In vessel composting

Types of in-vessel composting

In-vessel composting refers to a controlled composting process that occurs inside a container or vessel. This container is often large and can be either rectangular or cylindrical, made from concrete, stone, or metal, with a capacity ranging from a few hundred liters to several cubic meters.

In addition to the size and material of the composting vessel, various types of vessels used for in-vessel composting exist. The followings are some key features and functions of different in-vessel composters:

• Drum composter: A rotary drum composter is a cylinder that is mounted at an angle and rotated. Aeration of the compost mixture is accomplished by rolling the drum. The aeration box composter is a kind of drum composter that uses fan-blown air for aeration. The fans push air through the compost material by way of a plenum chamber.
• Tunnel and Bin Vessels: When static, the material in the bin vessel is aerated under pressure through forced air. Another type of bin composter is the open windrow variant. This variant aerates compost by blowing air through it.
• Heap in a Hoop: A geodesic dome made of hoop composting helps to contain and aerate compost material that is heaped within it. This kind of composter is movable and requires less energy to make than traditional vessel composters.
• Digesters and Reactors: Biochemical processes like anaerobic digestion, which takes place inside a digester or a reactor, may be involved in in-vessel composting. Microorganisms that recycle and digest organic material are enclosed by the vessel walls.
• Mashines: The shuffler machine regroups compost in a bin or static vessel. It mixes the material and hastens the decomposition process. Another machine is the screen, where the final compost product is screened to separate any remaining organic matter for further composting.

Specification and Maintenance

Specification

• Capacity: Industrial in-vessel composting systems typically have large capacities, often measured in cubic meters or tons per day/week/month. For instance, an in-vessel composting system with a 22.5 cubic meter/1,857 kg capacity can daily process 18,000 kg of food waste.
• Temperature control: In-vessel composters can have temperature control systems. The ideal temperature for composting is around 60 to 65 degrees Celsius. Some in-vessel composters have automatic temperature and humidity monitors and can adjust the temperature and moisture levels through ventilation systems and treated air pipes.
• Cylinders and tunnels: In-vessel composters have different cylinder sizes ranging from 3-6 meters in length and 2-3 meters in diameter. The test time of one batch is 8-12 hours, and the output time is 8-12 hours, too. Cylinder/Tunnel composters are suitable for processing a large quantity of waste in a short time. They can form a continuous composting production line by rotating, translating, or nesting. Cylinder/tunnel in-vessel composters are usually suitable for organic waste from food processing.
• Odor reduction: In-vessel composting can reduce odor emissions by up to 90%. The closed environment allows for better control of microbial degradation, minimizing the release of unpleasant odors.
• Equipment: In-vessel composting equipment includes the composting vessel itself and temperature monitors, deodorizers, fans, and other equipment.
• Komatsuzaki's technology: Some in-vessel industrial composting facilities use specific technologies. For example, Komatsuzaki utilizes Japan's unique biological deodorization technology, which can remove harmful gases such as NH3, H2S, and VOC. The efficiency can reach more than 99%.

Maintenance

• Regular Inspection: Check the overall re-processing equipment to ensure no parts are damaged, deformed, or loose. The door seals, pipes, and valves should be secure and leaky, and the ventilation holes should be smooth and not blocked. Also, inspect the pressure gauges and temperature gauges to ensure their readings are accurate.
• Cleaning: Periodically clean the interior and exterior of the re-composting facility. Use water and non-toxic cleaning agents to clean out the residual waste and dirt in the composting vessel. At the same time, keep the surrounding environment tidy and dispose of the cleaning waste appropriately.
• Replacement of Accessories: Over time, some accessories and components may be worn out or damaged and need to be replaced, such as the deodorizing filter element, the fan blade, and the sealing strip. Ensure that the replacement parts used meet the facility's requirements and are installed correctly.
• Equipment Maintenance: Maintain the relevant equipment of the in-vessel composting system, including the computer, the temperature monitors, and other equipment. Ensure that all equipment functions properly and is regularly calibrated.
• Waste disposal: Properly dispose of the waste generated in the maintenance process, such as used cleaning agents and filter elements, in order to protect the environment and public health.
• Preventive Maintenance: Carry out preventive maintenance periodically according to the manufacturer's guidelines. This may include replacing key components, cleaning specific areas, etc. Preventive maintenance can reduce the risk of equipment failure and extend the service life of the equipment.

Scenarios in-vessel composting

In-vessel composting is applied in various scenarios, both offline and online.

• Research institutions and universities

  Many research institutions and universities are exploring more efficient waste treatment methods to reduce their carbon footprint and promote sustainability. They often produce a significant amount of organic material, such as food waste from dining halls and leftovers from laboratory activities. By implementing in-vessel composting facilities on-site, these institutions can effectively manage their organic waste while simultaneously generating valuable compost that can be used to enrich soils on campus or for agricultural research projects.

• Hotels and resorts

  Hotels and resorts typically produce a large volume of organic waste, primarily food scraps from on-site restaurants and kitchens. Implementing in-vessel composting systems within these establishments not only provides a sustainable solution for managing food waste but also allows them to create nutrient-rich compost that can be used to maintain landscaping and garden areas.

• Restaurants and cafes

  In-vessel composting is widely used in various cafes and restaurants to effectively manage organic waste while contributing to sustainability efforts. On-site composting systems not only reduce food scraps but also engage customers and staff in environmentally friendly practices. The high-quality compost produced can be used to fertilize on-site herb and vegetable gardens, further enhancing the establishment's commitment to sustainable sourcing and reducing waste.

• Food processing facilities

  Food processing facilities generate large volumes of organic waste, including peels, trimmings, and other by-products. Implementing in-vessel composting systems within these facilities can significantly reduce the amount of food waste sent to landfills while providing a valuable source of compost to improve soil health and support sustainable agriculture.

• Municipal waste management facilities

  These facilities are responsible for collecting, treating, and disposing of various types of waste generated by the population within a specific municipality or local government area. Municipalities are exploring innovative solutions like in-vessel composting to enhance existing waste management systems. Centralized in-vessel composting facilities can efficiently process large quantities of organic waste sourced from households, restaurants, and other businesses throughout the municipality.

How to choose in vessel composting

There are some helpful tips for business buyers who need to choose the right in-vessel composting system.

• Understand the scale of operation:

  Consider the quantity of waste that needs to be processed and determine the ideal composting vessel size. A small-scale closed in-vessel composter may be adequate for a commercial kitchen. Larger-scale systems with greater capacity would suit industrial or municipal applications.

• Assess ventilation and heating mechanisms:

  Different vessels have diverse ways of maintaining temperature and airflow. Since temperature controls directly impact decomposition, choose an option whose temperature and moisture retention best align with specific composting goals.

• Review turner mechanisms:

  Some vessels have mechanical turners, while others use manual tools. Assess the ease of use and practicality of the turning method provided. Relying on automatic turning would be more convenient but may incur higher costs.

• Examine leachate collection and drainage:

  Proper leachate management is essential for preventing groundwater contamination. Choose a vessel with a well-designed leachate collection system to enable safe handling and disposal of liquid fractions.

• Consider end-product storage:

  Does the available storage space permit immediate use? If not, opt for a system that can store finished compost until it can be conveniently utilized.

• Investigate collection frequency:

  How often waste needs to be gathered depends on the vessel's capacity and the volume of material generated. Choose composting equipment that aligns with desired collection intervals to maximize operational efficiency and minimize costs.

• Research odour and pest management:

  In-vessel composting controls unpleasant smells and deters rodents and insects more effectively than open-air systems. Despite these advantages, carefully examine each vessel's odour and pest mitigation strategies, and ensure they are suitable for the intended location and waste stream.

• Understand regulations and incentives:

  Waste management rules differ by region. Some places require formal permits for composting facilities. Others give financial support to encourage businesses to compost. Research local policies to determine if in-vessel composting can meet legal requirements and qualify for funding.

In vessel composting Q & A

Q1: What materials can be used for in vessel composting?

A1: In vessel composters can handle a wide variety of organic wastes. Common materials include fruit and vegetable scraps, coffee grounds, egg shells, grain products, yard waste, and paper products. Some industrial composters also accept meat, dairy, and food-coated containers.

Q2: How does the temperature in an in vessel composting system fluctuate?

A2: Temperature changes throughout the composting process. Initially, there may be a temperature rise as microbial activity increases. After that, there could be a period of cooling. Eventually, the temperature may increase again if facilities add materials regularly or if the composting vessel is insulated or heated.

Q3: How does an in vessel composting system manage odors?

A3: One of the advantages of in vessel composting is that it can be contained. Therefore, properly designed and maintained in vessel systems produce fewer odors than other composting methods. In vessels, airflow, moisture levels, temperature, and microbial activity are usually sufficient to prevent bad odor development. Should some undesirable smells occur, they can usually be eliminated by adjusting the parameters within the vessel.

Q4: How much space does an in vessel compost system require?

A4: The amount of space needed for an in vessel composter depends on its type and size and the volume of materials planned for composting. Small-scale in vessel units can be fitted into standard kitchens or placed somewhere convenient in the home, whereas large-scale industrial in vessel composters will require a substantial amount of space in a dedicated facility.