Abstract: A reactor and a relative process are for precipitation of a solid substance from a solution, in particular a reactive precipitation or crystallization. The reactor is a reactive precipitation/crystallization reactor, including an outer tubular element and a coaxial inner tubular element along a longitudinal axis of the reactor, to form an annular channel between an outer wall of the inner tubular element and an inner wall of the outer tubular element. The outer tubular element includes, at a first end, an inlet opening for a first reactive fluid and, at a second end, an outlet opening for a reaction mixture. The inner tubular element includes an inlet opening for a second reactive fluid and, optionally, an outlet opening for the second reactive fluid. The inner tubular element includes, along the outer surface, dispensing openings for dispensing the second reactive fluid fed into the inner tubular element.

Abstract: A process for treating waste waters with TDS?20 g/l, possibly containing organic substances, includes the following steps: a. separating the saline wastewater or waste waters from suspended solids and heavy pollutants by physical separation, forming a saline stream free of suspended solids and heavy pollutants; b. subjecting the saline stream to reverse electro-dialysis, using a reservoir solution to reduce the saline concentration and forming a diluate and a diluted stream (waste water) with TDS not higher than 20 g/l; and c. biologically treating the diluted stream obtained in (b) forming biological sludge, or excess sludge, and clarified water.

Abstract: A process for treating waste waters with TDS?20 g/l, possibly containing organic substances, includes the following steps: a. separating the saline wastewater or waste waters from suspended solids and heavy pollutants by physical separation, forming a saline stream free of suspended solids and heavy pollutants; b. subjecting the saline stream to reverse electro-dialysis, using a reservoir solution to reduce the saline concentration and forming a diluate and a diluted stream (waste water) with TDS not higher than 20 g/l; and c. biologically treating the diluted stream obtained in (b) forming biological sludge, or excess sludge, and clarified water.