The Journal of Solid Waste Technology and Management
Abstract
Zero waste is now a strongly emerging issue for sustainable industrial development where minimisation and utilisation of waste are a priority in the leather industry. In a tannery hides and skins converted in to leather through various processes. Approximately 20% (w/w) of the chrome containing tannery solid waste (TSW) is generated from one tonne of raw hides and skins. However, tannery solid waste may also be a resource if it is managed expertly as we move towards zero waste. This research illustrates the potential of tannery solid waste as a poultry feed additive. An oxidation method was used to achieve 95% of dechroming rate of chrome tanned waste followed with thermal and enzymatic treatment to produce gelatin solution and collagen concentrates. The thermal stability and fibre structure of samples were analysed by Differential Scanning Calorimeter (DSC) and Scanning Electron Microscope (SEM). Protein content and fourteen amino acid concentrations were determined using amino acid analysis. High Performance Liquid Chromatography (HPLC) was used to compare the amino acid composition with wheat and soya bean meal that is conventionally used in poultry feed. The nutrient requirements for poultry feed vary according to the purpose for which they have been developed. The high content of arginine, leucine, threonine, serine and methionine in the extract were of a sufficient level for poultry feed. Hexavalent chromium test was performed and showed that levels of the metal were low enough to be used in feed additives. In addition, the extracted product showed 75% digestibility (in vitro) and appears that treated TSW may be utilised in poultry feed, this demonstrates a clear example of waste utilisation. In Bangladesh plans are being formed to use the extract in poultry feed production