  We study an infinite system of moving particles, where each particle is of
type A or B. Particles perform independent random walks at rates D_A>0 and
D_B>0, and the interaction is given by mutual annihilation A+B->0. The initial
condition is i.i.d. with finite first moment. We show that this system is
site-recurrent, that is, each site is visited infinitely many times. We also
generalize a lower bound on the density decay of Bramson and Lebowitz by
considering a construction that handles different jump rates.
