Recycling cellulose-rich waste
The UK alone produces over 3 billion soiled Absorbent Hygiene Products (AHPs) such as nappies and adult incontinence pads (Mintel 2019; NHS 2018; WRAP 2015). There is a need to improve on current disposal of such AHPs from medical and care home sources as well as household waste collections. This industry-academia collaboration in the form of a three-year Innovate UK-funded Knowledge Transfer Partnership (KTP) project hopes to use the principle of AHP material re-assignment and re-valuation to drive sustainable disposal of waste and to inform future product design to facilitate better recycling.
To identify the recyclable contents of non-hazardous healthcare waste in South-East England, an inventory of the contents of 200 randomly-selected offensive human waste bags collected from care homes, nurseries, hospitals, orthodontic practices and related institutions was performed. Furthermore, lab-scale chemical decontamination and material recovery trials have been performed in advance of plant scale-up.
In spite of marked variations in waste bags collected from different institutions, 76% of the waste was comprised of AHPs, followed by various mixed plastics (polypropylene, polyethylene, and polyester). The data obtained from our study suggests that two of the readily recoverable materials include superabsorbent polymer and fluff pulp, both of which may find use in sectors such as construction and agricultural industries. Depending on the end use, certain quality requirements must be met, including, but not limited to fibre length, mechanical strength, and absorption capacity. Waste decontamination shows potential via chemical disinfection with hypochlorites of sodium and calcium.
A number of factors influence the viability of AHP recycling including cost-effective sorting and separation, public perceptions, and sustainable recyclate market outlets. Overall however, given the range of non-food end uses identified as potential outlets for post-consumer AHP recyclates, there is potential for transforming an abundant waste stream into value-added products, particularly if source-segregation is encouraged.
Mintel (2019). Incontinence status by usage and volume. In: Feminine Hygiene and Sanitary Protection Products – UK – 2019. Available from: http:// academic.mintel.com/display/858711/ (accessed 30 January 2019).
NHS (2018). Excellence in continence care. Available from: https://www.england.nhs.uk/wp-content/uploads/2018/07/excellence-in-continence-care.pdf (accessed 31 March 2019).
WRAP (2015). Real nappies. Available from: http://www.wrap.org.uk/content/real-nappies-overview (accessed 31 March 2019).