Winnipeg's water and waste department could have measures in place by late 2022 or early 2023 to chemically reduce the phosphorus load into Lake Winnipeg, a city committee heard Thursday.

Senior staff outlined the challenges to introducing short-term solutions to reducing the phosphorus load at a meeting of the city's water and waste committee.

Phosphorus is a significant contributor to algae blooms, which are being reported with greater frequency in Manitoba's largest lake. The city accounts for between three and five per cent of the total phosphorus going into Lake Winnipeg, the water and waste department's director has previously told city council.

"There are so many connected issues, we have to be careful," with any changes to the city's treatment system, Geoff Patton, the city's manager of engineering services, told the committee Thursday.

"[With] this importance to the province of Manitoba, we are not going to play around."

The briefing came after a motion was introduced by councillors Kevin Klein, Shawn Nason and Jason Schreyer at city council's last meeting, directing the department to immediately test a proposal for chemical removing phosphorus from the city's waste water.

Water and waste managers say options for interim reductions to phosphorus were being planned before the motion.

The city will write and issue a request for proposals to do testing on three different options involving chemical phosphorus removal.

Water and waste manager Geoff Patton, centre, says a cost to introduce any of the three possible options isn't clear yet. (Sean Kavanagh/CBC)

One such process was proposed earlier this year by the International Institute for Sustainable Development and the Lake Winnipeg Foundation as an inexpensive interim solution to reducing Winnipeg's phosphorus load in its sewage, as the city works toward $1.8 billion in required upgrades to its treatment system.

The IISD proposal would involve the city adjusting its use of ferric chloride, a type of iron salt already used in maintenance of the North End Water Pollution Control Centre. The chemical would bind to phosphorus in wastewater and settle to the bottom of tanks for filtration before effluent leaves the treatment plant.

That proposal came up last month at a water and waste committee meeting, but managers in the department said at the time it wasn't operationally feasible.

On Thursday, Patton said months of testing and completion of upgrades to the city's south end treatment plant are required before any treatment solution can be implemented.

The city's sewage system uses organisms to digest material in masses of sludge that are sensitive to environmental change and require slow, incremental changes, he said, regardless of which chemical process is chosen.

Patton says any change in the system would also produce extra sludge. The city would need to consider the effect that would have on the digesters at its North End treatment plant, as well as calculate the impact of the growth of the city and its output of sewage, he said.

Winnipeg is waiting for a response from the province of Manitoba to a request to alter its licence for the city's North End treatment plant.

The city is looking for a two-year extension of that licence to Dec. 31, 2021, because it can't currently meet a target of "total phosphorus concentrations in the effluent of less than 1 mg/L on a rolling average."

The city also can't meet targets for nitrogen and ammonia removal.

None of the three interim proposals the city will test would cut phosphorus loads sufficiently to meet the requirements of its licence.

11 years of inaction while water and sewer rates rise

Water and waste staff faced a grilling from Charleswood-Tuxedo-Westwood councillor Kevin Klein.

The motion from Klein and his fellow councillors at city council last week prompted re-examination of which options were being explored to reduce phosphorus.

"I just want to see this moving forward. This is going to keep it in the public. If … truly we're doing something, why wasn't that discussed at council? We don't debate at council," Klein said.

'At least now we have some deadlines and something to follow up on,' Coun. Kevin Klein said Thursday. (CBC)

He says the city has been siphoning funds from residents' utility bills, but not moving more quickly on upgrades to its facilities.

The required $1.8 billion in upgrades required at the North End Water Pollution Control Centre are being split into three parts, as the work is complicated and expensive.

The city has yet to reach an agreement with the provincial and federal governments on sharing the costs of upgrades to the North End treatment plant.