Executive Summary: Ovation Woolskin offcuts

Summary of Project and Key Findings:
Background
Classic NZ is a tannery located in Napier making sheepskin products and generating at several tonnes of sheepskin offcuts per year. The company has been exploring ways to upcycle their woolskin offcuts, which are currently landfilled or composted at relatively high costs.

Project aim
The aim of the project is to explore the feasibility of various products with woolskin. The products are mainly directed towards agricultural applications. During the project different proof-of-concept product were tested. Hydro-mulching was identified as a potential route to product.

Previous Milestones

• The initial trial revealed that the presence of large chunks of leather was detrimental to many downstream processes. Therefore, a homogenisation step (attrition) was required.
• The second trial explored various attrition processes and characterization of the resulting short fibres and sub-millimetre size particles.
• The third trial aimed at producing potential proof-of-concept products such as paper, panels, briquettes, and pellets. It was found that handsheet papers with a grammage above 120 gsm and at least 30% wood fibres were quite satisfactory. This work confirmed that the production of short wool fibre products might be worth exploring further.
• The latest work was a techno-economic analysis (TEA) to establish the current costs of composting and landfilling. This work revealed that a short-term solution of pre-mixing woolskin with a Carbon source (bark) for composting applications would not be commercially viable. The TEA also highlighted that production of a woolskin paper to replace plastic mulch applications for horticulture purposes could be economically viable. However, the CAPEX needed to produce this type of product is likely prohibitive ($20+ millions).
• Therefore, Scion started to explore low CAPEX solutions to produce hydromulch using short wool fibres.

Key results and Implications of results for the client

• Shredded offcuts can be ground dry or wet using different method.
• The ground woolskin benchmark for hydroseeding provides encouraging results (mixability, volume, sheet forming, water retention).
• For hydroseeding mat formation, the ground woolskin needs to be part of a mix with lignocellulosic material. Pure short wool mats have no mechanical integrity.
• The ground offcuts have been successfully used for hydroseeding in a real-life trial. The 500 m2 trial used ground woolskin:newsprint at a ratio 30:70 (+ seeds).
• The capital expenditure (CAPEX) required to purchase equipment and set up the facility for the project has been estimated. The operational expenditure (OPEX) has also been calculated.
• The ground woolskin could be sold as a cheaper material than the woodmulch currently used.
• Selling the product in compacted 20 kg bales at a competitive price could make the product cost neutral to produce, therefore saving the landfill cost.
• Market analysis indicates that there is enough demand in Australasia to absorb a large part of the woolskin.
• A large international distributor of hydromulch mix is interested to performed tests on the material (flowability, ground cover, water retention). According to this distributor if the product can be proven to be pathogen free, it could easily find applications in large scale soil stabilisation projects in Australia.