Combined anaerobic/aerobic treatment of OFMSW: Performance evaluation using mass balances

• OFMSW treatment is conveniently performed by combined anaerobic/aerobic systems.
• Mass balances were performed with reference to a full-scale anaerobic/aerobic plant.
• Results indicates that both the anaerobic and aerobic phases are well operated.
• Mass balances in terms of compostable materials were found to be fundamental.

In the last years the treatment of the organic fraction of municipal solid waste has been carried out using combined anaerobic/aerobic processes, where anaerobic digestion is followed by the aerobic stabilization of the digestate. Such a treatment provides a positive net energy balance associated with the methane energy recovery as well as the production of a soil conditioner. However the high complexity of the treatment requires an accurate management of all the treatment units. To this end, mass balances represent a useful tool, allowing both the control and maximization of process yields as well as the minimization of the treatment costs.This work aims at evaluating the performances of a combined anaerobic/aerobic source-sorted OFMSW plant by means of mass balances, elaborated with reference to both conventional and non-conventional operational parameters.Results pointed out the key role of organic waste pretreatment as well as the effectiveness of both anaerobic and aerobic processes in providing an adequate biostabilization level of the treated waste.