On Wednesday, September 4, the Municipality of Les Cèdres held a public consultation in the Salle des délibérations of the Town Hall, to present draft by-law number 517-2024 on the management of water and sewer supply and treatment. Specifically, this by-law will impose a moratorium prohibiting the construction of residential projects on municipal territory for a period of two years. 

The decision is necessary because recent studies have shown that the residual capacity of the aerated ponds in the area around Autoroute 30 in Les Cèdres has been reached. This is what local general manager Jimmy Poulin told the dozen or so citizens present in the room to attend the public meeting. 

“The ponds date back to 1996 and, under an existing agreement between our municipality and that of Pointe-des-Cascades, wastewater from our two communities is treated there on a daily basis. The costs billed to the two municipalities are calculated on the basis of the flows carried in by each. Last year, Les Cèdres paid 68% of the costs, while Pointe-des-Cascades paid the remaining 32%,” he explained in the opening minutes of the public consultation. 

The design capacity of the aerated ponds is 1,708 cubic meters. For those who are not mathematicians at heart, one cubic metre is equivalent to 1,000 liters. The total volume of wastewater treated on site is 38,564 cubic meters. 

How do aerated ponds work? At Les Cèdres, wastewater is treated in two stages. The first is to aerate the water. This process lasts around 10 days, during which time the bacteria eat the biological matter. 

Then, for a further 10 days or so, the water changes basins and settles, while the sun's ultraviolet rays disinfect the water. After this stage, the water is ready to be discharged into the river. 

Studies show residual capacity has been reached

In October 2021, the Municipality of Les Cèdres initiated studies to better understand the problem and find solutions to the residential developments underway on its territory and that of Pointe-des-Cascades. 

In October 2021, an initial analysis was carried out to determine the possibility of adding wastewater from the Lucerne sector to the aerated basins. The conclusion was that this was possible, but only by optimizing the aeration system. 

In December 2022, a second study was carried out with a view to determining the possibility of adding substantial developments. The conclusion was that the addition of new developments connected to the sewer system could not be considered, as the residual capacity had almost been reached. If we were to do so, the treatment infrastructure would have to be optimized, representing an investment of around $5 million. 

In May 2023, elected officials adopt a resolution to impose a moratorium on residential development - in good faith, without a legal framework on its territory. 

In August 2024, a new study is carried out to determine whether the aerated ponds are at full capacity. The conclusion was positive, and the report concluded that this municipal infrastructure was at full capacity, and in some cases had exceeded certain standards. It therefore has no residual capacity.  

“To illustrate the problem, studies have shown a 10% increase in the hydraulic load between December 2022 and August 2024. This is attributable to the aging network, parasitic water infiltration, non-conforming connections and the combined sewer system found mainly in the village core. The design capacity is 1,708 cubic metres, but actual usage averages between 2,283 and 2,711 cubic metres. In 2022, two to three times design biological loads were recorded, but effluent standards were met. In 2024, biological loads are similar, but the additional hydraulic load reduces the water residence time in both basins. As a result, wastewater treatment cannot be carried out as it should,” explained Pierre-Olivier Henuset, head of Technical Services and Infrastructure at the Municipality of Les Cèdres.  

A moratorium to curb residential development 

In view of the findings of the studies, the Municipality of Les Cèdres has decided to impose a moratorium under Section 29 of the Municipal Powers Act.The objective of this approach is to prohibit the addition of new dwellings, the implementation of residential development projects, and the construction and enlargement of buildings with the effect of increasing wastewater discharges. 

Exceptions to this moratorium include the following: 

- Reconstruction of a building destroyed by a disaster, without the addition of a dwelling;

- Reconstruction of a building demolished by court order;

- Any work to ensure public safety;

- 4 construction projects in progress. 

“We are aware that citizens have recently applied for permits for various projects. It's not impossible that exceptions will be added, as we will reanalyze each file before adopting the by-law to determine whether or not it falls within the exceptions,” said Mayor Bernard Daoust. 

What about Pointe-des-Cascades? “We recently met with the mayor and general manager of Pointe-des-Cascades to inform them of the by-law imposing the moratorium. Elected officials will also have to adopt one to suspend the issuance of building permits on their territory,” said Mr. Poulin. 

What happens next? On August 13, notice of motion was given for draft by-law number 517-2024. On the same date, the freeze on building permits involving the addition of a dwelling came into effect. 

On September 4, the public consultation on by-law number 517-2024 was held. The by-law will be adopted on Tuesday, September 10, and come into force two days later, on September 12.

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