Tanwater - Reduction of the nitrogen discharge from the leather industry
Tanneries release a highly pollutant wastewater which usually contains a high concentration of nitrogen, which is difficult to remove due to its high solubility. The overall objective of the project was to reduce the nitrogen discharge from the leather industry through the creation of a new wastewater treatment technology in the Elmo Leather AB tannery in Sweden. The technology included nitrification and denitrification processes in the treatment of tannery wastewater to reduce the discharge of nitrogen. The project has successfully developed and tested in full scale the technology, achieving a reduction in nitrogen of 89%. 13-month monitoring of the environmental impact of the tannery also showed a reduction in BOD of 98%, COD of 91% and chromium of 89%. Economically, the cost of treating wastewater from the leather industry using the Tanwater concept is around the same as the conventional treatment even though it is more efficient.