Understanding Advanced Secondary Treatment

The specific characteristics of your land may require the installation of an advanced secondary treatment system to allow you to infiltrate the wastewater from your residence over a small area or discharge it into the environment. In this series of articles, our experts present the various advanced secondary treatment systems approved in Quebec.

Above all, it is essential to understand what an advanced secondary treatment system consists of. The advanced secondary treatment system as described in the provincial regulation Q.2. R-22 is a system designed to treat wastewater from a primary treatment system (e.g. septic tank) to meet effluent discharge standards. This type of treatment system is necessary only when the available infiltration space or the type of soil does not allow infiltration of water coming directly from the primary treatment system.

It is important to note that all advanced secondary treatment systems approved by the BNQ perform wastewater treatment that meets regulatory discharge standards. All of these systems require an annual inspection to ensure compliance with discharge standards.

In Quebec, the Bureau de normalisation du Québec (BNQ) has certified 5 advanced secondary treatment technologies for domestic wastewater. Among these, we find the System O)) distributed by the company DBO Expert based in Sherbrooke. This technology is based on the American Advanced EnviroSeptic system and has been certified by the BNQ since 2007.

System O)) biological treatment

The biological treatment of a System O)) is carried out by the bacteria naturally present in the wastewater which attach themselves and develop on the permanent filter medium present in the perimeter of the perforated System O)) pipes. Bacteria grow in this filter medium and carry out water purification. The purified water is then infiltrated at a specific speed into the filter sand covering the System O)) pipes in order to finalize the treatment.

The DBO Expert company produced a video clip clearly demonstrating how their technology works:

The 4 main advantages of a System O)) system

  • Permanent filter media
  • No mechanics present during a gravity installation
  • Water infiltrates directly under the system
  • Multiple configurations adapted to specific terrains

The 3 points to know before installing a System O))

  • Filter media will not be accessible when needed
  • A vent is necessary to ensure a sufficient air supply for bacterial activity
  • Choose a certified contractor for a quality installation

A System O)), what will it look like on my land?

As the final appearance of the secondary treatment system on your land could have an impact on your choice of treatment, it is important to know what your land will look like following the installation of the system. System O)) consists of an infiltration space made up of its lined perforated pipes and is preceded by a septic tank with two circular access chimneys. Therefore, the final appearance of the System O)) on your land will be 2 concrete, PVC or polyethylene covers and a 4 in. sampling chimney (piezometers) at the end of each of the perforated pipe lines . In addition, there is a ventilation vent to ensure the air supply to the system.

Note that it is essential that your treatment system be away from all motorized traffic and that no heavy weight should be affixed to it.

Source : dboexpert.com


In summary, with its unique characteristics and its permanent filter media and direct infiltration capacity, System O)) is an excellent choice for advanced secondary treatment. DBO Expert representatives are available to answer all your questions about the system and its implementation on your land. Go to https://dboexpert.com/installations-septiques-fosse-septic/ for more details.

In order to make an informed decision on the choice of your advanced secondary treatment system, we invite you to consult our articles on other treatment systems;

  1. Bionest – How does it work?
  2. Ecoflo – How does it work?
  3. Hydro-Kinetic – How does it work?

Our Soluo experts are also available to answer your questions about all advanced secondary treatments. Contact us today to start your septic installation project.

About the Author

Étienne Gaudette

Chief Executive Officer (CEO)

Étienne Gaudette is the president of the Soluo Group, a company specializing in inspection, design and residential septic installation work serving the majority of regions of Quebec for more than 30 years. Thanks to his creative mind and his background in marketing consulting and as director of the group of experts in decentralized water management at Réseau Environnement, Étienne brings a unique vision to the on-site sanitation industry in Quebec in order to bring together the all industry players for the benefit of Quebecker. One goal: Change the world, one septic installation at a time.

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