A binary composition is provided comprising two liquids, which are separately maintained prior to forming an admixture during delivery to a hard surface, vessel, or drain. The admixture generates foam of sufficient stability and quantity to effect disinfection and biofilm removal. A first liquid preferably includes a quaternary ammonium compound, a peroxygen agent and, optionally, surfactants, thickening and chelating agents (colorants, corrosion inhibitors, stabilizers, perfume, etc). The second liquid preferably includes a hypohalite generating agent, a source of alkalinity, and optionally, a surfactant and thickening and chelating agents (colorants, corrosion inhibitors, stabilizers, perfume, etc.). Because the two liquids are initially separated, the hy-pohalit and peroxygen agent can be maintained in an environment that is favorable to their stability until the time of use. When the two liquids are mixed, the hypohalite and peroxygen react to liberate oxygen gas. Foam generation occurs as the escaping gas contacts the quaternary ammonium compound and surfactants and creates foam, which expands to completely fill or cover the drain pipe, or other vessel or a hard surface being treated. The expanded foam contains quaternary ammonium compound and hydrogen peroxide not reacted with the hypohalite generating agent, which act to disinfect, clean and remove biofilm
