The basic technology behind the Biocyclers is a slowly rotating drum, where aeration is controlled to maintain a uniform degree of decomposition at a stable pace of the composted biomass. At the same time, the humidity of the discharged biomass is controlled in order to optionally limit further decomposition during storage. The air stream through the system is treated to convert emitted ammonia to aa aqueous fertilizer with a nitrogen content above 3%. The concentration of the fertilizer depends on the nitrogen content of the biomass, the decomposition rate, the retention time and the temperature in the biomass.
During composting considerable heat is developed. Up to 60% of the energy in the biomass may be released by microbiological respiration. The total respiration depends among others on the quality and composition of the biomass and the retention time in the Biocycler. Relatively nitrogen poor and woody biomass decomposes slower than nitrogen rich biomass with a low content of lignin and hemicelluloses. On the other hand, a certain degree of structure is needed in the biomass to secure proper aeration.

The process needs cooling and by using the reflux from a central heating unit as part of the cooling system the process heat from a Biocycler is utilized. The lower the reflux temperature, the more energy is retrieved. Alternatively, air can be used as coolant, thus creating a warm and dry air stream which is highly usable for drying purposes or direct ventilation heating of a building. Cooling must be correctly synchronized with the biological process in the Biocycler as the biological process as well as the efficacy of the production of nitrogen fertilizer is influenced by it.

Optimally, biomass should be fed to the Biocycler continuously while discharge can be performed at intervals e.g. once per day. A few hours before discharge the compost is dried in the Biocycler to obtain storage stability. If further ripening of the compost is needed after discharge water must be added.