What Is A Biodigestor?

by | May 11, 2024 | Glossary and FAQs

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In an era of environmental concerns and sustainable living, novel technologies are emerging to meet the urgent demand for eco-friendly solutions. Among these, biodigestor illustrates how natural processes may help with waste management, renewable energy production, and environmental conservation.

What is a Biodigestor?

Biodigestors are sealed containers where microorganisms break down organic waste in an oxygen-free environment to generate biogas and fertilizer. These organic materials, called feedstock, can include agricultural waste, food scraps, animal manure, and sewage. Biodigestors primarily imitate the natural anaerobic digestion process in wetlands and animal digestive systems.

Principle & Working of Biodigestor

Principle & Working of Biodigestor


The functioning of a biodigestor involves several essential stages:

  • Feedstock Preparation: Organic waste is collected and ready for digestion. This could include shredding or chopping the materials to enhance surface area and facilitate microbial action.
  • Loading: The prepared feedstock is loaded into the biodigestor, which performs anaerobic digestion. The container is sealed to keep oxygen out, necessary for anaerobic bacteria to function.
  • Anaerobic Digestion: Microorganisms in the biodigestor degrade organic waste into simpler chemicals using a series of biochemical events. This process produces biogas, which consists mainly of methane (CH4), carbon dioxide (CO2), and some trace gases.
  • Biogas Collection: Biogas generated during digestion accumulate in the biodigestor’s headspace. It is then removed and stored for various purposes, including cooking, heating, and power generation.
  • Digestate Handling: The residue left after digestion, known as digestate, is high in nutrients and makes an excellent organic fertilizer. It can be recovered from the biodigestor and utilized to improve soil fertility in agricultural applications.


Instrumentation and control systems optimize biodigestor performance and increase biogas production efficiency.

  1. Temperature Control: Anaerobic bacteria require an appropriate temperature range to function correctly. Biodigestors may be outfitted with heating systems to manage temperature, particularly in colder locations.
  2. Mixing systems: Proper mixing of the digesting material promotes uniform microbial activity and prevents stacked layers in the biodigestor. Mechanical stirrers and gas recirculation systems are frequently utilized for this purpose.
  3. pH Monitoring: Anaerobic digestion is sensitive to pH values, with an ideal range of 6.5–8.0. pH sensors are installed to monitor acidity and alkalinity levels, allowing modifications to sustain microbial activity.
  4. Gas Monitoring: Constant monitoring of biogas composition, particularly methane content, ensures the quality of the gas produced. Gas analyzers test methane concentrations and detect any anomalies that may indicate process inefficiencies or problems.
  5. Pressure and Flow Sensors: Pressure and flow sensors monitor gas pressure within the biodigestor, assuring safe operation and avoiding overpressure situations. Flow sensors monitor biogas production rate, providing useful information for process optimization and performance evaluation.

Septic Tank Vs Biodigestor

Feature Septic Tank Bio-Digester
Waste Decomposition Reduces about 30% of pathogens. Can reduce up to 99% of pathogens.
Maintenance Requires periodic sludge removal every 2 years or earlier, leading to high maintenance costs. Maintenance-free.
Discharge from Tank Produces odorous gases and hazardous waste. Discharged water is unsafe and may contaminate groundwater or bodies of water. Discharges odorless and hazard-free water, safe for irrigation, gardening, or release into bodies of water.
Sensitivity to Cleaning Agents Sensitive to toilet cleaning agents. Bacteria are conditioned to tolerate cleaning agents within permitted limits.
Size of the System Three times larger than Bio-Digester, costing more and requiring more space. One-third the size of a septic tank, resulting in lower construction costs and a smaller footprint.

In conclusion, biodigestors provide a sustainable and environmentally friendly alternative for organic waste management and renewable energy generation. These systems use anaerobic digestion to reduce environmental pollution while producing valuable resources such as biogas and nutrient-rich fertilizers. The instrumentation and control systems included in biodigestors are critical for optimizing performance, assuring efficient operation, and maximizing the benefits of this unique technology. As we look for new approaches to sustainability, biodigestors stand out as a great example of how humans may collaborate with nature to address serious environmental concerns.

Also Read: Biogas Generation from Food Waste



  • Dr. Emily Greenfield

    Dr. Emily Greenfield is a highly accomplished environmentalist with over 30 years of experience in writing, reviewing, and publishing content on various environmental topics. Hailing from the United States, she has dedicated her career to raising awareness about environmental issues and promoting sustainable practices.

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