Biogas Production Steps, Materials, Manufacturing Steps

Biogas, an alternative to fossil fuels, is a significant subject in the world to supply energy requirements for different purposes. Biogas production systems can be varied from household level to industrial level according to the amount of feedstock available. Usually, organic food waste is used as the main raw material for manufacturing biogas.

We will discuss the following in this tutorial.

  1. Requirements to start a biogas production system
  2. Steps of production of the biogas system
  3. Issues and failures occurred during running a biogas production
  4. Health and safety measures

Requirements to start a biogas production system

Raw material

Generally, following materials are used as raw materials for biogas production.

  • Organic food waste
  • Residues from livestock farming
  • Sewage sludge

Microorganisms participated in biogas production

Microorganisms who produces methane gas are called "methanogenic". There are three stages in bio gas production and details are given in below table.

microorganisms participated in biogas production three steps

Oxygen level

Microorganisms used in biogas production are grown in anaerobic conditions. Therefore, oxygen level should be maintained at very low level.

Temperature ranges for bacterial growth

Biogas production can be carried out in different temperature ranges. But, temperature effects to the bacteria growth.

biogas production temperature range for bacterial growth

Optimum temperature for bacterial growth in biogas production is identified as 350C

pH Level

Due to different type of bacterial activity, chemical composition of biogas reactor changes with time. Due to change of chemical composition, pH value is also changed with time. This is directly effected to growth and existence of bacteria. Some bacteria prefers acidic medium for growth while some bacteria prefers alkaline medium.

Most of the researches have proved that keeping pH range around 7 made favorable condition for bacterial growth in the digester and produced better biogas yield compared to the pH values.

Steps of production of the biogas system

The production of biogas is a sensitive process because maintaining a good environment for microorganisms is a challenging task.

Collection of biodegradable organic waste

Biodegradable waste are collected and transported to the processing plant. A proper segregation is important to enhance the quality of waste to increase the biogas production generation.

Biodegradable food waste from municipal councils

Generally, waste collection services are managed by municipal councils in cities. In such management processes, hundreds to thousands of waste are collected per day. People should be encouraged to segregate their waste properly to separate biodegradable organic food waste. Polythene, plastics, wood, and all non-biodegradable items are separated from waste streams to enhance the organic waste quality.

If some undesirable thing is entered to the biogas manufacturing system, the overall system can be collapses. So proper waste segregation at waste generation point a must in biogas production.

Anaerobic digestion of organic waste

When suitable conditions are supplied to microorganisms in the presence of biodegradable waste, microorganisms start to produce methane gas as the main product. As well, hydrogen sulfide and ammonia gases also are formed in minor quantities.

Issues and failures occurred during running a biogas production

There are issues of running a biogas plant and continuous attention should be a must.

Entering hazardous chemical

If hazardous chemical to bacteria is entered into a biogas reactor, total bacteria amount can be destroyed in a short time period. Then, total process has to be restarted and it will cost lot of money and time.

Challenges of operating a biogas manufacturing plant

Maintaining optimum conditions for microorganisms

Operational conditions should be accurate always when you operate a biogas plant. A small deviation can cause a sudden collapse in the system. Probably, these sudden collapses are caused due to loss of optimum conditions for the growth of microorganisms.

Unable to liquidize methane gas to a liquid

Because liquidation of methane gas is difficult, more scientific approaches are required for practical uses in the community.

Health and safety measures

The chemical composition of biogas and operational conditions causes us to be careful about health and safety factors.

Toxicity of methane and hydrogen sulfide

As products of anaerobic digestion, both methane and hydrogen sulfide are extremely toxic to humans. Therefore a safety system should be implemented to prevent the release of these gases to working areas of people.

Combustible gases

Because methane is a highly combustible gaseous product, safety systems should be installed to prevent sudden fires if methane is released into the atmosphere.

A fire hazard alarm system should be installed in process area. As well, the system should be periodically checked and maintained.

Also, preventing any open flame works close to the pipelines which carry combustible fuels.

High-pressure vessels

Exceeding pressure limit than the standard limit can cause to severe explosions.