new, more appropriate direction for wastewater treatment may emerge for Nunavut. Keywords: wastewater, Nunavut, lagoons, science, engineering
INTRODUCTION The so-called “leaky lagoon” was a generally accepted design concept for many years in the Nunavut Territory, formerly the Northwest Territories. However, because of the application of more stringent effluent quality standards, and the requirement of a controlled effluent discharge, this design concept is now unacceptable. The “leaky lagoon” had many positive characteristics regarding the treatment of wastewater. The leaky lagoon provided the opportunity for solids settle in the lagoon, and thus potentially providing primary sewage treatment. The effluent would discharge from the lagoon by “seeping” out through earth berms, which would provide further sewage treatment by filtration. These systems were simple to construct, and could make use of whatever granular materials were available for construction. With long term operation the voids in berms would clog after several