Non-collective sanitation: what is it?
Today, many buildings and residential houses, especially in urban areas, are connected to a public wastewater collection network, more commonly known as “all-in-sewer.” This collective sanitation system efficiently transports these waters to a treatment plant, where they are treated to be purified before being discharged into the natural environment. But what happens when a house cannot be connected to a public network? This is often the case for homes located in rural areas or isolated hamlets that are geographically difficult to access. In these cases, each house must install an individual and autonomous system for collecting and treating wastewater, known as non-collective sanitation (NCS).
Why choose non-collective sanitation?
The first reason is the legal obligation: every home not served by a public wastewater collection network must be equipped with an autonomous installation to treat its domestic wastewater. This obligation is essential to prevent any health risk. Indeed, domestic wastewater can contain various contaminants, such as pathogens, chemicals, and organic matter, which can pose serious dangers to public health if not properly treated. Furthermore, adequate wastewater treatment is crucial for reducing the environmental impact of discharged waters. Non-collective sanitation systems (NCS) allow for filtering and treating wastewater, thus minimizing soil and watercourse pollution.
Moreover, non-collective sanitation is a particularly suitable solution for houses located in rural or isolated areas, where connecting to the public network would be technically or financially too complex. In these regions, implementing an NCS system is often the only viable option to ensure effective wastewater treatment. Consequently, this type of system plays a vital role in protecting the local environment and preserving residents’ quality of life.
Here are some examples of non-collective sanitation installations:
- Septic tanks: Septic tanks are probably the most well-known NCS systems. They are designed to treat domestic wastewater through a sedimentation and anaerobic digestion process. Solids settle at the bottom of the tank, while clear water is discharged to a complementary treatment system, such as a drainage field.
- Micro purification stations: Micro purification stations are compact systems that treat wastewater biologically. They use bacteria to break down organic matter present in wastewater. These stations are often used for individual homes or small groups of houses.
- Phyto-purification: These gardens are planted filters that use semi-aquatic plants to treat wastewater. This system is ecological and offers the advantage of integrating harmoniously into the landscape.
In summary, installing a non-collective sanitation system is not only a legal requirement but also a necessity to protect public health and the environment.
What is wastewater?
Wastewater is all water that has been “polluted” through domestic use. In other words, it is water that has been used in daily household activities and consequently contains various contaminants from these uses. This water is mainly divided into two distinct categories: “grey” water and “black” water.
Grey water
Grey water is a byproduct of daily domestic activities and primarily comes from dishwashing, laundry, baths, and showers. It is distinguished from black water by its origin and composition, although it also contains various contaminants that require treatment.
Different sources of grey water include:
- Dishwashing: During the cleaning of kitchen utensils, food residues, fats, oils, and detergents mix with the rinse water.
- Laundry: Washing machines produce grey water rich in detergents, fabric particles (such as fibers), and sometimes specific cleaning chemicals
- Baths and showers: Water used for body washing contains soap and shampoo residues, as well as dead skin cells and other personal care products.
Although they are less contaminated than black water, grey water still requires appropriate treatment to remove polluting substances before being discharged into the environment or reused.
Black water
Black water, on the other hand, comes from toilets and contains feces and urine. This water is much more contaminated than grey water, as it contains a high concentration of organic matter and pathogenic microorganisms. Consequently, it requires more complex and rigorous treatment to ensure no pathogens are released into the environment.
A figure
According to Planestoscope, 2 billion liters of wastewater are produced every day worldwide. To put this in perspective, imagine that this volume of water could fill about 800 Olympic swimming pools daily. This impressive figure underlines the importance of efficient sanitation systems, whether collective or non-collective.
The importance of sanitation systems
The goal of these systems is to treat wastewater appropriately to minimize its environmental impact and protect public health. Without adequate treatment, wastewater could pollute drinking water sources, rivers, lakes, and oceans, causing irreversible damage to aquatic ecosystems and posing serious risks to human health.
In conclusion, non-collective sanitation is an essential solution for homes not connected to a public network. It allows for the efficient management of domestic wastewater while respecting legal obligations and protecting our environment.
