The aim of the project is to develop a small automated membrane-covered composting system. Composting technologies with a capacity over 1000 tonnes per year have already been properly solved regarding both automation of the process and material flow. In recent years, however, there is an increasing market interest in small-scale composting units with a capacity of a few hundred tonnes per year, both internationally and domestically. Market demand occurs in the following groups:
- smaller livestock farms (e.g. cows, horses);
- hotels, pensions, small food processing plants;
- small municipalities, green space maintenance companies;
- smaller sewage treatment plants.
The following important requirements for small-scale composting are made:
- be a fully enclosed system, the containers must be equipped with semipermeable membrane covers and integrated leachate collecting solutions;
- may be operated optionally in places without technical protection;
- be automated (regarding measurement and control), and do not require continuous monitoring;
- be mobile, that it can be easily migrated to another site of operation and be scalable depending on capacity needs;
- automated material handling within the units should be solved.
In its own development, ProfiKomp® Environmental Technologies Inc. has already established small composting equipment, which were built on container-based reactors. Although they function properly, we have explored more development needs during operation. As the most important development requirement, we have determined that small-scale composting systems should be in continuous operation, as opposed to larger, intermittent working composting systems. This means that the material has to be continuously agitated within the reactor. During intermittent operation, the larger amounts of waste (20-30 m3) are deposited in the reactor and the extraction occurs at the end of the treatment period. This mode meets the needs of larger systems. However, for smaller units, it is not viable because (in the case of 500-1000 litres of input material produced per day) the waste materials are expected to be administered daily. There is usually no space for storing raw materials for a longer period of time. However continuous addition makes it necessary to systematically agitate and mix the substrate in the reactor. Continuous operation also allows the treated material to be taken out daily after the treatment period has passed.
The objectives of the development project are:
- Development of technical solutions to ensure the material handling between elements of a continuously operating system;
- Development of a technical solution for mixing and agitating the substrate. It is necessary to continuously mix the fresh input material within the composting container; therefore, the goal of development is to ensure adequate mixing, together with a continuous flow of material.
- Development of technical solutions for controlling and synchronizing the two system part.
- Sizing of the system, taking the economic considerations into account.