Biomedical Engineering Reference
In-Depth Information
through a catalytic converter is converted into a distillate fraction by the cata-
lytic cracking process (enzymatically breaking the complex molecules down
into simpler ones). The distillate is cooled as it passes through a condenser
and then is collected in a recovery tank. From the recovery tank, the product
is run through a centrifuge to remove contaminates. The clean distillate then
is pumped to a storage tank.
About 950 mL of oil can be recovered from 1 kg of certain types of plas-
tics. A comparison of the distillate produced by pyrolysis and regular diesel
shows good similarity between the fuels, with the advantage that distillate
from pyrolysis burns cleaner.
In-house incineration has, however, not been widely adopted as a means
of minimizing solid waste in biopharmaceutical manufacture. With rising
disposal costs, this may change rapidly; in most instances, this would be
sourced out.
Landfilling of plastic wastes is expected to decrease in importance as a
disposal option for solid wastes. The supposed advantages of landfills such
as low operating and capital costs, high local availability, and energy pro-
duction may no longer realistically apply, if indeed they ever did. Current
landfilling practices include both direct disposal of nonhazardous waste and
disposal of hazardous wastes after pretreatment.
Grind and Autoclave
All materials that have been in contact with biopharmaceutical components
or with bioagents must be regarded as hazardous. Typical pretreatment for
hazardous wastes includes grinding and autoclaving, as is a common prac-
tice with hospital waste. Some items are pretreated and shredded before
landfilling. This option is appealing because it may be accepted as safe
in some cases and reduces landfill volume compared with unshredded
product. Additional discussions are ongoing regarding use of other hos-
pital waste treatments such as autoclaving, thereby making a single-use
system or component suitable for disposal in a standard municipal waste
incinerator or landfill (if allowed). Some companies dispose of their used
components or systems into a grinder-autoclave currently used at many
hospitals, the National Cancer Institute, and the National Institutes of
Health, among others.
This combination of mechanical and physical pretreatment significantly
reduces the amount of waste for disposal, which can be reduced still fur-
ther if it is then mechanically compacted. Furthermore, high-temperature
pretreatment at, for example, 75°C, will almost completely inactivate biolog-
ical contamination and destroy most (but not all) pharmaceutical contami-
nants as well. Higher temperature treatment up to 130°C, or gamma-ray
