by Chris Daponte
DRAYTON – Mapleton Township has taken the next step towards a 27% increase in the maximum amount of wastewater it can discharge into the Conestogo River.
On Jan. 8, council approved a recommendation directing staff to work with township engineer R.J. Burnside and Associates to increase the capacity at the Drayton sewage plant.
The ultimate goal is to increase the discharge capacity from 750 cubic metres per day to 950 – and sooner rather than later.
The township is under intense pressure from developers whose projects have stalled because of plant sewage capacity issues, and the increase would allow them to continue construction.
Clerk Patty Sinnamon told council that Ontario Clean Water Agency data indicates the township is “well below” the permitted levels for discharge at the plant.
“Staff believe it would be prudent to update the existing capacity allocation chart,” Sinnamon said in her report. “This would certainly help with immediate and near future demands.”
But an actual increase in capacity is dependent on two things: approval from the Ministry of the Environment, and a review of plant operations by Burnside staff to determine if the increase would necessitate construction work.
Public Works lead hand Don Culp said on Jan. 17 he expects Burnside has already submitted – or will submit shortly – an application to amend the certificate of approval to re-rate the plant to 950 cubic metres a day. As for the review of plant operations, Culp said that work is still ongoing.
Sinnamon said staff is “somewhat hopeful” that no construction will be required. But Burnside’s Bob Mayberry has noted it is possible the capacity increase may require the construction of an additional storage cell at the plant, or an addition to one of three existing lagoons.
According to Culp, the plant has to be able to store a one-year supply of wastewater.
Any addition or new lagoon means the township would likely have to purchase more land, because the current plant occupies almost the entire available property.
Sinnamon and Culp have told Mayberry that buying land would not be a major issue, and that the township expects to pair fair market price for any acquired land.
However, such a purchase would present a few problems.
“The acquisition of land for treated effluent storage would likely require a Class Environmental Assessment, which would further delay the process,” Mayberry said in his report.
And the environmental assessment itself can also become complicated because the MOE has to consult First Nations when it comes to discharging wastewater into the Grand River.
The Conestogo is a tributary of the Grand.
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Since 1998, Mapleton Township has been carrying out a series of phased upgrades to its plant in accordance with an environmental study report completed in 1996.
Until last year, the plant serviced only the village of Drayton, but now Moorefield sewage is also being pumped to the Mapleton plant, which is part of the reason the township was already considering expanding capacity and increasing its maximum flow rates.
The plant discharges treated municipal wastewater to the Conestogo River just upstream of the northeastern branch of the Conestogo Dam. That reservoir then discharges through the Conestogo Dam and the river meets the Grand River northeast of Waterloo.
To evaluate the affects of discharging the wastewater in the river and to determine future discharge rates, an extensive monitoring study was conducted in 2003-04.
Findings included:
– the Conestogo River has elevated levels of phosphorous, nitrate, and E. coli bacteria, but the problems already exist upstream of the Mapleton pollution control plant and are not caused by the plant;
– there is “more than adequate” capacity in the Conestogo River to allow the average flow rate to increase to 950 cubic metres a day; and
– proposed changes in the operation of the plant “will maximize the use of available dilution capacity in the stream, reduce the accumulation of nutrients in the reservoir prior to summer, and result in an overall improvement in river quality.”
Therefore, the report concludes, discharge rates should be allowed to increase to an average daily rate of 950.
