Biogas and Biomethane Plants

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Producing clean and renewable energy from Biogas

Eliopig offers the best technological solutions for biogas plants, which exploit manure from pig, cattle and poultry farming. Through special hoppers, biogas plants can also include biomass, waste from fruits, vegetables, and other organic residues in order to produce energy.

Plants’ capacity varies according to the client’s needs, and the installed electrical power can change between 100 kWe and 1000 kWe, or further.

What is Biogas?

BIOGAS is one of the most used alternative sources for energy production. It is a gaseous mixture derived from anaerobic digestion and from the decomposition of any organic animal or vegetal matter, such as zootechnical waste and its byproducts. These last-mentioned are mixed and maintained without oxygen at a mesophilic temperature of 39-42°C.

What is Biomethane?

Biomethane is a natural renewable methane gas, obtained from the process of refinement and purification of biogas. It is derived from renewable sources with the same characteristics and usage conditions of methane gas, and it is suitable for the feed into the grid of natural gas. Therefore, biomethane is generated from the enhancement of local sources. It has similar features to fossil fuels, so it can be used for heating, kitchen and transport leading to a decrease in the greenhouse gas emissions. This opportunity of development for all biogas producers has a high level of efficiency.

How does a Biogas Plant work?

The manure derived from pig, cattle and poultry farming are carried into an appropriate container, called fermenter. Later, thanks to special hoppers, different types of biomass can be added, such as waste from agri-food industry, vegetables and agricultural by-products like silage maize, wheat, sorghum and grain.

The organic matter is conveyed into the plant without oxygen and at a controlled temperature. In this way, the four different symbiotic bacteria are able to wear away the long organic chains until the production of simple compounds, such as methane. This biodegradation of the organic mass is a process known as anaerobic digestion.

This matter can be used for the production of electrical and thermal energy through cogeneration, otherwise, it can be purified in order to reach a composition similar to the fossil natural gas. Then, there are two possible alternatives; on one hand it can be fed into the grid, and on the other it can be used for means of transport, exploiting the possibilities of BIOMETHANE. Inside the fermenter a huge quantity of bacteria wear away the organic matter, in a condition of controlled temperature and without oxygen. From this degradation we obtained three results: biogas, heat and digestate (natural liquid fertilizer).

BIOGAS – it is turned into electricity thanks to a co-generator and then transferred to the national network. A part of it is transformed into further heat;

HEATit is used to heat some parts of the firm itself, such as barns, offices, for industrial processes, or for the fermentation process;

DIGESTATE – it is used as natural fertilizer inside the firm’s plantations for its higher quality than manure.

The Components

Our plants consist of:

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Modules of loading

Loading modules of solid biomasses with weighting cells and a system for the introduction of biomasses inside the digester through a screw pump system; modules of loading are available with a capacity of 20, 40, 60, 80 tons.

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Stainless steel mixers inclined 120° with an adjustable propeller according to the percentage of dry matter inside the digestate.

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Digester with a gasometer with a double membrane system.

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Collection system

System of biogas collection and distribution.

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Gas treatment and process instrumentation

Electrical device for the constant analysis of the parameters in order to reach the best performance.

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Medium and low voltage electrical system.

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Plumbing/hydraulic system

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Cogeneration unit

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Upgrading system

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Treatment of H2S (hydrogen sulfide) contained biologically and chemically inside gas

How Biogas is used?


Biogas has a high heating value, which can be turned into electricity and heat. This gaseous compound contains 50-70% of methane, while the remaining part is made of carbon dioxide and other components. After being dehumidified and treated, the gaseous compound is used to power endothermic engines that produce electrical and thermal energy.

The UN underlined the positive impact of biogas on the reduction of the current air pollution situation, and as a consequence on the greenhouse effect. Biogas is indeed a way to reduce methane emissions in the atmosphere, and it allows the production of renewable energy, creating a more sustainable system of green economy.



Starting from biogas, Eliopig is able to separate methane from other gasses, in particular carbon dioxide (CO2) through an upgrading system. As a result of this separation there are two solutions:

  • Methane (CH4) - It is fed into the grid of natural gas, it can be used as biofuel for vehicles or is located at the gas stations;
  • Carbon dioxide (CO2) - It is used in the food industry, or for the carbon fertilization in greenhouses, since increasing the carbon dioxide concentration the photosynthesis performance can be improved.
Plants fueled with organic fraction of MSW

In Italy and all over the world, over the last few years waste sorting has increased, and as a consequence also the enhancement of the organic fraction of municipal solid waste (MSW).

Eliopig offers biogas and biomethane plants completely fueled with MSW using the best technology. There are two sections which characterize MSW plants compared to the ones fueled with manure and zootechnical by-products:

  • Section for waste pretreatment, where impurities are removed from the waste, then it is mashed and sent to anaerobic digestion;
  • Section at the end of the biogas/biomethane plant, where the transformation from digestate to soil improver/fertilizer takes place through a composting plant.
Plants fueled with poultry manure

Poultry manure, in other words the waste produced in farms for laying hens’, chickens for fattening and turkeys, has been discussed for its use as fuel for biogas plants.

The interest around poultry manure derived both from its high methanogenic power and from the huge amount of poultry waste produced by our farms.

Up to now, the usage of poultry manure in biogas plants has been limited, reaching only 20-25% of the recipe. This is due to its high nitrogen content and the consequent inhibiting power on the anaerobic process.

Thanks to its experience in the usage of zootechnical waste inside its biogas plants, Eliopig developed a mechanical system for poultry manure treatment before sending it to the fermentation process. Furthermore, our company was able to develop a monitoring and organic management system of the process that allows to fuel biogas plants up to 50% with poultry manure. 

1 – Poultry manure management barn;
2 – Poultry manure treatment;
3 – Plant for anaerobic digestion;
4 – Upgrading system;
5 – Nitro-denitro plant;
6 – Emergency torch;
7 – Storage solid separated;
8 – Storage clarified digestate without ammonia.

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