Closed-Loop Processing: Management in Existing Tanneries and New Designed for Purpose

Closed-loop processing for unhairing/liming and tannage is established technology for the processing of raw hides to the wet blue state. This approach produces a high value product and, as part of sustainable manufacture, is significant. Savings are gained in chemicals, water and energy and reductions in the wastewater load. In effluent treatment, both the sulfide oxidation stage and chrome recovery/regeneration systems are eliminated. Both sulfate and chloride are minimised, and a reduction in solid waste generation. In November 2018 new-build tanneries with radically different layouts were at an advanced stage of construction and installation of new equipment. These were designed to management and technical requirements of this specific technology. In addition, the technology had made the transition from bovine manufacture to nappa leathers production in a major sheepskin tannery. And within small scale operations - bovine hides, bovine bellies, sheep and goat skins - chrome tannage was taking place with processing adapted around the prevailing conditions and tanners requirements.