ASSESSMENT ON THE REMOVAL OF ORGANIC-CHEMICALS FROM RAW AND DRINKING-WATER AT A LLOBREGAT RIVER WATER WORKS PLANT USING GAC

A screening study was conducted on samples from a Llobregat river wate r works plant (WWP) in order to establish a better treatment for the r emoval of organic pollutants. The Llobregat river is a polluted rivet supplying water to Barcelona (Spain) and its surroundings with a popul ation of approximately 3.2 million. A broad spectrum and high levels o f organic chemicals were found in river water, including hydrocarbons, pesticides, surfactants, plasticizers and trihalomethanes. Despite a variety of treatment processes employed in the studied plant, a satisf actory removal of organic compounds from water is not guaranteed. Give n that, improvement in water quality is achieved with the implementati on of filtration with Granular Activated Carbon (GAC). Seven control c olumn tests (CCT) with analytical GAC were conducted in series with th eir seven respective large column adsorbers to determine the performan ce of each GAG. Organic compounds from samples of raw and drinking wat er were collected by passing approximately 1000 l of water through a c olumn of analytical GAC (representing monthly averages). Selected targ et compounds previously identified in raw and drinking water (trihalom ethanes: bromoform: pesticides: terbutylazine and molinate, surfactant s: polyethoxylated nonylphenols: plasticizers: diethyl phthalate and t ri-n-butyl phosphate; halogenated compounds: trichlorobenzenes. 2-chlo ro pyridine: miscellaneous compounds: 2-ethyl hexanol, trimethyl-cyclo hexenone, bromo-trimethyl-benzenes, bromo-polyethoxylated nonylphenols ) were studied to predict the behavior of seven different commercial G ACs. These pollutants were efficiently removed by using GAC bituminous coal based. The determination of organic compounds was carried out by using Soxhlet extraction and high-resolution gas chromatography with low resolution mass spectrometry (HRGC/ LRMS) analysis. (C) 1998 Elsev ier Science Ltd. All rights reserved.