Various leather producers operating a tannery founded a joint animal waste disposal company which produces valuable proteins from the waste. The refining of the raw material and the treatment with ammonia compounds produces malodorous waste gases. As these contaminants are noticeable even in the smallest concentrations there is no solution for their disposal other than thermal oxidation and reduction. 

Together with our customer, CTP developed a multi-stage installation. At first, the ammonia and organic compounds are destroyed in a regenerative thermal oxidizer (RTO) which causes the emergence of nitrogen oxides (NO_x). These NO_x are reduced to nitrogen and water in a second catalytic stage while using a branch stream of the ammonia waste gas. Non-ammonia, or little contaminated, waste gases are purified in another, larger RTO.

Conclusion: the closed circuit process of complete elimination of ammonia without any additional reducing agent (which would have had to be ordered, stored and injected into the waste gas) is patented by CTP.