Alternative methods for Salt free / Less salt short term preservation of hides and skins in leather making for sustainable development – A review

Abstract

During the leather processing, large quantities of the salt as sodium chloride, about 30-50 % (% w/w on raw weight) is applied for short term preservation of hides and skins, which subsequently leaches out from the skins/hides and end up in waste streams. This raises a serious environmental concern as well as total dissolved solids (TDS) problem in the wastewater, for which there is no viable treatment method available. Remediation measures such as Reverse Osmosis (RO) or Ultra Filtration (UF) could only separate salt from these waste streams and end up as salt sludge, which necessitates Secured Land Fill (SLF) for disposal option. There are some concerns for SLF as it requires Land area as well as possible leaching due to highly soluble nature of Sodium chloride. Therefore, there is a pressing need for developing an alternative methods for Salt free / Less salt short term preservation of hides and skins. In this regard, Research and Development work is being carried out worldwide and several reports are available. Therefore, it would be beneficial to review and analyze the salt free alternative preservation methods. Even though, some reviews on this topic has been reported earlier, they have not taken into account the patent literature available on this subject. The present paper reviews various alternative methods for Salt free / Less salt short term preservation of hides and skins, taking into account both patent and other publications on this subject.