A waste collection and disposal unit including a tank, a float-switch sensing system, and a grinder pump. The tank contains a contoured and sloping floor, a front section, a back section, two side sections and a one-piece lid, which is securable onto the other sections of the tank. The floor slopes downwardly from below the float-switch sensing system to below the grinder pump at an angle of at least about 5 degrees and is contoured in a downward curved arc between the front and back sections of the tank.