Application of SAGR Bioreactors for Ammonia Treatment in Mining Effluents


Tanner Devlin, Nexom

Ammonia management is an increasing concern within the mining industry. Not only is ammonia, in its un- ionized form, toxic to aquatic life in receiving waters, but as a nutrient ammonia can also promote excessive algae growth, as well as the loss of dissolved oxygen in rivers, lakes and oceans. Commonly found in mining effluents as a by-product of cyanide degradation and a residual of blasting compounds, many mines have historically relied on natural degradation for the management of ammonia. However, in Canada, new Metal Mine Effluent Regulations (MMER) are currently in the stages of implementation through the legislative process and are expected to be enforced by 2021. With an eye on the future, this may mean stricter operational limits at metal mines for Total Ammonia Nitrogen (TAN), causing natural degradation to cease being a cost-effective option for hitting these limits due to the land area required to construct new water holding ponds at existing sites. As a result, many mines are now proactively exploring changes to past practices as they face new challenges for their ammonia management strategies. Using a Canadian gold mine as the story arc, this presentation will explore the facility upgrade, with a strong focus on effectiveness of treatment in cold climate applications. Using fundamental principles and related experiences for cold water ammonia treatment gained from other industry sectors and ammonia-removal applications, we will ultimately detail the benefits of the SAGR process, as well as a discussion on the testing process, piloting experience, and preliminary operating experience and results.