This work reviews the latest advances, methods and knowledge on the dewatering techniques and filtration characterisation of industrial sludge made of leather-fibre particles. The challenges related to the treatment of industrial wastewater continue to pose critical environmental concerns to the leather industries. The present work focuses on main aspects of leather-fibre filtration, including particle characterisation, sedimentation behaviour, and separation efficiency across multiple size scales. First, a review of the latest approaches is presented and analysed. Next, a raw sludge sample, collected from a local leather factory, is analysed in the light of the existing techniques. The sample is composed of leather fibre particles of different lengths and shapes, dissolved in some resins and vegetable retaining agents such as mimosa. The experimental setup used for the present work is composed of the following devices and equipment: A centrifuge machine, a spectrophotometer, a microscope, a filtration kit including two different filter systems. Time was recorded using a chronometer. Existing studies highlight that wastewater originating from leather processing contains a broad distribution of contaminants, ranging from micro- to nano-sized particles. Techniques such as sedimentation analysis, centrifugation, particle size distribution, and spectrophotometry have been widely employed to characterise these particles and evaluate their transport and settling dynamics, often interpreted through classical models such as Stokes’ law.

Furthermore, this review work compares the performance of different filtration media, including conventional fabric filters and foam-based structures, in capturing leather-derived particulates. Evidence suggests that porous, foam-type filtration systems may offer enhanced removal efficiency across a wider particle size spectrum compared to traditional filters. These findings underline the potential of engineered porous materials, including recycled leather fibres, as cost-effective and environmentally sustainable solutions for sludge dewatering and wastewater treatment. Overall, this work synthesises recent advances in leather-fibre filtration characterisation and identifies key challenges and opportunities for developing scalable, low-cost filtration technologies for industrial wastewater management.