at 13H30 | 518 B

Mining Waters: What to do With Nitrogen?

Moderated by: Aziz Gherrou
Innovation and clean technology

- Ammonia Nitrogen Removal from Mine Water at a Northern Quebec Gold Mine

A gold mine in northern Quebec was experiencing high levels of ammonia nitrogen in their water discharge from blasting operations. Authorities mandated the mine to reduce ammonia levels in the mine water discharge to under 10 mg/L to protect wildfire from ammonia toxicity. Traditional biological methods to ammonia abatement present certain challenges, given the northern climate and the unsteady flow of water from the mine. E2Metrix was approached to investigate whether its patented ECOTHOR™ electrolysis technology platform could be used to address these challenges. Through in-house and onsite testing over the second half of 2017, ECOTHOR demonstrate its capacity to control ammonia nitrogen to under 10 mg/L. As a result, the mine procured a commercial-scale, mobile ECOTHOR treament unit to process up to 400m3/day of mine water. The unit was delivered and started up over the summer of 2018. This presentation will outline the results from this successful deployment.

- Ammonia nitrogen valorization in struvite formation process using a novel electrocoagulation process

Treatment of ammonia nitrogen in groundwater, surface water, domestic and industrial wastewaters for various clients in the mining, food, slaughtering house and waste management (including landfill) industries is challenging with conventional treatment technologies due to several limitation factors. Such factors, when biological treatment systems are used, include the presence of toxic contaminants in the water that can affect the performance of the ammonia and nitrite oxidizing bacteria or the limited footprint available on site. Other challenges can be associated with the high operating cost in chemicals and energy of physico-chemical treatment technologies such as air stripping or chemical oxidation processes. We will describe this novel process to remove ammonia nitrogen based on the struvite (an agricultural fertilizer). In addition, two case studies will be presented: the retrofit of this novel process to an existing mine water treatment and a landfill impacted groundwater treatment.

- Denitrification: bacteria for the decontamination of mines wastewater.

Wastewater from the extraction of sulphide ore contains toxic contaminants such as ammonia and thiocyanates. Starting in the year 2000, the water treatment team at Agnico Eagle's LaRonde complex, together with external researchers, has developed and implemented a wastewater decontamination technology that uses bacteria. Today, at the height of its efficiency, this technology is the most efficient and natural way of treating wastewater. In order to reduce the nitrogen load resulting from this biological treatment, a partial denitrification is now carried out at the same time as the treatment of toxic contaminants, a process that is unique in the world. This conference will discuss how this technology works, the stages of its development, the development of other potential applications, as well as its numerous positive environmental impacts.