Biodegradation is the process by which organic substances are broken down into simpler components by microbes, such as bacteria and fungi. In nature, this process is essential for recycling and replenishing nutrients in ecosystems.
It also has applications in waste management, where biodegradation can be harnessed to break down organic waste and reduce its volume, making it easier to handle and dispose.
The main machinery used for biodegradation in sustainable waste management is called a digester. A digester provides the ideal environment for microorganisms to break down organic waste materials.
But what exactly can you put in a digester? Let's find out.
Understanding Your Digester
The main thing you need to know about digesters is that there are two types: anaerobic and aerobic.
Anaerobic Digester
An anaerobic digester is a sealed tank or vessel where organic material is broken down in the absence of oxygen. This process creates biogas — a mixture of methane and carbon dioxide — which is a renewable energy source.
Anaerobic digesters treat wastewater and organic waste from households, farms, and industries.
Besides biogas production, anaerobic digestion also lowers pathogen concentration in the waste. It can reduce the presence of common pathogens in waste by 95% to 98%.
How Digesters Work
Typically, a digester consists of the following components:
- Digestion tank: This is where the organic material is stored. Microorganisms are also present to digest the material.
- Heating system: The digestion process requires a specific temperature range for optimal performance. The heating system maintains this temperature in the digestion tank.
- Mixing system: To ensure the organic material is evenly digested, a mixing system agitates and circulates the tank's contents.
- Gas collection system: This system collects biogas produced during anaerobic digestion.
- Discharge system: The spent substrate and sediments are removed from the digestion tank through this system.
Some factors that can affect a digester's efficiency include temperature, pH level, and the type and amount of organic waste being fed. The optimal temperature in most digesters is between 35°C and 40°C (95°F and 104°F).
Similarly, for the process to work effectively, the pH in an anaerobic digester should be between 6.8 and 7.2.
What Can Go Into Your Digester
Here's what goes into the digester for sustainable waste management.
Acceptable Waste Types
The following organic materials are suitable for anaerobic digestion:
- Food waste
- Animal manure
- Crop residue
- Wastewater sludge
Meanwhile, the following waste types can be added to the digester for anaerobic digestion:
- Animal manure
- Crop residue
- Food waste
- Dairy farm waste
- Brewery and distillery waste
- Agro-industrial waste
Special Considerations
Here are some conditions for efficient breakdown of waste:
- Particle size: Smaller particle size leads to faster digestion and better mixing, due to a larger surface area available for microbial action.
- Moisture content: Moisture levels of around 70% are suitable for microbial activity. Some materials, such as wastewater, require dewatering. Others, like food waste and animal manure, may require additional water for proper digestion.
What Can't Go Into Your Digester
There are a few things that you should not add to your digester.
Prohibited Materials
The following materials should not go into your digester:
- Plastics: Since the digester cannot decompose plastics naturally, these materials will contaminate the digester.
- Metals: Metals like copper and aluminum must be kept out of the digester, as they can inhibit microbial activity and cause corrosion. They can also become a safety hazard by causing sparks and explosions.
- Glass: Do not add glass to the digester; it can break and pose safety risks.
- Toxic waste: Batteries and chemical toxic waste should not go into the digester. They can harm microbes and make the output hazardous for agricultural waste.
- Non-biodegradable waste: Some materials, such as synthetic fibers, do not decompose and should not go into the digester.
Common Misconceptions
Let's debunk some myths about what can go into your digester.
- All paper products: Some paper products, like paper towels and cardboard, can be digested. But glossy or coated paper, such as magazine paper or photographs, should not go into the digester.
- All food waste: Some food waste, such as excessive fats or oils, bones, and shells cannot be processed.
- Medications: Digesting pharmaceuticals in your digester can risk human health and the environment. Instead, dispose of them responsibly or take them to a collection site.
Conclusion
Knowing what can and cannot go into your digester is extremely important. You don't want to damage a business investment, harm the environment, or jeopardize your health.
Adhere to best practices for efficient digestion and sustainable waste management. This approach has immense benefits. Not only can you produce a reserve of renewable energy, but you can also reduce your carbon footprint.
Reach out to EcoRich for on-site commercial food waste to energy solutions to make your business and community more sustainable.
