New parameters to determine the optimum pretreatment for improving the biomethanization performance

Thermochemical and biological pretreatments have been applied to the organic fraction of the municipal solid wastes (OFMSW) coming from an industrial 30 mm-trommel placed in a full-scale mechanical–biological treatment (MBT) plant in order to study their effects on the organic matter solubilization yield and the biomethanization process.To compare the effect of theses pre-treatments on anaerobic biodegradability of pretreated OFMSW, a series of batch experiments were carried out. The accumulated methane production and the temporary evolutions of the volatile fatty acids (VFA) have been used to define two new parameters (tMAX and tOPT) in order to compare the effect of the pre-treatments on anaerobic digestion of pretreated OFMSW.From the point of view of the biomethanization, the results indicate that the optimum pretreatment is the “Precomposting”, since it presents the lower tOPT (12 days) and in only 15 days of operation (tMAX = 15) the reactor achieves the maximum accumulated methane production, 37.5 l vs. 7 l of the control digester for the same operation time.

► The biological pretreatment with mature compost improves the OFMSW anaerobic digestion.
► The total methane production is increased up to 37% over the control.
► The hydrolytic stage of the anaerobic digestion process is faster by means of application of pretreatments.
► New parameters (tMAX and tOPT) have been defined to select the optimum pretreatment.
► New parameters as new user-friendly tools have been used to characterize the biomethanization performance.