Biogas technology: a virtuous cycle

Biogas technology is one of the most used for renewable energy production, and a concrete example of circular economy. 

Biogas is a mixture of gases, mainly consisting of methane (50-70%) and carbon dioxide (30-45%), produced from the fermentation of organic substrates in absence of oxygen, known as anaerobic digestion process.

The advantages for a company installing a biogas plant include renewable energy production and flexible management of all types of biomasses.



When this technology is included in the production cycle of a company, it increases the company’s economic and environmental sustainability and autonomy of its production cycle.


Biogas technology is a sustainable solution that enables the clients to transform their waste into valuable resources, providing the environment and the society a circular and virtuous cycle.

Tegnologia biogas
Tegnologia biogas


A company with a biogas plant acquires multiple advantages, playing an active part in the fight against climate change, while making its business more sustainable and circular.

Installing a biogas plant allows you to:

  • Become energy independent, producing electrical and thermal energy for self-consumption
  • Concretely contribute to a sustainable energy policy, generating clean energy for the community
  • Minimise the waste management costs of its production process

Sebigas technology

Tecnologia biogas

CSTR – Continuous-flow Stirred Tank Reactor

SEBIGAS offers CSTR technology, based on a semi-continuous flow of fresh biomass, which is fed into temperature-controlled reactors and constantly stirred to ensure it is perfectly blended.


  • The process of wet anaerobic digestion takes place in a tank containing 10% or less dry matter
  • The process takes place under either thermophilic (50-55°C) or mesophilic (38-43°C) conditions.
  • The period of retention in the digester can vary from 25 and 50 days.
  • Flexible technology able to better manage every kind of available biomass
  • Simple and optimized maintenance in order not to have plant shutdowns
  • 98,2% plant availability thanks to high-quality equipment and materials
  • Low self-consumptions thanks to the optimization of the running time of mixers and pumps by the control system.

The plant with its material flows can be schematically shown as follow:

  •  The solid and liquid biomass is loaded via a pre-tank or feeder into the digesters

  •  The digesters are equipped with slow and fast mixers to enable the process of anaerobic digestion; this also ensures that the digestant in the tank is perfectly blended and prevents the formation of sediment or crusts. 
  • A heavy cover or gasometric dome is fitted on top of the digester to ensure that a sufficient quantity of the biogas produced is safely stored


Biogas, after appropriate treatments, can be used to produce heat from combustion or to produce electricity through a cogeneration system, and thermal energy through a waste heat recovery system. In addition, biogas can be separated to obtain biomethane and carbon dioxide for industrial and food use.


  • Is sold to the distribution grid
  • Is used to power the plant and supply the company


  • Helps maintain the temperature for the biological processes
  • Is a source of heat power for users outside the plant, such as stables, greenhouses, utilities or industrial processes

BIOMETHANE, which is derived from processes that purify biogas from the other gases in the mixture, can be used for multiple energy purposes:

  • Natural gas transportation or distribution network
  • CNG and LNG filling stations near the plant
  • Supply of cogeneration systems


The stable material leaving the plant provides an excellent fertiliser thanks to its content of nitrogen, phosphorus and potassium.

The separation of solids and liquids allows them to be exploited in the best possible way:

  • The LIQUID FRACTION can be used as a fact acting fertilizer
  • The SOLID FRACTION as a soil improver, making significasnt improvements to the soil structure of agricultural land

Both parts can act as useful semi-finished products for supply chains specialised in the production of quality fertilisers and soil improvers.

anMBBR – Industrial wastewater treatment

anMBBR (Moving Bed Bio Film Reactor) is a technological solution for wastewater treatment in the anaerobic digestion process. With a great energetical potential, industrial wastewater requires special treatment so that they can be used in company production processes, appropriately purified.

anMBBR technology application

SEBIGAS suggests anMBBR technology to companies that want to treat and valorise their industrial wastewater to produce renewable energy. SEBIGAS, in partnership with Headworks International, develops a high-value plant solution to be installed in multiple industrial sectors:

  • Paper mills
  • Breweries
  • Distilleries
  • Soft drinks producers
  • Sugar mills
  • Slaughterhouse
  • Cheese refineries

How does the industrial wastewater treatment in anMBBR work

anMBBR reactor is installed in new wastewater treatment plants or for the optimisation of existing treatment plants.
It is a solution that enables the anaerobic digestion treatment of highly diluted wastewater by preventing the ‘Bacteria wash out’ phenomenon.
By inserting into the reactor ‘CARRIER’, plastic moulds with a high protected surface area, the bacteria find a useful support surface to carry out their digestion action.

Carriers are left in suspension within the reactor and are kept in constant movement by a slow mixing, flushing and pumping system. The high surface area for the proliferation of bacteria provided by the carriers allows the creation of biofilm, which enables the digestion of the organic load by the bacteria in the effluent. The carriers significantly increase the productivity of the bacteria, making the process functional, reliable and efficient.

An attached growth reactor enables the anaerobic digestion of large quantities of effluent in a functional, sustainable and circular manner.

Funzionamento anMBBR

What are the advantages of industrial water treatment in anMBBR?

  • Valorise high volume of effluents in a low-volume biological reactor
  • Reduce the organic load content into the industrial wastewater
  • Produce biogas and recover renewable energy to be used for the plant self-consumption or to be injected into the grid
  • Reduce the sludge volume and disposal costs