Field of filtration: calculation, device. Biological wastewater and sewage treatment

If a septic tank is used in the section of your country house as a wastewater treatment system , you must create a filtration field for its normal operation. It will consist of several trenches with sprays located inside. Trenches are filled with gravel, crushed stone and sand, which are necessary for the filtration of treated wastewater. If the work on the design and further organization of such a system was carried out correctly, then there will be no additional problems in the operation and drainage.

Field Device

After the initial treatment of wastewater from helminths and mechanical impurities was completed, impurities enter through open channels, moving through a layer of sand. Further they pass to the equipped system from the drainage pipes and are diverted to the technical well, river or canal. The presence of air allows bacteria to live. And under their influence, organic effluents decompose into ecological components and harmless elements.

The filtration field is arranged in such a way that it allows the use of an aerobic cleaning process. The effectiveness of this system will depend on the composition of the soil, which is used for filtration. When developing the project, it is necessary to be guided by the sanitary norms, which indicate the need to prevent sewage from entering the water intake systems. The presence of drainage in the filtration field during septic operation is mandatory, when underground waters lie at a depth of 1.5 meters from the surface of the earth. The drainage system should also be equipped if underground filtration is in the ground, where the ability to purify is sufficiently small.

Drafting of the project

The filtration field device begins with the preparation of the project. Particular attention should be paid to choosing a place. It should be located as far as possible from the point of water intake and fruiting bushes / trees. If you do not comply with these requirements, then harmful substances can be in the soil, which will negatively affect the quality of berries, water and fruits. The drainage system can operate normally for 7 years or even less, so it must be unearthed after this period, clean and replace the employees for filtering gravel, soil and sand.

When the filtration field is arranged, it is important to perform a calculation that takes into account the penetration of the sand layer to a point below the freezing line. Otherwise, at low temperatures, the filtering fields will not be able to perform their functions.

Carrying out of calculations

If you decide to equip the filtration field, which is necessary for a septic tank of concrete rings, then the following example can be considered. According to the conditions on the site - sandy soil, and underground water lying at a depth of 2 meters. The capacity of a septic tank per day is one cubic meter. It is necessary to calculate the length of the irrigation pipe under the mentioned conditions.

It is still necessary to find out what is the average annual temperature in your area. For the Moscow region, this figure is 3 degrees. With a two-meter bed of groundwater and an average annual temperature of less than 6 degrees, the load per 1 meter of pipe will be 20 liters. This indicates that you will need field equipment with a length of irrigation pipe, which is 50 meters. If we take into account the subsidence of the soil, then the load on the pipes is taken with a coefficient ranging from 1.2 to 1.5. This indicates that the wastewater treatment system must have irrigation pipes, whose length is 41.7 meters (50 / 1.2).

Filtration field device technology

Biological wastewater treatment at the site will be effective if you create a filtration field that consists of underground pipes and ditches. At the bottom of the excavated hole is laid a layer of soil 10 cm thick, which will pass moisture well. The next layer will be sand of the same thickness. At this stage it is necessary to lay drainage pipes with holes, which will allow creating an effective filtration field.

When the described wastewater treatment systems are established, it is not recommended to use flexible pipelines, otherwise the norms of nature use will be violated. Each ditch should have a platform with gravel, the thickness of the layer is 40 centimeters. From above all is sheltered by textile material, which is designed to protect the drainage system from contamination and low temperatures. The area under which the filtration field is located must be covered with earth.

Advice of specialists

If you are interested in the question of how to create a water treatment plant, then you should familiarize yourself with certain rules. One of them says: complete biological purification can be provided if the field is located on sand, sandy loam or light loam. If the territory is on clay soil, the field will not be effective, since clay is not capable of passing moisture. As practice shows, in this case, the cost of work will be quite high compared with the installation of finished treatment facilities. After all, it is necessary to remove the clay to the location of the sand layer.

What else is necessary to know before carrying out the work?

Water treatment facilities of the type described operate according to the principle of self-cleaning of the soil. But this ability is not unlimited, therefore it is necessary to build additional cleaning systems during the work. If you consume water in large quantities, then for the disposal of drains from the drainage system, you can plant an artificial pond. There and will come cleaned liquid. For a day, adult birches, which should be planted around, will consume about 100 liters of water, this will eliminate the overflow of the artificial pond. The filtration field for a septic tank will last longer if the drains entering it are as clean as possible.

Possible causes of blockage of the field

Biological cleaning can break down, which becomes clear when the system stops absorbing water. This can lead to siltation of the soil. The flow of this process, unfortunately, can not be suspended, but it is quite realistic to slow down. The main thing at the same time is to exclude poorly purified impurities from entering the field. If the drainage layer is quickly filled with silt, then it is necessary to carry out unscheduled works for cleaning and replacing the filter. Otherwise, the septic will overflow the edge of the structure.

Conclusion

If you want the filtration field to work as efficiently as possible, then it is best to equip it with light loam, sandy loam or sandy soil. In the latter case, the load per meter of irrigation pipes will be 30 liters per day. As for sandy loamy soils, this figure will be halved. In the loams this value is even smaller, therefore, during the work, it is necessary to lengthen the pipes and make the thickness of the gravel bed much larger.

For the pipeline to be installed , it is necessary to choose the most rigid perforated drainage or sewage pipes. It is important in this case the presence of a sand filter, which will clean the system of the remaining impurities and foreign inclusions.