  This paper summarizes results and some open problems about the large-scale
and long-time behavior of asymmetric, disordered exclusion and zero-range
processes. These processes have randomly chosen jump rates at the sites of the
underlying lattice. The interesting feature is that for suitably distributed
random rates there is a phase transition where the process behaves differently
at high and low densities. Some of this distinction is visible on the
hydrodynamic scale.
