Technologies concerning the removal of organic compounds in drink water, especially those formed upon chlorination, are а matt of great importance in the water treatment industry. Computer modelling was evaluated in terms of predicting breakthrough of trihalomethanes in a full-scale water treatment plant employing granular activated carbon (GAC). Adsorption isotherm experiments were used to quantify competition from background organics and to assess the importance for trihalomethane adsorption of the slow fouling of GAC by natural organic substances. This fouling effect caused adsorptive capacity to decrease as a function of time due to the slow adsorption of background material. The Equilibrium Column Model was fouup useful in predicting chloroform breakthrough for two different carbons and two operating seasons. Results from experiments with pre-loaded carbon suggest that the observed reduction in capacity for trihalomethanes in the lower half of full-scale beds may be largely due to blockage of adsorption sites by pre-adsorbed background organics.

Quantitation of the removal capacity of GAC for the mutagenic compound MX [3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone] was examined under conditions representative of typical water treatment practe and attempts made to identify the removal mechanism. Isotherm experiments were conducted using both virgín carbon and carbon which had been pre-loaded with natural organic material. MX was shown to be very well removed over a we concentration range although, as observed for trihalomethanes, a significant reduction in capacity was observed for the pre-loaded carbon. To illustrate that an adsorption mechanism was involved in the removal of MX from water using activated carbon, various combinations of solvents and desorption conditions were examined in attempts to recover MX from activated carbon. While the removal of MX, is at least in part, attributable to adsorption, some reaction to other compounds does occur. Three of these compounds have been identified.