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Wastewater Treatment

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A Great Mission: Managing our Wastewater

The St. Lawrence River plays a vital role in economic development and recreational tourism in Québec.The region of Charlevoix is a prime example.Wastewater treatment for domestic and industrial use discharged into the river represents an important technical challenge.

The La Malbaie Wastewater Treatment Plant is a collective undertaking whose financial and administrative responsibilities lie with the city. Its mission is to protect the environment and contribute to better water quality of the St. Lawrence River.

Project Description:

The wastewater treatment plant serving the city of La Malbaie has a fully mechanized processing line.

The water flows first through a pre-treatment chain (screening and grit removal) and is then channeled to two circular decanters. The water then undergoes physicochemical treatment.

Chemical coagulants are injected at the entrance of the decanters to promote the separation of organic pollutants and their accumulation at the bottom of the basins. From May to October, water flows through a channel equipped with ultraviolet lamps, which ensures their disinfection before their discharge to the receiving environment.

 Rotary Press

The sludge produced by the physicochemical treatment is withdrawn from the decanters and pumped to the sludge treatment line. These are first concentrated in a thickener and then pumped to a rotary press which ensures their dehydration. This treatment chain reduces the volume of final sludge to be eliminated by almost 20 times.

Pre-treatment chain residues and dewatered sludge are transported to a sanitary landfill for final disposal.

The station also has two odor treatment systems that provide control of the air quality inside and outside the building.

The wastewater is conveyed to the treatment plant through a network of interception lines of several kilometers, including 13 pumping stations.

LM-2 pumping station.

The pumping stations are distributed as follows throughout the territory

La Malbaie Sector: 2 positions

Pointe-au-Pic Sector: 2 positions

Rivière-Malbaie Sector: 5 positions

Cap-à-l‘Aigle Sector: 4 positions

The main pumping station (LM-2) is located on De Comporté Blvrd. It conveys to the treatment plant all wastewater from La Malbaie, Pointe-au-Pic and Rivière-Malbaie. This station has two separate pumping systems. The main system pumps residential water and has an overflow to evacuate water during snowmelt or heavy rain. The second system pumps water from the hospital in a separate pipe with no overflow because no discharge is allowed for this type of effluent.

The monitoring of the operation of the various pumping stations is ensured by means of a telemetry system which transmits the information to the purification station.

The management and operation of the station are assumed by the City of La Malbaie. The works are operated by three people specially trained for this task.

The Treatment Plant:

Water covers three quarters of our planet's surface in the form of oceans, rivers, lakes, lakes and glaciers.

The St. Lawrence is one of the largest rivers in the world. Since the beginning of colonization, it is on its shores that we have built many of our cities and factories and it is in its depths that we draw the water we need. Until recently, this water, once used, was discharged to the river laden with domestic and industrial waste.

The Province of Québec has a growing environmental consciousness. In this spirit, wastewater from the region will now be transported to sanitation facilities before being returned to the river.

 As early as 1988, the municipal governments of four municipalities namely: Cap-à-l'Aigle, Pointe-au-Pic, La Malbaie and Rivière-Malbaie joined forces to put in place the sewage treatment system. Before the construction of the treatment plant, it was necessary to connect municipal sewer pipes and build new pipelines and pumping stations to intercept wastewater and convey it to the station.

Collaboration between the Ministère des Affaires municipales in terms of funding, and that of the Société Québécoise d’assainissement d’eau in terms of management and expertise, was essential to the realization of this major project.

Three years after the signing of the implementation memorandum of understanding, the City of La Malbaie benefits from a modern center designed in anticipation for future development of the region for many years.

Inaugurated in October 1998, the wastewater treatment plant is a collective undertaking that engages both the current population and future generations because it is a vital concern: the protection of the environment.