To maintain sterility, traditional durable equipment must be cleaned and steamed in place (CIP/SIP) between each batch. This
requires a large amount of process water, water for injection (WFI), acids, and bases. The energy and supporting equipment
required are all considered in this analysis. Single-use components that contact media do not require rigorous cleaning and
sterilization, but instead are pre-sterilized by off-site Cobalt-60 irradiation. The transport of single-use components to
and from the facility is included as well as the facility's operating energy, the Co-60 source, and the concrete required
for the irradiation cell. These impacts are allocated to each irradiated component as a mass fraction of irradiation facility
The traditional durable equipment is nominally assumed to have 10-year lifetimes, after which 25% of the equipment is re-used
while the remainder is either recycled (90%) or landfilled (10%). The single-use process trains contain components that are
designed to be used once and then discarded. The exceptions are the replacement of single-use chromatography columns, which
are typically reused for several batches depending on the number of cycles per batch. In this case, a recommended usable life
for a ReadyToProcess Capto S 2.5 chromatography column is 20–50 cycles. The LCA model assumed 7 cycles per batch for Protein
A and 5 cycles per batch for ion exchange chromatography (at 2000-L scale). The number of cycles for traditional chromatography
is assumed to be two cycles per batch for both Protein A and ion exchange chromatography.
Several assumptions were made regarding treatment at end-of-life. For single-use components such as cellbags, filters, and
connectors, disposal was assumed to occur by hazardous waste incineration without waste heat recovery. Non-hazardous waste
was sent to landfill or wastewater treatment. Process water was assumed to be used once without recovery.
Use-phase electricity was assumed to be from an average US grid mix. Selection of an average European electricity grid mix
exhibits lower environmental impacts but does not lead to any discernable shift of relative magnitudes between single-use
and traditional process technology.
The fuel mix for generation of WFI was composed of different ratios of fuel oil, natural gas and electricity. The default
mixture was equally weighted for fuel oil and natural gas at 45% each while electricity was weighted at 10%.
Sensitivity and uncertainty analyses
The sensitivity of the LCA results to variations in key assumptions was extensively analyzed using a Plackett-Burman experimental
design. Lifetime of durable equipment was varied from 5–25 years. Chromatography column lifetimes were varied from 10–100
cycles. Transportation distances were varied from 5–25 miles (local), 1000–5000 miles (domestic), and 1500–7500 miles (international).
Different ratios of WFI fuel mixes were examined. Equipment reuse was varied from 0–25%. Equipment recycling was varied from
50–100%. Co-60 irradiation facility parameters were varied as well. None of the variations in key assumptions had a significant
effect on the study conclusions. The detailed results of the sensitivity and uncertainty analyses will be reported in a subsequent