BIOTREATED COAL LIQUEFACTION WASTEWATER: IDENTIFICATION OF ORGANICS BY COMPOSITE RO MEMBRANE CONCENTRATION, HPLC, AND GC/MS.

The washwater from a coal liquefaction process (H-Coal) was H//2S-NH//3 stripped and dephenolized. The water was then treated by a powdered activated carbon assisted biological process. After the biotreatment most of the residual phenolics, polyaromatic hydrocarbons, and nitrogen compounds were destroyed. A strong residual color was still observed in the biotreated feed. A final treatment using thin-film composite reverse osmosis (RO) membrane was selected to remove the excess TOC (total organic carbon) and inorganic salts simultaneously. The membrane was also used as a concentration mode to obtain a better detection of the organic traces by HPLC (high-performance liquid chromatography) and GC/MS (gas chromatography/mass spectrometry). The membrane process provides an efficient treatment which makes the permeate even under high water recovery conditions suitable for recycling.