Well-posedness and invariant measure for quasilinear parabolic SPDE on a bounded domain

We study quasilinear parabolic stochastic partial differential equations with general multiplicative noise on a bounded domain in ${\mathbb{R}}^d$, with homogeneous Dirichlet boundary condition. We establish the existence and uniqueness of solutions in a $L^1$ setting, and we prove a comparison result and an $L^1$-contraction property for the solutions. In addition, we show the existence of an invariant measure in case of non-degenerate diffusion. Finally, we show the uniqueness and ergodicity of the invariant measure in $L^1$, in case of bounded diffusion and additive noise.