Implementation of a prototypal optical sorter as core of the new pre-treatment configuration of a mechanical-biological treatment plant treating OFMSW through anaerobic digestion

摘要

The pre-treatment of the organic fraction of municipal solid waste is one of the main challenges in mechanical-biological treatment plants equipped with anaerobic digesters. The present study shows the successful revamping of the Sant Adria del Besos plant pre-treatment line, where a prototypal optical sorter, a wet-crusher, and a hydrocyclone-decanter substituted the previous pulper and decanter system. The prototypal optical sorter, which uses near-infrared spectroscopy, was able to enhance the organic matter content from 40% to 60% in a more efficient and less energy demanding way than conventional systems. The new configuration not only improved digester feedstock and performance but also led to a significant reduction of the treatment and maintenance costs. The high methane yield of the digester, between 480 and 580 CH_4 m~3 t~(-1) VS, together with an energy efficiency index of 2.2 kW h_(produced)/kW h_(consumed). demonstrated the viability of this novel configuration with respect to conventional ones. Thus, optical sorting arises as a new alternative for mechanical-biological treatment plants that needs to be constructed or revamped.