  The effects of bulk viscosity on the elliptic flow $v_{2}$ are studied using
realistic equation of state and realistic transport coefficients. We find that
thebulk viscosity acts in a non trivial manner on $v_{2}$. At low $p_{T}$, the
reduction of $v_{2}$ is even more effective compared to the case of shear
viscosity, whereas at high $p_{T}$, an enhancement of $v_{2}$ compared to the
ideal case is observed. We argue that this is caused by the competition of the
critical behavior of the equation of state and the transport coefficients.
