Recovery Of Spent Caustic In Dairies

Introduction :
To maintain high hygienic standards and to ensure proper functioning of the equipments, dairy evaporators, pipe line and other equipments are regularly cleaned after each production cycle. The cleaning solution typically contains 2 to 4% caustic and additional compounds such as antifoams and chelating agents. This solution removes caramelized organics, precipitated proteins, pectins and fats from the surface of tanks, pipes, heat exchangers and evaporators.

The contaminated solution, after cleaning, still contains high concentration of active caustic. This solution is generally reused in one of the following ways :

The solution is reused 7-10 times and then the CIP tank is completely discharged. Approximately 10% of the caustic solution is discharged daily while the remaining volume is recycled to the CIP tank.

In both the cases, discharged caustic solution is heavily loaded with dispersed and soluble organic contaminant which has to be neutralized. It is also difficult to discharge this effluent due to pollution control regulations and also from ecological point of view. As a solution to the above, the spent caustic solution can be passed through membranes for very effective reuse. Membrane system is very compact, energy saving, easy to operate and eco friendly.