How to efficiently maintain a biogas plant without losing your mind!

The maintenance of a biogas plant is an essential step in its operation. For the project developer, this is a major investment that he must include in the operational costs of the biogas plant. However, paying special attention to certain aspects such as technical equipment, anaerobic digestion biological process and safety has several advantages.  How can the project developer optimize the maintenance of these aspects of the biogas plant? What technologies can be used to reduce maintenance costs? Here is an overview.

Please note: This article is writen for general information only using publicly available sources mentionned below. If you are planning a biogas project, please make sure to connect with a professional company to discuss applicable standards in your country.

What role does maintenance of a biogas plant play in its operation?

Maintaining a biogas plant means doing minor repairs to the equipment, changing its oil as needed, removing debris from organic matter that falls to the bottom of the tank, solving problems in the process and many other actions.

Of course, staying on the lookout for such situations and resolving them quickly requires time and money for the project developer. Maintenance accounts for about one third of the annual costs of operating a biogas plant.

Source: ADEME

Source: BioEnergy Farm

This share may vary depending on the type of project. Because it is such an investment for the project developer, it must be taken into account during feasibility studies of the biogas project to evaluate the profitability of anaerobic digestion.

The Guide about Biogas [PDF, French, 7416 kb], written by the German Society for International Cooperation (GIZ), further clarifies these issues.

Benefits of rigorous maintenance of a biogas plant

Despite some obstacles, regular maintenance of the biogas plant is advantageous for the project developer.

Among other things, the advantages include:

• Prevention of technical failures or problems in the process
• Increase in the life cycle of the equipment
• Prevention of accidents and safer plant environment
• Optimization of a plant operation or of biogas production.

How to maintain a biogas plant?

How can the developer of biogas projects optimize the maintenance of his biogas plant? Here are our tips.

Check the correct operation and reliability of the equipment

The developer must keep a close eye on the operation of the technical equipment of the biogas plant to ensure its availability. Indeed, the stability of the biogas production process depends on the proper operation of the equipment.

In general, it is advisable to:

• Respect maintenance intervals for parts warranty
• Install measuring equipment to identify problems
• Keep several spare parts, especially for equipment vital to the operation of the plant or with a long delivery time
• Find a supplier or repairer available in the area for more complex or emergency repairs.

In addition, parts of the technical equipment require other maintenance actions. The EnergyPedia page about the maintenance of a biogas plant offers some more details.

What to do in case of technical failure of the equipment?

If the developer identifies a technical malfunction of the equipment, he must first consult the instructions for using the plant. They contain recommendations on what to do if there is a problem with a particular part.

In general, the project developer must detect and repair the technical problem as quickly as possible to limit its impact on the biogas plant. It can also be equipped with an automated alert system that alerts a manager when a technical failure occurs.

Perform regular monitoring and control of the process

Regular monitoring and control of the biological process of biogas is an essential part of the maintenance of a biogas plant. Indeed, problems in the biological process is the fifth most frequent cause of malfunctions of the plant, according to the Bioenergy Farm Website.

Source: Bioenergy Farm

This is why the project developer must equip himself with technologies to monitor the biological process, detect deviations from the desired characteristics and those obtained, and solve them. They must be adapted to the conditions of the biogas plant.

These technologies can be automated, which gives the plant independence from specialized personnel, but it is expensive. Here are some variables of the biological process to monitor and control:

• The rate of biogas production: The amount of gas produced per unit of time is important to evaluate the efficiency of the biological process and adjust it as needed.
• Formation of floating mud layers or moss: Floating mud layers sometimes form on the surface and must be removed manually as they accumulate. The foam can plug the pipes or escape through the safety valves.
• The composition of some gases: A significant drop in methane concentration, for example, may indicate a problem in biogas production.
• A wide variation in temperature: The optimum temperature varies according to the process.
• pH value: This variable has a strong impact on the biological process. In the case of methane, it must be between 7 and 7.5.

Ensure the safety of work in the biogas plant

In order to ensure the safety of the biogas plant, the operator must regularly assess and mitigate the potential risks.

The project developer must therefore establish security rules, some of which are specific to maintenance, and monitor them regularly. Risks include, for example:

• Fire and explosion
• Chemical products
• Falls

To prevent possible accidents, the project developer can, among other things:

• Install the equipment with ladders or pits with protective panels or grilles
• Clearly identify moving parts
• Install signage in hazardous areas.

For more information, take a look at our article on the risks associated with a biogas plant.

How to reduce the maintenance costs of a biogas plant?

Biogas plant maintenance comes at a high cost, especially when talking about the digester tank. The project developer must, among other things, acquire the relevant technological tools and call in specialized personnel.

The need to shut down the plant for a long period during maintenance has consequences:

• Disturbance of the biogas production process
• Loss of money due to reduced production and tipping fees
• Obligation to refuse input shipments
• Deterioration of the relationship with the waste supplier.

Faced with these complex challenges of maintaining a biogas plant, the project developer can turn to using certain technologies. Here is an example.

The self-cleaning digester system by Fitec

The self-cleaning digester system by Fitec is composed of a sediment separator and a floor grit cleaner. This system reduces costly digester shutdowns for cleanouts and to remove non-digestible residues that accumulate at the bottom of the digester.

Tom Ferencevic, President of Fitec Canada explains how this technology works:

 ” The floor cleaning system is made up of three main components, a double arm floor sweeper, a floor drain with integrated pump and a sediment trap. Each component of the floor cleaning system works in a coordinated and fully automated manner (24/7) to continuously remove any settled material from the bottom of a digester or vessel. The floor sweeper and floor drain are installed in all tanks but the sediment trap can be shared between two tanks to reduce costs.”

Among the advantages of this technology are:

• Allows a high-quality separation of contaminants, all in one step, with residues composed of more than 25% solids or organic without going through the solid dilution step
• Process several different types of waste streams reliably
• Created a minimal amount of digests
• Meets the standards of non-visible contaminants

The self-cleaning digester system can be installed on existing tanks and on any new tank with a minimum internal diameter of 18 m. Most of Fitec’s customers have chosen to integrate the system with concrete fermenters with concrete roof.

See the self-cleaning digester system page  for more information.

About Fitec

Fitec is the manufacturing arm of Finsterwalder Umwelttechnik, an environmental engineering firm specializing in design of anaerobic digestion systems. They are particularly dedicated to the treatment of urban organic materials.

Fitec is in charge of the equipment for the treatment of organics and for anaerobic digestion. Currently, Fitec manages projects with a combined capacity of 4 MW of biogas and the equivalent of 100,000 tonnes of organic matter per year.

Currently, the company is working on 2 major projects that will use its self-cleaning digester system :

•  In Nova Scotia: 500 kW capacity project and 20 year operating support contract
• In Ontario: A project to design a biogas-sharing cooperative for the Toronto Zoo with a capacity of 500 kW.

Need help with maintenance of a biogas plant?

In addition to the costs, the maintenance of a biogas plant presents other challenges for the project developer. Other companies, among our members, could lend you a hand! Here are some examples.

• Bahler Biogas

This Quebec company is the Canadian representative of Fitec. They offer a turnkey solution for the design, management, building, installation and commissioning of biogas projects. Through their work on more than 150 anaerobic digestion projects, they have developed a unique expertise that they adapt to each client’s budget and needs. Their great reputation allows them to forge strategic alliances with the manufacturers of the best and most quality products on a global scale. They are known for their ability to optimize the biogas production of biogas plants through their expertise and performance-oriented actions.

• Streisal

This German company specializes in agitators, mixing systems and design. It offers a design service, help you choose the right technology and support for the maintenance of biogas projects, among others.

• Balmoral Tanks

Balmoral Tanks is the European leader in anaerobic digestion and biogas tanks. The company also provides technical services for the installation, inspection, repair and maintenance of biogas plants.

• Schumann Tanks

Schumann Tanks designs, manufactures and installs custom bolted storage tanks, including bolted stainless-steel tanks, and epoxy coated steel tanks. The company offers impeccable after-sales service.

• Boerger

Boerger specializes in the development, production and marketing of pumps and grinding and booster systems for the delivery of abrasive liquids. The company also offers support for the maintenance of biogas plants, among others.

Moreover, do not hesitate to consult our catalog of suppliers to find a company that will meet your needs!

To know more 

• Guide on biogas, German Society for International Cooperation (GIZ)
• Operation & Maintenance, Bioenergy Farm
• Maintenance of a biogas plant, Energypedia