CONCENTRATION OF AQUATIC DISSOLVED ORGANIC-MATTER BY REVERSE-OSMOSIS

Dissolved organic carbon (DOC) was concentrated from natural streams using reverse osmosis equipment. Quality control tests show that from 95.6 to 98.5% of total DOC was rejected by the membrane, though only 70% could actually be recovered, most likely because of losses within the plumbing system. Comparison of the acid-base characteristics of the original water sample with re-diluted concentrate show that modifications occurred. Visual evidence showed that polycondensation reactions which modify acid-base characteristics occurred in the concentrate. Analysis of the material passing through the membrane (permeate) shows that it is < 200 Da in weight with a pK(a) distribution suggesting that a range of molecules with carboxylic and phenolic acid sites are leaking through the membrane.