Abstract: Contemplated wastewater treatment plants and processes comprise a unit in which a silicate-containing waste stream is combined with an alkaline process stream to so form a pH-controlled intermediate that is then fed to a reactor in which carbonization effects precipitation of the silicate. Following a particle growth step in the reaction vessel that renders the precipitate suitable for filtration, the so produced silicon dioxide can be safely disposed of in a landfill while the liquid can be discharged or sent to a zero liquid discharge pond to precipitate sodium carbonates.