Characterization of the separately collected organic fraction of municipal solid waste (OFMSW) from rural and urban districts for a one-year period in Germany

Abstract

Knowledge on material properties is beneficial to fully exploit inherent utilization potentials of the organic fraction of municipal solid waste (OFMSW). The objective of this study was to analyze and compare the physico-chemical characteristics of separately collected OFMSW (biowaste bin) originating in southwestern Germany. Therefore, 22 rural and 20 urban OFMSW samples, each from the same location were analyzed in the course of one year. Next to the basic characteristics such as the impurity, dry matter (DM) and organic dry matter (oDM) contents, this study focused on the analysis of 37 major, minor and trace elements. In addition, stoichiometric CH₄ potentials for the anaerobic digestion were calculated. The fresh mass (FM) based DM contents were significantly (p = 0.001) higher in rural OFMSW (32.86 ± 2.35% vs. 30.50 ± 1.75%) while the DM based oDM content was higher (p = 0.07) in urban OFMSW (84.59 ± 3.90% vs. 82.22 ± 4.16%). The impurities in rural OFMSW were significantly lower (2.83 ± 1.67% DM vs. 5.07 ± 2.71% DM with p = 0.004) while oDM based CH₄ potentials were higher for urban OFMSW (533 ± 22 L/kg vs. 519 ± 26L/kg). For both OFMSW types, contents >1000 mg/kgDM were detected for Ca, K, Si, Na, Al, Fe, Mg, P and S while Ti, Mn, Ba, Zn, Sr, Cr, Cu, V, Ni, Li, Pb and B were measured between 1 and 1000 mg/kgDM. The determined element concentrations are useful for an improved classification of OFMSW as a biorefinery resource.

Keywords: Anaerobic digestion; Physico-chemical analyzes; Rural and urban biowaste; Trace elements; Waste characterization; Waste treatment.