Environmental impact of leather

Leather has several impacts on the environment,the main reasons being:Carbon footprint of raising cattle.Use of chemicals in the tanning process (eg chromium,phthalates,nonylphenol ethoxylate soaps, pentachlorophenol and solvents).Air pollution from reforming processes (hydrogen sulfide is formed when it mixes with acids and ammonia released during deashing,solvent vapors)

Carbon Footprint

The carbon footprint of bovine leather is estimated at 65 to 150 kg CO2 equivalent per square meter produced.

Water footprint

One ton of hides and hides typically produces 20 to 80 cubic meters of wastewater containing 100-400 mg/l of chromium,200-800 mg/l of sulphides, high levels of fat and other solid waste, and significant pathogen contamination.Production Merchants often add pesticides to protect hides during transport.Solid waste makes up 70% of the wet weight of raw hides,and the tanning process puts considerable stress on the water treatment unit.

Disposal 

Leather biodegrades slowly-it takes 25 to 40 years to break down.Verification failed] However,vinyl and petrochemical derived materials take 500 years or more to decompose.

Chemical Waste Treatment

Tanning is particularly polluting in countries with lax environmental regulations,such as India,the world's third-largest leather producer and exporter.As an example of an effective pollution prevention system, the load is typically reduced from 8 kg to 1.5 kg per tonne of chromium produced.In well-managed facilities,VOC emissions are typically reduced from 30 kg/t to 2 kg/t. According to the United Nations Industrial Development Organization,a review of achievable reductions in total pollution load published precise data on the reductions achievable through industry-proven low-waste advanced Reduced by 94% Introduction of advanced technology, minimum residual load 0.15 kg/t hides Considering the current regulations in some countries,it still causes difficulties when using composted sludge from landfills and wastewater treatment."In Kanpur, the self-proclaimed "Leather City of the World"--home to 10,000 tanneries and a city of three million people on the banks of the Ganges as of 2011--pollution levels are so high that despite an industry crisis However,the Pollution Control Board still decided to close 49 out of 404 highly polluting tanneries in July 2009.For example,in 2003, the wastewater treatment unit of a major tannery dumped 22 tons of chromium-containing solid waste in the open air every day.In the Hazaribagh community of Dhaka,Bangladesh,chemicals from tanneries end up in Dhaka's main river.In addition to environmental damage,the health of local factory workers and end consumers is also negatively affected.After some 15 years of ignoring the High Court ruling,the government closed more than 100 nearby tanneries over the weekend of 8 April 2017.Costs associated with sewage disposal are higher compared to untreated sewage discharge, leading to illegal dumping to save costs. For example, in Croatia in 2001,the cost of proper pollution abatement was US$70-100 per tonne of hides and hides processed, compared to US$43 per tonne for irresponsible behaviour.In November 2009, a major leather manufacturing company in Uganda was found to have discharged wastewater directly into wetlands near Lake Victoria.

Role of enzymes

Enzymes such as proteases,lipases and amylases play an important role in the soaking,unhairing, degreasing and softening operations of leather manufacturing.Proteases are the most commonly used enzymes in leather production.The enzyme must not destroy or dissolve collagen or keratin, but should hydrolyze casein, elastin, albumin, globoids and non-structural proteins not necessary for leather manufacture. This process is called softening.Lipase is used in degreasing operations to hydrolyze fat particles embedded in the skin.Amylase is used to soften the skin, bring out particles,and give the skin strength and flexibility.These enzymes are rarely used.