Methods for the removal of alkaline and sulfate scales from aqueous saline streams such as seawater, oil-gas fields produced waters, formation waters, and the like. Such processing methods can also be extended for the simultaneous removal of hydrogen sulfide, and/or sulfur dioxide, and/or oxides of nitrogen, and/or carbon dioxide from gaseous streams. The same processing concept with modified methods can further be employed for the removal of gases such as radon, hydrogen sulfide, sulfur dioxide, oxides of nitrogen, and carbon dioxide from gaseous streams.