What is and how is compost produced from municipal waste

Compost from municipal waste is the end product of a Controlled biological process of decomposition of the organic fraction from municipal solid waste and is the result of aerobic decomposition of organic materials from household waste, such as food scrap, paper, cardboard and vegetable waste. It is a stable, humus-like product that can be used as an amendment for the soil. 

Municipal waste compost is a sustainable solution for managing the organic fraction of household waste, which accounts for approximately 50-55% of total municipal waste, providing benefits for both waste management and soil quality improvement.

What type of municipal waste can be used for composting

• Organic household waste: leftovers of fruits and vegetables, leftovers of cooked food (without meat, bones or dairy), egg shells, coffee grounds and tea bags
• Plant waste from gardens and parks: dry leaves, cut grass, shredded branches, withered flowers
• Paper and cardboard: newspapers, egg cartons, paper towels and towels (uncontaminated)
• Other biodegradable materials: sawdust and chips of untreated wood, hair and nails cut
• Organic waste from the markets: vegetable waste, spoiled fruits and vegetables

It is important to note that in the case of composting raw materials we must take into account the following:

• Materials contaminated with chemicals or oils should be avoided.
• Meat, bones and dairy products are not recommended for small-scale composting, as they can attract pests and generate unpleasant odors.
• The correct proportion between „green” (nitrogen-rich) and „brown” (carbon-rich) materials is essential for an efficient composting process.
• Certain materials, such as branches, require shredding before composting.

Composting process

• Collection and sorting: Separation of the organic fraction from non-compostable materials.
• Pretreatment: Shredding and Homogenization of organic materials.
• Composting itself: Microbiological decomposition of organic matter under controlled aerobic conditions.
• Maturation: compost stabilization.
• Refining: sifting and removing any remaining unwanted materials.

How to compare passive and active aeration methods in composting

Process efficiency:

• Active aeration uses High-performance industrial equipment for compost production It is generally more efficient, accelerating the composting process. The active aeration reactor reduced the maturation period by 37.30% compared to the passive aeration.
• Passive aeration is slower, being able to take over a year to obtain final compost.

Reaching high temperatures

• Active aeration systems more easily reach high temperatures (above 50°C) needed to remove pathogens and weed seeds.
• Passive systems rarely reach the temperatures required for the removal of pathogens and seeds.

Process control

• Active aeration allows better control of oxygen level and temperature in compost.
• Passive aeration provides less control over process parameters.

Operational effort and costs

• Active aeration requires more effort and cost for operation (equipment, energy).
• Passive aeration requires less effort and low operating costs.

Compost Quality

• Active aeration compost tends to be of superior quality with better germination index and nutrient content values.

Small scale applicability

• Active aeration has proven more suitable for household composting, reducing unpleasant odors and insect problems.

In conclusion, although both methods have their advantages, active aeration tends to be more efficient and produce higher quality compost in a shorter time, but with higher operational costs. Passive aeration is simpler and cheaper, but the process takes longer and may not reach the temperatures needed to completely eliminate pathogens.

How does active aeration influence the final quality of compost

Active aeration, carried out with an industrial compost production line, significantly influences the final quality of the compost in several ways

• Improves the quality of nutrients: Compost obtained by active aeration tends to have better nutrient content values, especially nitrogen, phosphorus and potassium.
• Germination index increases: Active aeration has been observed to result in compost with a higher root index and root length index, indicating a higher quality for use in agriculture.
• Ensures the necessary temperatures: Active aeration systems more easily reach high temperatures (above 50°C), necessary for the elimination of pathogens and weed seeds.
• Maintains optimal aerobic conditions: Active aeration prevents the formation of anaerobic areas in the compost pile, which could lead to the production of unwanted compounds.
• Controls the humidity: By adjusting the air flow, it can better control the moisture of the compost, avoiding both excessive drying and water saturation.
• Reduces unpleasant odors: Adequate aeration reduces the formation of compounds that produce unpleasant odors, resulting in a less offensive olfactory compost.
• Improves homogeneity: Active aeration helps to evenly distribute oxygen and moisture throughout the compost mass, resulting in a more homogeneous decomposition.
• Reduces nitrogen loss: Although excessive aeration can lead to nitrogen losses through volatilization, controlled aeration can minimize these losses, maintaining a higher nitrogen content in the final compost.

In conclusion, municipal waste composting is an efficient and sustainable solution for managing the organic fraction of household waste, providing benefits for both waste management and soil quality improvement.

The process involves the controlled decomposition of organic materials such as food scraps, plant waste and paper, resulting in a stable, humus-like product, valuable for agriculture and horticulture. 

Aeration techniques play an important role in the efficiency and quality of the composting process, with active aeration demonstrating significant advantages in terms of accelerating the process, controlling parameters and quality of the final product. This leads to a compost with superior nutritional content, improved germination index and better elimination of pathogens.

However, the successful implementation of large-scale composting requires careful process management, proper selection of compostable materials, and the education of the population on correct waste separation practices. By adopting these practices and technologies, composting municipal waste can significantly contribute to reducing the amount of stored waste and promoting a more sustainable circular economy.