A numerical study has been performed to investigate the characteristics of bubble growth on, and detachment from, an orifice. The FlowLab code, which is based on a lattice-Boltzmann model of two-phase flows, was employed. Macroscopic properties, such as surface tension (a) and contact angle (beta), were implemented through the fluid-fluid (G(sigma)) and fluid-solid (G(t)) interaction potentials. The model was found to possess a linear relation between the macroscopic properties (sigma, beta) and microscopic parameters (G(sigma), G(t)). The separate effects of the body force (gravity), gas injection rate, surface tension, and wettability were analyzed for both horizontal and vertical surfaces. It is shown that results of the lattice-Boltzmann modeling exhibit correct parametric dependencies of the departure diameter of bubbles generated on the horizontal surface on the above factors as previously established in experiments. For the case of bubble growth and departure on the vertical surface, the different effects of hydrodynamic parameters, except gas generation rate, were predicted.