A simple diagram of a biogas plant. Biogas and biogas plants. Video - Do-it-yourself biogas plant

The technology is not new. It began to develop back in the 18th century, when Jan Helmont, a chemist, discovered that manure emits gases that are flammable.

His research was continued by Alessandro Volta and Humphrey Davy, who found methane in the gas mixture. At the end of the 19th century in England, biogas from manure was used in street lamps. In the mid-20th century, bacteria were discovered that produce methane and its precursors.

The fact is that three groups of microorganisms alternately work in manure, feeding on the waste products of previous bacteria. The first to start working are acetogenic bacteria, which dissolve carbohydrates, proteins and fats in the slurry.

After processing the nutrient supply by anaerobic microorganisms, methane, water and carbon dioxide are formed. Due to the presence of water, biogas at this stage is not able to burn - it needs purification, so it is passed through treatment facilities.

What is biomethane

The gas obtained as a result of the decomposition of manure biomass is an analogue of natural gas. It is almost 2 times lighter than air, so it always rises. This explains the artificial production technology: free space is left at the top so that the substance can be released and accumulate, from where it is then pumped out for use for one’s own needs.

Methane greatly influences the greenhouse effect - much more than carbon dioxide - 21 times. Therefore, manure processing technology is not only an economical, but also an environmentally friendly way to dispose of animal waste.

Biomethane is used for the following needs:

cooking;

in internal combustion engines of automobiles;

for heating a private house.

Biogas produces a large amount of heat. 1 cubic meter is equivalent to burning 1.5 kg of coal.

How is biomethane produced?

It can be obtained not only from manure, but also algae, plant matter, fat and other animal waste, and residues from the processing of raw materials from fish shops. Depending on the quality of the source material and its energy capacity, the final yield of the gas mixture depends.

The minimum amount of gas obtained is 50 cubic meters per ton of cattle manure. Maximum - 1,300 cubic meters after processing animal fat. The methane content is up to 90%.

One type of biological gas is landfill gas. It is formed during the decomposition of garbage in suburban landfills. The West already has equipment that processes waste from the population and turns it into fuel. As a type of business, it has unlimited resources.

Its raw material base includes:

food industry;

livestock farming;

poultry farming;

fisheries and processing plants;

dairies;

production of alcoholic and low-alcohol drinks.

Any industry is forced to dispose of its waste - it is expensive and unprofitable. At home, with the help of a small homemade installation, you can solve several problems at once: free heating of the house, fertilizing the land with high-quality nutrients left over from manure processing, freeing up space and eliminating odors.

Biofuel production technology

All bacteria that take part in the formation of biogas are anaerobic, that is, they do not need oxygen to function. To do this, completely sealed fermentation tanks are constructed, the outlet pipes of which also do not allow air to pass through from the outside.

After pouring the raw liquid into the tank and raising the temperature to the required value, the bacteria begin to work. Methane begins to be released, which rises from the surface of the slurry. It is sent to special pillows or tanks, after which it is filtered and ends up in gas cylinders.

The liquid waste from bacteria accumulates at the bottom, from where it is periodically pumped out and also sent for storage. After this, a new portion of manure is pumped into the tank.

Temperature regime of bacteria functioning

To process manure into biogas, it is necessary to create suitable conditions for bacteria to work. some of them are activated at temperatures above 30 degrees - mesophilic. At the same time, the process is slower and the first product can be obtained after 2 weeks.

Thermophilic bacteria work at temperatures from 50 to 70 degrees. The time required to obtain biogas from manure is reduced to 3 days. In this case, the waste is a fermented sludge that is used in the fields as fertilizer for agricultural crops. There are no pathogenic microorganisms, helminths and weeds in the sludge, as they die when exposed to high temperatures.

There is a special type of thermophilic bacteria that can survive in an environment heated to 90 degrees. They are added to raw materials to speed up the fermentation process.

A decrease in temperature leads to a decrease in the activity of thermophilic or mesophilic bacteria. In private households, mesophylls are more often used, since they do not require special heating of the liquid and gas production is cheaper. Subsequently, when the first batch of gas is received, it can be used to heat the reactor with thermophilic microorganisms.

Important! Methanogens do not tolerate sudden changes in temperature, so in winter they must be kept warm at all times.

How to prepare raw materials for pouring into the reactor

To produce biogas from manure, there is no need to specially introduce microorganisms into the liquid, because they are already found in animal excrement. You just need to maintain the temperature and add a new manure solution in time. It must be prepared correctly.

The humidity of the solution should be 90% (the consistency of liquid sour cream), Therefore, dry types of excrement are first filled with water - rabbit droppings, horse droppings, sheep droppings, goat droppings. Pig manure in its pure form does not need to be diluted, as it contains a lot of urine.

The next step is to break up the manure solids. The finer the fraction, the better the bacteria will process the mixture and the more gas will be released. For this purpose, the installations use a stirrer that is constantly running. It reduces the risk of a hard crust forming on the surface of the liquid.

Those types of manure that have the highest acidity are suitable for biogas production. They are also called cold - pork and cow. A decrease in acidity stops the activity of microorganisms, so it is necessary to monitor at the beginning how long it takes for them to completely process the volume of the tank. Then add the next dose.

Gas purification technology

When processing manure into biogas, the following is obtained:

70% methane;

30% carbon dioxide;

1% impurities of hydrogen sulfide and other volatile compounds.

In order for biogas to become suitable for use on the farm, it must be cleaned of impurities. To remove hydrogen sulfide, special filters are used. The fact is that volatile hydrogen sulfide compounds, dissolving in water, form acid. It contributes to the appearance of rust on the walls of pipes or tanks if they are made of metal.

The resulting gas is compressed under a pressure of 9–11 atmospheres.

It is fed into a reservoir of water, where impurities are dissolved in the liquid.

On an industrial scale, lime or activated carbon, as well as special filters, are used for cleaning.

How to reduce moisture content

There are several ways to get rid of water impurities in gas yourself. One of them is the principle of a moonshine still. The cold pipe directs the gas upward. The liquid condenses and flows down. To do this, the pipe is laid underground, where the temperature naturally decreases. As it rises, the temperature also rises, and the dried gas enters the storage facility.

The second option is a water seal. After exiting, the gas enters a container with water and is cleaned of impurities there. This method is called one-stage, when biogas is immediately cleaned from all volatile substances and moisture using water.

Water seal principle

What installations are used to produce biogas?

If the installation is planned to be located near a farm, then the best option would be a collapsible structure that can be easily transported to another location. The main element of the installation is a bioreactor into which raw materials are poured and the fermentation process occurs. Large enterprises use tanks volume 50 cubic meters.

In private farms, underground reservoirs are built as a bioreactor. They are laid out of brick in a prepared hole and coated with cement. Concrete increases the safety of the structure and prevents air from entering. The volume depends on how much raw material is obtained from domestic animals per day.

Surface systems are also popular at home. If desired, the installation can be disassembled and moved to another location, unlike a stationary underground reactor. Plastic, metal or polyvinyl chloride barrels are used as tanks.

By type of control there are:

automatic stations in which the filling and pumping out of waste raw materials is carried out without human intervention;

mechanical, where the entire process is controlled manually.

Using a pump, you can facilitate the emptying of the tank into which the waste after fermentation falls. Some craftsmen use pumps to pump gas from cushions (for example, car inner tubes) into a treatment facility.

Scheme of a homemade installation for producing biogas from manure

Before constructing a biogas plant on your site, you need to become familiar with the potential hazards that could cause the reactor to explode. The main condition is the absence of oxygen.

Methane is an explosive gas and can ignite, but to do so it must be heated above 500 degrees. If biogas mixes with air, overpressure will arise, which will rupture the reactor. Concrete may crack and will not be suitable for further use.

Video: Biogas from bird droppings

To prevent the pressure from tearing off the lid, use a counterweight, a protective gasket between the lid and the tank. The container is not completely filled - there should be at least 10% volume for gas release. Better - 20%.

So, to make a bioreactor with all the accessories on your site, you need to:

It is good to choose a place so that it is located away from housing (you never know).

Calculate the estimated amount of manure that animals produce daily. How to count - read below.

Decide where to lay the loading and unloading pipes, as well as a pipe for condensing moisture in the resulting gas.

Decide on the location of the waste tank (fertilizer by default).

Dig a pit based on calculations of the amount of raw materials.

Select a container that will serve as a reservoir for manure and install it in the pit. If a concrete reactor is planned, then the bottom of the pit is filled with concrete, the walls are lined with bricks and plastered with concrete mortar. After this, you need to give it time to dry.

The connections between the reactor and the pipes are also sealed at the stage of laying the tank.

Equip a hatch for inspection of the reactor. A sealed gasket is placed between it.

If the climate is cold, then before concreting or installing a plastic tank, consider ways to heat it. These can be heating devices or tape used in “warm floor” technology.

At the end of the work, check the reactor for leaks.

Gas quantity calculation

From one ton of manure you can get approximately 100 cubic meters of gas. Question: How much litter do pets produce per day?

chicken – 165 g per day;

cow – 35 kg;

goat – 1 kg;

horse – 15 kg;

sheep – 1 kg;

pig – 5 kg.

Multiply these figures by the number of heads and you get the daily dose of excrement to be processed.

More gas comes from cows and pigs. If you add energetically powerful plants such as corn, beet tops, and millet to the mixture, the amount of biogas will increase. Marsh plants and algae have great potential.

The highest is for waste from meat processing plants. If there are such farms nearby, then we can cooperate and install one reactor for everyone. The payback period for a bioreactor is 1–2 years.

Biomass waste after gas production

After processing manure in a reactor, the by-product is biosludge. During anaerobic processing of waste, bacteria dissolve about 30% of organic matter. The rest is released unchanged.

The liquid substance is also a by-product of methane fermentation and is also used in agriculture for root feeding.

Carbon dioxide is a waste fraction that biogas producers strive to remove. But if you dissolve it in water, then this liquid can also be beneficial.

Full utilization of biogas plant products

In order to completely utilize the products obtained after processing manure, it is necessary to maintain a greenhouse. Firstly, organic fertilizer can be used for year-round cultivation of vegetables, the yield of which will be stable.

Secondly, carbon dioxide is used as fertilizing - root or foliar, and its output is about 30%. Plants absorb carbon dioxide from the air and at the same time grow better and gain green mass. If you consult with experts in this field, they will help you install equipment that converts carbon dioxide from liquid form into a volatile substance.

Video: Biogas in 2 days

The fact is that to maintain a livestock farm, the energy resources obtained can be a lot, especially in the summer, when heating the barn or pigsty is not needed.

Therefore, it is recommended to engage in another profitable activity - an environmentally friendly greenhouse. Remaining products can be stored in refrigerated rooms - using the same energy. Refrigeration or any other equipment can run on electricity generated by a gas battery.

Use as fertilizer

In addition to producing gas, the bioreactor is useful because the waste is used as a valuable fertilizer, which retains almost all nitrogen and phosphates. When manure is added to the soil, 30–40% of nitrogen is irretrievably lost.

To reduce the loss of nitrogen substances, fresh excrement is added to the soil, but then the released methane damages the root system of plants. After processing the manure, the methane is used for its own needs, and all nutrients are preserved.

After fermentation, potassium and phosphorus pass into a chelated form, which is absorbed by plants by 90%. If you look at it in general, then 1 ton of fermented manure can replace 70 - 80 tons of ordinary animal excrement.

Anaerobic processing preserves all the nitrogen present in manure, converting it into ammonium form, which increases the yield of any crop by 20%.

This substance is not dangerous for the root system and can be applied 2 weeks before planting crops in open ground, so that the organic matter has time to be processed by soil aerobic microorganisms.

Before use, the biofertilizer is diluted with water. in a ratio of 1:60. Both dry and liquid fractions are suitable for this, which after fermentation also goes into the waste raw material tank.

Per hectare you need from 700 to 1,000 kg/l of undiluted fertilizer. Considering that from one cubic meter of reactor area up to 40 kg of fertilizers are obtained per day, in a month you can provide not only your own plot, but also your neighbor’s, by selling organic matter.

What nutrients can be obtained after manure processing?

The main value of fermented manure as a fertilizer is the presence of humic acids, which, like a shell, retain potassium and phosphorus ions. Oxidizing in air during long-term storage, microelements lose their beneficial qualities, but during anaerobic processing, on the contrary, they gain.

Humates have a positive effect on the physical and chemical composition of the soil. As a result of adding organic matter, even the heaviest soils become more permeable to moisture. In addition, organic matter provides food for soil bacteria. They further process the residues that have been “not eaten” by anaerobes and release humic acids. As a result of this process, plants receive nutrients that are completely absorbed.

In addition to the main ones - nitrogen, potassium and phosphorus - the biofertilizer contains microelements. But their quantity depends on the source material - plant or animal origin.

Sludge storage methods

It is best to store fermented manure dry. This makes it more convenient to pack and transport. The dry substance loses less useful properties and can be stored closed. Although such fertilizer does not deteriorate at all over the course of a year, it must then be sealed in a bag or container.

Liquid forms must be stored in closed containers with a tight-fitting lid to prevent nitrogen from escaping.

The main problem of biofertilizer producers is marketing in winter, when plants are dormant. On the world market, the cost of fertilizers of this quality fluctuates around $130 per ton. If you set up a line for packaging concentrates, you can pay for your reactor within two years.

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Small installations can also be installed at home. As an aside, I will say that producing biogas with your own hands is not some kind of new invention. Even in ancient times, biogas was actively produced at home in China. This country is still the leader in the number of biogas installations. But here how to make a biogas plant with your own hands, what is needed for this, how much it will cost - I will try to tell you all this in this and subsequent articles.

Preliminary calculation of a biogas plant

Before you start purchasing or independently assembling a biogas plant, you must adequately assess the availability of raw materials, their type, quality and the possibility of uninterrupted supply. Not every raw material is suitable for producing biogas. Raw materials that are not suitable:

raw materials with high lignin content;
raw materials that contain sawdust from coniferous trees (with the presence of resins)
with humidity exceeding 94%
rotting manure, as well as raw materials containing mold or synthetic detergents.

If the raw material is suitable for processing, then you can begin to determine the volume of the bioreactor. The total volume of raw materials for the mesophilic mode (biomass temperature ranges from 25-40 degrees, the most common mode) does not exceed 2/3 of the reactor volume. The daily dose is no more than 10% of the total loaded raw materials.

Any raw material is characterized by three important parameters:

density;
ash content;
humidity.

The last two parameters are determined from statistical tables. The raw material is diluted with water to achieve 80-92% humidity. The ratio of the amount of water and raw materials can vary from 1:3 to 2:1. This is done to give the substrate the required fluidity. Those. to ensure the passage of the substrate through the pipes and the possibility of mixing it. For small biogas plants, the density of the substrate can be taken equal to the density of water.

Let's try to determine the volume of the reactor using an example.

Let's say a farm has 10 heads of cattle, 20 pigs and 35 chickens. The following excrement is produced per day: 55 kg from 1 cattle, 4.5 kg from 1 pig and 0.17 kg from chicken. The volume of daily waste will be: 10x55+20x4.5+0.17x35 = 550+90+5.95 =645.95 kg. Let's round up to 646 kg. The moisture content of pig and cattle excrement is 86%, and that of chicken droppings is 75%. To achieve 85% moisture in chicken manure, you need to add 3.9 liters of water (about 4 kg).

It turns out that the daily dose of raw material loading will be about 650 kg. Full reactor load: OS=10x0.65=6.5 tons, and reactor volume OR=1.5x6.5=9.75 m³. Those. we will need a reactor with a volume of 10 m³.

Biogas yield calculation

Table for calculating biogas yield depending on the type of raw material.

Raw material type	Gas output, m³ per 1 kg of dry matter	Gas output m³ per 1 ton at humidity 85%
Cattle manure	0,25-0,34	38-51,5
Pig manure	0,34-0,58	51,5-88
Bird droppings	0,31-0,62	47-94
Horse dung	0,2-0,3	30,3-45,5
Sheep manure	0,3-0,62	45,5-94

If we take the same example, then multiplying the weight of each type of raw material by the corresponding tabular data and summing up all three components, we obtain a biogas yield of approximately 27-36.5 m³ per day.

In order to get an idea of the required amount of biogas, I will say that the average family of 4 people will need 1.8-3.6 m³ for cooking. To heat a room of 100 m² – 20 m³ of biogas per day.

Reactor installation and fabrication

A metal tank, a plastic container can be used as a reactor, or it can be built from brick or concrete. Some sources say that the preferred shape is a cylinder, but in square structures built from stone or brick, cracks form due to the pressure of the raw materials. Regardless of the shape, material and installation location, the reactor must:

be water- and gas-tight. Mixing of air and gas should not occur in the reactor. There must be a gasket made of sealed material between the cover and the body;
be thermally insulated;
withstand all loads (gas pressure, weight, etc.);
have a hatch for carrying out repair work.

Installation and selection of the reactor shape is carried out individually for each farm.

Manufacturing theme DIY biogas plant very extensive. Therefore, in this article I will focus on this. In the next article we will talk about choosing the remaining elements of a biogas plant, prices and where it can be purchased.

You can get a cheap source of energy yourself, at home - you just need to assemble a biogas plant. If you understand the principle of its operation and structure, then this is not difficult to do. The mixture it produces contains a large amount of methane (depending on the loaded raw material - up to 70%), so it has a wide range of applications.

Refilling car cylinders running on gas as fuel for heating boilers is not a complete list of all possible options for using the finished product. Our story is about how to install a biogas plant with your own hands.

There are several designs of the unit. When choosing a particular engineering solution, you need to understand how suitable this installation is to local conditions. This is the main criterion for assessing the feasibility of installation. Plus, you have your own capabilities, that is, what type of raw materials and in what volume you can use, what you can do with your own hands.

Biogas is produced by the decomposition of organic matter, but its “yield” (in volumetric terms), and therefore the efficiency of the plant, depends on what exactly is loaded into it. The table provides relevant information (indicative data), which will help determine the choice of a specific engineering solution. Some explanatory graphics would also be helpful.

Design options

With manual loading of raw materials, without heating and stirring

For domestic use, this model is considered the most convenient. With a reactor capacity of 1 to 10 m³, approximately 50–220 kg of manure will be needed daily. This is what you need to proceed from when deciding on the size of the container.

The installation is installed in the ground, so it will require a small pit. A location on the site is selected in accordance with its calculated dimensions. The composition and purpose of all elements of the circuit is not difficult to understand.

Installation feature

After installing the reactor on site, it is necessary to check its tightness. Then the metal must be painted (preferably with a frost-resistant composition) and insulated.

Removal of waste occurs naturally - either during the process of adding a new portion, or when there is an excess of gas in the reactor with the valve closed. Therefore, the capacity of the waste collection container should be no less than that of the working one.
Despite the simplicity of the device and the attractiveness for do-it-yourself assembly, due to the fact that mixing and heating of the mass are not provided, this installation option is advisable to operate in regions with a mild climate, that is, mainly in the south of Russia. Although, with high-quality thermal insulation, in conditions where underground water layers are deep, this design is quite suitable for the middle zone.

Without heating, but with stirring

Almost the same thing, only a small modification that significantly increases the performance of the installation.

How to make a mechanism? For someone who assembled it with their own hands, for example, this is not a problem. A shaft with blades will have to be mounted in the reactor. Therefore, it is necessary to install support bearings. It is good to use a chain as a transmission link between the shaft and the lever.

The biogas plant can be operated in almost all regions, with the exception of the northern regions. But unlike the previous model, it requires supervision.

Stirring + heating

The thermal effect on biomass increases the intensity of the decomposition and fermentation processes occurring in it. The biogas unit is more versatile in use, as it can operate in two modes - mesophilic and thermophilic, that is, in the temperature range (approximately) 25 - 65 ºС (see graphs above).

In the above diagram, the boiler runs on the resulting gas, although this is not the only option. Heating of biomass can be done in different ways, depending on how it is more convenient for the owner to organize it.

Automated options

The difference between this scheme is that it is connected to the installation. This allows you to accumulate gas reserves rather than using it immediately for its intended purpose. Ease of use is also due to the fact that almost any temperature regime is suitable for intensive fermentation.

This installation is even more productive. It is capable of processing up to 1.3 tons of raw materials per day with a similar reactor volume. Loading, mixing - pneumatics are responsible for this. The outlet channel allows waste to be removed either into a bunker for short-term storage, or into mobile containers for immediate removal. For example, for fertilizing fields.

These biogas plant options are hardly suitable for domestic use. Installing them, especially with your own hands, is much more difficult. But for a small farm it is a good solution.

Mechanized biogas plant

The difference from previous models is in the additional tank in which preliminary preparation of the raw material mass occurs.

Compressed biogas is fed into the loading hopper and then into the reactor. It is also used for heating.

The only thing that is necessary when assembling any of the installations with your own hands is accurate engineering calculations. You may need to consult a specialist. Otherwise everything is quite simple. If at least one of the readers becomes interested in a biogas unit and installs it themselves, then the author did not work on this article in vain. Good luck!

Here in Serbia, and in Europe as a whole, people do not want to depend on energy and gas companies, so they strive to purchase alternative energy sources. Be it solar panels, thermal collectors, or biogas plants.

I once already talked in my magazine about industrial biogas plants, now my story is about a home-made plant that can produce gas for your home or cottage. The principle of operation is clear from the figure. I will just make some explanations and tell you the purpose of some elements.

To make the installation you will need:

*Two plastic barrels of 200 liters each (in Serbia, cabbage is salted in such barrels), but there may also be metal barrels for diesel fuel.

* Five adapter fittings for connecting elements with a hose with a thickness of at least 13 mm.

* Plastic hose (length depending on installation needs).

* Plastic bucket.

* Plastic canister 3 - 5 liters (for automobile oil with a screw cap) for the emergency valve.

* Two plastic tubes with a diameter of 5 cm.

Element 1 - in the picture, BIO gas generator

It consists of: a sealed barrel, two plastic pipes and an outlet fitting for biogas.

In the generator, the organic mass decomposes during the process of decay, releasing 60% methane and 40% SO2.

Through the first plastic tube with a funnel, finely chopped biomass waste is poured in and mixed with water in a ratio of 10% biomass and 90% rainwater (soft water).

It would be good if we could also add a natural mixture of fresh manure from cows, pigs and poultry, thus introducing microorganisms on which the production of biogas depends. Failing that, you can add a little mud from a river or pond to speed up the process.

The process takes about 3 weeks for the gas to be formed. Early on you will notice gas being released, but be aware that it is SO2 - carbon dioxide, which is not flammable. Only after 3 weeks have passed does the formation of methane, or biogas, occur.

A residue appears at the bottom of the container over time, which is an excellent natural fertilizer for vegetables in gardening.

The ideal temperature is from 12 to 36 degrees, protect the barrel from direct sunlight in the shade, and in winter from freezing. Keep in mind that this is a “living” barrel, that is, it contains billions of microorganisms working on the process of biomass decomposition.

If you “overcook” or “freeze” the BIO Gas Generator, the microorganisms will disappear, so the whole process will have to start again.

Element 2 in the figure is a container for collecting biogas and a water seal

It consists of an open plastic barrel, a bucket and two fittings (valve) for gas flow and weight (tag).

In this container - a 200 liter barrel, gas is collected, as shown in the figure. Provides a simple and flexible solution without wasting gas. In addition, water also acts as a filter, purifying methane from impurities.

Notice that the gas has lifted the water container and this indicates the amount of gas collected.

The weight of the weight will help make the gas pressure sufficient, which is then sent to the emergency valve, element No. 4.

Keep this container filled with water and protected from freezing.

Element 3 - burner

Element 4 - Emergency valve

The emergency valve consists of a plastic canister of water with a screw cap and two adapters.

Empty oil cans for a car are a good improvisation.

The safety valve is designed to intercept the flame to stop the reverse effect. The emergency valve is located between Element 3 - the burner and the gas collection container, Element 2.

It is imperative that you install an emergency valve to prevent the gas container from igniting, causing an accident or explosion.

Farmers annually face the problem of manure disposal. The considerable funds required to organize its removal and burial are wasted. But there is a way that allows you not only to save your money, but also to make this natural product serve you for your benefit.

Thrifty owners have long been putting into practice eco-technology that makes it possible to obtain biogas from manure and use the result as fuel.

Therefore, in our material we will talk about the technology for producing biogas, and we will also talk about how to build a bioenergy plant.

Determining the required volume

The volume of the reactor is determined based on the daily amount of manure produced on the farm. It is also necessary to take into account the type of raw material, temperature and fermentation time. For the installation to fully operate, the container is filled to 85-90% of the volume, at least 10% must remain free for gas to escape.

The process of decomposition of organic matter in a mesophilic installation at an average temperature of 35 degrees lasts from 12 days, after which the fermented residues are removed and the reactor is filled with a new portion of the substrate. Since waste is diluted with water up to 90% before being sent to the reactor, the amount of liquid must also be taken into account when determining the daily load.

Based on the given indicators, the volume of the reactor will be equal to the daily amount of prepared substrate (manure with water) multiplied by 12 (the time required for biomass decomposition) and increased by 10% (free volume of the container).

Construction of an underground structure

Now let's talk about the simplest installation that allows you to get it at the lowest cost. Consider building an underground system. To make it, you need to dig a hole, its base and walls are filled with reinforced expanded clay concrete.

Inlet and outlet openings are located on opposite sides of the chamber, where inclined pipes are mounted for supplying the substrate and pumping out the waste mass.

The outlet pipe with a diameter of approximately 7 cm should be located almost at the very bottom of the bunker, its other end is mounted in a rectangular compensating tank into which waste will be pumped. The pipeline for supplying the substrate is located approximately 50 cm from the bottom and has a diameter of 25-35 cm. The upper part of the pipe enters the compartment for receiving raw materials.

The reactor must be completely sealed. To exclude the possibility of air ingress, the container must be covered with a layer of bitumen waterproofing

The upper part of the bunker is a gas holder, which has a dome or cone shape. It is made of metal sheets or roofing iron. You can also complete the structure with brickwork, which is then covered with steel mesh and plastered. You need to make a sealed hatch on top of the gas tank, remove the gas pipe passing through the water seal and install a valve to relieve gas pressure.

To mix the substrate, you can equip the installation with a drainage system operating on the principle of bubbling. To do this, vertically fix plastic pipes inside the structure so that their upper edge is above the substrate layer. Make lots of holes in them. Gas under pressure will fall down, and rising up, gas bubbles will mix the biomass in the container.

If you do not want to build a concrete bunker, you can buy a ready-made PVC container. To preserve heat, it must be surrounded by a layer of thermal insulation - polystyrene foam. The bottom of the pit is filled with a 10 cm layer of reinforced concrete. Tanks made of polyvinyl chloride can be used if the reactor volume does not exceed 3 m3.

Conclusions and useful video on the topic

You will learn how to make the simplest installation from an ordinary barrel if you watch the video:

The simplest reactor can be made in a few days with your own hands, using available materials. If the farm is large, then it is best to buy a ready-made installation or contact specialists.