AWWA MTC61231

This study investigated enhanced removal of viruses and natural organic matter (NOM) using ceramic microfiltration (MF) with polymerized aluminum chloride (PACl) coagulation and submicron powdered activated carbon (PAC) adsorption pretreatments. For virus removal by the MF with the coagulation pretreatment, the study confirmed the method's unexpectedly high performance: virus removal was more than 6 logs, even though the tested Qß virus was much smaller than the membrane nominal pore size of 100 nm. Virus adsorption onto the floc particles retained on the membrane surface and the virus inactivation by the addition of the PACl contributed to the virus removal. The coagulant dose, membrane pore size, and coagulation time affected virus removal, but increasing coagulant dose was most effective for overall virus removal. To enhance removal of NOM by ceramic MF of water samples pretreated with PAC and the PACl, manufacturer-supplied normal PAC was crushed to produce submicron-sized PAC particles. The submicron PAC removed NOM much better than the normal PAC because of improvements in both adsorption capacity and kinetics. Because of the drastically improved NOM removal rate, a 30-s retention time for the PAC pretreatment was sufficient for adsorptive removal of NOM in the ceramic MF. No additional transmembrane pressure buildup or membrane fouling caused by addition of the submicron PAC itself was observed. Includes 10 references, figures.