  The structures and dynamics of molecular, atomic, and ionized gases are
studied around a low-luminosity active galactic nucleus (AGN) with a small
($2\times 10^6 M_\odot$) black hole using 3D radiation hydrodynamic
simulations. We studied, for the first time, the non-equilibrium chemistry for
the X-ray dominated region in the "radiation-driven fountain" (Wada 2012) with
supernova feedback. A double hollow cone structure is naturally formed without
postulating a thick "torus" around a central source. The cone is occupied with
an inhomogeneous, diffuse ionized gas and surrounded by a geometrically thick
($h/r \gtrsim 1$) atomic gas. Dense molecular gases are distributed near the
equatorial plane, and energy feedback from supernovae enhances their scale
height. Molecular hydrogen exists in a hot phase ( > 1000 K) as well as in a
cold ( < 100 K), dense ( >$10^3$ cm$^{-3}$) phase. The velocity dispersion of
H$_2$ in the vertical direction is comparable to the rotational velocity, which
is consistent with near infrared observations of nearby Seyfert galaxies. Using
3D radiation transfer calculations for the dust emission, we find polar
emission in the mid-infrared band (12$\mu m$), which is associated with bipolar
outflows, as suggested in recent interferometric observations of nearby AGNs.
If the viewing angle for the nucleus is larger than 75 deg, the spectral energy
distribution (~ 2 -- 60 $\mu m$) of this model is consistent with that of the
Circinus galaxy. The multi-phase interstellar medium observed in
optical/infrared and X-ray observations is also discussed.
