Tanneries

In leather production water is not only needed for transportation in the production process but also for various tasks such as unhairing or soaking the hides. As a result of the specific production methods, the waste water not only has high alkaline levels (pH value 10), but is also contaminated with chemicals such as sulfite and chrome, and has a high level of organic substances. Biochemical processing of the waste water is a standard operation in many installations and GEA decanters lay a significant role.

After the waste water has been collected from the tanning process and polymer has been added, the decanters continuously separate all organic solids such as hair from the thickened sludge. The separated solids can be composted and find application, for example, in horticulture or forestry. The liquid phase is then subjected to biological treatment. The resultant sludge is recycled into the dewatering process; the waste water can be sent safely to conventional municipal waste water treatment plants. The advantages of decanters provide optimum dewatering capacity and use very little rinsing water. The closed system prevents aerosols from escaping; such aerosols would otherwise pose a hazard for humans and the environment.