Carbon monoxide treatment
AFAIK, production scale processes are highly optimized, producing just traces of $\ce{CO}$. There traces are either not managed, or can by passed through catalyzators.
On the other hand, burning coke with limited air or oxygen $\ce{2 C(s) + O2(g) -&gt; 2 CO(s)}$ or passing water vapour through burning coke $\ce{C(s) + H2O(g) -&gt; CO(g) + H2(g)}$, are used intentionally, to produce $\ce{CO}$, eventually with hydrogen, for further synthesis.