Traitement des effluents urbains ou industriels par entrainement des polluants a l'occasion d'une precipitation de CaCO3

Abstract Studies carried out in our laboratories on calcium carbonate precipitations have led to the conclusion than substantial amounts of organic matter could be entrained by the crystals that are produced and in particular when the precipitate is in the form of vaterite. Moreover entrainments of this type are used currently in sugar-refining for the purification of sugar juices. Such CaCO 3 precipitation may be easily induced by means of the reaction of lime with a current of CO 2 -enriched gas which is bubbled through the solution. Given also the well-known coagulating properties of lime, it has been considered worthwhile investigating the treatment of certain wastes by means of this method. The initial trials were sufficiently conclusive for the SOAF Company to taken an interest in the project and for a decision to be made to construct a pilot plant of 10 cm h −1 capacity. Concurrently with this, a 301 h −1 laboratory unit was also built, and it is this which has provided the initial results that we propose to set out here.