Upon collection at the source, hazardous wastes are transported
to the appropriate processing facility according to their type (blue
lines in Fig. 2). The model allows co-location or establishment of
integrated facilities at the same node. It is especially important that
incinerators and landfills be integrated since residues from haz-
ardous waste incineration are likely to be hazardous and must be
sent to a hazardous waste landfill.
The proportions of treatment and incineration residues with
respect to total amount of waste entering a process step are ob-
tained from the literature and current practices. They are incor-
porated into the model by means of mass reduction ratios (denoted
by upper case M in Fig. 1) provided in SI Table S1. These coefficients
represent the relation between the amount of waste and the
amount of residues entering the process and are needed for flow
balance constraints.