How a cesspool of concrete rings is constructed: diagrams + step-by-step tutorial
Do you select the simplest way to collect and partially process sewage for your summer cottage or a seasonal residence? Agree that the arrangement of sewage will significantly improve the site and make your stay in the countryside incredibly enjoyable. The usual cesspool of concrete rings will cope with this task, but you do not know how to build it correctly?
We will help you deal with this type of septic tank - the article describes the construction of the pit, the popular construction schemes. The process of designing a vygre from the rings with the calculation of the required volume is disassembled in detail, its stage-by-stage construction is described.
The material is provided with visual photographs and diagrams; video recommendations on construction from experienced craftsmen are given. Also considered are ways to decorate a technical hole.
Design and purpose of the cesspool
Cesspools, like septic tanks, are used to collect sewage. But these are primitive structures that cannot clean a liquid.
In storage tanks, waste is only partially disintegrated, in contrast to VOC, where wastewater is divided into solid waste and liquid, which is further clarified and reaches a purity of 60-98%.
All varieties of cesspools can be divided into two categories:
- tight accumulative capacities;
- drain pits with filtering bottom.
For users, 2 differences are important - the device of the tank bottom and the frequency of waste removal. The first type retains the entire volume of sewage, therefore it is emptied quite often, once every 1-2 weeks.
For the second type, dumpers are called less often, since the tank is filled slightly slower.Part of the liquid seeps through a kind of filter that replaces the bottom, and enters the ground.
At first glance, the second option is more acceptable, however, it is acceptable only for the processing of gray wastewaters and when it is set up a number of factors must be taken into account:
- compliance with sanitary standards;
- soil type;
- availability and location of aquifers.
If the soil in the selected area is clayey, which is not able to absorb water quickly, there is no sense in making a filtering bottom. The same with aquifers - there is a risk of contamination and environmental disturbances.
There are many solutions for the organization of cesspools: building structures of brick, tires, concrete. Concrete structures and finished plastic containers are considered the most reliable.
Reservoirs made of concrete, created by erecting formwork and pouring, are more difficult to build than analogs of prefabricated rings, which we will discuss in more detail.
The grave of concrete cylindrical billets in finished form is a well from 2 m to 4 m in depth. Rings in the amount of 2-4 pieces put one on another, seal the seams.
The lower element, depending on the type of pit, may be closed or completely absent. Sometimes, instead of a finished factory blank, a concrete slab is placed on the bottom.
The upper part is made in the form of a neck with a technical hatch and a tight-fitting lid.
The main accumulative part of the reservoir is about 1 m deep, since the supply sewer pipe must be below the ground freezing level. The capacity is selected, taking into account the amount of daily waste.
What is attractive drain pits?
The main advantage of drives - the budget cost. It is for this reason that many stop at the simplest device, rather than acquire a more expensive and functional septic tank.
The ridge is also convenient for those who come to the country rarely - only in the warm season or only on weekends.
If there are relatively few sewage drains and regular waste pumping is established, a cesspool is a suitable option.
But with large volumes of wastewater we recommend purchasing a septic tank - a more expensive device that partially cleans waste and reduces garden soil pollution to a minimum (if a model with a filter well or an infiltrator is selected).
Disadvantages of a cesspool, which can be a cause of failure of its construction:
- limited volume;
- the need for frequent pumping;
- low (or zero) degree of waste treatment;
- peculiar smell, which is difficult to get rid of.
Those who want to install a filter sewer should be aware that from time to time, along with pumping, it will be necessary to clean and even replace the filter - a gravel or crushed stone layer at the bottom of the pit.
Overview of popular building schemes
Even the construction of two main types of cesspools can have nuances.Consider the features of the most popular schemes of concrete rings.
The first scheme is a cumulative pressurized well of two standard rings and one narrower ring for the neck.
The following diagram clearly shows the difference between the storage tank and the tank with the filter bottom.
The third option is a modernized drive, a primitive septic tank.
The use of a two-section drive is more expedient, since it increases the degree of environmental friendliness.Sometimes models from three compartments are used - the more of them, the more effective the cleaning of drains.
Short photo-manual for the construction of the pit
The device of a cesspool with the use of concrete rings includes a number of traditional steps. In order for readers to visually present the process, we suggest reading the photo report of the builders:
Drafting and calculations
Starting construction without preparation, you risk to violate sanitary standards and create a device with limited functions. To cesspool worked at 100%, it is necessary to provide all the nuances and difficulties of construction.
Step # 1 - determining the place for the drain hole
When choosing a place for a cesspool, it is important to consider two points: ease of maintenance and compliance with sanitary standards.
Accordingly, to facilitate the installation process and the best functionality of the entire sewer system, the tank should be installed as close as possible to the house.
Many do just that - they bury a container 2-3 meters away from the building, disregarding the smell and forgetting the rules and regulations for the use of drain holes and various septic tanks. By the way, the recommended minimum distance from the pit to the house is 5 m.
The scheme can be supplemented with the following information: an airtight container is installed in any type of soil, and a tank with a filter is only sandy, well-absorbed and permeable to liquid.
The base of the filter structure must be at least 1 m higher than the aquifer.
To determine the depth of the aquifers, it is best to contact the project or drilling organization for conducting geological engineering surveys or the drilling of a water well for the area of construction.
Step # 2 - Calculate Capacity
To determine the size and volume of the well, it is necessary to make simple mathematical calculations. If the house of permanent residence has a shower, toilet, washing machine, then for 1 person there are about 150-200 liters of sewage per day.
Suppose you want to install an airtight rake in the yard of a house where 3 people live - it turns out 450-600 liters per day.
Do not forget that when calculating we take into account at least 3-fold quantity, that is, multiply by 3 again, we get 1.35-1.8 m³. This is the minimum amount.
The dimensions of the neck and the parts of the well located above the entrance of the sewer pipe are not taken into account. That is, the resulting volume is the parameters of the part located below the pipeline.
Sometimes they are repelled by the timing of the call of vacuum trucks. If the same family of 3 people is served every week, then it turns out: 150 l (200 l) x 3 x 7 = 3.15 m³ (4.2 m³). Once every two weeks - 6.3 m³ (8.4 m³).
If the utility or private company serving your site has a 6-8 m³ transport in the park, it makes sense to install the maximum volume reservoir.
Step # 3 — Select Concrete Rings
The volume of the cesspool is calculated by the size of the rings, so it is easier to purchase models from the range of the company located nearby (delivery is required).
The standard version - with a height of 0.89 m and a meter diameter - it is produced by almost all concrete goods factories. For a small family, three blanks are enough (plus the neck and the bottom).
Construction of cesspools is so popular that factories began to produce complete kits for their device.
The set includes the bottom element with the bottom, from 1 to 5 (a larger number will cause difficulties with cleaning and pumping out) of standard rings, a narrowed neck, the upper floor slab with a hole under the hatch.
Rings can be plain and perforated (for absorbing wells). Manhole cover purchased separately.
In addition to standard meter diameter products, you can find more dimensional blanks.
Preference should be given to rings with a groove-tongue joint, which guarantees a higher degree of tightness and strength of the finished structure.
Step # 4 - preparation of materials and equipment rental
In addition to a set of concrete blanks, the following building materials may be required:
- brackets for connecting parts;
- sealant for sealing seams;
- bitumen mastic or other material for sealing the tank from the inside and outside;
- cement to reinforce the backfill;
- crushed stone, gravel and sand for the preparation of leveling screed or filter layer.
Do not forget about buckets, shovels and winches for dredging.
It is not possible to deliver concrete rings on your own - it is necessary to rent a truck for overall and heavy parts.
If the site is not provided for a winch, it is better to order special equipment with a manipulator. One person can not cope. The only thing you can do yourself is to dig a pit.
For the installation of blanks, you need at least 2-3 pairs of workers plus a truck driver.
Ideal - the help of friends with whom you can negotiate a low payment. If there are no special equipment drivers and installers among friends, you can rent a car and pay for the services of a team of workers.
Often the help of professional installers is offered by a company that sells rings for wells and drain holes.
Instruction for the construction of a sump
The installation of each specific reservoir has its own nuances associated with the features of the landscape, the ground, the location of the sewer network, etc. We consider the typical scheme of the device cesspool.
Stage # 1 - excavation
The first stage is land works. They can be done alone (long, hard and free) or with the help of a brigade (fast and fun, but for the money).
If there is a possibility, it is possible to attract a mini-excavator, then working hands will be needed only for “grinding” the walls and leveling the bottom of the excavation.
The shape and size of the pit should be consistent with the configuration and dimensions of the tank. Accordingly, there should be a round well, the width of which exceeds the concrete rings by 0.3-0.5 m on each side around the circumference.
This gap is required for sealing / warming of the structure from the outside and subsequent backfilling with compaction.
There is one nuance that should not be forgotten - this is the level of soil freezing (information is relevant for residents of the middle zone and the north of Russia).
The sewage drainage pipe and the main part of the tank must be below this level in order for the system to function during the winter period. If you lay a net near the surface, the liquid will just freeze when it gets cold.
In this regard, it is necessary to add the height of the neck to the dimensions of the working capacity, which essentially serves as a technical opening. The neck should protrude 15-20 cm above the ground.
Thus, the reservoir will be buried, as well as the sewer pipe, embedded in it below the freezing level.
By the beginning of the construction work it is necessary to level the base with the walls and dig a ditch leading from the house (bath, summer kitchen, garage) to the drain hole.
When constructing a ditch, do not forget that in order to avoid blockages the pipe should have a slope in the direction of the pit - approximately 2 cm per meter.
Stage # 2 - bottom arrangement
If you install an ordinary storage tank, the bottom, like the walls, must be airtight. For the construction of concrete rings, the best option is to prepare from the same material.
The part is specifically designed to design the bottom of the well and has a groove around the circumference. The only thing that is necessary for its installation is an even dense base.
Possible subsidence of the base is eliminated by pouring cement screed. Prepare it according to a simple scheme: for each part of the cement - 4 parts of sand. For strength, you can add crushed stone fines in the ratio of 1: 6.
The mass is prepared in a container, then poured over the entire area of the bottom of the pit and leveled. During the week, the concrete screed is slightly irrigated with water so that it does not become covered with cracks. The lower element of the structure is mounted not earlier than in a week.
For those who value time, there is a more practical solution - prefabricated concrete slab. It is placed on a flat bottom, and already on it - the first concrete ring.
On the backfill of crushed stone or gravel, colonies of anaerobes live - bacteria involved in the process of decomposition and cleaning of waste. The thickness of the underlying backfill varies from 0.3 m (for shallow wells) to 0.6-0.7 m (for tanks of 3-4 rings).
The power of the filtering bed placed in the wellbore should be at least 1.0 m. Layer placement is as follows: the bottom one is a layer of sand, above it is a layer of crushed stone of a small fraction, on top is a crushed stone of a large fraction.
Unlike a concrete tank, the “cushion” and filter are replaceable elements. When they become clogged with solid waste and cease to let the liquid through, the old filling is taken out and a new one is placed at the bottom of the pit.
Stage # 3 - Concrete Ring Mounting
The first ring, fitted with a bottom, is placed directly on the concrete slab (or screed).Smooth installation of parts - a guarantee of a strictly vertical position of the entire structure, without tilt and skew. A second one is placed on the bottom element and the joint is immediately sealed.
For sealing and waterproofing seams using a variety of solutions, coating and roll materials. With the help of roofing paper, glued to the bitumen solution, close the joints and cracks on the outside, it is not suitable for interior work.
The usual cement mortar is also considered to be weak: when the ground moves, its fragility appears, as a result of which it cracks and crumbles.
There are many modern modified mastics and solutions that have sufficient strength and elasticity. Some of them can be applied to wet joints or seams that are already under pressure from water.
Others are able to protect concrete from the damaging effects of an aggressive chemical environment, which is often found in sewage.
Here are some of the effective means for sealing joints and internal sealing:
- hydraulic sealsthat expand during solidification, tightly closing any cracks (Waterplug, Peneplag, Hydrostop); their only negative is the high cost;
- coating solutions for the entire surface(Antigidron, Hydrotex, Bastion);
- caulking iron materialsdeep stitchesKiilto FIBERPOOL impregnated with fibrous rubber - cords and ropes of jute, flax, hemp;
- rubber sealing tape(e.g. RubberElast)
- liquid glassadded to cement mortar;
- water based sealants(Peneplag, Penetron, Penekrit).
High-quality waterproofing ensures the integrity of the structure for up to 35 years.
Making sure that the connection between the rings does not let water through, you can install the following part.
Approximately 20-30 cm below the depth of seasonal soil freezing it is necessary to make an inlet for the sewer line. At the same stage, pave the pipe and connect it to the tank. The junction is carefully sealed.
In the northern areas of the pipe, passing above the depth of freezing, additionally warmed, as the upper part of the storage tank.
3 or 4 ring mount the neck, then - the slab. In the stove factory made there is a round hole for the hatch. Another hole of smaller diameter is needed for the ventilation pipe.
The final touch is backfilling. If dry cement is added to the soil, the reliability of the structure will increase, and the risk of destruction by ground motions will decrease.
Stage # 4 - Making a Technical Opening
The best option for exterior design is a metal hatch with a tight-fitting lid. Its inexpensive counterpart is simply a wooden lid, hinged.
A manhole is necessary for servicing the sump - pumping out waste or replacing the filter bed.
Recently, it is customary to mask sewers, especially if they do not look quite aesthetically pleasing.For this purpose, buy decorative products that mimic green spaces or large stones.
But it is not necessary to use a purchased decor; it is possible to assemble an elegant flower stand from wooden slats and decorate it with flowering plants.
Conclusions and useful video on the topic
A few tips from professionals will help you determine the type of pit and build a reservoir of concrete rings according to all the rules.
Stages of the construction of a sump with detailed comments:
Installation of concrete rings:
Useful information about hatches:
As you seethe device of a cesspool from concrete preparations is available even to an inexperienced builder. But remember that the construction of a functional building requires compliance with standards, a verified project, accurate calculations and, most likely, will require the help of installers.