An Improvement in Oil and Grease Extractioh Techniques Serial extraction and evaluation of Freon-soluble constituents from wastewater can be unnecessarily complicated by even relatively law quantities of suspended solids and other agents. These materials sometimes develop into emulsions of varying degrees. When emulsions fail to dissociate they must be dealt with by filtering the emulsion through anhydrous crystalline sodium sulfate. This technique1 offers many opportunities for unintentional incorporation of the sodium sulfate into the distilling flask. Such difficulties can effectively be avoided by the use of phase-separatory filter paper (such as Fisher #09-790-5F). This naoer retains the water nhase while allowine oreanic nhases both liehter and heavier than water to nass throueh. This " i s idenl for "~ ernvimetrie oil and erease determinations because asmall ouantitv of water mav be drained from the senaratow n~~~ lunnrl airer the organic phase and emulsion. This permits toll rrmwry uf all tlf the hcsvicr-than-water conlponents wirhuut the pnlhlemicc,mmunly arsociatrd u,ith this p r a c t m The phne-seprrmrry paper alleviates a l l d o ~ b t concernlnp s the proper amount of sodium sulfate to use as well as any questions eoncerningcontamination of the organic phase by water or filtcrrng agent. Based upon our exprriencej with both the phase.repant
