Wastewater treatment by radial freezing with stirring effects

• Published in: Water research (Oxford) Vol. 37; no. 10; pp. 2520 - 2524
• Main Authors: Gay, Guillaume, Lorain, Olivier, Azouni, Aza, Aurelle, Yves
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.05.2003; Elsevier Science
• Subjects: Applied sciences; Combining; Controlled atmospheres; Dilution; Drinking water; Exact sciences and technology; Freezing; Freezing purification; General purification processes; Heavy metals; Imposed stirring; Lead - isolation & purification; Nitrates; Nitrates - isolation & purification; Pollution; Purification; Stirring; Waste Disposal, Fluid - methods; Wastewater treatment; Wastewaters; Water Movements; Water Purification - methods; Water treatment and pollution; Zinc; Zinc - isolation & purification; Nitrates; Freezing purification; Wastewater treatment; Imposed stirring; Heavy metals; Physicochemical purification; Waste water purification; Experimental study; Freezing; Heavy metal
• ISSN: 0043-1354; 1879-2448
• DOI: 10.1016/S0043-1354(03)00020-4

Radial freezing experiments on wastewater models were conducted in the presence of imposed stirring in order to remove impurities. The studied samples (dilute Na-montmorillonite suspensions charged with nitrates and with zinc or lead) were placed inside a cylindrical annulus, cooled at a controlled temperature around −7°C at its inner wall which rotated around a vertical axis. The freezing front propagated toward the still outer wall which was maintained at a constant temperature around +1°C. Thanks to stirring, considerable purification rates up to 99.97% were attained. It was also demonstrated that combining radial freezing and stirring ended in residual concentrations which agreed with drinking water standards.