Erin Town Council has approved preliminary investigation of a wastewater system that would dispose of treated effluent in the ground, instead of in the river, as an option within the Environmental Assessment (EA).
The move will cost $31,500, including $5,000 for EA consultants Ainley & Associates to host an extra meeting of the Public Liaison Committee. Councillor Matt Sammut cast the only vote against, due to concern about the cost and doubt about the viability of the option.
It is a variation from the EA Terms of Reference, since it includes the possibility of an additional, smaller sewage treatment plant in Hillsburgh. That idea was previously rejected when Credit Valley Conservation said it was unacceptable to discharge treated effluent from a sewage plant into the West Credit River near Hillsburgh.
However, it could be practical to discharge effluent into a large sub-surface bed, where the liquid could percolate deep into the ground, minimizing the nutrient impact on the river.
The costs of constructing and maintaining such a system have not been determined, and there are questions about how many acres of land would be required.
Joe Mullan Project Manager for the EA, said a subsurface discharge system to service Hillsburgh’s current and projected population would make it one of the largest of its type. Subsurface discharge for Erin village will also be examined.
The proposal comes as a response to a suggestion from the Transition Erin group to consider a decentralized system with more than one sewage treatment plant.
Councillor Jeff Duncan asked if the provincial government would even consider funding “something that is non-traditional”. Mullan said that issue would be covered in the report.
He said the initial investigation could be done within four weeks, without causing delay to the main study. If the concept were found to be viable, further research would require more time and funding.
He said the investigation would make the EA process more “robust”, and possibly avoid having the final report being challenged because an option was not considered.
Councillor Rob Smith said there could be significant costs if the Town has to buy or expropriate a large amount of land for the discharge bed. Councillor John Brennan said the option should only be considered if it produces a lower overall cost.
A facility that could treat Hillsburgh’s waste in Hillsburgh would save the cost of building a sewage pipeline along the Elora Cataract Trailway to a treatment plant south of Erin. Such a pipeline would cause major disruption and cost well over $2 million.
The EA is already looking at the feasibility of a “small bore” collection system, in which waste is treated in septic tanks on homeowners’ land, with the effluent collected for communal discharge. For Hillsburgh, the effluent could be treated locally or piped to Erin.
Mullan noted the latest projections of future population are much higher than in the Servicing and Settlement Master Plan report, and said subsurface disposal could help “meet the needs of growth”.