Environment and waste
The idea of discarding plastic bags appears intuitively wasteful, but disposal must be compared with traditional technology
that requires cleaning and sterilization between batches. Recent studies estimate that single-use technology is 25–50% less
carbon-dioxide intensive than is stainless steel (3, 4). Consuming and heating large volumes of water to clean and sterilize
stainless-steel equipment is more energy demanding than producing and inactivating plastic bags, which can also be incinerated
for energy recovery. Sinclair and colleagues notably demonstrated that automobile emissions from facility staff's daily commute
were the overwhelming contributors to carbon-dioxide emissions (3).
The typical approach to solid waste disposal is to deactivate locally and then physically dispose of single-use equipment
in an incinerator or landfill. As the amount of solid waste increases, waste storage, deactivation autoclave capacities, and
transportation may be limited by the facility's physical boundaries. Depending on policies for the transport of material potentially
containing live genetically modified organisms and process-containment requirements, an alternative is to handle solid waste
as hospital waste and postpone the investment in deactivation capacity. The waste is then subject to stricter control and
visual markings. A specialized vehicle takes the waste to a power plant (off- or on-site) for incineration, where some of
the energy used to produce the plastic film is recaptured. Costs for this strategy can amount to about $100/metric ton of
waste. The volume also affects the cost because of the number of trips necessary. This cost is relatively low because one
could avoid installing a deactivation autoclave, although one must factor in the cost for additional handling. In one example,
NNE Pharmaplan calculated that off-site incineration would enable production for five years before accumulated running costs
outweighed the cost of investing in an autoclave.
Conclusion
The new single-use production paradigm shifts quality away from in-facility testing to supplier auditing and storage costs.
These activities mainly take place before the equipment enters the production facility. Quality costs and waste costs are
still not well described, but future work on the cost advantages of single-use technologies will address these aspects to
a larger extent.
Niels Guldager is a senior consultant for bioprocess and technology at NNE Pharmaplan, Vandtarnsvej 108–110, 2860 Soborg, Denmark, tel.
+45 3079 7246, fax +45 4444 3777, ngu@nnepharmaplan.com
.
References
1. N. Guldager, "Economic Drivers for Implementation of Single-Use Technology" (whitepaper, NNE Pharmaplan, Soborg, Denmark)
in press, 2010.
2. B. Barnoon and B. Bader, BioPharm Int. Nov. supplement, "Guide to Disposables," 30–43 (2008).
3. A. Sinclair et al., BioPharm Int. Nov. supplement, "Guide to Disposables," 4–15 (2008).
4. B. Rawlings and H. Pora, BioProc. Int.
7
(2), 18–26 (2009).
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