Bacteria improving at sewage-treatment plant: engineers

Hey there, time traveller!
This article was published 04/11/2011 (5088 days ago), so information in it may no longer be current.

WINNIPEG – City waste-water engineers are cautiously optimistic the bioreactors in the South End Water Pollution Control Centre will soon resume functioning properly.

Since Oct. 7, the South St. Vital sewage-treatment plant has been discharging 50 million to 60 million litres of half-treated sewage into the Red River every day because of the death of micro-organisms that normally digest particles of solid waste inside aeration tanks.

While the cause of the die-off is still unknown, the beneficial bugs – bacteria, protozoans and rotifers – are beginning to recover, water and waste engineering manager Mike Shkolny said Friday afternoon.

Late last month, engineers transported beneficial bacteria from the North End Water Pollution Control Centre to the South End plant. It appears the infusion has been somewhat successful in reinvigorating the micro-organisms at the ailing plant, but not to the degree where biological treatment is effective, Shkolny said.

Engineers are also certain that the South End bioreactors have too much filamentous bacteria – micro-organisms that grow in strings – and this growth is both crowding out the beneficial bacteria and preventing particles of solid waste from settling out in one of the plant’s clarifiers.

The engineers now plan to add chlorine to the plant to kill off the filamentous bacteria without harming more robust beneficial bacteria, Shkolny said.

If this works, it may take three weeks for the plant to return to normal, he added. The ailing bioreactors are also hampering the ultraviolet disinfection component of the plant.

Shkolny also said officials may never find out what killed off the bacteria in the plant. Preliminary tests for pesticides, heavy metals and other toxic chemicals have turned up negative, he said, adding the investigation is not like the television show CSI.