Method for treating an effluent containing sorbic acid and/or a salt thereof and an effluent disposal device

Abstract

An effluent containing sorbic acid or its salt from, for example, a sorbic acid production line is (1) treated with a hypohalogenous acid or its salt, e.g. sodium hypochlorite, or (2) subjected to membrane separation or activated carbon treatment and further to biological treatment such as activated sludge treatment. The required amount of the hypohalogenous acid or salt may for example be about 0.01˜10 parts by weight, in terms of effective halogen, based on 100 parts by weight of the effluent. Optionally the effluent thus treated with the hypohalogenous acid or salt is further subjected to a biological treatment such as an activated sludge process.

What is claimed is:  
     
         1 . A method of treating an effluent containing sorbic acid and/or its salt which comprises a step of subjecting said effluent to membrane separation or to activated carbon treatment, and a step of subjecting the membrane downstream fluid or the activated carbon-treated effluent to biological treatment.  
     
     
         2 . The method as claimed in    claim 1    wherein the membrane separation is performed using a nanofiltration membrane.  
     
     
         3 . The method as claimed in    claim 1    wherein the effluent containing sorbic acid and/or its salt is adjusted to pH 7 or higher in advance of said membrane separation.  
     
     
         4 . A device for effluent disposal which comprises a means of treating an effluent containing sorbic acid and/or a salt thereof with a hypohalogenous acid or a salt thereof.  
     
     
         5 . A device for effluent disposal comprising (1) a membrane separation means for separating an effluent containing sorbic acid and/or its salt or a means for treating said effluent with activated carbon, and (2) a biological means for treating the membrane downstream fluid or the activated carbon-treated effluent biologically.