Comparing removal of trace organic compounds and assimilable organic carbon (AOC) at advanced and traditional water treatment plants

Stability of drinking water can be indicated by the assimilable organic carbon (AOC). This AOC value represents the regrowth capacity of microorganisms and has large impacts on the quality of drinking water in a distribution system. With respect to the effectiveness of traditional and advanced processing methods in removing trace organic compounds (including TOC, DOC, UV254, and AOC) from water, experimental results indicate that the removal rate of AOC at the Cheng Ching Lake water treatment plant (which utilizes advanced water treatment processes, and is hereinafter referred to as CCLWTP) is 54%, while the removal rate of AOC at the Gong Yuan water treatment plant (which uses traditional water treatment processes, and is hereinafter referred to as GYWTP) is 36%. In advanced water treatment units, new coagulation-sedimentation processes, rapid filters, and biological activated carbon filters can effectively remove AOC, total organic carbon (TOC), and dissolved organic carbon (DOC). In traditional water treatment units, coagulation-sedimentation processes are most effective in removing AOC. Simulation results and calculations made using the AutoNet method indicate that TOC, TDS, NH3-N, and NO3-N should be regularly monitored in the CCLWTP, and that TOC, temperature, and NH3-N should be regularly monitored in the GYWTP.