In order to solve ongoing wastewater capacity issues, Guelph-Eramosa Township may spend $3.5-million for a sewage storage facility in Rockwood.
“The bottom line is, there’s no choice,” Mayor Chris White said, explaining the township has to do something to address a growing population and limited sewage capacity.
Last summer the township and City of Guelph signed a new Rockwood sewage deal, increasing the maximum daily flow from 1,323 cubic metres to 1,710 cubic metres, which officials say is enough to cover the remainder of developable lands within the village – plus some extra for in-filling.
The agreement included a one-time payment of almost $800,000 to the City of Guelph, in addition to annual township treatment bills that in the past have totalled upwards of $350,000.
A few weeks later the township also approved $3 million in costs to upgrade infrastructure at the Rockwood treatment plant, including a new pump, and also to cover increased treatment costs in Guelph.
However, after an analysis uncovered other issues, the township did not proceed with that plan, spending only about $75,000 for the study and engineering costs.
The problem now, explained R.J. Burnside and Associates engineer John Burns, is that the 12-inch underground pipe, which carries sewage by gravity from the Rockwood pre-treatment facility on Alma Street to the city facility about 8km away, does not have the capacity to deal with peak flows in the system.
Burns said the current pipe, installed in 1976, has a rated capacity of about 60 litres per second (L/s), which is more enough to handle the average flow of about 15L/s.
However, the peak flow could reach 102L/s for the current 1,551 Rockwood households, Burns told council. He added the long-term projection is a peak flow of about 132L/s for 2,155 households – which is more than double the pipe’s capacity.
Burns and fellow engineer Dave Paetz noted the township does not hit its peak flow very often, but the municipality has to either increase the amount of wastewater it can get to Guelph with changes in Rockwood or build a facility to store effluent when the flow is above 60L/s.
The engineers offered six possible solutions, all of which require rebuilding the Rockwood pre-treatment plant:
– pressurizing the existing pipe to Guelph with a liner and adding a new pump, at a cost of just over $6.2 million;
– installing a new “gravity forcemain” to Guelph for $6.5 million; – installing both a new pressurized forcemain and a new pump, at a cost of just under $6.2 million;
– building a new 2,400-cubic metre storage tank (15 metres wide by 13m high) on the site of the Rockwood plant, at a cost of almost $3.5 million;
– installing the storage facility at another location in the village, which would cost just over $3.7 million; and
– building two smaller storage tanks in Rockwood (one at the Valley Road pumping station and one at the Alma Street facility), at a cost of just over $3.7 million.
Councillors seemed to agree the best idea was to install the storage facility at the Alma Street treatment plant.
“It’s the least amount of upheaval to the least amount of people,” said councillor Doug Breen. He noted there already is an underground storage container on the site, but the township does not use it because of its age and deteriorating condition. Paetz confirmed the new storage tank is “only there when needed” (when flows go above 60L/s) and it will remain empty most of the time.
Councillor Corey Woods said he would prefer another buried tank over a new above-ground one.
White said the township will have to explore that option as well as several different sources for funding the project, including development charges and a possible debenture.
Finance director Linda Cheyne said the township could get a reasonable rate of 3.9% interest over 30 years on a debenture. She also noted there may be infrastructure funding from the provincial or federal governments.
White said the township can make a final decision at its next meeting on July 2 and consider funding options at that time.
“We need to move on this immediately,” the mayor said.
Paetz noted the goal is to have the project completed by the fall of 2015.
