Tracking disinfection by-products and arsenic removal during various drinking water treatment trains

In the central Banat region (Northern Serbia), groundwater is used as a drinking water source. Raw water originates from a 40-80m and 100-150m deep layer. It contains a high amount of natural organic matter (DOC = 9.17 +/- 0.87mgC/L) with a trihalomethanes formation potential of 448 +/- 88.2 mu g/L and a haloacetic acid formation potential of 174 +/- 68.9 mu g/L. A high amount of arsenic (86.0 +/- 3.4 mu g/L) is also found in this water. This study used a pilot-scale system to investigate the possibilities of combining polyaluminium chloride and ferrous-chloride to remove disinfection by-products precursors and arsenic by coagulation. Two treatment trains with different pre-treatment steps were investigated (ozone vs. H2O2/O-3). For the final water polishing, filtration with granulated activated carbon (GAC) was applied. Both investigated treatment lines achieved a satisfactory chemical water quality. Simulation of disinfection conditions was performed and the contents of trihalomethanes and haloacetic acids measured, to investigate whether the chemical quality of the water remained satisfactory over a 48 hour period.