Terpolymers and use thereof are provided comprising one or more nonionic monomers, one or more anionic monomers and one or more cationic monomers, These terpolymers and compositions containing may be used as flocculants, for example, for treating tailings, such as oil sands tailings, to facilitate solid-liquid separation, for example, in order to efficiently recycle water and/or to reduce the volume of tailings which may be transferred to a tailings pond and/or to a dedicated disposal area.