When you choose to build a new house on isolated land not connected to the public collective sanitation network, the famous mains drainage, it is necessary to use an individual sanitation system to treat the polluted waters of his home. They are called the ANC for non-collective sanitation. Discover the different existing systems and their characteristics in this file.
The septic tank followed by spreading
This traditional sector replaces in a way the septic tank, prohibited since September 2009. This tank receives domestic water and solid matter which it liquefies thanks to the action of bacteria naturally present in the waste water.
The septic tank is adapted to the size of your home, in particular to the number of rooms that make it up. This real-size sizing allows you to choose a model that meets your needs and to limit unnecessary expenses. It is an ecological system that does not require any specific energy to operate. Buried, it is totally invisible in your garden.
On the other hand, you should know that this traditional system requires regular maintenance, with an oil change every four to five years. In addition, its footprint can reach 100 m², which condemns a good part of your land.
These compact filters treat wastewater through a physical and bacterial purification system. In this sense, they are close to traditional techniques and the all-water pit, but their footprint is much smaller with an average of 10 to 20 m².
This device works by means of a water pre-treatment phase in a conventional all-water pit in order to decant the solid matter. The filtration phase then takes place in a second tank which contains a filter made of coconut fibre, rock wool, zeolite or hazelnut shells.
This compact system is easy to use. Perfectly silent and ecological, it does not need electricity to operate and its filtering materials are efficient and durable (10 to 25 years).
On the other hand, it must be maintained more regularly and is more sensitive to ground movements. A sump pump may also be necessary and increases the cost of its installation.
Count 7,000 to 12,000 euros on average for this type of device.
The wastewater treatment plant
This compact system remains the most popular today. Today, it remains the most efficient wastewater treatment system. The water is purified thanks to the presence of bacteria. There are three different technologies:
- The activated sludge micro-treatment plant: this device works like municipal plants, but on a housing scale. It generates sludge in large quantities.
- The fixed culture micro-purification station: it is based on the use of a bacterial culture support and generates less sludge. This is the most common device.
- The SBR micro-purification station: this compact system alternates, thanks to an electronic device, the phases of settling and treatment of waste water.
This space-saving system is suitable for small yards and is odorless. Its maintenance is simplified and the purified water generated is of high quality. Count 6,000 to 10,000 euros on average.
On the other hand, the necessary permanent electricity supply means that these devices are not suitable for second homes. More sensitive, they also need more regular maintenance and oil changes to function properly.
The planted filter
This device, approved by the Ministry of Health and the Environment, uses the action of plants to naturally purify waste water after passing through an all-water pit. These waters pass through gravel basins where macrophyte plants such as rushes or reeds are planted. These oxygenate the purifying bacteria in the soil and help them grow to purify the water.
This system produces almost no mud, only a little humus during the decomposition of the plants. Also, the water can be reused to water the garden.
Choosing the right ANC device
The owner of a dwelling not connected to the public sewage system is considered responsible for the ANC system he chooses. It is therefore recommended to call on a professional to study the solutions available to you. As part of the construction of a new house, the builder generally offers you suitable solutions and records them in the CCMI.
Do not hesitate to make several quotes and make sure that the professionals contacted respect your needs, the characteristics of your accommodation and the constraints of your land. Ask for a feasibility study before committing.
Once this has been done, contact the SPANC in your area, a public service in charge of monitoring non-collective sanitation facilities. This service will thus be able to ensure the conformity of your project and verify that the chosen system respects the local context.