PTSA (pressure and thermal swing adsorption) method to remove trihalomethanes from drinking water

Abstract

It has been widely recognized that trihalomethanes (THMs) in drinking water pose a risk to human health. THMs can be removed to a certain extent by the conventional point-of-use (POU) unit which is composed of activated carbon (AC) and microfilter. But it's life on THMs is relatively shorter than on residual chlorine or musty odor. To extent the life of AC adsorber, pressure and thermal swing adsorption (PTSA) was applied by preferential regeneration of chloroform. PTSA was effective to remove THMs, especially chloroform. Adsorption isotherms of chloroform at 25 and 70°C showed a remarkable difference so that thermal swing was considered effective. Chloroform was also desorbed by reducing pressure. By vacuum heating at 70°C, chloroform was almost desorbed from AC and reversible adsorption was considered possible. A prototype of POU unit with PTSA was proposed. Regeneration mode would consist of dewatering, vacuum heating and cooling (backwashing). The unit was maintained in bacteriostatic condition and could be used for a long time without changing an AC cartridge.

Disinfection characteristics of the dissolved organic fractions at several stages of a conventional drinking water treatment plant in Southern China

“…Although THMs removal [18,19] and control [20] methods have been widely investigated, regression models were developed in order to predict spatial and seasonal variations of THMs [21][22][23]. In order to effectively control THMs formation and remove the main molecular weight THMs precursors in the water treatment process, water samples were collected from a conventional drinking water treatment plant in Southern China for this investigation.…”