  In this contribution we propose an optimally stable ultraweak Petrov-Galerkin
variational formulation and subsequent discretization for stationary reactive
transport problems. The discretization is exclusively based on the choice of
discrete approximate test spaces, while the trial space is a priori infinite
dimensional. The solution in the trial space or even only functional
evaluations of the solution are obtained in a post-processing step. We detail
the theoretical framework and demonstrate its usage in a numerical experiment
that is motivated from modeling of catalytic filters.
