  We study a waveguide array with an embedded nonlinear saturable impurity. We
solve the impurity problem in closed form and find the nonlinear localized
modes. Next, we consider the scattering of a small-amplitude plane wave by a
nonlinear impurity mode, and discover regions in parameter space where
transmission is fully suppressed. We relate these findings with Fano resonances
and propose this setup as a mean to control the transport of light across the
array.
