The presence of autonomous communications is the key to a comfortable stay in a country house. At the same time, they will have to be serviced independently. To spend a minimum of effort and money on cleaning the waste pit, it is recommended to make a sewer system that does not require pumping waste. In the circles of experienced masters, it is called a “septic tank”. Such a sewage system without pumping and odor can do without a sewer from 2 to 5 years.
Varieties and principle of operation of structures without pumping
The septic tank is a sealed well for drains, in which there is a phased cleaning / filtering of sewage waste. Structurally, septic tanks are:
- Single chamber (biological). Standard cesspools operating with active bacteria.
- Two-chamber (mechanical). The design allows high-quality wastewater treatment without the involvement of a sewage system.
- Three-chamber (mechanical / combined). Septic tank for the highest quality wastewater treatment. The resulting fluid can be used for irrigation and industrial purposes.
The operation of the sewage system without pumping proceeds according to this principle:
- Drains from plumbing points in the house go to the first receiver of the septic tank. If it is single chamber, add bacteria that process organics. As a result, dry sludge sediment and moderately purified water remain.
- If the septic tank is two-chamber, sediment settles in the first receiver. Heavy fractions of impurities plus debris settle to the bottom, and a film of fat and feces forms on the surface of the water. The remaining clarified liquid flows through the overflow hole into the next chamber.
- In the second receiver, additional water settling takes place according to the same principle. The thoroughly cleaned liquid flows into the third tank.
- The bottom of the third receiver is leaky - it works on the principle of natural drainage. Treated water goes into the ground or drains into a ditch without the risk of environmental pollution.
For the installation of sewage chambers without pumping, you can use concrete rings, concrete castings, brickwork or ready-made polymer tanks. Such a sewer needs to be cleaned no more than once every 2-4 years. In particular, silt must be removed.
Benefits and cesspool location rules
Features and benefits of sewage without pumping are as follows:
- simplicity of design and ease of wastewater treatment;
- environmental friendliness and respect for nature;
- saving family funds on the services of a cesspool worker;
- the possibility of using purified water in people;
- the absence of a characteristic specific odor on the site;
The sewage system without pumping out is regulated by SNiP 2. 04.03-85. The norms for the location of the septic tank on the site are as follows:
- wells are installed 5-15 m from a residential building;
- the system should be located 20 m from clean water sources;
- the upper level of the receivers should not exceed the height of the sewage;
- the bottom of the filter / drainage chamber should not be below groundwater.
It is advisable to provide access to transport to the sewer.
Sewerage calculation
According to SNiP, the volume of sewage should be calculated by the formula: number of family members X 200 l (average rate of water consumption per person). Thus, if three people live in the house, the total amount of sewage should be 6 cubic meters. The distribution of volumes between the receivers looks like this:
- the first receiver - 3/4 of the total sewage;
- drainage well - the remaining volume (i.e. 1.5 m3).
If three chambers are planned, the first should have 2/3 of the total volume, the second should be 2/3 of the remaining volume, and the filtration well should be the rest of the volume.
The dimensions of the pits are determined depending on the level of GW occurrence and the total volume of sewage: the receivers can be wide and low or deep and narrow.
If the family has 2 people, a two-chamber septic tank is enough. For a larger number of households, it is better to mount a sewer with three cameras.
Project drafting
In the design of the septic tank, the relief of the site should be taken into account. If it has a slope, the sewer is located at the bottom. The design documentation includes the length of sewer pipes. Their slope should be 1-2 cm per 1 meter of pipeline length. Inspection wells are required at the turns of the collector, but it is advisable to make the pipeline without sharp bends.
Installation Steps
Installation of a septic tank begins with a pit device. Its depth is focused on the level of GW. For example, if the depth of groundwater is 2 m, then the depth of the pit is 1.5 m, plus 40 cm is left on a sand pad / concrete base (divided evenly) and the filter base in the third receiver. At the same time, it is taken into account that the depth of the sewage pipes is 40-50 cm. Thus, the height of the septic tank will be 1 m. Using the method of mathematical calculations, knowing the recommended height of the sewage system, calculate its width and length for the required volume.
Dig a pit with a margin of 20 cm on each side for thoroughly compacting the soil around.
A septic tank made of PVC is covered with soil / clay in a filled state. Otherwise, its walls will burst later under soil pressure.
After preparing the pit and installing the cameras, you need to make a filter cushion in the third / second receiver. For this, the bottom of the last chamber is first covered with a layer of sand (tamped), and then with a layer of finely grained gravel. The depth of the filter cushion is 30-50 cm.
A drain pipe is brought to the first receiver. All joints are carefully sealed. Sewer chambers are covered with soil from all sides with their careful ramming. When starting a septic tank, the system is checked for leaks.
A finished septic tank is an excellent alternative to a standard cesspool. Groundwater remains clean, there is no specific odor, and the family budget remains intact.
