Global food wastage is one of the most alarming issues in today's world. In the US, the situation is worse than in any other country worldwide. The country discards 60 million tons or 120 billion pounds of food annually, which is 325 pounds per American and 40% of all nationally produced food.
The most evident effects of this food waste are environmental and financial. Rotten and discarded food ends up in landfills where it decomposes, producing methane gas, a significant contributor to climate change.
The US Environmental Protection Agency (EPA) reports that food is the largest percentage of waste in landfills. Even worse, 58% of methane emissions from solid waste landfills are due to food waste.
There's a dire need for commercial waste producers to adopt food waste solutions. These solutions include aerobic and anaerobic food waste treatment. Let's look at them closely.
What Is Aerobic Digestion?
Aerobic digestion is a natural process in which microorganisms break down organic matter into compost, water, and carbon dioxide. The decomposition occurs upon the exposure of food waste to air or oxygen.
Aerobic food waste treatment systems are designed to enhance this process by providing optimum conditions for aerobic bacteria to thrive.
Aerobic digestion treats food with a high organic loading, such as food waste from supermarkets, restaurants, and food processing companies.
Advantages of Aerobic Digestion
Here are the advantages of aerobic digestion of food waste:
- Reduction of volatile solids
- Production of an odorless, stable end product
- Relatively easy operation
- Low capital cost
- Recovery of fertilizer in the form of compost
Disadvantages of Aerobic Digestion
Although aerobic digestion has its pros, it also comes with some disadvantages. These include:
- High power cost for required oxygen supply
- Process affected by location, tank material, and temperature
- No recovery of valuable by-products like methane
- Poor dewatering (separation of solid and liquid by-products) characteristics of the produced sludge
What Is Anaerobic Digestion?
Anaerobic digestion is a biological process that breaks down organic matter without oxygen. It involves a series of microorganisms that decompose the waste and produce biogas, primarily methane and carbon dioxide.
Biogas can be used in many applications, such as:
- Powering engines to produce mechanical power
- Fueling furnaces and boilers
- Running alternative-fuel vehicles
- Providing natural gas to homes and businesses
The remaining material, called digestate, is a nutrient-rich fertilizer that can serve as a soil amendment or bedding for livestock. An anaerobic digester processes organic waste, such as:
- Animal manures
- Food scraps
- Fats, oil, and grease
- Sewage sludge
Advantages of Anaerobic Digestion
Anaerobic digestion has several advantages over aerobic digestion, such as:
- Lower power costs due to not needing an oxygen supply
- Little effect due to location or temperature
- Recovery of by-products like biogas and digestate
- Better dewatering characteristics of the produced sludge
Disadvantages of Anaerobic Digestion
However, there are also some disadvantages to consider when using anaerobic digestion, such as:
- Longer process time compared to aerobic digestion
- Higher capital costs for equipment and installation
Comparing Aerobic and Anaerobic Digestion
Aerobic Digestion:
- Capital investment: Relatively low
- Energy Consumption: Medium
- Net Sludge Yield: High
- Waste Suitability: High moisture content
- By-products: Soil amendment
Anaerobic Digestion:
- Capital investment: Relatively high
- Energy Consumption: Low
- Net Sludge Yield: Low
- Waste Suitability: High biochemical methane potential (BMP)
- By-products: Biogas and liquid fertilizer
Both aerobic and anaerobic digestion are feasible food waste solutions. However, they differ in terms of efficiency, environmental impact, suitability for specific food waste types, and other factors.
Efficiency
Aerobic digestion is a faster process compared to anaerobic digestion and can handle a larger range of waste types. However, anaerobic digestion is more efficient overall in terms of energy production and waste reduction.
Energy Output
The energy output from aerobic digestion is lower than that of anaerobic digestion. This is because organic matter is only partially converted into biogas, whereas anaerobic digestion produces a high energy output from methane in biogas.
Environmental Impact
Aerobic digestion requires oxygen, which can be supplied through mechanical aeration, resulting in higher energy consumption. On the other hand, anaerobic digestion produces biogas, which is a renewable energy source. The process also doesn't need any oxygen input.
Suitability for Food Waste Types
Food waste with a higher moisture content is better suited for aerobic digestion. The method can serve a wide range of food waste streams, including food processing facilities, wastewater treatment plants, and breweries.
Anaerobic digestion is ideal for food wastes with high biochemical methane potential (BMP). These include organic waste from the food and beverage industry, livestock farms, municipal solid waste facilities, supermarkets, and restaurants.
Considerations for Choosing a Food Waste Solution
Keep the following factors in mind when choosing between aerobic and anaerobic digestion for sustainable waste management:
- Operation scale: Opt for anaerobic digestion for large-scale operations due to its higher efficiency and energy output. Aerobic digestion is suitable for smaller-scale operations.
- Cost: Aerobic digestion has a lower upfront cost, but a higher ongoing cost due to aeration and other operational expenses. Anaerobic digestion requires a higher initial investment, but operational costs are low. Decide based on your budget.
- End products: The end product of aerobic digestion (compost) has agricultural benefits. Products from anaerobic digestion, such as biogas and digestate, have multiple uses, including heating fuel and agricultural fertilizer.
After you've selected the proper sustainable waste management process, it's time to implement it. Make sure you conduct a waste audit beforehand to understand your waste composition and potential for reduction.
Invest in adequate infrastructure, such as aeration systems, digesters, composting vessels, nutrient management facilities, etc. You also need to familiarize yourself with government permits and licenses for regulatory compliance.
If this sounds like too much of a hassle and too high of a cost, work with a food waste management solution like EcoRich. Since EcoRich offers on-site biodigesters and composters, you don't have to invest in costly infrastructure.
EcoRich offers both aerobic and anaerobic digestion options, streamlining food waste management for various business types and waste streams. Check out EcoRich's solutions to learn more.
Conclusion
A sustainable future should be on every company's vision board. Food waste solutions, such as aerobic and anaerobic digestion, can assist in reducing greenhouse gas emissions, conserving resources, reducing your carbon footprint, and creating valuable end products. It's a win-win for the planet and your bottom line.
