title: The circular conomy of equine surfaces
title: investigating the recyclability of surfaces produced by Equestrian Surfaces LTD.
titleType: Subtitle
Creators: name: Nicholson, Steven
Publisher: name: Lancaster University
Year: 2024
Subjects: Equestrian Surfaces, wax, sand, mechanical separation, trommel, fibre, microplastics, reuse, circular economy.

description: As an ever-growing sector, the equestrian industry is constantly
 developing, with a range of synthetic surfaces available in the market.
 Typically, synthetic equine surfaces comprise three major components –
 sand, wax, and fibre. Currently, most equine surfaces are disposed of in
 landfill when they reach the end of their life. This is an unsustainable
 waste solution; hence alternative strategies need to be explored. 
 
 This project has been completed in collaboration with Equestrian Surfaces
 LTD, with the main aim of this research being the development of a more
 sustainable end-of-life (EOL) solution for equine surfaces that allows the
 individual components to be recovered and potentially recycled into new
 surfaces. Equestrian Surfaces LTD are a company specialising in the
 production and installation of synthetic equine surfaces, offering a range
 of surfaces suitable for indoor and outdoor use in all weathers and for
 all disciplines. 
 
 The research presented in this thesis focusses on the small-scale
 extraction and separation of the individual surface components (sand, wax,
 and fibre) as well as identification of any changes to the quality and
 physio-chemical properties of the separated materials compared to their
 composition at time of manufacturing. After presenting the general context
 for this work (chapter 1), the results section is comprised of 4 chapters
 focusing on the following aspects: experimental methods (chapter 2), wax
 extraction (chapter 3), sand and fibre separation (chapter 4), and
 conclusion and future work (chapter 5) as well as an appendix containing
 additional experimental detail.
 
 Results discussed in chapter 3 show that wax can be extracted efficiently
 from used surfaces using a range of organic solvents, with ethyl acetate
 identified as a suitable non-toxic, high-yielding green solvent.
 Alternative green extraction routes were also explored, with microemulsion
 extraction proving promising for removal of wax from surfaces. The major
 obstacle with this technique was the recovery of organic material from the
 aqueous solution, with this highlighted as an important area for further
 research. Analysis of extracted wax using a range of analytical techniques
 (GC-MS, IR, DSC, and CHNS elemental analysis) showed that wax decomposes
 rapidly and is lost from surfaces progressively over time. The extracted
 wax can be purified (silica gel column chromatography) however, since a
 considerable mass of wax is lost during usage, and the yield of reusable
 wax recovered following purification was as low as 9.5%, this was deemed
 an unsustainable solution. 
 
 Chapter 4 focussed on utilising size-based separation techniques to
 isolate the sand and fibre from surfaces. Results discussed in this
 chapter revealed that surfaces, in both the waxed and dewaxed forms, can
 be separated in this way, with sand recovery yields of up to 93% recorded
 for some used surfaces. It was also discovered that the extent of wax
 remaining on a surface affects the efficiency of separation, with high
 remaining wax content resulting in poor sand recovery. The quality and
 purity of the isolated sand was evaluated using analytical techniques
 including SEM, EDX and IR spectroscopy, showing that the recovered sand
 has a particle size distribution similar to that of the supplier sand. 
 
 Results discussed in chapter 4 also revealed how fibres can also be
 separated from surfaces by utilizing size-separation techniques; however,
 the fibres recovered from used surfaces appear heavily contaminated with
 sand and other solid materials. The quality of the fibres was briefly
 evaluated via SEM-EDX analysis and tensile strength tests, both of which
 highlighted a reduction in quality and purity following surface usage.
 Further testing is necessary to evaluate the reusability of the fibres,
 however, since this material is already recycled it may not be
 economically viable to pursue further recycling. In this way, further
 research to provide an end-of-life solution for the used surface fibres
 should be conducted. 
 
 We concluded that, equestrian surface recycling is not a trivial process,
 and that wax removal from surfaces is a complex, costly, and unnecessary
 step that can be avoided due to loss of the coating during surface usage.
 The small-scale separation techniques developed in this report provide a
 tool that can be used by Equestrian Surfaces LTD to determine the EOL
 state of their surfaces. Surfaces which meet the set requirements detailed
 in chapter 5 can be deemed as fully EOL and subsequently subject to direct
 mechanical separation without the need for wax removal. This has been
 recognised as the most suitable recycling strategy for use in industry due
 to the simplicity of separation and the high yields of sand recovery
 attainable. The sand recovered from this process can then be incorporated
 into newly manufactured surfaces, with further testing needed to establish
 the quality of the surfaces made from reused non-dewaxed sand. Further
 research is also required to improve the circularity of the proposed
 process, with the ability to reuse both the large fibres and microplastics
 isolated from surfaces being key examples.