A Prescriptive Approach To Management Of Solid Waste From Single-Use Systems

By Bruce Rawlings and Hélène Pora

In biopharmaceutical manufacturing, the disposal of solid waste from single-use systems is becoming an increasingly important issue. The new focus is driven by several major factors including a broadening range of disposable technologies enabling, in some cases, the installation of completely disposable multistage systems; improved scalability of singleuse components offering production capacities to thousands of liters; and the environmental impact of waste disposal. The latter concern includes not only regulatory and cost constraints, but also the need for users to implement a responsible approach for environmental sustainability.

All those factors must be balanced against the potential benefits of singleuse systems over those of traditional stainless steel processes (1–4). For example, disposables generate more solid waste but consume much lower quantities of water, chemicals, and energy to use. Sinclair et al. compared a model stainless steel system with a single-use system on a scale of 3 × 2,000 L (5). They calculated that the total water use (both water for injection, WFI, and purified water, PW) for a disposable system was nearly eight times lower, and the use of cleaning chemicals was more than 20 times lower. Similar calculations for energy consumption of model systems showed that the combined value for sterilization, cleaning, and materials was ~50% lower for the single-use system. These benefits, which often provide a net cost savings, can also translate to a more favorable environmental impact, which may be further enhanced by a structured approach to waste management of single-use components. Model Disposable System The model system illustrated in Figure 3 represents the main components of a process typically found in biotechnology manufacturing for products such as monoclonal antibodies (MAbs) at 2,000-L scale. To simplify the assessments described below, this model does not include every component in a process. For example, a typical process may contain as many as 30–90 bags and biocontainers used for buffers, media, product, flush liquids, and product samples.