Morris, Manitoba

Waterbody:Raw water reservoir serving a municipal district in southern Manitoba

Water Quality Problem: The aging aeration infrastructure (a lateral arm system that did not reach the sediments) was not delivering enough oxygen to the sediments. This was confirmed with dissolved oxygen (O) monitoring. One of the water quality challenges was that manganese levels in the water column had become a significant management problem impacting downstream water treatment operations.

Aeration Solution: We did a manganese study and determined that the manganese spikes were from sediment redox and that the spikes could be managed with bottom diffused aeration. The system is designed to maintain sufficient oxygen levels at the sediment-water interface to prevent the redox of manganese which happened in “spikes” throughout the year.

To manage the overall budget, the in-reservoir portion of the system was replaced and the existing compressors were retained. There are 18 7-disc AC-7 diffusers, which were manufactured from stainless steel in Red Deer, Alberta.