For a comfortable stay in an individual building, the arrangement of the sewer system is important. To do this, you need to correctly determine the size of the cesspool for a private house.
Features of the arrangement of the cesspool
In a private building, the cesspool is designed in accordance with SanPiN 42-128-4690-8 and SNiP 30-02-97. The regulation provides for the following rules:
- Storage and cleaning tanks are located on the territory adjacent to the house, no closer than 10 m to the dwelling.
- The distance to the water supply is at least 10 meters, to the well or well –20.
- According to some regulations, a cesspool is allowed to be installed at a distance of 5 meters from a dwelling if the size of the site is small.
- The system is located at least 2 meters from the border of the neighboring site.
- According to SNiP, the depth of the pit should not exceed 3 meters.
- The permissible distance from the bottom to the groundwater level is at least one meter.
Moreover:
- the structure must have a sealed cesspool and a ground part that is closed with a lid;
- filling the underground part is allowed no higher than 35 cm from the top of the pit;
- cleaning is carried out as soon as it is filled, but at least twice a year.
- disinfection is required.
The system should be located below the water well along the slope of the site. Waste water from the house flows by gravity through pipes connected to the pit.
Arrangement of a cesspool is not a difficult process, but laborious, since it is associated with earthworks. There are no special requirements for its type and design, since the entire system is located in the ground.
Choice of design
The options differ in the material of manufacture and the principle of operation, the duration of operation. According to the principle of operation, there are two main types. The sealed structure consists of a closed bottom and sturdy walls. It can be single-chamber or consist of several compartments. The reservoirs are interconnected with pipes, supplied with biological filters, pumps. Such waste containers do not harm the environment, but they quickly become dirty and require regular cleaning.
Bottomless pits absorb accumulations of all soil layers. One of the simplest tanks is a sump made from car tires. This is a budget option. It has a small volume, is not cleared and silts up quickly.
The service life of a drum tank depends on the quality of the metal. If you choose an expensive material with an anti-corrosion coating, the device will last for many years.
There are special plastic containers. If the pit is up to 1m3, polypropylene barrels can be used.
A brick structure becomes unusable due to the decomposition of the material under the influence of moisture. Walls can be repaired with concrete inserts, extending the service life.
The best option for the ratio of quality and cost is concrete rings. They do not rot, they are resistant to soil movement. The service life of such a device can be up to 100 years.
Calculation rules
A family of three will drain into the cesspool per day: 3 * 150 = 450 liters. The sealed pit is cleaned every 15 days. In two weeks, 6750 liters or 6.75 m3 of waste will accumulate. It is necessary to reserve a reserve for unforeseen situations. The volume of the tank in this case will be 9 m3. For a country house, where people are for a short time during planting and harvesting, it is enough to have a capacity of 1-2 m3.
The bottomless device is cleaned with anaerobic bacteria, and the wastewater partially goes into the ground. Such designs also require periodic pumping. Special biological products allow to lengthen the term. The calculation is carried out for the maximum possible volume of wastewater.
Wastewater from household appliances that use water is added to the average consumption of 150 liters per person. Thus, the volume increases to 50 liters per day. A family of three has a minimum of 600 liters of effluent. To determine the volume of the pit, the amount per day should be increased three times, and will be 1.8 m3.
Calculation of the parties
The required cubic capacity affects the parameters of the well. There are no clear rules for aspect ratio. You need to calculate based on the depth of the groundwater. A pit depth of 2.5–2.7 meters is considered standard. The pit for the cesspool is a parallelepiped. The calculation of its sides is as follows:
Volume formula: V = a * b * h,
where a is the length,
b - width,
h - height,
then the width is b = a * h / V,
length a = b * h / V
If the required volume is 9 m3, we get the following parameters:
- depth 2.0 m;
- length 3.0 m;
- width 1.5 m.
Cesspools are not recommended to be made deeper than three meters. If necessary, in leaking devices, the level can be raised using a sand-crushed stone cushion.
The cesspool machine is equipped with a sleeve about three meters long. If the pit is deeper, it will not be cleared of silt and solid build-up at the bottom. When positioning the device, you should take into account the access routes for the equipment.
If the water table is high, the construction of a cesspool is not advisable. During a flood, it will be filled with groundwater. In this case, it is better to choose septic tanks or use barrels of suitable diameter. They should be protected with a concrete or metal casing.
Selection of materials
Knowing the dimensions of the well, you can calculate the required amount of building materials. The dimensions of the red brick are 250x120x65. A checkerboard two-row masonry is used. Consideration should be given to the thickness of the concrete slab at the bottom and the cement layer.
A cinder block measuring 390x180x190 is stacked in a checkerboard pattern in one row. Through four rows, a solid reinforced belt is poured.
Reinforced concrete rings of round or square section are manufactured industrially. They have a standard height. Knowing the diameter, you can calculate the depth of the pit. As a rule, two or three rings are mounted. The joints are sealed.
Tire sizes are also standard. It is better to buy tires from trucks, their diameter can reach a meter. This makes it possible to reduce the depth of the pit.
When calculating the material, you need to remember that the height of the structure will have to be reduced by the thickness of the bottom and top. The bottom of a closed pit is covered with sand and crushed stone in equal amounts. For an open one, it is sand, fine, then coarse gravel. Fragments of broken brick or cinder block are laid on top.
The top is made 40 cm lower, an overlap is performed and covered with earth to prevent the freezing of drains. To eliminate the odor in the upper part of the pit, ventilation from a plastic pipe with a diameter of 10 cm is required.
Correctly calculated volume and parameters will allow you to equip a cesspool at no extra cost and safely dispose of wastewater in a private house.
