Liming is known as a main source of tannery pollution, including sulphides and nitrogen-containing compounds. TFL can offer the tanner amine-free and nitrogen-free auxiliaries to accomplish the goals of reducing pollutant load on the environment.
Without doubt the beamhouse processes and in particular the liming process produces large amounts of polluting solids and waste waters.
ERHAVIT EF has been developed to be free from amines and nitrogen.
At the moment the process options to reduce this are few but the most significant in recent years is the development of the HAIR SAVING liming process. This process removes the hair intact, this intact hair can then be recovered from the vessel by recirculating the process liquor through a suitable screening filter and the liquor free of hair is returned to the drum, mixer or paddle.
This process uses the same chemicals apart from special HS grades of ERHAVIT as normal liming. However since only the roots of the hair are attacked less sulphide can be used. This reduces the sulphide load on waste water and this plus the absence of pulped hair greatly reduces the COD.