Saving energy and reducing waste

across the world, environmental engineers have been looking into new or alternative methods of reducing tannery waste. It is no longer acceptable, anywhere, to discharge waste directly into the environment and it is becoming increasingly more expensive to landfill solid waste, especially in the developed world. A number of projects are currently being investigated and trialled to either recycle solid waste such as lime fleshings into fertilisers and other byproducts or to incinerate or combust the waste and provide 'free' energy for the tannery. French cow belly tanners, Tanneries Nouvelles Pechdo, have been looking at the latter method and over this summer have installed a 'fat fuel burner' at their production site in the Southern French town of Millau. The tannery is situated next to the River Tarn on the outskirts of the town, close to a populated area. 'We are developing a new system that combusts our waste fleshings and trimmings. The gases created by this process are then collected and subsequently ignited to heat the water for the tannery', Gérard Moussa, technical director, told Leather International. Tanneries Nouvelles Pechdo transferred production from box calf for shoe upper leather and began making specialised gloving leathers specifically from cow bellies some twenty years ago. Monthly production is approximately 650,000ft² and they process wet-salted bellies through to finished leather. Ownership of the business has changed hands several times over the years and the current owner, Marc Barthelemy, former sales manager from the business, took over in January 2001. Since new ownership, the business has invested heavily in new technologies, especially in the area of environmental control. The tannery was also modernised throughout in 1994. Fat fuel burner The second phase of the fat fuel burner was installed in June and trials have taken place either side of the European summer holiday season. The plant was due to be fully operational this month. The new system is a collaboration with several large partner companies and organisations and is funded partially by the tannery, the Regional Council authority and ADEME. The latter is a French governmental agency which supports all projects designed to produce energy and reduce pollution. Pechdo produce approximately eight tons of solid waste a day from the fleshing operation. This represents 90% of the total solid waste produced in the tannery. Before the arrival of the fat fuel burner unit, the waste was sent to landfill as a category two material. This is more expensive to dispose of than typical household landfill. A conveyor system transports the fleshings and other trimmings from the fleshing/splitting machines to a storage tank next to the burner. The fleshings are placed in a boiler, which is heated to 70ºC, to separate the water from the fats. Then solid fat waste is combusted and the water is directed back to the tannery effluent treatment plant. Fully operational, the fat fuel burner will consist of three burners and will have the capacity to heat all the water requirements for the tannery. The fat fuel burner works as a combustion system and not an incineration method. Latent heat is produced to heat the water. In the past three years Pechdo have spent €500,000 on green projects including an upgraded water treatment plant. The plant was completed in January of this year. Pechdo also re-sell limed belly splits for gelatine manufacture. They recycle all paper, plastic and metal not required at the tannery. Additionally they have invested a further e600,000 on the fat fuel burner equipment. 'The owners of the company have spent heavily in new environmentally sustainable techniques. Using this new system we can both reduce our costs to landfill and use a waste product as a fuel to provide our hot water energy needs', says Moussa. The burner forms part of a two-year trial to assess the viability of the system on a commercial scale. Both the cost benefits and the impact on the local environment will be measured during the trial period. Tanneries Nouvelles Pechdo The town of Millau is located in southern France close to the southern tip of the Massif Central. The picturesque town is the former centre of the French gloving industry and is home to five or so tanneries. The local gloving industry has slowly evaporated from the area in the past few decades but tanneries such as Pechdo have remained, largely due to increased export sales. Today, 52% of total sales are for the export market. Major foreign markets include the US, China and Hong Kong, South Korea and western European businesses working out of northern African countries. Approximately 60 people work at the Pechdo tannery. Pechdo produce three main lines of gloving leather: industrial, sport and dress; and supply the major US brands. The majority of production is made from chrome tanned leather although Pechdo are developing a range of chrome-free leathers. However, chrome-free leather is currently more expensive and some of the technical characteristics are lower. Cow bellies Pechdo are the largest producers of cow belly leather in Europe. The softness, stretch and thinness of the belly area makes it a suitable material for gloving leather. Pechdo make a range of full grain and nubuck leather, which are available in up to 100 different colours. In the beamhouse, Pechdo daily process approximately 15 tons of wet-salted cow bellies, a byproduct from tanners who use the shoulders for shoe upper leather and leathergoods. Raw material origins include bellies from France mainly, Germany, Spain, Italy and Sweden. The bellies are stored at 5ºC under the tannery in a purpose built storeroom. Following liming, each belly is fleshed and split. Following splitting each piece is tied-up to prevent knotting inside the drum. In order to achieve the stretch in the final article, each piece spends twelve hours in the liming paddles. Liming is a key part of the process for Pechdo. Tanning and post tanning operations are all carried out in 18 wooden drums. Each belly is then toggle dried followed by air conditioning on an elaborate overhead conveying system which covers the entire roof space of the finishing area. A large proportion of the crust leather is aniline or semi-aniline finished on a single spray line. Finally the leather is trimmed, area measured and packed for shipping. Technical standards 'Basic gloving leather can be found from other sources', says Nadine Rancher, export manager. 'We produce high quality leather with much stronger technical specifications such as water, heat and abrasion resistance. Our customers prefer to have higher and more consistent specs especially when the end-user may be a fireman, policeman or an electrician.' Production is tested to all the physical and chemical specification required using Tanneries Nouvelles Pechdo's technical laboratory. New lines are constantly being developed in the R&D department. They have developed washable leather to be used with textiles and also a waterproof and heatproof glove for firemen. 'We have to constantly innovate and lead with technical leathers to maintain our customers', says Rancher. Tanneries Nouvelles Pechdo are ISO 9001 (2000 version) accredited and over the next two years intend to obtain ISO 14001 environmental standards. The fat fuel burner is part of that ongoing process.