Abstract

The leather industry generates highly contaminating liquid effluents with current process methods. In this work, the contamination by nitrogen in wastewater was evaluated for two of the most nitrogen generating steps of beamhouse processing, the soaking and the unhairing/liming steps. Total Kjeldahl nitrogen (TKN), ammoniacal nitrogen (N-NH3), total organic carbon (TOC) and soluble protein analyses were realized from bath samples collected at varying times. It was observed that in long duration soaking, nitrogen liberation to the bath eventually levels out whilst, in unhairing/liming, the nitrogen content did not stabilize even with 27 hours processing.

It was possible to observe a relationship between nitrogen liberation, TOC and soluble protein contents of the soaking baths.