Odour Reduction

Responsible stewardship combined with a continuous improvement process, makes possible sustained economic development and an improved quality of life. In this spirit, AV Terrace Bay commits to implement and maintain an effective environment management program that will govern its actions in a way that will benefit the environment, the community, and our employees.

Our sulphur gas emission reduction strategy

Odour improvement since 2013 is illustrated in the following table with data for the ambient monitoring stations in the township of Terrace Bay.  Odour is caused by certain sulphur gases (hydrogen sulphide, methyl mercaptan, dimethyl sulphide, dimethyldisulphide).  The total concentration of these gases is tracked as total reduced sulphur (TRS).  The number of events with TRS concentrations at monitoring stations in the community higher than desired targets has reduced significantly since 2013.

New initiatives for 2016: TRS emission reductions

  • To reduce process losses to sewer: Install & configure PI software to collect and display all data relevant to mill operations and environmental performance.

    Software installed. Phase 1 (of 3) configuration and programming started February 1, 2016

  • Install CO monitors on both No. 2 & No. 3 Recovery Boilers to improve monitoring of combustion efficiency.

    Installation planned for 2016 MSD

  • Improve combustion (& incineration of TRS) in the kiln: install carbon monoxide monitor.

    Instrument installed in 2015 – must collect sufficient data to establish appropriate guidelines for operators.

  • Reduce flow of foul condensates to steam stripper to improve steam-to-condensate ratio and stripping efficiency.

    Flow from evaporators is too high. Repaired leaks in 2015, but suspect low contaminated condensates are unknowingly being diverted to the contaminated condensate flows to the stripper surge tank.

  • Investigate potential improvements to the turpentine decanter to reduce contamination of underflow to the stripper surge tank.

    Frequent incidents where underflow from decanter contains turpentine-water emulsion.

  • Clean RSH scrubber and replace packing

    Work planned for annual maintenance shutdown

  • Manage TRS emissions from Spills Pond during July & August with odour reducing additives

    No additives currently on site

  • Reduce TRS emissions from ASB cell 1 by maintaining effluent pH entering the ASB above 6.8. Install automatic caustic addition to correct low pH.

    Fewer periods with low pH in 2015 compared to 2014, but existing acid neutralizing system utilizing lime cannot maintain required pH.

  • Monitor operating parameters (s.35 Technical Standard) for kiln, SF scrubber, RSH scrubber, No. 3 dissolving tank scrubber, foul condensate stripper and effluent treatment system for any deviation from good operating conditions and implement corrective actions in response to deviations.

    Designed alternate equipment setup for pH probes at highly alkaline scrubbers because high pH destroys probes, but new system is not yet installed.

  • Install additional conductivity probes in mill sewers for improved feedback regarding process losses to sewer

    Some probes installed in 2015, but insufficient coverage in high risk areas.

  • Reprogram No. 2 Boiler to allow incineration of DNCG when burning oil. This will reduce DNCG venting.

    Boiler currently has permissive in logic that requires a certain minimum flow of black liquor.

  • Install new doctor board and drive for dregs filter to obtain drier dregs.  

    Wet slaker dregs currently result in high-TRS leachate flowing to Recaust sewer at dregs filter.