  In order to investigate the temporal evolution of binary populations in
general, double compact star binaries and mergers in particular within a
galactic evolution context, a most straightforward method is obviously the
implementation of a detailed binary evolutionary model in a galactic chemical
evolution code. To our knowledge, the Brussels galactic chemical evolution code
is the only one that fully consistently accounts for the important effects of
interacting binaries on the predictions of chemical evolution. With a galactic
code that does not explicitly include binaries, the temporal evolution of the
population of double compact star binaries and mergers can be estimated with
reasonable accuracy if the delayed time distribution (DTD) for these mergers is
available. The DTD for supernovae type Ia has been studied extensively the last
decade. In the present paper we present the DTD for merging double neutron star
binaries and mixed systems consisting of a neutron star and a black hole. The
latter mergers are very promising sites for the production of r-process
elements and the DTDs can be used to study the galactic evolution of these
elements with a code that does not explicitly account for binaries.
