How to make a sump with overflow for sewage in a private house

An overflow cesspool is suitable for private houses that use appliances that increase comfort: water heaters, washing machines and dishwashers, showers, bathtubs. Only this option of a non-purchased device is able to cope with an abundance of liquid waste.

Varieties of cesspools

Wastewater treatment plants differ in design and scope. Most often, the following types of pits are equipped on personal plots:

• Absorbent without a bottom. The structures are suitable for areas where the daily volume of wastewater does not exceed a cubic meter. Their principle of operation is that wastewater, passing through the drainage layer in the well, is purified, and then absorbed by the soil.
• Sealed chambers for the accumulation of sewage. Environmentally friendly, since waste water does not penetrate into the environment - it is pumped out by sewer trucks. A variant of such a treatment design is storage septic tanks - due to the influence of biological products, they need to be cleaned less often.
• Sediment tanks with overflow. This is an even more advanced option. The liquid after clarification is allowed to be used for watering garden plants.

Each of the varieties can be made by hand, including a sump with an overflow for sewage in a private house.

The principle of operation of the structure

Wastewater treatment plants of this type are capable of filtering sewage effluents up to 90–95%. The scheme of the overflow two-chamber septic tank is quite simple. The two tanks are aligned with each other using plastic pipes.

There may be more containers, but a couple is enough for a small cottage. The first plays the role of a sedimentation tank and accumulator of water-insoluble heavy dirt particles. It must have a hatch for the hose of the sewage equipment, since such septic tanks still require pumping, albeit less often than just accumulative ones.

Getting into the second chamber, the clarified liquid is re-settled and purified by bacterial flora, which feeds on organic matter and biowaste.

After cleaning in the second tank, the liquid is directed to the filtration fields or to the infiltrator. In the overflow pipe, it is also allowed to install mesh filters and grease traps that trap part of the dirt when overflowing wastewater from one container to another. Bacteria are placed on the filtration devices to help decompose the waste. When using an aerobic type of microorganisms, the structure is equipped with ventilation shafts or an aerator.

There is an even simpler option: the cleaning device also consists of two containers, while the first is sealed, and the second is installed without a bottom. Instead, a mixture of sand and crushed stone is poured, acting as a filter. Flowing from the first tank to the second, the clarified liquid undergoes mechanical cleaning, passing through the sand-gravel bed, and then enters the ground.

Advantages and imperfections of an overflow pit

The main plus of the sewage system is the lack of frequent cleaning with special equipment. In addition, the settled liquid can be used for household needs: watering plants, fertilizing the beds.

Additional advantages of such a device:

• Cleansing efficiency. Sewage water is subjected to several stages of treatment in the settling and filtration chambers.
• High throughput - 0.2–0.5 cubic meters per hour.
• Almost complete absence of odors.

The disadvantages include the complexity of installation. It consists in accurately calculating the angle for connecting the pipe and the location of the containers in relation to each other. Also, construction in comparison with a conventional pit will be more expensive, because even a two-chamber overflow device requires a pair of wells for sewage.

Construction Materials

For the construction of overflow structures, concrete rings, bricks and even old car tires are used. The first option is preferable: it is inexpensive and reliable. But for each of the cameras, you can choose your version of the performance.

Additionally, you will need gravel and sand, concrete mix.

From tools, a shovel, rope, bucket, hammer, chisel, and devices for mixing concrete mortar will come in handy.

Preparation for the construction of the structure

For the pit, a site is selected at a distance of at least 20 meters to the nearest water intake point and at least 10 meters from the building. The groundwater level should not be high. The liquid in the receiver should be located below the freezing layer of the earth.

Each drain is positioned to each other at an angle of up to 20 degrees. Their connection is carried out with pipes in the shape of the letter T. These fitting elements are installed at a distance of at least one meter from the extreme upper part of the tank.

The volume of each tank is at least two cubes. It is calculated depending on the total number of residents and plumbing fixtures. The more there are, the wider and deeper the cleaning chambers will be required.

Construction of a sewage treatment plant

The creation of an overflow cesspool from concrete rings on the site of a private house goes as follows:

1. The pit is dug out manually or with the use of special equipment. The size of the earthen hole should be 10 cm larger than the section of the selected building materials to strengthen the walls of the drainage chambers. This is necessary for the subsequent sealing of the sides of the tank.
2. The distance between the tanks is about a meter. To create a slope between them, the first camera can be made at a slight elevation. But they are also placed on the same level. The second option provides for the arrangement of a differential for the flow of liquid using pipes.
3. A cushion of sand and gravel is poured into the bottom of the pit. From above, it is covered with a layer of waterproofing material. Additional insulation of drains is performed depending on the depth to which the soil freezes. For these purposes, geotextiles, clay or foam insulation are used.
4. In the same way, the cushion for the second well is filled up, only without laying a layer of waterproofing. Instead, a thicker layer of gravel is poured.
5. A concrete slab is installed at the bottom of the first pit. The first ring is placed on it. Its installation is carried out according to the level: the correctness of the vertical installation of the camera depends on the location.
6. The outer side of each ring is necessarily covered with a thick layer of resin. This is necessary for a longer service life and increased drain tightness. A layer of concrete mortar is applied between the rings, the joints are also coated with resin.
7. To connect the domestic sewage main, a hole of the required size is punched in the upper ring element with a perforator. After installing the pipe, it is reinforced with a flexible sleeve and sealed with resin or sealant. On the other side of the well, a tee-shaped fitting is installed to connect the first and second chambers to each other.

Both wells must be covered with lids to control the operation of the drains and periodic repairs.

To increase the efficiency of wastewater treatment, it is recommended to put metal mesh filters on the connecting pipes and clean them regularly.

Caring for the purification system does not cause any particular difficulties.Cleaning with sewer trucks is performed as needed - on average, no more than once every six months. Do not forget about the monthly inspection of filters for contamination and silting. If cleaning with bacteria is used, then the biofilters will need to be replaced every half month.