The optimal solution for organizing the treatment of domestic wastewater in a private household is a monolithic concrete septic tank. To install it, you can attract a team or do it yourself. This will further reduce the budget, do you agree? Materials for its devices are easy to purchase in hardware stores.
We will tell you in detail how to build a monolithic septic tank. Let us consider which variant of the concrete treatment plant is best for your site. With us you will learn how to care for an autonomous sewer system, what to do with sewage treated in a septic tank.
We offer step-by-step instructions to independent home craftsmen. Visual perception of the information will provide useful schemes, collections of photos and video instructions.
The content of the article:
- Typical monolithic septic device
- Specificity of a single-chamber cleaning station
- Scheme of the two-chamber version
- Necessary tools and materials
The device is a monolithic septic system
- Development and preparation of the pit
- Formwork construction for casting
- Installation of overflow pipes
- Preparation and pouring of concrete solution
- Overlap device
- Manhole cover manufacturing
- Proper care of the septic system
- How to use peeled drains?
- Conclusions and useful video on the topic
Typical monolithic septic device
Standard concrete septic tanks for cottages and houses have from one to three adjacent chambers. Between them there is a movement of drains through overflow pipes, mounted in partitions.
Due to the multi-day sedimentation, separation of insoluble sediment from water and the activity of microorganisms, natural purification of wastewater occurs. All chambers of the septic system are used only for settling.
It is impossible to do adjacent a filtering well. Over time, this will lead to the deformation of the entire septic tank, so you need to install a filter system separately. It must be selected on the basis of the area and the desired quality of cleaning.
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Single-chamber version of the sewage structure is essentially a drive designed for the accumulation and subsequent pumping of waste
The two-chamber version, in addition to the accumulation of waste, also produces their cleaning. During settling, the waste water is separated from the insoluble sediment and flows into the after-treatment system.
The more chambers in the septic tank, the higher the degree of cleaning and disinfection of wastewater. Besides gravity, anaerobic bacteria are involved in processing.
The sewage treatment plant for independent sewage can be poured on the spot or made of prefabricated concrete modules
Single chamber cumulative design
Two-chamber septic system
Three-stone concrete septic tank
Prefabricated concrete modules
This may be a stand-alone well, a filter trench or filter field. The purification system can be installed after installing a monolithic septic system, but in this case, the trenches will have to be digged by hand. The use of technology will be impossible, as it can damage pipes and floors.
Specificity of a single-chamber cleaning station
A septic tank that has one chamber is called a drain pit. Its device does not involve multistage cleaning and serves mainly for storing sewage with subsequent pumping.
Pumping and transportation of waste is carried out using a special machine. The disadvantage of such a drainage system is its rapid filling and costly maintenance.
In a single-chamber septic tank, the settled water flows into the sewer pipe and undergoes purification in the filtration field or filter well. The solid fractions settled to the bottom should be pumped out every 4-6 months.
The depth on the diagram of this concrete septic tank is 2 m, it is designed to serve two or three people. Due to the lack of cleaning and draining, the tank quickly overflows.
An alternative to a monolithic single-chamber septic tank is concrete ring cesspit, with the features of the construction which we recommend to read.
Scheme of the two-chamber version
In this system, water undergoes preliminary sedimentation before discharge or pumping. According to sanitary standards, such water can be discharged into the ground. The advantages of this system are in its compactness. With the same volume, two separate containers from RC rings take up more space than a solid concrete structure.
The diagram shows the proportions of the septic system. The optimal size of the receiving chamber should exceed the volume of the second settling tank in a ratio of 1: 3 (+)
This septic tank has an internal partition of concrete, which allows water to settle in two stages. In addition, it can be equipped with an overflow sensor.
The second overflow at the opposite end of the tank is located slightly below the first, which excludes the return drains into the receiving compartment and provides spontaneous overflow of the settled liquid into the next chamber.
The two-chamber drain hole should be pumped out once a year, the single-chamber - at intervals of 3-6 months, i.e. 2-3 times more often. A two-compartment will require more construction costs, but in the long run, budget overrun will pay for itself quickly.
How to build a two-chamber septic tank using concrete rings, written here. We recommend to get acquainted with this material.
Necessary tools and materials
For installation of a concrete septic tank with your own hands you will need the following materials:
- PGS (2.5 tons).
- Cement (18 bags of 50 kg).
- Liquid bitumen (20 kg).
- Iron corner 40 x 40 (25 m).
- Iron sheet with a thickness of 2 mm 1.250 x 2.0 m (1 pc.).
- Sheets of plywood 1,5 X 1,5 m (8 sheets).
- Flat slate 1500x1000x6 (6 l).
- Polyethylene film (two - three cuts with a total area of 13 x 9).
- Boards 40 x 100 mm.
- Plasticizer (depending on the type in the calculation of 5.9 cubic meters of concrete).
- Wire rod with a cross section of 0.6 mm (the metering depends on the density of the grid).
- Bars 50 x 50 mm.
- Bricks (120 pcs.).
- Pipes for outdoor sewage (individually, depending on distance).
- Pipes for domestic sewage (individually, depending on the design).
- Branch pipes (individually, depending on the design).
- Fittings (according to the number of pipe joints).
- Sealant (1 pc.).
- Screws (300 pcs.).
- Cutting disc for metal (1 pc.).
- Grinding nozzle for angle grinders (1 pc.).
For the installation of a concrete septic tank, the following tools and equipment will be needed:
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A concrete mixer will significantly speed up the process of preparing and pouring mortar when setting up a monolithic septic tank. With it, the entire amount in the formwork can be poured in one day
The spade is necessary for leveling the walls of the pit. A rebate is used to remove excess ground.
LBM need for cutting iron corners, iron for hatches and grinding. Wear safety glasses when working with this tool.
It will need to build the formwork. It is better to fix the form for pouring concrete on the screws, since it will be faster and easier to disassemble this structure.
The construction level is constantly required to control the horizontal position and verticality of individual elements and the structure as a whole, it is necessary to level the surface of the walls and the bottom of the excavation. The optimum length for earthworks is 100 - 200 cm
The square is necessary for marking the pit. Also helps to adjust the angle of the walls. Also needed when sawing plywood for formwork
The laser level is useful at all stages of the installation of a concrete septic tank. In the absence of an expensive instrument, it will be able to replace it with a tape measure and plumb that are needed to determine the boundaries and depth of the pit, the formwork device and the upper floor slab
Useful for transporting heavy building materials such as bricks, cement and sand and gravel mix. It also serves to transport the soil extracted from the pit.
Equipment for kneading solution
Hand tools for work
Grinding machine for cutting
Drill and screwdriver for assembling formwork
Laser instrument for large-scale breakdown
Wheelbarrow for transportation of various goods
All calculations of materials are made for a monolithic concrete septic tank with dimensions: width -2 m, length - 3 m, depth - 2.30 m.
The device is a monolithic septic system
The complexity of the installation forces many to buy ready-made RC structures. Their use allows for installation much faster.
The organization of a septic system of prefabricated elements will take a couple of days, and for the installation of monolithic concrete construction will take more than a month, including the construction of the formwork and the technological break for hardening concrete stone.
Each stage, starting with excavation and ending with the welding of manholes, is carried out in strict sequence. Before you get started, you need to stock up on time or negotiate help with other people on a commercial basis.
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Stage 1: In the pit designed according to the dimensions of the septic tank, the waterproofing is laid - reinforced polyethylene film or roofing material
Stage 2: The reinforcement cage is installed from 8 to 10 mm bar. To connect the elements used knitting wire
Stage 3: Construction of the formwork for the design dimensions of the septic tank and the input of overflow pipes. For the device of the walls of the formwork fit unedged board inch
Step 4: At least 28 days later, the formwork is dismantled. The walls of the construction are treated with clay mortar or bitumen waterproofing.
Step 5: The support frame for the overlap device is constructed from a metal angle. The frame rests on the walls of the monolithic septic tank
Stage 6: For sections formed by a frame from a metal corner, cut overlap fragments from plywood or flat slate
Step 7: Fill the joints between the sheets with a clay mortar or sealant. Fragments on the site of the hatches are removed, arrange a formwork around them from the board and pour the solution to form a concrete floor
Step 8: After 28 days, waiting for the concrete solution to completely cure, a cap is made of bricks, blocks or board around the septic tank necks
Preparation of the pit for the device septic tank
Aroma frame construction
Construction of formwork for pouring
Dismantling formwork after 28 days
Installation of supports for the upper floor
Device plane to fill
Arrangement of holes for manholes
Arrangement of openings for a septic tank
Since leaving the house / bath and entering the septic tank should fit with a regulatory bias it is better to prepare a trench for it in advance. This is necessary to accurately determine the height of the input pipeline in the concrete structure.
Development and preparation of the pit
Since the pit will be used as a form, it is necessary to make its edges as smooth as possible. Dredging should be done without the use of technology or using only at the initial stage.
Align the edges of the pit manually. Periodically it is necessary to check the flatness of the surface. To do this, use the level. For evenness of the corners, periodically you need to measure the construction area.
Excess soil must be removed or distributed evenly across the site. After completion of the excavation work it is necessary to lay a plastic wrap on the bottom of the pit. It may consist of several cuts.
The film should cover the pit completely. The use of polyethylene performs two tasks. It reduces the consumption of cement mortar, and also serves as an additional waterproofing. The joints of polyethylene sheets do not need to be sealed. The film can be fixed with bricks, so it will not move with strong gusts of wind.
To descend into the pit, you can hammer together a ladder of scrap materials. With a significant recess on the stairs you can transport the soil in buckets.
Formwork construction for casting
The service life of the entire structure depends on how the formwork is set. Since there will be a volume of liquid inside the container, it will exert pressure on the walls of the tanks. Therefore, before you put the formwork you need to make reinforcement.
To do this, you can use reinforcement, knitting wire or already finished mesh. It is necessary to reinforce the walls so that the grid is in the middle of the monolith. Its distance from the outer edges of the pit should be 7 cm.
After the wall is mounted mesh for partitions. It must be placed at a distance of 2 meters from the sewer pipe. It should turn out two compartments. Larger for primary settling, and smaller for secondary
After mounting the partition, you can reinforce the floor. The net for it should be raised 7 cm from the bottom surface. This is necessary for the greatest bonding effect.
The construction of the formwork is made before the device reinforcing frame. To do this, from plywood and bars need to build shields. It should be two boxes without a bottom. Each fits in a container.
- for the first tank: width and length 1.7 m;
- for the second tank: 1.7 m wide and 0.085 m long;
It is necessary to check that there are no gaps during installation. After organizing the formwork and before concreting, installation of overflows is necessary. If you do this after concreting, you will have to hammer holes. This can lead to deformation of the structure.
Installation of overflow pipes
Two overflow pipes are required for overflows. The first nozzle is put on sewer pipeleaving the house. To do this, you need to cut a suitable hole in plywood and bring the end to the receiving tank.
The pipe is attached to the pipe with a rubber ring and sealant. The drain hole of the nozzle should be directed downwards.
A pipe 40 cm long must be inserted on the partition between the two tanks. The pipe is fixed in plywood on both sides of the containers. On the ends of the pipe on both sides of it are put on the nozzles, directed downward drain holes.
Preparation and pouring of concrete solution
Since the layer thickness is small (15 cm), it is necessary to make a strong solution. First you need to take a container for kneading the solution. At its bottom place the cement and the CBC in the ratio of 1: 3.
The amount of water depends on the moisture content of the gravel mix. The consistency of the solution should be moderately thick. To improve the properties of the solution you need to use a plasticizer. The amount of its addition depends on the brand of cement substance.
For the convenience of pouring cement mortar into narrow gaps between the formwork and plastic wrap, you can use a chute made of metal, half pipe or a gutter. This will allow you to evenly pour the solution, avoiding the formation of cavities.
So you can speed up the process of pouring. It is better to fill the entire volume in one day. Such monolithic concrete will last longer, since there will be no stratification in the cement stone along the pouring boundary on different days.
You can start with the walls or the floor. This is not very important. After finishing the concrete work, you need to wait until the mortar has set and harden. On it according to construction standards for 28 or several days.
The rate of hardening depends on the ambient temperature. When dry, the concrete changes its color and becomes lighter. The structure embedded in the formwork must be protected from drying out with wet sawdust or polyethylene.
The freezing of the cement stone during the hardening period should be completely excluded. After the specified period, the formwork can be dismantled.
The installation of the upper slab begins with placing the frame.
It consists of iron corners, which are installed in the following order:
- Four corners with a length of 3 meters, you need to lay on the wall of the septic tank. One corner from each edge and two close to each other in the middle of the tank.
- Several transverse corners are stacked on top, forming a lattice. They need to be laid according to the size of future hatches.
The resulting design needs additional fastening. To do this, you need to make holes in the corners and with the help of anchors to attach them to the concrete base. The cross corners must be attached with bolts or special screws.
After mounting the corners, suitable squares should be cut from flat sheet slate. After that, sheets of slate need to lay over the grill. To prevent the flow of the solution is to handle the joints with liquid bitumen.
Next you need to fence boards perimeter hatches. Better to make them contiguous. In addition to the hatches, additionally set formwork over the entire floor area. After that, you need to insert the ventilation pipe by making a hole in the slate above the second chamber.
Upon completion of the installation of the pipe can be filled with mortar overlap area. After drying and hardening of the solution, the formwork should be removed.
The empty space for the hatches is necessary to impose bricks, so that they do not rise above the surface. Mortar for bricks to be made without filler, using cement and sand
Since the amount of sand required is small, it is possible to sift the sand and gravel mix. The proportions of the solution can be made 1: 4. After completion of the laying it should harden. It takes 2-3 days. After waiting for this period, you can insulate and bury the pit. Periodically you need to tamp the ground.
Manhole cover manufacturing
In order to prevent the septic system from overcooling and debris from entering it, it is necessary to install hatches. Covers for them can be made of wood and metal. The wooden cover is set as internal.
It protects against temperature extremes, and an insulation is put on it. For its manufacture, you can use plywood or individual boards, knit together. The cover does not need to be mounted on the sheds, it should be removable.
The outer cover must be made of metal. To do this, you need a building angle (40x40). From it welds a rim for the hatch, which is attached to the base with anchors.
The size of the rim of the sheet metal must be cut off the cover. The edges must be processed with a grinding nozzle for angle grinders. It is necessary to attach canopies to a cover. They can be welded or fixed to the bolts. After that, the cover is attached to the rim in the same way.
For self-made septic tank necks, you can make two or one common cover from the board. It will have to be changed periodically. The place around is covered with soil, and the cover is closed with a water-repellent material.
Proper care of the septic system
During operation, any sewer pipes are periodically covered from the inside with a bold bloom, which reduces their throughput. It must be removed by special means.
They can be chemical or bacterial. Microbial based products preferably, since they do not spoil the pipes and do not lead to the death of microflora inside the septic tank.
In winter, when the temperature drops to -25 degrees Celsius, it is necessary to warm the holes in the hatches. Otherwise, the processing of organic matter in tanks will slow down, which will lead to a decrease in purification.
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Drains from the septic tank should not be immediately dumped onto the relief for soil purification, since they are cleaned only by 60%. For the disposal of water, an underground after-treatment is needed, one of the variants of which is a filtering well.
If the area of a country allotment allows, an underground system of tertiary treatment is arranged in the form of a group of infiltrators
As a variant of a horizontally oriented system, filtering fields are used, which are a construction of perforated pipes laid on a soil filter.
The functions of a filtration field or a group of infiltrators will be successfully performed by a filtering trench, which is arranged for assembly into the soil of a small volume of treated wastewater.
Absorbing well in tertiary treatment
Installing Infiltrating Cassettes
Filtration field for soil purification
Recycling through the filter trench
How to use peeled drains?
The water purified and disinfected in a septic tank can be used to organize the irrigation of plants and trees in the garden plot. It is characterized by a small percentage of pollution (10 -15%).
The water that has passed through the purification process is quite suitable for domestic use. This will significantly reduce water consumption for the organization of watering the garden or garden in the summer. So, it will save.
The use of pumping equipment involves power consumption. For power supply, you can use a small solar power and rechargeable battery
In a couple of years of operation, the system will fully pay for itself, since with the help of solar energy converted into electricity, it is possible to reduce the consumption of electricity supplied by centralized networks. Solar battery quite able to cover the pump needs.
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If it is not possible to dispose of treated wastewater into the ground, it can be accumulated in sealed wells and used for watering plants and caring for the area.
The waste water that has passed through the ground treatment system can be dumped onto a relief or into a gutter.
If local specificity permits, a perforated drainage pipe can be brought into a green zone that does not have the status of a park or a public garden.
Purified water is acceptable to water ornamental plants. It is impossible to swim and wash pets
Purified waste water tank
Gutter for waste disposal
Utilization of waste water on the relief
Watering non-agricultural plants
The pump can pump out water from the secondary or tertiary clarifier, as well as excess sludge mass from the receiving chamber. Pumped sludge can be used in compost maturation. It is used as a self-fertilizer or mixed with other components.
In the compost pit you can pour the remnants of organic matter. This may be fallen leaves, weeds and manure. After three to four years of rotting, an excellent fertilizer is obtained, which increases the fertility of the soil in the household plot.
Conclusions and useful video on the topic
The first video shows the principle of the device of a concrete septic tank before pouring cement mortar:
The second video shows the casting stage, dismantling the formwork and the final view of the septic tank:
This is one of the most budget options. Its production is cheaper than the concrete analogue of the rings, not to mention the factory-made biological treatment stations. The price gap is more than 50,000 rubles, including installation.
Another advantage of the design is durability. Concrete does not decompose, but under the influence of moisture is partially destroyed. This can be avoided by treating the walls of the tanks with liquid waterproofing materials.
Interesting facts about the construction of a monolithic septic tank of concrete or a story about how you independently performed the casting, please leave in the block below. Here you can ask questions and share useful information.