As the leather industry becomes increasingly global, a new type of tanner has emerged: those who produce wet-blue or crust leathers on behalf of other manufacturers. Südleder have been at the forefront of this new breed of contract tanners, which have sprung up all over the world, especially where production costs are higher.

Located in the town of Rehau, northern Bavaria, Südleder have only been in existence for 22 years, yet their growth has been a major success story in the German leather industry when many other tanneries have been forced to close. Südleder are owned by three other large German tanning groups: Louis Schweitzer, Heller Company and Schafstall who operate as the tannery’s largest customers. Schafstall have located their own hide cooling and storage facility adjacent to the Südleder tannery.

Südleder are ideally situated close to the prized southern German raw hides which are well known for their high quality. Most production (70-75%) arrives directly as fresh hides from the slaughterhouse and thus removes the need for preservation on most of Südleder’s production. This means that not only are the hides fresh without any problems associated with preservation such as bacterial attack, but the hides do not need the extra steps to remove the salt in processing. Salt is therefore also reduced in the effluent.

The tannery operates six days a week, in two shifts, processing approximately 3,200 hides per day from calf skins to large 60kg+ bull hides. The tannery employs a total of 280 people. From the total production, approximately 50% is sold directly as wet-blue hides with the bulk of the remainder processed through to crust and a small number finished.

‘Normally we process raw hides through to wet-blue or crust on behalf of our customers. The customer then finishes the hides themselves. Our job is to stabilise and control production in a consistent manner for our customers’, says Peter Pöppel, managing director, Südleder GmbH & Co. Pöppel has been with the company since 1981 and has overseen the expansion of business during that period. ‘Today, we are producing hides close to our capacity. 80% of our customers are German tanners or traders and the remaining customers export our hides directly’, he told Leather International.

Constant upgrading

When Leather International visited Südleder, they were in the middle of upgrading the plant. ‘Upgrading the plant is an ongoing process’, says Pöppel. ‘We have spent over DM4 million (US$1.9 million) in the last 18 months, but we have been expanding and improving the plant and the effluent treatment facilities over the past ten years’, he added. ‘The tannery has doubled production over the last three years.’ Pöppel estimates that Südleder have invested around DM50 million (US$23.5 million) since the tannery was opened.

This year they have installed a new wet-blue storage area and replaced a number of processing drums. Italian drum manufacturers, Vallero, are supplying the new retanning equipment. They are also relaying part of the floor where chemicals and water have eroded the concrete.

The constant upgrading of the plant and process enabled Südleder to achieve ISO 9001 and 9002 certification as long ago as 1994. In fact, they were one of the first tanners in the world to achieve the accreditation and have since been reassessed and passed.

Environmental control and oil from sludge

Südleder’s effluent treatment plant is located approximately 1.5km away from the tannery outside the town centre of Rehau. ‘We have to comply with very strict legislation here in Germany as German law is very tough when it comes to environmental controls. This is why we have put a lot of emphasis on environmental matters at Südleder’, says Pöppel. One example of the company’s involvement in green issues is their participation in a German/Brazilian environmental project for the leather industry.

The tannery has been heavily involved in a project entitled ‘Production integrated environmental protection in the leather industry’. The project is run in conjunction with the Lederinstitut Gerberschule Reutlingen (LGR), Institut für Textil- und Verfahrenstechnik (ITV), Bader Tannery, Louis Schweitzer Tannery, BASF, TFL, Amtec and Prosys Weida as well as a number of partners in the Brazilian tanning industry, and aims to find an alternative to waste disposal of sludges and other organic waste.

The whole project has a budget of DM20 million (US$9.4 million). As part of the project, Südleder have established a pilot plant for low temperature conversion to remove solid wastes. The plant has been built and promoted by the German Federal Ministry for Education and Research. In the beginning of the 1990s, sludge disposal costs in Germany went sky-high and further legislation due to come into effect in 2005 prescribes stricter sludge disposal guidelines which cannot be satisfied with current disposal methods. At this point, Südleder decided to act.

The low temperature conversion process in principle simulates the natural formation of petroleum and coal deposits where bacteria and animal corpses were formed into crude oil and vegetable biomass such as cellulose, lignin etc into coal. The correct catalyst was found to be aluminium silicates and suitable raw materials for the process sludges were found to be a good choice. Following promising laboratory tests, it may be possible to produce oil from sludge (OFS). The pilot plant at Südleder has been established to see whether the theory can be applied in practice.

The project is due to be completed later this year and the final part of the report is due from Dr Hauser of Südleder shortly after the completion of the trials. The first results of the trials were published at the beginning of this year.

Production

The tannery is situated in two buildings either side of a public road. One side produces the hides up to wet-blue and the other takes the blue production through to crust or finished leathers. A bridge crossing over the road joins the two buildings. A quality control laboratory, pilot plant and administration offices are also located on site.

Approximately 50% of production is for automotive leathers with furniture (20%) and footwear upper and leathergoods leathers making up the remaining 30%. The majority of production is, therefore, carried out on full hides. Most hides are chrome tanned but Südleder also produce a wet-white tannage for some automotive leather customers.

Raw hides are soaked and processed through the beamhouse in one of 16 liming drums. Limed hides are then removed from the drum for fleshing and splitting. The grain layers return to the drum for chrome tanning while the splits are trimmed and tanned then sold as wet-blue croupons. Südleder have a total of 16 tanning drums.

Following draining and sammying/setting, around half of the hides are returned to the customer as wet-blue and the remainder taken across to the other building in the Südleder complex for processing through to crust. Südleder do not buy or sell any of the hides, they always belong to the customer. Some wet-blue is sourced from other tanneries who use Südleder to process the hides through to crust or finished leather.

All the drums have an automated dosing and control systems, which have been installed by German automation specialists, Prosys Weida. Operatives are able to monitor the performance of each process from a PC.

Wet-blue shavings (Rizzi shaving machines) are sold to be pressed into leatherboard. Following shaving, the hides are retanned in one of twelve retanning drums (supplied by Vallero). Following retannage, the hides are dried on one of two Carlessi full hide toggling machines or two Finclip stretching machines from Finvac.

Part or fully processed hides are then prepared to be shipped to the customer directly or the customers’ customer.