A troublesome treated waste water pipe will be replaced following a vote by the Regional District of Nanaimo board of directors Tuesday.
The Greater Nanaimo Pollution Control Centre on Hammond Bay Road will have its effluent outfall – a three-metre diameter, epoxy-coated, steel pipe – replaced in its entirety by 2015 at a cost of $18 million. The original pipe, installed in 1973, carries treated effluent from the pollution control centre to its discharge point 2.5 kilometres away and 70 metres below sea level near Five Fingers Island in Georgia Strait.
The pipe experienced two major failures in the intertidal zone near Morningside Park in 2011 and 2009. Failures in the pipe are becoming more frequent with five identified in 2012. Those failures have been caused by the breakdown of the pipe’s interior coating and corrosion. Several repair or replacement options were studied, including one proposal to replace the land and marine sections of the pipe separately at an estimated cost of $19 million. Regional district staff determined that replacing the entire pipe all at once is the more practical and less expensive option.
The new pipe will be large enough to handle the outfall flows of 160,000 people, about double the population the sewage treatment centre currently serves.
Sean Depol, RDN manager of wastewater services, said work will hopefully start in 2014 following approvals from Fisheries and Oceans Canada and the B.C. Ministry of Environment and coordination with other agencies. The old pipe will be left in place while the new one is constructed along a new alignment that will place it closer to Hammond Bay Elementary School. “There is a project there that, as part of the replacement, will recover the heat out of the treated effluent and use it to heat the school as well,” Depol said. “It will be a little bit disruptive, but at the same time there will be side benefits as well.”
The project will be financed with $16 million from development cost charges and general reserves, plus a $2-million contribution from the Gas Tax Revenue Transfer Program.