Composting of limed fleshings generated in a tannery: sustainable waste management.

In tanneries, limed fleshing is an unavoidable waste generated in beamhouse operation. Proper management of limed fleshing with protein, fat, lime, and sulfide will help to protect the natural environment and at least reduce the pollution that ends up in it. In this study, excluding any pretreatment, limed fleshing is used for compost production. Chopped and mixed limed fleshing with chicken manure, cow dung, and sawdust was heaped onto a horizontal bamboo frame. Three composting heaps were fabricated weighing 720, 700, and 760 kg. The turning of composting materials in the heaps causes temperature changes in the thermophilic range. The thermophilic temperatures in these heaps were 69.07 °C (heap 1), 69.9 °C (heap 2), and 69.19 °C (heap 3) which ensured the death of the pathogenic organism. The quality of compost was assessed based on the nutrients-nitrogen (N), phosphorous (P), potassium (K), and sulfur (S) content. NPKS in the compost fulfils the requirements of the investigated materials as compost. The largest amounts of metals- zinc (Zn), copper (Cu), chromium (Cr), lead (Pb), and nickel (Ni) of the compost detected in the heaps were, respectively, 200.3, 37.4, 20.3, 12.0, and 3.9 mg/kg. Cadmium (Cd) in the compost was below the detection limit. Scanning electron microscope (SEM) photographs show the decomposing of composting materials. This study indicates that limed fleshing can be converted into nutrient-enriched compost without any pretreatment. Using an easy, simple, and adaptable technique could reduce the volume of solid waste generated in the tannery to reduce environmental pollution.

Goatskin preservation with plant oil: significant chloride reduction in tannery wastewater.

Preservation of raw hide/skin is the prime technique to stop bacterial deterioration. Universally, salt curing is the most prevalent technique for hide/skin preservation. In this study, extracted oil from Aphanamixis polystachya seed was evaluated for the preservation of goatskin to reduce the chloride in tannery wastewater. The oil-induced goatskin preservation method was assessed observing diverse factors, e.g., hair slip, odor, moisture content, bacterial colony counting, total Kjeldahl nitrogen, and hydrothermal stability in evaluation to the conventional salt curing method. Results indicate that 15% oil-induced preservation technique could preserve the goatskin for 30 days. A small-scale experiment was performed for the preservation of goatskins. The preserved goatskins both monitoring and study samples were processed for shoe upper leather. The leather quality was evaluated by examining physical properties and fiber structure by a scanning electron microscope (SEM). Pollution load generated during leather making was determined in terms of total dissolved solids (TDS), chloride (Cl-), chemical oxygen demand (COD), and biochemical oxygen demand (BOD). The proposed oil-induced preservation method reduced Cl-, TDS, and BOD by 98.3%, 82.3%, and 86.8%, respectively, in the soaking liquor. The leather readied from the empirical goatskin shows the equipotential properties of leather from conventional goatskin. The oil-induced preservation method is substantiated to be favorable nonconventional preservation instead of conventional wet-salting for the contraction of pollution from soaking operation.