A massive sewage-treatment project ordered up by the province in 2003 won't be finished by the City of Winnipeg until the 2020s.

Upgrades to the North End Water Pollution Control Centre, the largest of Winnipeg's three sewage-treatment plants, won't begin in earnest until after 2019, water and waste officials concede in a report published on Monday.

The $795-million project — the most expensive capital-construction job in the city's history — involves building two new facilities at the North End sewage treatment plant.

One facility will remove phosphorus and nitrogen from the effluent produced by the North End sewage-treatment plant. Right now, these nutrients wind up in the Red River and are carried north to Lake Winnipeg, where they promote the growth of algae that alters the ecology of the lake.

The other facility will dispose of biosolids — partly treated solid waste — produced by all three of the city's sewage plants.

The provincial Clean Environment Commission ordered Winnipeg to build both facilities in 2003 after it conducted hearings into a 2002 mechanical failure at the North End plant that resulted in 427 million cubic metres of untreated, unfiltered sewage spilling into the Red River.

That order also called for upgrades at the West End and South End sewage plants. The former have been completed and the latter are in the works.

But in a report headed to city council's finance committee on Friday, Winnipeg's water and waste department says it doesn't even know when construction will begin on the North End Water Pollution Control Centre upgrades.

​"The project schedule for the NEWPCC upgrade is under review. The project completion date of December 2019 is not achievable," writes Geoff Patton, engineering manager for Winnipeg's water and waste department.

The report states the city plans to issue a request for proposals to consulting firms interested in designing and building the project in 2018 and intends to award the contract in 2019.

The report does not indicate when the project will be completed. Requests for interviews with water and waste officials were denied on Monday.

St. Vital Coun. Brian Mayes, who chairs council's water and waste committee, said he intends to ask this precise question of city officials when his own committee meets on Tuesday morning.

"This is now expected to be the biggest project in the city's history and they're telling me they don't know the answer," Mayes said on Monday.

In the past, the province has chided the city for the slow pace of conducting sewage-treatment upgrades. The city was warned to get going on the South End upgrades as recently as November.

The city, meanwhile, has complained intermittently that Broadway and Ottawa have not contributed their fair share of the funds needed to complete the upgrades. To date, they've been financed primarily by increases to the city's water-and-sewer bills.