An Innovative Green Process for the Stabilization and Valorization of Organic Fraction of Municipal Solid Waste (OFMSW): Optimization of the Curing Process II Part

Abstract

This work is focused on the optimization of an innovative and cheap process for the valorization of the organic fraction of municipal solid waste (OFMSW), through its transformation into an odorless and environmentally compatible material to be employed for building applications or as a thermal and acoustic insulator. The process starts with the grinding of OFMSW, followed by its sterilization in order to obtain a complete removal of the bacterial activity. Afterwards, the incorporation in a catalysed thermosetting matrix is carried out by mixing the OFMSW to a water soluble urea formaldehyde based resin (UF), characterized by a formaldehyde content lower than 1% wt. The OFMSW/UF blends were firstly analysed by the dynamic rheological analyses, as a function of the content of a proper catalyst, that is able to decrease the curing temperature and time. Rheological analyses results allowed the selection of times and temperatures necessary for the polymerization (T = 60 °C, t = 1 h). The effect of the presence of different additives on both the cure process and the mechanical properties of the cured samples was finally analysed, evidencing that the OFMSW/UF composites possess improved mechanical properties in comparison to that of the neat resin.

An Innovative Green Process for the Stabilization and Valorization of Organic Fraction of Municipal Solid Waste (OFMSW) I Part

“…Furthermore, the carried out mechanical tests confirmed that the produced panels can't be employed as structural elements, given their unsuitable mechanical properties, but they can be used for not structural applications (e.g as filler of not structural elements in place of chipboard or blockboard panels) [14] and for indoor and outdoor furnishings. Specifically, the realized bricks can be used for realizing panels to be covered in order to hide the unavoidable imperfections (e.g sandwich panels with coverage through wooden sheets); they can't be used for decorative applications or, in general, in the case of visible uses, because have residual defects (mm-scale depressions or roughness) arising from the OFMSW transformation process.…”

An Innovative Green Process for the Stabilization and Valorization of the Organic Fraction of Municipal Solid Waste

“…Both methods proposed in this paper could be considered suitable for the production for example of Medium-density fibreboard (MDF)-like panels for building applications or thermal and acoustic insulating waste-based bricks to be used as filler in non-structural applications, as in detail previously discussed. A rough cost estimation of the developed procedure is presented in second part of the present paper, proving the potential cost saving compared to the neat matrix [17]. Such a cost estimation must account for the fact that, compared to the standard processing of the UF resin, an additional cost is given by the sterilization, but the production of the blend, allows to reduce the cost due to the reduced UF consumption.…”

“…As preliminary approach, the ratio 70/30 between the solid phase (which includes the matrix and the dried OFMSW) and water was chosen. Tests on different compositions are shown in the second part of the present paper [17]. A further simplified transformation process was also employed in order to reduce time duration and costs.…”

“…( Figure 9C, purple box). Finally, the inertised OFMSW is injected, by means a cochlea conveyor, into a mold heated by thermal film resistors powered by a programmable controller for the curing step ( Figure 9C, yellow box) [17]. The first prototype machinery of Figure 9 allows the treatment of about 5 Kg/hour of OFMSW.…”

“…The mechanical tests carried out confirmed that the produced panels are not suitable for the production of structural elements, but they can be used for not structural applications (e.g., as filler of non-structural elements in place of chipboard or blockboard panels) [17] and for indoor and outdoor furnishings. Specifically, the realized bricks can be used for realizing panels to be covered in order to hide the unavoidable imperfections (e.g., sandwich panels with coverage through wooden sheets); they can't be used for decorative applications or, in general, in the case of visible uses, because they have residual defects (mm-scale depressions or roughness) arising from the OFMSW transformation process.…”