If a septic tank is used as a sewage treatment system in the area of your country house, then for its normal operation it is necessary to create a filtration field. It will consist of several trenches with spray tubes located inside. Trenches are filled with gravel, crushed stone and sand, which are necessary for filtering treated effluents. If the work on the design and further organization of such a system was carried out correctly, then additional problems during operation and disposal of effluents will not arise.
Field device
After the initial treatment of wastewater from helminths and mechanical impurities has been completed, sewage flows through open channels, moving through a layer of sand. Then they pass into the equipped system from drainage pipes and are diverted to a technical well, river or canal. The presence of air provides bacteria with the opportunity for life. And under their influence, organic waste decomposes into environmental components and harmless elements.
The filtration field is arranged in such a way that 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 a project, it is necessary to be guided by sanitary standards, which indicate the need to prevent sewage from entering the water intake systems. The presence of drainage in the filtration field during the operation of the septic tank is mandatory when groundwater lies at a depth of 1.5 meters from the surface of the earth. The drainage system should also be equipped if the underground filtration is in the soil, for which the ability to clean is small enough.
Project drafting
The filtering field device begins with the preparation of the project. Particular attention should be paid to the choice of place. It should be located as far as possible from the point of intake and fruiting shrubs / trees. If you do not comply with these requirements, then harmful substances may be in the soil, which will negatively affect the quality of berries, water and fruits. The drainage system is able to work normally for 7 years or even less, so it must be excavated after this period, cleaned and replaced crushed stone, soil and sand used for filtering.
When the filtration field is equipped, it is important to carry out a calculation that takes into account the depth of the sand layer to a mark below the freezing line. Otherwise, at low temperatures, the filtration fields will not be able to perform their functions.
Settlement
If you decide to equip the filtration field, which is necessary for a septic tank made of concrete rings, then you can consider the following example. According to the conditions on the site - sandy soil, and groundwater lies at a depth of 2 meters. The septic tank capacity per day is one cubic meter. It is necessary to calculate the length of the irrigation pipe under the mentioned conditions.
You also need 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 underground water bed and an average annual temperature of less than 6 degrees, the load per 1 meter of pipe will be 20 liters. This indicates that field equipment with an irrigation pipe length of 50 meters will be required. If you take into account the soil backfill, then the load on the pipes is taken with a coefficient in the range from 1.2 to 1.5. This indicates that wastewater treatment systems should have irrigation pipes whose length is 41.7 meters (50 / 1.2).
Filtration Field Device Technology
Biological wastewater treatment at the site will be carried out effectively if you create a filtration field, which consists of underground pipes and ditches. A layer of soil 10 centimeters thick is laid at the bottom of a dug hole, which will allow moisture to pass through well. The next layer will be sand of the same thickness. At this stage, drainage pipes with holes will be laid, which will create an effective filtration field.
When the described wastewater treatment systems are created, it is not recommended to use flexible pipelines, otherwise the environmental standards will be violated. Each ditch should have a platform with crushed stone, the layer thickness in this case is 40 centimeters. From above everything is covered with textile material, which is designed to protect the drainage system from pollution and low temperatures. The area under which the filtration field is located must be covered with earth.
Expert Advice
If you are interested in the question of how water treatment plants are created, then you should familiarize yourself with certain rules. One of them says: full biological treatment can be provided if the field is located on sand, sandy loam or light loam. If the territory is on clay soil, then the field will not be effective, since clay is not able to pass moisture. As practice shows, in this case, the cost of the work will be quite high compared with the installation of finished treatment facilities. After all, in this case, clay has to be removed before the location of the sand layer.
What else you need to know before working
Water treatment facilities of the described type operate on the principle of soil self-cleaning. But this ability is not unlimited, therefore, during the work it is necessary to build additional cleaning systems. If you consume large quantities of water, you can plant an artificial reservoir to dispose of drains from the drainage system. There, the purified liquid will flow. During the day, adult birch trees, which should be planted around, will consume about 100 liters of water, this will eliminate the overflow of an artificial reservoir. The filtration field for the septic tank will last longer if the drains entering it are as clean as possible.
Possible causes of field clogging
Biological treatment can fail, which will become clear when the system ceases to absorb water. This can lead to siltation of the soil. Unfortunately, this process cannot be stopped, but it is quite possible to slow down. The main thing at the same time is to exclude the entry into the field of poorly cleaned sewage. If the drainage layer is quickly filled with sludge, you will have to carry out unscheduled work on cleaning and replacing the filter. Otherwise, the septic tank will overflow over the edge of the structure.
Conclusion
If you want the filtration field to work as efficiently as possible, 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 loam soils, this indicator will be halved. In loams, this value is even smaller, so during the work it will be necessary to lengthen the pipes and make the thickness of the crushed stone layer much larger.
For laying the pipeline , it is necessary to choose the most rigid perforated drainage or sewer pipes. It is important that there is a sand filter that will clean the system of the remaining impurities and impurities.